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A Comparative Study of the Characteristics of French Fries Produced by Deep Fat Frying and Air Frying
Journal of Food Science
Abstract
Air frying is being projected as an alternative to deep fat frying for producing snacks such as French fries. In air frying, the raw potato sections are essentially heated in hot air containing fine oil droplets, which dehydrates the potato and attempts to impart the characteristics of traditionally produced French fries, but with a substantially lower level of fat absorbed in the product. The aim of this research is to compare: (1) the process dynamics of air frying with conventional deep fat frying under otherwise similar operating conditions, and (2) the products formed by the 2 processes in terms of color, texture, microstructure, calorimetric properties, and sensory characteristics. Although, air frying produced products with a substantially lower fat content but with similar moisture contents and color characteristics, it required much longer processing times, typically 21 min in relation to 9 min in the case of deep fat frying. The slower evolution of temperature also resulted in lower rates of moisture loss and color development reactions. Differential scanning calorimetry (DSC) studies revealed that the extent of starch gelatinization was also lower in the case of air fried product. In addition, the 2 types of frying also resulted in products having significantly different texture and sensory characteristics.Practical ApplicationDespite air fryers being available in our markets, systematic comparisons of the quality and sensory characteristics of products such as French fries produced by air frying and deep fat frying are not available. This study shows that the color of air fried products can be similar to deep fat fried product, but the texture is harder, and mouth feel and appearance are dryer—more akin to puffed/baked products. This study will advance our quest to develop truly competing alternatives to deep fat frying, which yield products having the same mouth-feel and eating experience.
... Fish skin (Fang et al. 2021), chicken nuggets (Castro-López et al. 2023), surimi (Yu et al. 2020), and french fries (Teruel et al. 2015) also absorbed less oil during air frying than deep oil frying. Air frying is a recently developed technique where fried food undergoes cooking through the circulation of hot air around the product to enhance contact between the product and hot air (Yu et al. 2020). ...
... Air frying is a recently developed technique where fried food undergoes cooking through the circulation of hot air around the product to enhance contact between the product and hot air (Yu et al. 2020). In contrast to conventional frying methods, air frying demonstrates superior effectiveness in reducing oil absorption, primarily attributed to the minimal or absence of oil usage (Teruel et al. 2015). ...
... Conversely, the kinetics of colour changes are markedly influenced by frying techniques. In uncoated samples, higher L* values were observed with air frying, which aligns with findings that L* values are higher in air frying compared to deep fat frying, a difference attributed to the Maillard reaction (non-enzymatic browning) involving reducing sugars and amino acids, as described by Teruel et al. (2015), where L* decreases, leading to a darker appearance. Notably, the Maillard reaction progresses more rapidly during oven frying compared to air-frying for uncoated samples. ...
This study aims to compare the effects of various coating materials, including cherry stem powder (C) or leek powder (L), Aloe vera (A), or glycerol (G) on the quality parameters of potatoes during different frying methods (air frying, conventional oven frying, and deep oil frying), considering factors such as moisture content, texture, oil uptake, frying loss, colour, total phenolic content (TPC), lipid oxidation, and sensory analysis. The moisture content of air-fried CG was higher compared to oven frying and deep oil frying. The air frying yields a firmer texture for LG and LA compared to the deep oil frying of these samples. Additionally, uncoated potatoes exhibited greater hardness than CG, CA, and LA samples when oven-fried. The frying method had no notable impact on surface oil; coated samples absorbed less oil than uncoated ones, notably in air frying. Incorporating cherry stem powder into coatings significantly increased the phenolic content to 228.63 ± 0.106 mg GAE/100 g, surpassing that of samples containing leek powder and the control, which measured at 190.76 ± 1.98 mg GAE/100 g. Coatings with elevated levels of TPC (CA, CG) decreased secondary oxidation in fried potato to 1.275 ± 0.021 mg MDA/kg, which was 18.5% lower than the control. Cherry stem powder-added samples, when air-fried, showed promise in reducing oil uptake and lipid oxidation.
... The second alternative is the oven-frying method, in which hot air convection is used with some secondary radiation coming from the oven walls and some conduction coming from the baking tray. Even though both methods are commonly preferred in both household and industrialized setups, there remains a lack of understanding about acrylamide formation in products prepared with them [5,6]. ...
... Oil was added to the potatoes in a proportion equivalent to one tablespoon of oil per kilogram. After setting the air fryer to 180 • C and achieving the target temperature, the potatoes were added, and they were taken out after 21 min [5]. In the oven frying method, 12 g of oil was added per 1 kg of potato, using a spray for homogeneous distribution. ...
... Oil was added to the potatoes in a proportion equivalent to one tablespoon of oil per kilogram. After setting the air fryer to 180 °C and achieving the target temperature, the potatoes were added, and they were taken out after 21 min [5]. In the oven frying method, 12 g of oil was added per 1 kg of potato, using a spray for homogeneous distribution. ...
Fried potato products are the largest dietary source of acrylamide, a potential carcinogen formed at high temperatures. Previous studies suggested that garlic powder could decrease the development of acrylamide; however, there has not been much focus on the effect of garlic extract. The aim of this study was to investigate the effect of garlic extract exposure on the development of acrylamide in French fries in popular home cooking techniques such as pan-frying, air-frying, and oven-frying. Initially, the antioxidative profile, total phenolic content, and chlorogenic acid content of garlic were analyzed. Subsequently, potatoes were treated with garlic extract and fried using pan-frying, air-frying, and oven-frying techniques. Acrylamide levels were then quantified through HPLC and compared to control groups. The findings showed that garlic exposure increased the acrylamide formation in French fries obtained with air-frying (311.95 ± 0.5 μg/kg) and with oven-frying (270.32 ± 23.4 μg/kg) (p < 0.005 *). This study offers new insights into varying acrylamide formation levels in domestic practices. Unlike previous studies, this study is the first to question the effect of aqueous garlic extract exposure. Further research is required to comprehend the interaction between garlic exposure and acrylamide formation in household settings.
... The adherence of fat on the surface of food results in increased fat content of that product. A significant increase in fat content of potato slices when thickness was increased from 0.8 to 1.2 mm could be due to the longer frying time required by thicker food [9]. An increasing surface area to volume ratio of simulated potato strips affected the moisture and oil content positively. ...
... Millin and coauthors [14] observed that increasing temperature and decreasing the frying time results in lower moisture content and high oil content. Baumann and Escher [9] on the other hand confirmed that lower frying temperature (150ºC) leads to prolonged frying time resulting in high fat content while a higher temperature (180ºC) leads to the rapid development of tougher crust in shorter time with lower oil absorption. Teruel and coauthors [9] also determined upto 35% decrease in fat content was observed when temperature was increased from 150 to 190ºC using a 3-D mathematical model to simulate a domestic deep fryer. ...
... Baumann and Escher [9] on the other hand confirmed that lower frying temperature (150ºC) leads to prolonged frying time resulting in high fat content while a higher temperature (180ºC) leads to the rapid development of tougher crust in shorter time with lower oil absorption. Teruel and coauthors [9] also determined upto 35% decrease in fat content was observed when temperature was increased from 150 to 190ºC using a 3-D mathematical model to simulate a domestic deep fryer. ...
... In addition to other factors, such as colour and sensory attributes (i.e., crunchiness), moisture residue plays a crucial role in determining the quality and flavour of food. If the quantity of moisture is insufficient, the food will become excessively dry, and in excess, the food will become overly soft, leading to potential rejection by the consumer [43]. It has been reported that the moisture content is reduced proportionally with the temperature and process time because the food is heated in a closed system where the heat transfer occurs by forced convection. ...
... Similarly, Pande-Snehal et al. [30] found a significant decrease in FC using air frying, commenting that the samosa is wholly submerged in oil in the conventional frying process, and in the air fryer, only oil is applied to the surface. A similar trend was found by Teruel et al. [43], who reported a content of 15 times less oil in air-fried samples than in traditionally fried samples, which is attributed to the differences in FC to the frying medium surrounding the potatoes. Ghaitaranpour et al. [12], Shaker [37], Andrés et al. [2], Giovanelli et al. [15], Tian et al. [44], and Haddarah et al. [18] found more than twice the FCs in traditionally fried donuts, potatoes, potatoes, potatoes, and potatoes, respectively, than in hot air-fried products. ...
... The scholars attributed the variation in colour to the difference in frying. Similar results were reported by Teruel et al. [43], who stated that L* decreases with time in traditional and hot air frying processes, while a* and b* increase; this trend is relevant with potatoes that turn dark and yellowish red. Therefore, air frying can achieve the characteristic colour of deep-fat French fries while requiring a long processing time. ...
Hot air frying is a relatively new technique used to produce fried food. The aim of this review is to understand the influence of this approach on food quality. Based on the existing research in the literature, a range of findings have emerged regarding changes in textural properties and decreases in moisture content. These outcomes are associated with variations in frying time and temperature parameters. Furthermore, as the duration and temperature of the process increase, lightness decreases, and compared to the traditional frying method, foods exhibit satisfactory sensory characteristics after hot air frying. This technique offers advantages in reducing oil use and the development of relatively few acrylamides during the process. Additional studies evaluating the
microstructure are necessary using other techniques, such as transmission electron microscopy and atomic force microscopy. Moreover, future research should be focused on optimizing the process and studying other foods. As a critical process in the food industry, hot air frying directly affects food quality and influences the microstructure. An inadequate frying process can result in unpleasant food for the consumer; thus, process optimization and sensory attributes of the food are addressed. This work provides essential information about advances in food quality using hot air frying.
... In the air fryer method, potato slices are heated with oil droplets under hot air conditions, resulting in the drying and cooking of the potatoes (15). In this way, potatoes are fried with less oil. ...
... The most significant share in this increase can be stated as the practical use of hot air fryers and the cooking of potatoes using less oil. Since many companies around the world produce it, it has taken its place in the kitchens of thousands of houses with the effect of being at relatively affordable prices (15,25,26). However, there is insufficient awareness that this new generation of frying equipment may play a role in forming harmful compounds such as acrylamide (27). ...
... In the present study, almost none of the potatoes cooked in the air-fryer had texture and the sensory characteristics of deep-fried potatoes (such as desired crispness, taste, and aroma), although an objective examination of sensory characteristics was not performed in the present study. To provide the selected sensory properties in the potatoes cooked in the air-fryer, the potatoes should be cooked longer times (15,25) because the heat transfer rate is much slower in a gas phase (oil mist) than in liquid phase (bulk oil) (15,25), and this increases the risk of acrylamide formation. In a study, it was found that French fries obtained by air frying (using an acti-fry) contain higher acrylamide and poor quality characteristics according to the deep frying (18). ...
Introduction
Present study investigates the effects of different home pre-treatment processes and cooking techniques on the acrylamide content of fried potatoes.
Methods
Potato sticks were prepared in two different pre-treatment ways (washing and soaking) and cooked with three other techniques (air frying, deep frying, and oven frying). Acrylamide analyses were performed on cooked potatoes using an LC-MS/MS method.
Results
The highest acrylamide content was found in potatoes cooked using the air fryer (12.19 ± 7.03 μg/kg). This was followed by deep frying (8.94 ± 9.21 μg/kg) and oven frying (7.43 ± 3.75 μg/kg). However, the difference between the acrylamide contents of the potatoes according to the cooking methods was not statistically significant. The acrylamide content of the potatoes that were subjected to soaking in all three ways was lower than the potatoes that were not soaked and only washed. In the deep-frying method, it was found statistically significant that the soaked potatoes contained less acrylamide (p = 0.029).
Discussion
It is important to highlight the relatively low acrylamide levels found in oven-frying, lower than air frying in both washing and soaking groups in the present study. Although air fryers, which have become widely used as an alternative to deep frying in recent years, provide French fries with less oil, their role in the formation of acrylamide should be further investigated.
... Although betaine is known to withstand harsh treatment during sugar beet processing, cooking and baking may result in loss of betaine in enriched foods, although it is thermostable in pure form [36]. In this study, the betaine content ranged from 845 to 1497 mg/100 g for DO-40 and VD-40, respectively. ...
... It is also interesting to notice that the betaine loss in AF was lower with higher infill levels. This could be due to the fact that AF produces extremely high heat transfer rates during which the hot air is also distributed uniformly through the product at high velocities [36], resulting in lower losses of betaine for snacks with denser structure and less open surface. Previous studies reported varying levels of betaine losses during thermal processing. ...
... The observed positive firmness-infill correlation (r = 0.60) was expected since a higher infill level implies more deposited material and a more stable structure, most likely contributing to snack firmness. Likewise, Liu et al. [36] reported that increasing infill percentage increased the hardness of 3D-printed mashed potatoes. Huang et al. [29] also found that the hardness of 3D-printed shapes of brown rice positively correlated with infill density. ...
Betaine is a non-essential amino acid with proven functional properties and untapped potential for cereal food enrichment. While 3D printing represents a viable approach for manufacturing enriched cereal-based foods with novel shapes and textures, it is crucial to consider the impact of printing parameters and post-processing on the betaine content and properties of these products. The aim of this study was to investigate the influence of the infill level (20, 30 and 40%) of 3D-printed cuboid shapes and the post-processing techniques (drying oven, vacuum dryer, air fryer) of betaine-enriched oat-based snacks on the print quality, texture, and sensory properties, as well as the content of preserved betaine. The interaction of post-processing technique and infill level influenced the length deviation and texture properties, as well as the betaine content of snacks. Height stability was only influenced by post-processing technique. In general, oven-dried snacks showed the best dimensional stability, having the lowest width/length deformation (about 8%) at the infill level of 20%. Betaine was best preserved (19–31% loss) in snacks post-processed in a vacuum dryer (1281–1497 mg/g), followed by an air fryer and a drying oven, where betaine loss was in the range 28–55%. Air-fried snacks with 40% infill level had the highest values of instrumentally measured crunchiness (38.9 Nmm) as well as sensory test values for liking of texture (7.5), intensity of odor (6) and overall flavor (6). Overall, air frying proved to be a convenient and quick post-processing technique for 3D-printed snacks, but infill patterns for preserving betaine should be further explored. Vacuum drying could be used to preserve bioactive compounds, but efforts should be made to minimize its negative impact on the physical deformations of the 3D-printed products.
... Studies have shown that potatoes fried at higher temperatures and with lower moisture content contain more acrylamide (Sansano et al., 2018). Deep-fat fried products exhibited hard and thick crust surface due to elevated temperature at the surface, which caused confined water loss, hindering starch gelatinization in the crust region (Teruel et al., 2015). Additionally, oil flavor and stability are altered by hydrolysis, oxidation, and polymerization during frying, which results in micro-structural changes throughout the product (Oke et al., 2018). ...
... The oil replaces both the water and the water vapor from large capillaries during frying (Dehghannya & Ngadi, 2021). According to Teruel et al. (2015). Food that undergoes frying increases almost linearly with temperature and time until it reaches the boiling point of water. ...
... Penetrated surface oil or structural oil on the surface of fried food is as oil residues absorbed inside the fried food via capillary or pressure-driven forces (Kansou et al., 2022). Many (Heredia et al., 2010;Teruel et al., 2015;Kutlu et al., 2022) studies address the information on the modelling of oil uptake through both capillary and pressure-driven flow. Multiphase transport contributes to three processes inside a porous media: molecular diffusion, capillary diffusion, and convention for Darcian flow (pressure driven) for liquids or gases. ...
Frying is one of the most popular and traditional processes used in the food industry and food services to manufacture products that are high in quality and with unique sensory characteristics. The most common method of frying is deep-fat frying, used worldwide due to its distinct flavor profile and sensory aspects, which leads to physio-chemical changes at both macro and micro levels. One of the major concerns with deep-fried foods is their high oil content, and a variety of metabolic disorders can be caused by overconsumption of these foods, including heart disease, obesity, and high cholesterol. Due to their enticing organoleptic properties with their delicious flavor, pleasing mouthfeel, and unique taste, making them irresistible, it is also responsible for undesirable and unacceptable characteristics for consumers. Oil absorption can be reduced by developing novel frying methods that limit the amount of oil in products, producing products with fewer calories and oil while maintaining similar quality, flavor, and edibility. In addition, different pretreatments and post-frying treatments are applied to achieve a synergistic effect. The transfer of mass and heat occurs simultaneously during frying, which helps to understand the mechanism of oil absorption in fried food. Researchers have discovered that prolonged heating of oils results in polar compounds such as polymers, dimers, free fatty acids, and acrylamide, which can alter metabolism and cause cancer. To reduce the oil content in fried food, innovative frying methods have been developed without compromising its quality which also has improved their effect on human health, product quality, and energy efficiency. The aim is to replace the conventional frying process with novel frying methods that offer fried food-like properties, higher nutritional value, and ease of use by replacing the conventional frying process. In the future, it might be possible to optimize frying technologies to substantially reduce fried foods' oil content. This review focuses on a detailed understanding of different frying techniques and attempts to focus on innovative frying techniques such as vacuum frying, microwave cooking, and hot-air frying that have shown a better potential to be used as an alternative to traditional frying.
... Sensation after consuming the potato, where the fingers feels slick and oily Note: The sensory attributes for french fries from Teruel et al., (2015) Consumer panelists involved in FGDs must meet the criteria of commercial chili sauce consumers who have consumed it 1-2 times in the past week and consumers who consume commercial chili sauce with consumption patterns combined with complementary foods. ...
... French fries with code 719 have a distinctive fried aroma, like hot oil fried fries, with a slightly sweet taste and crispy texture. According to Teruel et al., (2015), products fried in oil can give a fried aroma and taste, and the crispy texture of fries is due to the result of reaching high temperatures quickly on the surface of the product, which causes intense evaporation of water, thus inhibiting starch gelatinization. The sweetness of the potato is due to caramelization during frying. ...
Food pairing was the process of combining food or food and beverages to produce sensory characteristics. The consumption of snacks with commercial chili sauce as a supplement was widespread among consumers. Research on food pairing of commercial chili sauce with French fries was limited. The research aimed to describe and understand the sensory profile of chili sauce with its accompanying foods and identify changes in sensory attribute intensity when chili sauce was paired based on consumer perception. The methods used were Quantitative Descriptive Analysis and Rate All That Apply. The main ingredients were four commercial chili sauces and three commercial French fries. The sensory characteristics of chili sauce and French fries pairs were evaluated using QDA with trained panelists and RATA with consumer panelists. The results from the QDA method showed dominant characteristics such as potato flavor, crunchy texture, oily mouthfeel, sweet taste, and sour taste. According to PCA and spider web in QDA, it can be observed that the sample pairs with the highest intensity were sample pairs 47 and 87. Based on the RATA test results, According to PCA and spider web in RATA, it can be observed that the sample pair with the highest intensity was sample pair 65.
... The air-frying process can be considered as a dehydration operation, involving simultaneous heat and mass transfer, leading to water loss and chemical reactions [7]. Numerous food products have been successfully fried using air-frying technology, including falafel [8,19], French fries [7], fish skin [1,5], fried potato [7,[20][21][22][23][24][25][26], surimi [27], and doughnuts [28]. Recently, air-frying gains popularity due to many offered benefits particularly reducing the fat content of the product. ...
... This technique facilitated the assessment of moisture content in all 8 segments across the thickness of the fish skin (z axis). (22) whereas the lower activation energy was observed for airfried US-SS ( Table 4). This implied that the sensitivity of air-fried US-SS to temperature change was comparatively lower. ...
Fried seabass fish skin is one of the favorite snack products in Asian countries. This study was aimed to examine the influence of ultrasonic pretreatment and varying air-frying temperatures on the dehydration and thermodynamic characteristics of fried seabass fish skin product. Additionally, the research sought to assess mathematical models for understanding the kinetics of moisture transfer and moisture distribution within the fish skin during air-frying. Results showed that irrespective of frying temperatures, the moisture content and water activity (aw) of the air-fried fish skin decreased as the frying duration extended. The accuracy of the mathematical models was confirmed in portraying moisture transfer dynamics (proposed models), fat content (FC), activation energy, and Gibbs’ energy during the air-frying process through regression analysis. As a result, Fikry`s model has accurately described mass transfer in fish skin during air-frying process. Furthermore, the diffusion model effectively illuminated the spatial moisture distribution within the fish skin across diverse processing conditions. Applying ultrasonic pretreatment and elevated air-frying temperatures resulted in reduced FC, effective moisture diffusivity, and enthalpy, accompanied by an increase in the Gibbs energy difference. This knowledge holds the potential to inform the design and optimization of the frying process in the food industry.
... Through the AF, a "fried" product could be produced by spouting hot air around foods instead frying in hot oil (Andrés et al., 2013;Heredia et al., 2014). The AF allows for direct contact between food materials and fine droplets of oil within the heated air, enabling heat exchange between the hot air and foods, and significantly reducing oil absorption (Teruel et al., 2015). Nevertheless, evidence has shown that the heat and mass transfer rates of fries during AF are lower than DF, thereby leading to products with textures different from those prepared by DF (Gouyo et al., 2021;Teruel et al., 2015). ...
... The AF allows for direct contact between food materials and fine droplets of oil within the heated air, enabling heat exchange between the hot air and foods, and significantly reducing oil absorption (Teruel et al., 2015). Nevertheless, evidence has shown that the heat and mass transfer rates of fries during AF are lower than DF, thereby leading to products with textures different from those prepared by DF (Gouyo et al., 2021;Teruel et al., 2015). Moreover, the structure and texture development of fried foods is fundamentally influenced by frying conditions and time-temperature combinations (Gouyo et al., 2021). ...
... ( Gharachorloo et al., 2017 The oil content in deep fat frying was 5.63 g oil/100 g defatted dry matter, and 1.12 g oil/100 g defatted dry matter for air frying. ( Teruel et al., 2015 ) Air Cooled at ambient temperature Air frying and microwave oven cooking reduced oil content by 45-50%, but appearance, texture, flavor, and odor characteristics were significantly different from deep fat fried. ( Giovanelli et al., 2017 ) French fries ...
... In addition, a considerably lower amount of oil needs to be used in this frying process than the conventional frying process, which results in low oil content food. According to Teruel et al. (2015) , the oil content of potato chips varied between 0.37 and 1.12 g/100 g defatted dry matter for chips processed by air frying and between 5.63 and 13.77 g/100 g defatted dry weight for deep fat fried chips. Giovanelli et al. (2017) evaluated the quality characteristics of French fries using a deep-fat fryer, air-frying, convection oven, and microwave oven. ...
Background: Deep-fat fried foods are widely popular due to their distinct organoleptic and sensory characteristics. Deep-fat frying allows physical and chemical structural changes at the macro and micro levels. One of the greatest concerns regarding fried foods is their high oil content, and the excessive consumption of these foods has been linked to a range of metabolic diseases, including heart ailments, obesity, high cholesterol, and high blood pressure.
Scope and approach: This review paper presents a comprehensive and up-to-date review of various innovative frying processes, such as vacuum frying (VF), microwave frying, microwave-assisted vacuum frying (MVF), ultrasound combined microwave vacuum frying (UMVF), air frying, and radiant frying. Additionally, it explains the oil uptake mechanism, oil quality, and the effects of different pretreatments and post-frying treatments on the frying process.
Key findings and conclusions: Innovative frying processes are considered promising and capable of producing healthier fried foods compared to traditional frying; they reduce oil uptake without deteriorating organoleptic and sensory characteristics. Specifically, vacuum-assisted frying technologies, such as VF, MVF, and UMVF have significantly reduced oil uptake and acrylamide production while preserving oil quality. In addition, appropriate pretreatment and post-frying techniques play an essential role in reducing oil uptake and optimizing the frying process by saving energy.
... This method has become popular recently as air fryers are commercially available and consumers look for healthier alternatives to fried foods (Zaghi et al., 2019). Air fryers achieve high transfer rates between air and the food, using an air blower, high convective rates, radiative heat transfer, and especially designed cooking chambers (Teruel et al., 2015). However, air frying requires a longer cooking time compared to deep frying, as air has a lower heat transfer coefficient than oil (Zaghi et al., 2019). ...
... This may be due to the construction of the appliances, as it was noticed that the air fryer was more insulated than the convection oven. Average and maximum temperatures inside the air fryer rose as the set temperature was increased (Figure 1) (Teruel et al., 2015). It is possible that the larger size of the convection oven allowed for faster heat transfer to the chicken wings. ...
Chicken wings are among the most popular poultry products for home and foodservice consumption. Poultry products must be handled and cooked safely to decrease the risk of foodborne salmonellosis for consumers. This study aims to validate the use of domestic appliances (convection and air fryer ovens) for the thermal inactivation of Salmonella on chicken wings. Wings (n = 3, 46.5 ± 4.3 g) were inoculated with a five‐strain cocktail of Salmonella (ca. 8 log10 CFU/wing) and cooked in a convection oven (179.4°C) or an air fryer (176, 190, or 204°C) for 2, 5, 10, 15, 20, 22, or 25 min. Thermocouples recorded temperature profiles of wings and appliances. Salmonella counts were determined on XLD agar for rinsates (100 ml/sample), and rinsates were enriched to recover bacteria below the limit of quantification. The recommended internal cooking temperature (73.8°C) was achieved after a range of 7.5 to 8.5 min in both appliances. Salmonella counts were reduced by 6.5 log10 CFU/wing when this temperature was achieved. Cumulative lethality (F‐value) calculations predicted a 9‐log reduction after 7.0 to 8.1 min of cooking. However, sample enrichments tested positive for Salmonella for all cooking times below 22 min. Ultimately, cooking at the temperature–time combinations recommended by manufacturers and online recipes helped achieve complete microbial elimination in both appliances. This study contributes to the validation of home cooking methods to ensure consumer safety.
... Air frying technology helps dry foods faster and removes surface moisture from foods, creating a texture comparable to conventionally processed foods (Teruel et al., 2015). Moreover, air frying provides to protect health-boosting components in foods such as phenolics, essential oils, natural color pigments, and various antioxidative compounds (de Oliveira et al., 2024). ...
In this study, quinoa, which is a good alternative for celiacs, was tried to be used instead of flour by sprouting it and drying it in the airfryer. Flour obtained from quinoa seeds prevents spreading and hardens the product. It was predicted that this problem could be overcome by germination and drying in the airfryer. Morphologically, clean‐cut structures were in the cookies using airfryer‐dried quinoa flour. The melted surface appearance was characteristic of all airfryer‐baked cookies. The thermal and pasting properties of quinoa flour were improved, resulting in better textural properties and digestibility of the cookie. Airfryer‐baked cookies spread less. However, the spread increased with the use of airfryer‐dried quinoa flour. Cookies containing airfryer‐dried quinoa flour had low baking loss, high protein digestibility, and hardness values that were relatively closer to the control cookies. Airfryer‐baked cookies were at moderate hardness level. Minimum baking loss and highest protein digestibility were found in airfryer‐baked cookies with airfryer‐dried quinoa flour. The spread problem can be alleviated by drying the grain sprouts in the airfryer. The highest color difference was seen in oven‐baked cookie with airfryer‐dried quinoa flour. Due to the airfryer's superior airflow properties, it is possible to reduce drying and baking time by 50%. However, airfryer drying has been found to further improve functional properties compared to airfryer baking.
... Consequently, it is imperative for researchers and manufacturers to gain a thorough understanding of the mechanisms underlying oil absorption across different frying methods. This has led to significant research on oil penetration in the context of deep frying [2,6]. ...
Frying serves as a critical process in doughnut production, fundamentally affecting their porous texture, flavor, color, and sensory properties. However, the oil content in the product creates significant challenges, particularly due to the risks associated with oxidation. This research investigates the impact of varying concentrations of Nasunin extract derived from eggplant skin (0.1%, 0.15%, 0.2%, and 0.3%) on the formation of malondialdehyde in doughnuts for 1, 7, and 14 days. Observations indicated that doughnuts prepared with higher concentrations of Nasunin exhibited increased moisture content. Furthermore, the acidity levels of the doughnut samples significantly (p < 0.05) decreased with rising Nasunin concentrations. There was no significant variation (p > 0.05) in the fat content, which ranged from 19.36 to 18.80%. Peroxide values were found to decrease with higher Nasunin levels in the doughnut formulation (p < 0.05). The findings revealed that elevated concentrations of Nasunin caused a significant (p < 0.05) difference in the p-anisidine value and totox index of the doughnut samples in comparison to the control. An inverse linear correlation was observed between Nasunin concentration and malondialdehyde levels. A significant difference (p < 0.05) was noted among treatments concerning color changes, which became more pronounced with higher Nasunin concentrations. During 7 days, no significant variations were detected in the sensory properties (flavor, texture, color, aroma, and acceptability) between the control sample and the one containing 0.2% Nasunin. However, On the 14th day, the sample containing 0.2% Nasunin was found to possess the most enhanced sensory attributes and received the highest acceptability, thus being recognized as the superior sample.
... Conversely, the kinetics of color changes are markedly in uenced by frying techniques. In uncoated samples, higher L* values were observed with air frying, which aligns with ndings that L* values are higher in air frying compared to deep-fat frying, a difference attributed to the Maillard reaction (non-enzymatic browning) involving reducing sugars and amino acids, as described by Teruel et al. (2015), where L* decreases, leading to a darker appearance. Notably, the Maillard reaction progresses more rapidly during oven frying compared to air-frying for uncoated sample. ...
This study aims to compare the effects of various coating materials, including cherry stem powder (C) or leek powder (L) , aloe vera (A) or glycerol (G) on the quality parameters of potatoes during different frying methods (air frying, conventional oven frying, and deep-oil frying), considering factors such as moisture content, texture, oil uptake, frying loss, color, total phenolic content (TPC), lipid oxidation, and sensory analysis. The moisture content of air fried CG was higher compared to oven frying and deep oil frying. The air frying yields a firmer texture for LG and LA compared to deep oil frying of these samples. Additionally, uncoated potatoes exhibit greater hardness than CG, CA, and LA samples when oven fried. Frying method had no notable impact on surface oil; coated samples absorbed less oil than uncoated ones, notably in air frying. Incorporating cherry stem powder into coatings significantly increased the phenolic content to 228.63±0.106 mg GAE/100 g, surpassing that of samples containing leek powder and the control, which measured at 190.76±1.98 mg GAE/100 g. Coatings with elevated levels of TPC (CA, CG) decreased secondary oxidation in fried potato to 1.275±0.021 mg MDA/kg, which was 18.5% lower than the control. Cherry stem powder-added samples, when air fried, showed promise in reducing oil uptake and lipid oxidation.
... The removal of moisture results in the formation of pores and crusts, which, combined with the texture, color, and unique flavor, make fried foods more appealing to consumers (Andrés et al. 2013;Manjunatha, Mathews, and Patki 2019). This technology has been successfully applied to a wide range of food products, including falafel (Fikry et al. 2021(Fikry et al. , 2022, French fries (Andrés et al. 2013), fried potato (Abd Rahman et al. 2017;Andrés et al. 2013;Gouyo et al. 2021;Haddarah et al. 2021;Heredia et al. 2014;Sansano et al. 2015;Shaker 2014;Teruel et al. 2015), surimi (Yu et al. 2020), fish skin (Fang et al. 2023;Fikry, Benjakul, Al-Ghamdi, et al. 2024), and doughnuts (Ghaitaranpour et al. 2018). ...
The combination of pretreatment with ultrasonic technology and air‐frying could improve the quality and efficiency of apple slice processing. This research aimed to explore how ultrasonic treatment prior to frying and varying temperatures during air‐frying impact the drying and thermodynamic characteristics of apple slices. The study also aimed to assess mathematical models that explain the moisture transfer kinetics and to numerically simulate the moisture distribution in apple slices during air‐frying operation. The results revealed that the moisture content and water activity (aw) of apple slices consistently decreased with longer frying times, regardless of the temperature. The mathematical models' precision was confirmed through regression analysis, which accurately represented the dynamics of moisture transfer, activation energy (Ea), and Gibbs free energy (ΔG) throughout the frying process. The results of the statistical analysis showed that the two‐term (exponential) model was effective in predicting moisture transfer in apple slices throughout air‐frying process, while the spatial distribution of moisture was successfully illustrated by the diffusion model under different conditions. Additionally, numerical simulations showed that moisture removal is faster at higher frying temperatures, and ultrasonic pretreatment led to a shorter frying time. Ultrasonic pretreatment combined with higher frying temperatures led to reduced differential enthalpy, along with an increased effective moisture diffusivity and Gibbs free energy difference. These findings are essential for improving and optimizing the frying process in food manufacturing.
... Las freidoras de aire exponen los alimentos a la circulación de aire caliente en lugar de sumergirlos en aceite e irradian calor desde la cámara de fritura para un proceso más eficaz. En este proceso ocurre una alta transferencia de calor que se distribuye uniformemente por todo el alimento, dando lugar a la manufactura de productos fritos de buena calidad y con un color similar a lo alcanzado en la fritura profunda (Teruel et al., 2015); además, se ha demostrado que la freidora de aire puede reducir la formación de acrilamida en papas fritas en comparación con la fritura profunda (Dong et al., 2022). ...
The addition effects of B. alicastrumseed flour (30 % HR, w/w) to corn snacks were analyzed with different cooking methods on consumer acceptance, antioxidant capacity and oxidative stability. Physicochemical changes during storage were also evaluated for the snackswith the highest consumer acceptance values. When deep fried, the HR/TSD (tortilla without dehydration) snack had the highest antioxidant capacity (39.36±0.61 mM Trolox/100 g), while the HR/TD (dehydrated tortilla) snack exhibited the highest oxidative stability (<29 TOTOX). The deep-fried HR/TSD snack had the highest consumer acceptance. During storage, the HR/TSD snack had the lowest peroxide index value. Adding B. alicastrumseed flour in deep-fried corn snacks improves consumer acceptance and storage performance
... Acrylamide is a by-product of the Maillard reaction in food, which often occurs when the food is processed above 120 C. Besides that, the changes in the lightness of French fries were due to the non-enzymatic Maillard reaction that occurs between amino acids and reducing sugar, resulting in the darkened of fried foods (del Teruel et al., 2015;Yang et al., 2016). The sensory characteristics such as appearance, taste, mouthfeel, and smell of conventional and microwave-fried French fries should be further evaluated in future studies to reflect the acceptability of consumers. ...
This study aimed to evaluate the effect of microwave power and duration on French fries using palm olein. The deep‐fat frying was served as a control. The microwave frying of French fries was conducted at low (100 W), medium (600 W), and high (1000 W) for 1, 3, and 5 min. The physicochemical properties of French fries and the quality of palm olein were analyzed. The French fries microwaved at 600 W for 3 min showed comparable hardness (300 g), cohesiveness (0.76), springiness (3.5 mm), adhesion (0.3 mJ), and water activity (0.88 A w ) to deep‐fat frying. The palm olein demonstrated lower peroxide and para‐anisidine values in microwave frying; while deep‐fat frying had lower total polar compounds in frying oil and lower oil content in oil extracted from French fries. Nevertheless, the high oxidation stability in terms of peroxide and para‐anisidine value in frying oil from microwave frying showed its potential as an alternative frying technique to deep‐fat frying.
... Healthier cooking methods are being explored to provide similar sensory properties due to adverse health effects. Hot air frying (air fryer), which has been used recently, is one of them (Teruel et al., 2015). Oil content of the products cooked by air fryer are reduced without losing their product quality and oxidative deterioration of lipids in these products are also reduced (Tian et al., 2017). ...
... This result is in agreement with the observations of Joshy et al. 6 and Fikry et al. 52 It was suggested that several factors might inuence the complication of deep-fat frying mechanisms, like the moisture content of food products, oil characteristics, frying time, frying temperature, chemical reactions, structural characteristics of the product, and the drainage time. 63 These results indicated that the hot-air frying technology is a good choice for frying the sausage product, especially for consumers who are health-oriented. Protein is oen an indicator of the nutritional quality of the material. ...
Deep-fat frying is still a very popular food processing method among consumers of different age groups despite the negative health implications of consuming too much fat. However, the application of innovative frying techniques such as hot-air frying is on the rise to produce low-fat fried foods owing to its acceptable characteristics. Response surface methodology has been used to study the effects of hot-air frying temperature (HFT; 170–190 °C) and time (HFt; 15–25 minutes) on some critical quality attributes of chicken sausages incorporated with corn bran. HFT and HFt had significant (p < 0.05) effects on the moisture content, colour change, total phenolics, carotenoid contents, and chewiness of samples. Hot-air frying resulted in a significant reduction in the oil content; high retention of total phenolics, carotenoids, and dietary fiber; as well as improvement in chewiness and acceptable quality attributes. The optimum processing conditions obtained were 170 °C and 25 minutes at a desirability index of 63%. Significant (p < 0.05) differences were observed in some qualities of the optimized and control samples. The study concluded that the incorporation of corn bran into sausages using the hot-air frying process can improve the quality attributes of chicken sausages and serves as a means of value addition and waste valorisation; the hot-air frying technique could be an alternative method to produce healthier, fibre-rich and acceptable fried chicken sausages in a sustainable manner.
... Teruel et al. and Restrepo et al. [25,26] compared the traditional oil frying method with air fryers for plantain chips. Their experimental method included cooking at 180 • C, monitoring variables like temperature, moisture, oil absorption, and microstructure, and conducting sensory evaluations. ...
Due to their contribution to human health, healthy snacks have garnered the attention of the scientific community and the food industry. This study was conducted to determine the suitability of frying and baking processing methods for producing green banana chips using two varieties: Barraganete and Dominico. The aim was to identify a treatment geared toward producing healthy snacks. Initially, the physicochemical properties of the raw materials were analyzed, revealing significant differences in starch, fat, fiber, and protein content. Subsequently, the bananas were processed into baked and fried chips. Multivariate statistical techniques such as ANCOVA, MANOVA, and post-hoc tests were applied to examine the influence of initial characteristics and detect variations attributable to the cooking method. The main findings show that the initial protein level had a significant covariate effect on the final content in the chips. The Dominico variety generally proved more suitable for making baked chips, retaining higher percentages of protein, starch, and fiber and lower fat content than Barraganete. Baked chips showed significantly lower sodium and fat values than fried ones when differentiated by processing method. The “Dominico + Baked” treatment emerged as the superior alternative, with favorable levels of protein and starch and low levels of sodium and fat, positioning it as the most suitable for producing a healthy snack.
... The main strength of this design is its ability to examine multiple variables simultaneously, although it does not provide quantification of the chemical composition. In the comparative study [20], plantain chips fried in oil were analyzed in contrast to the use of air fryers. The experimental method included cooking green plantain slices at 180°C, monitoring variables such as temperature, moisture, and oil absorption, examining microstructure, conducting calorimetric analyses, and conducting sensory evaluations. ...
Due to their contribution to human health, the production of healthy snacks has garnered the attention of both the scientific community and the food industry. This study was conducted to determine the suitability of frying and baking processing methods for producing green banana chips using two varieties: Barraganete and Dominico. The aim was to identify a treatment geared towards producing healthy snacks. Initially, the physicochemical properties of the raw materials were analyzed, revealing significant differences in starch, fat, fiber, and protein content. Subsequently, the bananas were processed into baked and fried chips. Multivariate statistical techniques such as ANCOVA, MANOVA, and post-hoc tests were applied to examine the influence of initial characteristics and detect variations attributable to the cooking method. The main findings showed that the initial protein level had a significant covariate effect on the final content in the chips. The Dominico variety generally proved more suitable for making baked chips, retaining higher percentages of protein, starch, fiber, and lower fat content than Barraganete. Baked chips showed significantly lower sodium and fat values than fried ones when differentiated by processing method. The "Dominico + Baked" treatment emerged as the superior alternative, with favourable levels of protein, starch, and low sodium and fat, positioning it as the most suitable for producing a healthy snack.
... For instance, van Loon et al. [17] identified 122 compounds in fried potatoes, including 2-and 3-Methylbutanal, whereas the number soared to 182 and over 400 in boiled and roasted potatoes respectively, encapsulating compounds like (E)-2-Nonenal, Methional, and 2,3-Diethyl-5-methylpyrazine [18]. The flavor composition is highly dependent on the cooking methods applied, primarily owing to the variations in thermal effects and moisture alterations in different culinary environments [19,20]. ...
Sulfur and phosphorus are important plant nutrients required for potato growth, influencing the synthesis of primary metabolites that serve as the material foundation of potato flavor quality. However, little is known about the effects of sulfur and phosphorus application on potato tuber flavor. This study experimentally compared the effects of the individual and combined application of phosphorus and sulfur fertilizers on the flavor of potato tubers. The research examined the sensory characteristics of flavor under various fertilization methods, investigated changes in the types and contents of volatile flavor compounds, and conducted analyses on flavor precursor compounds. The experimental results showed that the application of phosphorus and sulfur fertilizers, either individually or in combination significantly increased the content of linoleic acid and linolenic acid. After the combined application of phosphorus and sulfur fertilizers, the starch and the reducing sugar content also significantly increased. (E,E)-2,4-Nonadienal and Decanal are closely correlated with fatty acid content. Dimethyl sulfide and Trimethyl sulfide contents are significantly related to methionine content. This also significantly enhances the fatty taste characteristics of the tubers but weakens the potato flavor characteristics. Hence, the application of phosphorus and sulfur can affect the accumulation of primary metabolic products in tubers, thereby affecting flavor quality. Compared with the individual application of phosphorus or sulfur fertilizers, when phosphorus fertilizer is applied at 180 kg·ha−1 and sulfur fertilizer at 90 kg·ha−1 in combination, it can further enrich the roasted flavor characteristics of potatoes and maximize the enhancement of potato flavor quality. This provides valuable theoretical support for achieving high-quality agricultural development.
... 2022 Gıdaların nem içeriğindeki azalma sıcak hava fritözünde derin yağda kızartmaya göre daha yavaş gerçekleşmektedir. Bu fark ısı transfer hızının sıvı fazda gaz faza göre daha hızlı olmasından kaynaklanmaktadır (Teruel, 2015). Gouyo vd. ...
Son yıllarda insanların sağlıklı ve enerji değeri düşük gıdalar tüketme eğilimi göstermesi yeni pişirme tekniklerinin gelişmesine yol açmıştır. Sıcak hava fritözü son 10 yılda ortaya çıkan, tüketiciler tarafından kabul görmüş bir pişirme cihazıdır. Bu cihazlar klasik kızartma tekniklerine oranla daha az yağ ilavesi ile kızartma işlemine olanak sağlamaktadır. Bu sayede derin yağda kızartmaya kıyasla enerji değeri ve yağ oranı daha düşük gıdalar elde edilebilmektedir. Derin yağda kızartma tekniği en eski pişirme tekniklerinden biri olmasına rağmen pişirilen ürünün yüksek oranda yağ içermesi ve proses sırasında gıdada bazı istenmeyen bileşenler (akrilamid vb.) oluşumuna sebep olması nedeniyle tüketiciler tarafından çekinceye sebep olabilmektedir. Son yıllarda sağlıklı beslenmeye olan ilginin artması da bu tarz gıdaların tüketiminin sınırlanmasına sebep olmaktadır. Bu derlemenin amacı sıcak hava fritözü ve derin yağda kızartılan gıdalara yönelik yapılmış çalışmaların incelenerek elde edilen fiziksel, kimyasal, duyusal niteliklerin literatür verileri doğrultusunda açıklanmasıdır.
... One of the major sensory characteristics of fried french fries that have impact on consumers' acceptance is the color [12]. Formation of color on french fries' surface during frying is caused by a Maillard reaction: interactions between amino acids and reducing sugars. ...
Fast-food establishments today often sell fried food without proper control over the frying oil, and french fries are a prime example. Neglecting the maintenance of frying oil can lead to decreased taste, health concerns, and operational inefficiencies. The following plant oils were used in the frying process: rapeseed, sunflower, and palm oil. The degree of frying was measured by the total polar meter (TPM), until the achievement of 24%. To accurately assess the color characteristics of the french fry samples, Minolta CM 2600d color measurement instrument was used. Statistically significant differences were observed between some color parameters (L, a, b, C, and h) and TPM values. The following correlations were observed: 0.530 was obtained for TPM and h (hue angle) in french fries fried in palm oil; negative correlation (−0.214) between TPM and L (lightness) was obtained in french fries fried in rapeseed oil. While we have observed certain correlations from our experimental data, it is important to note that the color of french fries may not be the sole determinant of fried oil quality. Other external factors, such as temperature, chemical composition, and potato cultivar, can also significantly influence the color of french fries.
... Also, it can form the characteristic shell of fried food due to dehydration (5). Moreover, AF has the advantage of inhibiting the formation of acrylamide (6). Compared with DF foods, the oil content of AF food exhibits 70-80% lower and the acrylamide content can be reduced by about 90% (7). ...
This study aimed to compare the changes in the quality characteristics of air-fried (AF) shrimp meat and deep-fried (DF) shrimp meat at different frying temperatures (160, 170, 180, 190°C). Results showed that compared with DF, the moisture and fat content of air-fried shrimp meat (AFSM) was lower, while the protein content was higher. At the same frying temperature, the fat content of the AFSM was 4.26–6.58 g/100 g lower than that of the deep-fried shrimp meat (DFSM). The smell of the AFSM and DFSM was significantly different from that of the control group. The results of the electronic tongue showed that each of the two frying methods had its flavor profile. Gas chromatography-ion mobility spectrometry (GC-IMS) identified 48 compounds, and the content of volatile compounds detected in AFSM was lower than that in DFSM. Among them, the highest level of volatile compound content was found in the DF-190. E-2-pentenal, 2-heptenal (E), and methyl 2-methyl butanoate were identified only in DFSM. In addition, a total of 16 free amino acids (FAAs) were detected in shrimp meat. As judged by sensory evaluation, the AFSM at 170°C was the most popular among consumers.
... Aj iné štúdie hodnotili textúru hranolčekov inštrumentálnymi prístupmi za rôznych testovacích podmienok a sond. Najbežnejšie metódy na určenie textúry hranoliek zahŕňajú vpichový test (Heredia et al., 2014;Teruel Mdel et al., 2015), kompresný test (Millin et al., 2016), trojbodový ohybový test (Quan et al., 2016) a rezný test (Amaral et al., 2015). V kontexte s uvedeným bolo cieľom práce skúmať zmeny texturálnych vlastností zemiakových hranolčekov v čerstvom a hlbokozmrazenom predsmaženom stave pred a po fritovaní. ...
Scientific articles deal with hygiene and food technology
... In a comparative study of the characteristics of french fries treated with high temperature oil frying and air frying by (Teruel et al., 2015), it was found that although the air frying technique produces lower fat substances than frying, air frying requires a long processing time, namely 21 minutes compared to potatoes which is 9 minutes. ...
This study examines the characteristics and composition of macro and micronutrients in kenyang diet in obesity therapy compared with a regular obesity diet, a low-energy diet. The approach is qualitative, Diet Quality Index (DQI-I) instruments is used for kenyang diet and low-energy diet consumers. Kenyang diet and the low energy diet have different characteristics from qualitative and quantitative aspects. Kenyang diet has the principle of natural food ingredients without processing and elimination of food additives. In comparison, the low-energy diet focuses on consuming foods low in energy, high in protein, sufficient in fat, and high in fiber. The composition of the kenyang diet obtained was 22% protein, 45% fat, and 35% carbohydrates from the total energy intake. Compared to kenyang diet, low-energy diet meets a balanced nutritional composition. Processing the menu in kenyang diet and low-energy diet has differences in frying technique. Kenyang diet as a qualitative diet has advantages and disadvantages in terms of nutrition and health. Consumption of natural foods and avoiding processed foods is a good health approach. Kenyang diet uses mindful techniques as the initial stage of the diet by giving full attention to what is eaten. However, kenyang diet has a risk of iodine and potassium deficiency due to the absence of consumption of table salt and milk in the long term.
... In this regard, "air-frying", a recently developed easy, rapid, and relatively cheap frying technique, ensures high heat transfer rates via circulating hot air to obtain favorable structural and textural properties in fried products [12,13]. Compared with traditional frying methods, air-frying can avoid a large amount of fried oil usage and absorption [14,15]. However, an adequate amount of oil compounds on the surface of the food is helpful for improving the quality of final products via air-frying, especially for low-fat seafood such as squid and fish. ...
High internal phase emulsions (HIPEs) have been introduced as an alternative to liquid oil to improve the quality of air-fried seafood products. In this study, the effect of HIPE coating compared to that of liquid oil or no oil on air-fried squid quality was investigated. The exudation content of oil droplets (ranging from 0.021 ± 0.002 to 0.067 ± 0.005 g) and water loss (7.19 g) in air-fried squid with HIPE coating were significantly reduced compared to those with liquid oil coating. Owing to the homogeneous HIPE coating, the air-fried squid possessed acceptable textural properties (hardness, 2845.04 ± 570.48 g; chewiness, 2405.77 ± 203.55 g), excellent color, and a fried-like flavor, when compared to air-fried squid with or without liquid oil. Interestingly, there was a lower content (5.90 ± 0.18 ng/g) of heterocyclic aromatic amines in air-fried squid with HIPE coating than in those with liquid oil coating (20.18 ± 0.26 ng/g) or without oil coating (21.25 ± 0.50 ng/g). In summary, HIPE, as a novel oil medium, is advantageous for the development of air-frying products.
A large part of the world population consumes fast food on a regular basis. Most of these menus are accompanied by french fries. Their consumption does not represent a major nutritional contribution, and the frying process incorporates a considerable amount of oil into the french fries, increasing the risks of diseases such as obesity. The objective of the present work was to evaluate the physical and textural properties of a potato chip substitute made by extrusion technology with the incorporation of flours of a nutritious cereal such as quinoa and prickly pear peel in its formulation. Color and porosity were evaluated by image analysis. Texture by mechanical compression tests with an Instron universal testing machine and oil absorption rate by a modified compression method. Sticks of a potato substitute were obtained and fried by immersion in oil at 180 °C in the same way as a commercial pre-fried product. The firmness of the sticks (4.5 N) is 30 % higher than the commercial product, while the oil absorption rate (6.25 %) of the products obtained is three times lower. This phenomenon could be due to the fiber content present in the prickly pear peel flour and protein content in the quinoa flour. It is concluded that is possible to elaborate products similar to traditional and commercial potato chips, so that, without altering the consumption habits of the population, it can allow the intake of healthier foods.
Tahin üretiminde en önemli aşama susamın fiziksel ve kimyasal özelliklerini etkilediği için kavurmadır. Bu çalışmada tahin üretiminde kullanılan kabuksuz susam tohumlarının sıcak hava fritözünde optimum kavurma koşullarının belirlenmesi ve özelliklerinin konvansiyonel yöntemle karşılaştırılması amaçlanmıştır. Çalışma kapsamında kabuğu soyulmuş susam tohumları farklı sıcaklık (160°C, 180°C ve 200°C) ve sürelerde (15-70 dakika) sıcak hava fritözünün haznesine 0,8 gr/cm3 olacak şekilde yayılarak kavrulmuştur. Kavurma işlemindeki sıcaklık ve süre parametreleri yanıt yüzey yöntemi kullanılarak optimize edilmiştir. Kavrulmuş örneklerin ΔE (toplam renk değişimi) ve su aktivitesi verilerine göre sıcak hava fritözünün optimum çalışma sıcaklığı ve süresi 181,1°C ve 36,7 dk olarak belirlenmiştir. Sıcak hava fritözünde kavurma neticesinde konvansiyonel kavurmaya göre yağ verimi %50’den %60’a çıkmıştır. En düşük peroksit değeri 1,69 meq O2/kg ile 180°C de 35 dk da sıcak hava fritözünde tespit edilmiştir. FTIR sonuçları da sıcak hava fritözü ile kavrulmuş susamların oksidasyona karşı daha dayanıklı olduğunu desteklemiştir. Sıcak hava fritözü ile 5 kat daha kısa sürede kavrulan susamların konvansiyonel kavurmaya göre asitlik değerleri ve yağ asidi kompozisyonları benzer bulunmuştur. HMF içeriğinde ise sağlık açısından riskli seviyede bir oluşum gözlenmemiştir.
Hot air frying is a relatively new technology for producing fried foods, therefore, the objective of this review is to know the impact of this frying technology on the quality properties of fried potato products, addressing its effect and recommendations with the series of scientific studies in the literature. According to research available, the moisture content decreases with frying, but the final moisture contents are higher by about 35% compared to traditional frying. In the texture analysis, acceptable characteristics are obtained, and the lightness decreases with frying, attributing the desirable color characteristics of fried foods, in addition, in sensory attributes, no differences were found in flavor and crispiness between hot air frying and traditional frying, but in appearance, color and overall acceptability were higher in conventionally fried potatoes. In conclusion, future work should focus on assessing the impact on health and biofunctional properties (e.g. resistant starch, antioxidant properties) by the consumption of fried potato products, due to the scarce information available and the importance that this represents, since the literature has focused on quality parameters.
Two samples, simple-battered chicken (SBC) and normal-battered chicken (NBC), with different batters were deep-fat fried at various conditions and volatile compounds and 5-hydroxymethylfurfural (5-HMF) was analysed. The moisture content of the air-fried samples was significantly higher than that of the deep-fat fried samples in the same batter samples. A total of 72 volatile compounds (8 aldehydes, 15 monoterpenes, 12 sesquiterpenes, 2 terpene alcohols, 4 benzenes, 13 pyrazines, 2 pyridines, 6 furans, 5 alcohols, 2 pyrroles, and 3 others) were detected in fried chicken breast, and air-fried SBC possessed the highest total amount of volatile compounds. Furthermore, 5-HMF was exclusively detected in NBC samples; in particular, 1.27 ± 0.06 and 0.41 ± 0.02 μg/mL were detected in deep- and air-fried NBC, respectively. This study indicates the potential of air frying to reduce the formation of 5-HMF while maintaining quality characteristics, suggesting the need for further study on other hazardous compounds.
Sweetpotato is an important food, feed and vegetable crop in most tropical developing countries. The decision to adopt a new cultivar is complexly related to field and yield performance as well as consumer taste acceptability. The objective of this study was toidentify sweetpotato management system andconstraints to farmers, traders and consumers in Niger and Nigeria. The study was carried out for both Focus Group Discussion (FGD) and Semi-Structured Questionnaire (SSQ) in Niger and Nigeria. Data was collected using established Participatory Rural Appraisal (PRA) tools and was analysed using "R" software version 3.1.5. The results revealedthat in Niger, sweetpotato is men crop, while it is women crop in Nigeria mostly in SouthEast part. The main top five production constraints in Niger were sweetpotato weevil (Cylaspuncticolis) (61.11%), caterpillar (44.44%), drought stress (40.00%), post-harvest storage (35.55%), and low price (33.33%). In Nigeria the first five top constraints were sweetpotato weevil (Cylasformicarus) (33.33%), SPVD (30%), caterpillar (24.44%), price fluctuation (27.77%), and drought tolerant (21.11%). The main consumption constraint in both countries was constipation. In the difference with Nigeria, in Niger low sugar is a constraint, while high sugar content limited sweetpotato consumption in Nigeria. Résumé La patate douce est une culture vivrière, fourragère et légumière dans la plupart des pays tropicaux en développement. L'adoption d'un nouveau cultivar est complexe et est liée à la performance au champ et au rendement ainsi qu'à l'acceptabilité gustative des consommateurs. L'objectif de ce travail est d'étudier le system de production de la patate douce aussi bien d'identifier les contraintes liées à la production, à la commercialization et à la consommation au Niger et au Nigeria. L'étude a été réalisée à la fois en administrant le focus groupe et le questionnaire semi-structuré individuel au Niger et au Nigeria. Les données ont été collectées à l'aide d'outils établis d'évaluation rurale participative (ERP) au Niger et au Nigéria et ont été analysées à l'aide du logiciel "R" version 3.1.5. Les résultats ont révélé qu'au Niger, la patate douce est cultivée et commercialisée par les hommes, alors qu'elle est cultivée et commercialisée par les femmes au Nigeria, principalement dans la partie Sud-Est. Les cinq principales contraintes de production au Niger étaient le charançon de la patate douce (Cylaspuncticolis) (61,11%), la chenille (44,44%), le stress hydrique (40,00%), le stockage après récolte (35,55%) et le bas prix (33,33%). Au Nigéria, les cinq premières principales contraintes étaient le charançon de la patate douce (Cylasformicarus) (33,33 %), lamaladie virale de la patate douce (30 %), la chenille (24,44 %), la fluctuation des prix (27,77 %) et le stress hydrique (21,11 %). La principale contrainte de consommation dans les deux pays était la constipation. A la différence du Nigéria, au Niger, la faible teneur en sucre est une contrainte, tandis qu'une forte teneur en sucre limite la consommation de la patate douce au Nigéria.
Hot air frying is a new method of frying food, where the use of a small amount of oil is optional but recommended. The objective of this review was to know the state of the art of hot air frying technology, focusing on trends, and thus obtain new ideas for future work in this area of food. In conclusion, the availability of advanced devices will increase the demand for hot air fryers as demonstrated by the trend generating a great economic and social impact. This new technology not only provides health benefits, but also has environmental advantages. In addition, work focusing on food (i.e. tortilla chips, plantain chips, eggs and meats) is recommended, since there are not enough studies on the subject. Currently, research is being conducted on home fryers, so the use of fryers and their impact at the industrial level is a developing area that will require further research.
Deep-fat frying is one of the most used methods to obtain fried food. However, alternative methods are sought to get fried products with lower fat content, but with similar attributes. In this study, air fat-frying was compared with deep-fat frying for chicken nuggets. Both frying methods were carried out at temperatures between 160 and 190 °C for 0, 3, 6, 9, 12 and 15 min for each temperature. Activation energy was 70.3 kJ/mol for the moisture diffusion during deep fat-frying while a value of 131.37 kJ/mol was found for air-frying. The highest oil reduction was obtained when chicken nuggets were air-fried at 170 °C, being 25.6% lower than those nuggets obtained from deep-fat frying process. However, texture and color were affected by the air frying process.
Cooking at home has experienced a decline in many countries since the mid-20th century. As rates of obesity have increased, there has been an emphasis on more frequent home cooking, including its incorporation into several food-based dietary guidelines around the world as a strategy to improve dietary quality. With the recent trend towards the adoption of diets richer in plant-based foods, many consumers cooking at home may now be cooking plant foods such as vegetables, potatoes and pulses more often. It is, therefore, timely to explore the impact that different home cooking methods have on the range of nutrients (e.g. vitamin C and folate) and bioactive phytochemicals (e.g. carotenoids and polyphenols) that such plant foods provide, and this paper will explore this and whether advice can be tailored to minimise such losses. The impact of cooking on nutritional quality can be both desirable and/or undesirable and can vary according to the cooking method and the nutrient or phytochemical of interest. Cooking methods that expose plant foods to high temperatures and/or water for long periods of time (e.g. boiling) may be the most detrimental to nutrient content, whereas other cooking methods such as steaming or microwaving may help to retain nutrients, particularly those that are water-soluble. Dishes that use cooking liquids may retain nutrients that would have been lost through leaching. It may be helpful to provide the public with more information about better methods to prepare and cook plant foods to minimise any nutrient losses. However, for some nutrients/phytochemicals the insufficient and inconsistent research findings make clear messages around the optimal cooking method difficult, and factors such as bioaccessibility rather than just quantity may also be important to consider.
To investigate the physico-chemical characteristics of deep fried chayote chips snack foods and their impact on storage stability under different packaging materials, deep fried ready-to-eat chayote chips was prepared under optimised processing parameters at temperatures of 150–170°C for 5–15 s using refined soybean oil. The results revealed that chayote chips fried for 15 seconds at 170°C had the highest overall acceptability (7.09), the lowest hardness (50.29 N), and the best colour value. Chayote chips were deep fried and then stored in aluminium coated laminate (ACL) & low density polyethylene (LDPE) packaging material to estimate the shelf life stability (LDPE). The ACL packing material was found to be more successful in terms of reducing free fatty acids (0.68 percent), peroxidase value (3.76 meq/kg), and colour value "L," "a," and "b" retention. The shelf life of chayote chips packed in ACL packaging material was 120 days, with superior quality retention.
The main goal of this work was to investigate the stability of standard palm olein (SPOo) and special quality palm olein (SQPOo)
under continuous frying conditions. The rate of free fatty acid (FFA) formation was slightly higher for SPOo than SQPOo during
56h of frying. An equilibrium state was reached at around 40h for SPOo and 32h for SQPOo, whereby FFA varied within a narrow
range of 0.30–0.32 and 0.22–0.25%, respectively. Smoke point of SPOo and SQPOo progressively dropped from 212 to 184°C and
from 227 to 191°C. Tocols of SPOo and SQPOo declined from 550to 273mg kg−1 and from 720 to 447mg kg−1 after 56h of frying, respectively. Oxidative stability of both oils decreased after the successive frying. Induction time
of SPOo dropped from 22.3 to 14.9h while SQPOo decreased from 25.5 to 18.3h. Polar and polymer compounds increased as frying
progressed. The SPOo had higher levels of polar compounds, averaging 11.8%, compared to the 10.2% in SQPOo. However, SPOo
had lower levels of polymer compounds compared to SQPOo, averaging 2.1 and 2.5%, respectively. Hence, this work confirms that
frying performance using SPOo was comparable to SQPOo for use in industrial production of snack foods (potato chips).
Deep fat frying is an important, ubiquitous and highly versatile process, which has been used since antiquity to cook a wide spectrum of products. Its unique contribution to sensory characteristics, together with the relatively low cost of large-scale frying, has made fried foods the staples of the ever growing late 20th century fast food industry. Despite its considerable fat content and intensified consumers’ awareness of the relationships between food, nutrition and health, frying remains a principal cooking method. Oil consumption especially saturated fat is considered a major factor increasing health risks such as coronary heart disease (CHD), cancer, diabetes and hypertension, and even linked to increased causes of deaths. Fried foods contribute a significant proportion of the total fat consumed in the Western world. Yet, aside from their high caloric value, fried foods can be nutritious and favourably compared with other cooking methods such as baking and boiling. Fried foods are popular due to their taste, distinctive flavour, aroma and crunchy texture. Misconceptions about frying extend beyond nutrition to the fundamental aspects of the process, such as the role of water and oil quality during frying. The water released during frying enhances heat transfer, may cause oil deterioration, and also can prevent oxidation. Improving oil quality, the mechanism of oil, coating, engineering considerations of residence time and design, are typical examples of frying technology that is still evolving. To provide quality products that meet consumers’ expectations and satisfaction, and simultaneously improve their quality characteristics, a new paradigm is required. These topics are discussed and data presented to suggest that fried foods do not have to be a health risk in a balanced diet, when frying technology and oil quality are carefully maintained. Future research needs are also highlighted.
The retrograded starches have good compaction properties that make they useful for direct compaction tableting. It was owing to the special particle characteristics, the presence of insoluble amylose and the high swelling amylopectine capacity. In this study it was analyzed the compaction properties of retrograded chayote starch compared with retrograded potato starch and the commercial Starch 1500. The results showed that chayote starch has better properties because gave hardest tablets, more resistant to magnesium stearate and with better dilution potential than potato starch and the commercial one. When the starch has a high pregelatinization level, it modified the drug liberation profiles of tablets, so they look useful for controlled release pharmaceutical forms.
This work determines pore characteristics of the French-fry crust and their development at two time intervals during frying. dynamic wicking (DW) and scanning electron microscopy (SEM) are used for that reason. DW is used to determine the effective mean pore radius of the crust. SEM is used to observe the microstructural characteristics of the crust interior and surface. The shapes and sizes of openings/pores in the crust and surface and cell sizes in the crust and core are determined by analysis of the SEM images. Except from new to the literature data on pore sizes in French-fry crusts the above observations provide insight on phenomena occurring in the crust during frying. In addition, the behavior of the interconnected crust porous network during capillary penetration is assessed by DW. Finally, an approximate rate of frying oil uptake in the crust region is estimated considering a capillary penetration theory for oil uptake.
Light microscopy was used to study changes in cell size, blister formation and crust evolution during potato frying. Frying experiments with both French fries and crisps of different thickness (1–5 mm) were performed at temperatures of 140 and 180 °C. Thickness, volume and density changes were also measured. The formation of crust in French fries starts after the potato surface reached approximately 103 °C, and then the crust thickness increased linearly with the square root of frying time, this increase being faster at 180 °C. The potato volume decreased during frying, although in the late stages the volume may increase because of oil uptake and cell separation caused by entrapped water vapour. Shrinkage was adequately described by the Weibull model with a residual value, with shrinkage rate increasing with temperature and decreasing with potato thickness. The residual volume was not affected by temperature (65% for French fries and 59–30 for crisps, depending on thickness). Volume appeared to decrease mainly as the result of water loss, except for very low water content, and thus potato density changes were very small.
The use of vacuum for the cooking of food is one of the techniques that has been developed in the field of haute cuisine over the last 10 years. Despite this, very little research work has been undertaken which analyses the changes that these procedures can make to the product. In this paper, the effect of the use of continuous vacuum cooking, the sous-vide method and the atmospheric pressure cooking treatment
on textural changes in the potato (cv. Monalisa) were studied. To do this, potato cylinders were cooked using the previously mentioned procedures at temperatures of 60, 70, 80 and 90 �C for time periods which ranged between 5 and 60 min. The samples obtained were evaluated by texture profile analysis (TPA) and the microstructure by the Cryo-SEM. TPA parameters, such as hardness, chewiness, cohesiveness and adhesiveness values, were affected by temperature and treatment duration.
Confocal laser scanning microscopy (CLSM) was used in fluorescence mode for oil and cell wall detection, and in reflective mode to observe the surface morphology of potato chips. Oil distribution in chips fried at 170°C in oil mixed with the thermoresistant probe Nile Red was studied as the crust developed during frying. Oil was trapped only in intercellular spaces for short frying times while at longer times it was strongly linked to the developed crust microstructure (not only in intercellular spaces but also over some cells) and not easily extractable by hexane washing. Chips infiltrated with a solution of the dye Congo Red (CR) before frying revealed drastic changes in cell walls but no signs of rupture during frying at the magnification used in this research (20X). Topographical data acquired by CLSM in reflective mode confirmed that several cells are broken during the cutting operation. Image representation of the reconstructed surface of a fried chip (170°C, 3 min) allowed observe oil location in potato surface after frying.
The production of healthier fried foods requires the adaptation of industrial processes. In this context, air frying is an alternative to deep oil frying to obtain French fries with lower fat content. Kinetic analysis of compositional changes and main fluxes involved in air frying were carried out, and the results were compared to those obtained for deep oil frying. The influence of the type of sample (unpretreated, frozen, or blanched potatoes) was also analyzed. The results showed that oil uptake is much lower in air frying although a much longer processing time is required. Also, water loss and thus the loss of volume were much higher in air frying compared to the conventional process.
Several studies have highlighted the importance of the cooling period in oil absorption in deep-fat fried products. Specifically, it has been established that the largest proportion of oil which ends up into the food, is sucked into the porous crust region after the fried product is removed from the oil bath, stressing the importance of this time interval. The main objective of this paper was to develop a predictive mechanistic model that can be used to understand the principles behind post-frying cooling oil absorption kinetics, which can also help identifying the key parameters that affect the final oil intake by the fried product. The model was developed for two different geometries, an infinite slab and an infinite cylinder, and was divided into two main sub-models, one describing the immersion frying period itself and the other describing the post-frying cooling period. The immersion frying period was described by a transient moving-front model that considered the movement of the crust/core interface, whereas post-frying cooling oil absorption was considered to be a pressure driven flow mediated by capillary forces. A key element in the model was the hypothesis that oil suction would only begin once a positive pressure driving force had developed. The mechanistic model was based on measurable physical and thermal properties, and process parameters with no need of empirical data fitting, and can be used to study oil absorption in any deep-fat fried product that satisfies the assumptions made.
Potatoes are the fourth most important vegetable crop in the world, and in 2003, it was a 2.7 billion dollar business in the US alone. Nearly one-third of the potato production is processed into par-fried frozen potatoes and fried chips (snacks). Frying imparts desirable taste and textural properties to these products, the latter described usually by the sensorial term crispness. Frying is reviewed as a structuring process, and methodologies to determine texture in fried potato products are discussed. It is demonstrated that the histological and microstructural heterogeneity of potato tubers have hampered clear interpretation of experimental data and a rigorous modeling of frying. Moisture uptake during post-frying is critical in the loss of crispness (limpness) of fries and in softening of potato chips. Methods to evaluate these changes and alternatives to prolong the shelf life are discussed.
The objective of this work was to investigate the effect of processing frying conditions, simulating possible home and catering practices, in order to optimize the process to obtain a good final product limiting the acrylamide (AA) formation. Experiments were performed using commercially frozen pre-fried potato strips, a fixed initial frying temperature of 180°C, two different fryers for domestic (A) and catering (B) use, and two potato-to-oil ratios (1/4 and 1/8w/v). Several batches were fried at different fixed times, and for each batch the temperature of oil and stick surface were acquired by thermocouples. Analysis of AA and other quality characteristics (water and oil content, color, texture) of French fries were carried out. In all adopted frying conditions the increase of oil and potato surface temperature was faster in fryer A than in fryer B due to its peculiar manufacturing characteristics and employment mode. As a consequence, higher AA levels and a more cooked product were obtained using fryer A. With the immersion of a lower potato quantity (1/8w/v), higher oil temperatures and AA levels and a more cooked product were obtained in shorter time in both fryers. Considering quality parameter results, the best quality characteristics were obtained in potatoes from fryer B between 10 and 13min of frying with a product-to-oil ratio of 1/4 (around 250±20μgkg−1 of AA), and after about 7min of processing with a product-to-oil ratio of 1/8 (around 260±50μgkg−1 of AA).
In this study, the influence of oil temperature, water migration and surface temperature of potato dough ball on convective heat transfer coefficient was investigated. The convective heat transfer coefficient during deep-fat frying was determined at temperatures 160, 170, 180 and 190 °C. The dough ball of wheat flour with different amounts of whole potato flour having a radius of 2.5 cm was used as a sample. Heat transfer coefficient was the highest at the beginning of deep-fat frying process (197.25±1.39 to 774.88±3.90 W/m2K), and the lowest in the case of setting up a uniform period of water migration from sample, which corresponded to surface temperatures slightly higher than 100 °C (94.22±0.33 to 194.84±0.91 W/m2K). Addition of whole potato flour in dough considerably decreased heat transfer coefficient regardless of the frying oil temperature. Higher oil temperature for deep-fat frying increased values of heat transfer coefficient for the same composition of spherical shape dough.
Vacuum frying was tested as an alternative technique to develop low oil content potato chips. The effect of oil temperature (118, 132, 144 °C) and vacuum pressure (16.661, 9.888, and 3.115 kPa) on the drying rate and oil absorption of potato chips and on the product quality attributes such as shrinkage, color, and texture was investigated. Furthermore, the characteristics of the vacuum-fried potato chips (3.115 kPa and 144 °C) were compared to potato chips fried under atmospheric conditions (165 °C).During vacuum frying, oil temperature and vacuum pressure had a significant effect on the drying rate and oil absorption rate of potato chips. Potato chips fried at lower vacuum pressure and higher temperature had less volume shrinkage. Color was not significantly affected by the oil temperature and vacuum pressure. Hardness values increasedwith increasing oil temperature and decreasing vacuum levels.Potato chips fried under vacuum (3.115 kPa and 144 °C) had more volume shrinkage, were slightly softer, and lighter in color than the potato chips fried under atmospheric conditions (165 °C). It was concluded that vacuum frying is a process that could be a feasible alternative to produce potato chips with lower oil content and desirable color and texture.
A relationship between moisture loss and oil adsorption with frying time during deep fat frying of french fries has been developed. A first order kinetic equation was used, in which the rate constant is a function of the main process variables (oil temperature, sample thickness and oil type). This model was applied to a wide range of experimental data and its parameters were estimated using non-linear regression analysis. The results showed that oil temperature and thickness of potato strips have a significant effect on oil uptake and moisture loss of french fries, while the use of hydrogenated oil in the frying medium does not affect mass transfer phenomena.
Vacuum frying is an alternative method to produce high quality vegetable or fruit chips. The effect of frying temperature and vacuum degree on moisture content, oil content, color, and texture of fried carrot chips were investigated. During the early stage of vacuum frying, the rate of moisture removal and oil absorption increased with increasing frying oil temperature and degree of vacuum. Statistical analysis of the color data showed that there were no significant differences P > 0.05) in lightness (L), redness (a), and yellowness (b) of carrot chips as a function of vacuum degree and temperature. The breaking force of carrot chips decreased with increasing frying temperature and vacuum degree. The statistical analysis also showed that there were no significant differences P
Reduced pressure frying is an alternative to conventional frying that enables products to be obtained at lower processing temperatures with lower fat content. The oil uptake in frying mainly occurs during the subsequent cooling stage. With vacuum frying, this stage necessarily includes a period of vacuum break when the system recovers the initial pressure. The different conditions under which this pressurisation occurs can influence the final oil content of the product. To study this effect, potatoes of the “Monalisa” variety, with different geometries, were fried at 140°C and moderate vacuum (24.9kPa). Various combinations of draining times (30, 60, and 90s) and vacuum break velocity, VBV (0.75, 2.21, 4.43 and 12.43kPas−1), were tested for this stage, and the final oil content of the product determined by comparison with the dry weight. The results showed that both parameters have a significant influence (α
RESUMEN: los almidones retrogradados tienen buenas propiedades de compactación para ser utilizados en la elaboración de tabletas por compresión directa, debido a sus características granulares, a la presencia de amilosa insoluble y la alta capacidad de hinchamiento de la amilopectina. En este trabajo se estudiaron las propiedades de compactación del almidón de chayote retrogradado, en comparación con las del almidón de papa retrogradado y del producto comercial Starch 1500. Los resulta- dos mostraron que el almidón de chayote tiene mejores propiedades, ya que da lugar a tabletas más duras, más resistentes al estearato de magnesio y con mayor capacidad de dilución que el producto comercial. Cuando el porcentaje de gelatinización del almidón es alto, se modifican los perfiles de liberación de las tabletas, lo que resulta interesante para su aplicación en la elaboración de formas de liberación controlada. ABSTRACT: the retrograded starches have good compaction properties that make they useful for direct compaction tableting. It was owing to the special particle characteristics, the presence of insoluble amylose and the high swelling amylopectine capacity. In this study it was analyzed the compaction properties of retrograded chayote starch compared with retrograded potato starch and the commercial Starch 1500. The results showed that chayote starch has better properties because gave hardest tablets, more resistant to magnesium stearate and with better dilution potential than potato starch and the commercial one. When the starch has a high pregelatinization level, it modified the drug liberation profiles of tablets, so they look useful for controlled release pharmaceutical forms.
the retrograded starches have good compaction properties that make they useful for direct compaction tableting. It was owing to the special particle characteristics, the presence of insoluble amylose and the high swelling amylopectine capacity. In this study it was analyzed the compaction properties of retrograded chayote starch compared with retrograded potato starch and the commercial Starch 1500. The results showed that chayote starch has better properties because gave hardest tablets, more resistant to magnesium stearate and with better dilution potential than potato starch and the commercial one. When the starch has a high pregelatinization level, it modified the drug liberation profiles of tablets, so they look useful for controlled release pharmaceutical forms.
Thermal properties of tofu were determined in the temperature range of 5-80°C (10-105°C for specific heat) and the moisture content range of 0.3-0.7 (wb). Thermal conductivity (k: 0.24-0.43W m-1K-1) and thermal diffusivity (α: 7.6 × 10-8 - 1.15 × 10-7m2s-1) were measured simultaneously using dual probe method, and specific heat (CP: 2.52-3.69 kJ kg-1 K-1) with modulated differential scanning calorimetry. Good agreement was observed between perpendicular model and the thermal conductivity data, but not with parallel model. Simple empirical models were also developed as a function of the moisture content and temperature of the tofu.
Background and aimsThe consumption of fried foods is believed to be linked with obesity and higher weight gain, however, the evidence from long-term randomized trials or prospective epidemiological studies is scarce. Therefore, the aim of our study was to prospectively evaluate the association between the consumption of fried foods and weight change and the incidence of overweight/obesity in a Mediterranean cohort.Methods and resultsProspective cohort study of 9850 men and women with a mean age of 38.1 years (SD 11.4) were followed-up for a median of 6.1 years to assess average yearly change in body weight, and incidence of overweight/obesity. The consumption of fried foods was associated with higher weight gain, but the differences were of small magnitude and statistically non-significant. The incidence of overweight/obesity during follow-up was also assessed in the subset of 6821 participants with initial body mass index <25 kg/m2 (initially free of overweight/obesity), after adjusting for potential confounders, the odds ratio for developing overweight/obesity among participants who consumed fried foods >4 times/week was 1.37 (95% confidence interval: 1.08 to 1.73) in comparison with those who consumed fried foods <2 times/week (p for trend = 0.02).Conclusion
In this Mediterranean prospective cohort, a more frequent consumption of fried foods at baseline was associated with a higher risk of subsequently developing overweight/obesity during follow-up.
Color, as a quality attribute of cooked and fried potatoes, is affected by the extent and nature of heat during thermal processing. Improvement of color parameters has been made possible by the increase in knowledge of kinetics of color change. Analysis of kinetic data allows processors to minimize undesirable changes and optimize color retention. the objective of this study was to evaluate kinetics of color change during cooking and frying of potatoes. Potatoes were cut into cylinders (diameter × height: 20 mm × 20 mm for cooking and 10 mm × 20 mm for frying) and cooked in a temperature controlled water bath at 80–100C or fried in a commercial fryer at 160–190C for selected times. Color changes associated with cooked and fried potatoes were evaluated using a tristiumulus colorimeter in the L, a, b mode. For cooked potatoes, L and b values decreased while ΔE and a values increased with time at each cooking temperature. For fried potatoes, L value decreased while a, b and ΔE values increased as frying time increased. A modified first order model was used to characterize color change kinetics of both cooked and fried potatoes based on changes occurring between the initial and a maximum or minimum value. Temperature sensitivity of rate constants was adequately described by the Arrhenius and z-value models.
Deep-fat frying is a rapid and low cost process widely used to prepare tasty food. During this cooking process, oil is used both as the heating medium and as an ingredient producing calorific products. Nutrition has become a major health issue, especially in developed countries where increasing obesity is a problem, particularly among children. Many food research projects involving snack food industries therefore attempt to understand oil uptake during the frying process in order to control and reduce the fat content of fried products without deteriorating their desirable organoleptic characteristics. The main objectives of this paper are to review the literature on the frying process and more precisely the mechanisms and parameters involved in the oil uptake phenomenon. Both products and processes will be considered and their influence via experimental results will be discussed.
The gelatinization process of waxy corn starch under different pressures up to 10.0 MPa was investigated using a high pressure DSC. Compressed air and carbon dioxide were used as pressure resources. Effect of pressure and annealing under pressure on gelatinization of waxy corn starch was systematically studied, in particular on the gelatinization temperature and enthalpy. The results show that the peak temperature of gelatinization was increased slightly initially then remained stable with increasing pressure. The gelatinization enthalpy was decreased under pressure processing. Annealing the starch under pressure condition, just below its gelatinization temperature, increased gelatinization temperature but kept gelatinized enthalpy constant. Morphologies of starch granules treated under pressure were studied using an optical microscope and SEM. There is no discernable difference of starch granules treated with and without pressure, which indicates the pressures are not high enough to destroy crystalline structure. The intensity of the pressure acts as a key factor to influence the gelatinization of starch rather than the nature of the gas. Effect of pressure on the multi-endotherm detected by DSC for starch with intermediate water is used to study the mechanisms. The effect of pressure can be explained by the enhancement of water diffusion in the amorphous range.
The aim of this work was to identify the transitions in the complex DSC profiles of potato starch at a low water content. Preparative DSC involves the thermal processing of samples in stainless steel DSC pans in a way that allows their subsequent structural characterization. The low temperature (LT), dual melting (M1–M2), and high temperature (HT) endotherms observed in DSC profiles of potato starch with 16% water were assigned to enthalpy relaxation, melting with preservation of granular identity, and transition of the melted granules into a molecular melt, respectively. Granular melting was accompanied by a strong reduction of swelling capacity. Significant molecular degradation was observed after the HT transition. There is evidence that HT does not represent a true thermodynamic transition, but is due to a volume change in the sample. In contrast to potato starch, maize starch with 16% water gave inhomogeneous samples after processing, presumably because of its low packing density.
The purpose of the study was to determine some changes in the structure of potato tissue and the contents of non-starch polysaccharides and lignin in potatoes at particular stages of French fries production. The samples for laboratory studies were taken from potato tubers, strips and French fries collected from six locations of the technological line. Immediately after the samples were collected from the processing line, the texture of potatoes was determined using an Instron 5544. Structural changes in the tissue were determined using a Leo-435VP scanning electron microscope. Dry matter and non-starch polysaccharide contents were determined in the samples of processed potatoes. It was found that the texture of potato was changing during the technological process due to water losses and damages of potato tissue and consequent changes in non-starch polysaccharides and lignin. The greatest changes in potato tissue resulted from thermal processes: blanching, pre-drying and frying. Increases of non-starch polysaccharide and lignin contents were observed during these processes, owing to water losses in potato strips. The ultimate texture of French fries was developed during frying, by penetration of fat primarily into the external layer of strips.
The paper describes the effect of different factors influencing the concentration of acrylamide in deep-fat fried potato products. In French fries the amount of acrylamide increased with the temperature as well as the frying time, especially at temperatures higher than 175 °C. The increase of acrylamide with the time followed a linear function, whereas a non-linear relationship was given with the temperature of frying. As a result, a reduction of the processing temperature led to lower concentrations of acrylamide in the product.
Both, oil type and silicon oil as antifoaming agents had no significant influence upon the acrylamide concentration in the food.
The variety of potatoes had a strong effect on the acrylamide concentration in potato crisps and French fries. The investigation showed a significant correlation (r = 0.73) between the concentration of acrylamide and reducing sugars in raw potatoes, and no significant correlation with the asparagine concentration. The storage temperature of the raw material had an effect on the acrylamide concentration in the product. Lowering of the storage temperature from 8 to 4 °C resulted in an increase of the concentration of reducing sugars in the raw material, which led to a higher potential of acrylamide formation in the products.
The experiments showed that the acrylamide concentration of French fries depended on the surface-to-volume ratio (SVR).
The effect of frying time on quality and acrylamide (AA) content of French fried potatoes, obtained simulating home-cooking
practices, was studied in order to investigate the optimal conditions to minimize the amount of produced toxicant together
with the maintenance of good culinary quality. French fries were obtained from fresh potatoes using a domestic fryer with
static basket; a 4:1 oil:product ratio and a fixed initial oil temperature of 180°C were used. Several batches were fried
at different times (3, 4, 5, 6, 7, 8, 9min). During frying tests the oil, the sticks surface and core temperatures were measured
by thermocouples. Analysis of water removal, oil uptake, colour, texture and AA content were carried out on fried final products.
AA content increased exponentially increasing the frying time. In our working conditions after around 4min of frying, when
the temperature of potato surface and the oil bath reached, respectively, 120 and 140°C, the increase of time became a key
factor in terms of the quantity of AA and its formation rate. On the basis of colour, oil content and AA level the best culinary
product was obtained after 5min of frying.
Vacuum frying is an alternative way to improve the quality of the fried food and could reduce the final oil uptake in the
product. The product is heated at low pressure thus decreasing the boiling points of the frying oil and the water in the product.
Moreover, the absence of air during vacuum frying may inhibit lipid oxidation and enzymatic browning, and therefore, the color
and nutrients of samples can be largely preserved. Many food research projects involving snack food industries therefore attempt
to understand oil uptake during the vacuum-frying process in order to control and reduce the fat content of fried products
without deteriorating their desirable organoleptic characteristics. This article is an update of the state-of-the-art in vacuum-frying
technology, showing the effect of pretreatments and frying conditions on quality characteristics of the products. Facts pertaining
to equipment and operation conditions are included. On the other hand, mathematical models to describe oil uptake and water
loss are also mentioned. The effect of this treatment on color, texture, and nutritional value of the final products is also
discussed.
KeywordsVacuum frying–Oil uptake–Process parameters–Water loss–Pretreatment
Colour is an important quality attribute in the food and bioprocess industries, and it influences consumer’s choice and preferences. Food colour is governed by the chemical, biochemical, microbial and physical changes which occur during growth, maturation, postharvest handling and processing. Colour measurement of food products has been used as an indirect measure of other quality attributes such as flavour and contents of pigments because it is simpler, faster and correlates well with other physicochemical properties. This review discusses the techniques and procedures for the measurement and analysis of colour in food and other biomaterial materials. It focuses on the instrumental (objective) and visual (subjective) measurements for quantifying colour attributes and highlights the range of primary and derived objective colour indices used to characterise the maturity and quality of a wide range of food products and beverages. Different approaches applied to model food colour are described, including reaction mechanisms, response surface methodology and others based on probabilistic and non-isothermal kinetics. Colour is one of the most widely measured product quality attributes in postharvest handling and in the food processing research and industry. Apart from differences in instrumentation, colour measurements are often reported based on different colour indices even for the same product, making it difficult to compare results in the literature. There is a need for standardisation to improve the traceability and transferability of measurements. The correlation between colour and other sensory quality attributes is well established, but future prospects exist in the application of objective non-destructive colour measurement in predictive modelling of the nutritional quality of fresh and processed food products.
The aim of this study was to evaluate the suitability of a computerized image analysis technique (with a flatbed scanner for image acquisition) in order to measure the amount and distribution of the most important visual aspects of potato chips: colour components (L*, a* and b*) and brown and oily areas on the surface. The potato slices were fried at three temperatures (170, 180 and 190 °C) and times (2, 3 and 4 min). Pre-processing, segmentation and colour analysis were carried out by a software programmed in Matlab v6.5. Results showed a high linear relationship (R2 > 0.962) between image RGB values and those measured by conventional colorimeter. The applied image analysis technique was able to differentiate with high sensitivity among potato chip colours after the frying processes. On average the percentages of normal, brown and oily areas detected on the samples were 53.24, 24.04 and 22.96%, respectively. While data of brown area appearance were congruous with browning incidence bound to the entity of the frying process, discrepant results were obtained using the objective colour pattern for the evaluation of the extension of oily area in the surface of potato chips. Anyway, this technique presents a high potential to develop a computer vision on-line system for frying process optimization, as a function of the fat content of the final product.
The objective of this work was to study oil absorption and the kinetics of texture development of fried potato slices during frying. Prior to frying, potato slices were blanched in hot water at 85 °C for 3.5 min. Unblanched slices were used as the control. Control and blanched potato slices (Panda variety, diameter: 37 mm, width: 2.2 mm) were fried at 120, 150 and 180 °C until reaching moisture contents of ∼1.8% (total basis) and their texture and oil content were measured periodically. Oil uptake was higher in ∼15% for blanched samples than for control samples after 20 s of frying. Besides, the higher the frying temperature, the lower the oil absorption in control samples. Textural changes in fried potato slices were followed by the parameter maximum force (MF) extracted from the force vs. distance curves corresponding to different sampling times. Normalized maximum force (MF*) was used in modeling textural changes in the potato slices during frying in both the initial tissue softening process and the later crust development process. Higher temperatures accelerated these processes; however neither the temperature nor the pre-treatment had a significant effect (P > 0.05) over the final texture of the fried potato chips.
Mass transfer coefficient, hm during frying of sweetpotato was estimated by inverse simulation of the frying process using finite element method and experimental data on temperature and moisture content change in the product. Frying with three disc sample sizes (diameter of 2.5, 3.5 and 4.0 cm and all of 1 cm thickness) were simulated at oil temperatures of 150, 160, 170 and 180 °C for 5 min. The range of maximum hm reached was 4 × 10−6–7.2 × 10−6 m/s. Both h and hm during the process increased with increase in frying oil temperature but decreased with increase in sample size. No general correlation was established between h and hm due to its insignificancy. Furthermore, there was discrepancy between the periods during frying when the maximum h and hm appeared. However, a correlation was established between maximum h and maximum hm and also between maximum h and the corresponding hm at that time.
The objective of this work was to study the kinetics of browning during deep-fat frying of blanched and unblanched potato chips by using the dynamic method and to find a relationship between browning development and acrylamide formation. Prior to frying, potato slices were blanched in hot water at 85 °C for 3.5 min. Unblanched slices were used as the control. Control and blanched potato slices (Panda variety, diameter: 37 mm, width: 2.2 mm) were fried at 120, 150 and 180 °C until reaching moisture contents of ∼1.8% (total basis) and their acrylamide content and final color were measured. Color changes were recorded at different sampling times during frying at the three mentioned temperatures using the chromatic redness parameter a∗. Experimental data of surface temperature, moisture content and color change in potato chips during frying were fit to empirical relationships, with correlation coefficients greater than 90%. A first-order rate equation was used to model the kinetics of color change. In all cases, the Arrhenius activation energy decreases alongside with decreasing chip moisture content. Blanching reduced acrylamide formation in potato chips in ∼64% (average value) in comparison with control chips at the three oil temperatures tested. For the two pre-treatments studied, average acrylamide content increased ∼58 times as the frying temperature increased from 120 to 180 °C. There was a linear correlation between acrylamide content of potato chips and their color represented by the redness component a∗ in the range of the temperatures studied.
A method that mimics the frying operation was implemented to observe microstructural changes in potato cells and starch. Isolated cells were obtained by successive treatments of potato tissue with acid and alkali solutions. Potato cells were heated in oil at a rate of 40 °C/min or directly in hot oil (180 °C) using a hot stage attached to a light microscope and studied by video-microscopy. Starch granules in cells underwent rapid gelatinization, deformation and compaction into one mass that occupied the whole volume of the cell. After dehydration cells showed a distinctive outer zone and a homogeneous core. Cell walls showed no signs of disruption but at temperatures >100 °C a reduction in cell area occurred. Immersion of cells in hot oil resulted in rapid swelling of starch. Relative projected area increased by 12% after 45 s of heating. Wet isolated starch granules began to expand and gelatinize at 65 °C and became disrupted at 120 °C. No changes were observed in dry starch granules subjected to a similar treatment.
Vacuum deep-fat frying is a new technology that can be used to improve quality attributes of fried food because of the low temperatures employed and minimal exposure to oxygen. In this paper atmospheric and vacuum frying of apple slices were compared, in terms of oil uptake, moisture loss and color development. In addition, some apple slices were pre-dried (up to 64% w.b.) before vacuum frying to determine the overall effect. To carry out appropriate comparisons between both technologies equivalent thermal driving forces were used in both processes (ΔT = 40, 50, 60 °C), keeping a constant difference between the oil temperature and the boiling point of water at the working pressure. Vacuum frying was shown to be a promising technique that can be used to reduce oil content in fried apple slices while preserving the color of the product. Particularly, drying prior to vacuum frying was shown to give the best results. For instance, when using a driving force of ΔT = 60 °C, pre-dried vacuum fried slices absorbed less than 50% of the oil absorbed by atmospheric fried ones. Interestingly, a strong relationship between water loss and oil content was observed in both technologies, allowing the extension of observations that have been made for atmospheric frying.
The effect of duration of pre-drying on structural properties (apparent density, true density, specific volume and internal porosity) and color parameters (lightness, a, b) of fried potatoes was also investigated. The results showed that pre-drying pre-treatment had a significant effect on oil uptake and moisture loss, as well as structural properties and color parameters of french fries. Air drying decreased the oil and moisture contents of french fries, while the porosity increased. A negative effect on color development with drying time was also observed. A relationship between frying kinetics and drying time before frying of french fries has been developed.
Quality changes in chicken nuggets fried in different mixtures of hydrogenated and non-hydrogenated canola oils were studied. Colour, texture, oil and moisture contents of the chicken nugget samples fried at 190 °C for 30, 60, 90, 120, 180, 240 and 300 s were investigated. The proportions of hydrogenated to non-hydrogenated frying oils used in the study were 0%, 20%, 40%, 60%, 80% and 100%.Results indicate that increase in frying time resulted in decreased product lightness (L*) whereas redness (a*) and yellowness (b*) increased. The maximum load to puncture increased with increasing frying time. In addition, oil content increased slowly with frying time, and moisture content decreased as expected. Both frying times and oil types have significant effects on the quality parameters investigated. First-order kinetic equation was used to describe colour changes as well as oil and moisture contents of the samples. Oil and moisture contents had negative correlation relationship. With increasing degree of oil hydrogenation, the surface colour of the fried chicken nuggets samples were lighter, texture increased, oil and moisture contents decreased.
This paper investigates the effect of frying time and temperature on acrylamide formation in the surface and core regions of French fries. Surface and core temperatures of the potato strip were monitored during frying at 150, 170 and 190 °C. The core temperature did not exceed 103–104 °C within 9 min of frying regardless of the frying temperature, whereas the temperatures attained in the surface were much higher. The results showed that there was a large difference between the acrylamide concentrations of the surface and the core regions. Acrylamide content of the surface was found to be 72, 2747 and 6476 ng/g after frying for 9 min at 150, 170 and 190 °C, respectively. The core was free of acrylamide after frying for 9 min at 150 and 170 °C, while only 376 ng/g of acrylamide was formed at 190 °C. Although the surface temperature did not exceed 120 °C during 9 min of frying at 150 °C, formation of acrylamide at this temperature suggests that the temperature need not be higher than 120 °C for acrylamide to form.
Over the past 5 years growing demands for reducing fat content of fried foods have greatly stimulated the amount of research spent on the issue of fat uptake during deep-fat frying. The results of these efforts are summarized in this review. Most of the increased understanding of the mechanism of fat uptake has been brought about by improved imaging techniques. It turns out that fat uptake is basically determined by two mechanisms: the condensation effect and the capillary effect. Major reductions claimed in literature and patents are found for coating and batter formulations using various types of biopolymers.
Sweet potato, green beans, Tommy Atkins mango, and blue potato were fried in a vacuum frying process at a temperature of 120–130 ± 1°C. Before frying, green beans and mango slices were soaked in a 50% maltodextrine 0.15% citric acid solution. The products were also fried in a traditional (atmospheric pressure) fryer at 160–165 ± 1°C for 4 min. A 30-member consumer panel rated the sensory quality of both types of fried snacks using a 1–9 hedonic scale. Compared with traditional frying, oil content of vacuum-fried sweet-potato chips and green beans was 24% and 16% lower, respectively. Blue potato and mango chips had 6% and 5% more oil, respectively, than the traditional-fried samples. Anthocyanin (mg/100 g d.b.) of vacuum-fried blue potato chips was 60% higher. Final total carotenoids (mg/g d.b.) were higher by 18% for green beans, 19% for mango chips, and by 51% for sweet-potato chips. Sensory panelists overwhelmingly preferred (p < 0.05) the vacuum-fried products for color, texture, taste, and overall quality. Most of the products retained or accentuated their original colors when fried under vacuum. The traditional-fried products showed excessive darkening and scorching. These results support the applicability of vacuum frying technology to provide high-quality fruit and vegetable snacks.
Unlabelled:
Consumers look for products that contribute to their wellness and health, however, even health-conscious consumers are not willing to sacrifice organoleptic properties, and intense full-flavor snacks remain an important trend. The objective of this study was to examine most important quality parameters of vacuum (1.92 inHg) and atmospheric-fried carrot, potato, and apple slices to determine specific advantages of vacuum technology. Slices were fried using equivalent thermal driving forces, maintaining a constant difference between oil temperature and the boiling point of water at the working pressure (ΔT = 60 and 80 °C). This resulted in frying temperatures of 160 and 180 °C, and 98 and 118 °C, for atmospheric and vacuum frying, respectively. Vacuum-fried carrot and potato chips absorbed about 50% less oil than atmospheric-fried chips, whereas vacuum-fried apple chips reduced oil absorption by 25%. Total carotenoids and ascorbic acid (AA) were greatly preserved during vacuum frying. Carrot chips vacuum fried at 98 °C retained about 90% of total carotenoids, whereas potato and apple slices vacuum fried at 98 °C, preserved around 95% of their initial AA content. Interestingly, results showed that the antioxidant capacity of chips may be related to both the presence of natural antioxidants and brown pigments developed at elevated temperatures.
Practical application:
A way to reduce detrimental effects of deep-fat frying is through operating-pressure reduction, the essence behind vacuum deep-fat frying. In this way, it is possible to remove product moisture at a low temperature in a low-oxygen environment. The objective of this research was to study the effect of oil temperature reduction when vacuum frying traditional (potatoes) and nontraditional products (carrots and apples) on most important quality attributes (vitamins, color, and oil uptake). Results are promising and show that vacuum frying can be an alternative to produce nutritious and novel snacks with desired quality attributes, since vitamins and color were greatly preserved and oil absorption could be substantially reduced.
Four protocols involving the application of low pressures, either toward the end of frying or after frying, were investigated with the aim of lowering the oil content of potato chips. Protocol 1 involving frying at atmospheric pressure followed by a 3 min draining time constituted the control. Protocol 2 involved lowering of pressure to 13.33 kPa, 40 s before the end of frying, followed by draining for 3 min at the same pressure. Protocol 3 was the same as protocol 2, except that the pressure was lowered 3 s before the end of frying. Protocol 4 involved lowering the pressure to 13.33 kPa after the product was lifted from the oil and holding it at this value over the draining time of 3 min. Protocol 4 gave a product having the lowest oil content (37.12 g oil/100 g defatted dry matter), while protocol 2 gave the product with highest oil content (71.10 g oil/100 g defatted dry matter), followed by those obtained using protocols 1 and 3 (68.48 g oil/100 g defatted dry matter and 52.50 g oil/100 g defatted dry matter, respectively). Protocol 4 was further evaluated to study the effects of draining times and vacuum applied, and compared with the control. It was noted that over the modest range of pressures investigated, there was no significant effect of the vacuum applied on the oil content of the product. This study demonstrates that the oil content of potato chips can be lowered significantly by combining atmospheric frying with draining under vacuum.
Practical Application: Application of vacuum toward the end of the frying process is aimed at hindering the surface oil from entering into the food structure, and result in a product with lower oil content. Since frying is undertaken, more or less, under conventional conditions, the product quality is essentially the same in all other respects.
Consumption of hot chips is a convenience food in most countries. Unfortunately, these are high in fat and contribute to fat-related diseases in societies with a high fat consumption. There is substantial scope through best-practice deep-frying techniques for producing lower fat, high-quality chips. From a review of the literature, the main factors associated with a lower-fat content of chips are thick (>12 mm), straight cut chips; cryogenic freezing methods; low moisture content of potatoes (specific gravity >1.1); frying fat: chip volume ratio of 6:1; frying at optimal temperature (180 to 185 degrees C) during cooking and turning the temperature down (approximately 140 degrees C) and covering the vats during slack periods; vigorously shaking the basket and hanging it over the deep fryer to drain after frying; maintaining the quality of the frying fat by regularly skimming the cracklings, filtering the fat, and topping up the fryer with fresh fat; keeping the fat turnover <5 days; regular cleaning of frying equipment. It is important that all deep frying operators are adequately trained in these techniques. It is also important that the frying medium is low in saturated and trans fatty acids (<20%) because of their effects on blood lipids and low in linolenic acid (<3%) because it is readily degraded. The widespread implementation of best-practice deep-frying would reduce fat content of hot chips and thus lower overall fat consumption.
Three mechanisms have been previously proposed to explain the complex process of oil uptake during deep-fat frying. The mechanisms reviewed are water replacement, cooling-phase effect and surface-active agents. The former mechanism describes mainly oil uptake of relatively large voids in the fried food created due to water evaporation. The second mechanism furnishes an explanation for the significant amount of oil absorbed when the food is removed from the fryer. At this point, product surface characteristics and oil viscosity play paramount roles. Surface-active agents' formation provides only a limited explanation for the increased oil uptake during prolonged frying. Reviewed literature, theory and new data show contradicting values and do not support the myth that during extended frying time the surfactants generated reduce the contact angle and/or the interfacial tension, and consequently, influence oil uptake significantly. Higher oil uptake after extended frying time is probably related to higher oil viscosity caused by polymerization reactions and oil adherence to the product surface. Further research is needed for establishing the interrelationships between surface-active agents' formation and their effect on fried product oil uptake and quality to resolve this myth.
A kinetic model based on 2 irreversible serial chemical reactions has been proposed to fit experimental data of texture changes during thermal processing of potato products. The model links dimensionless maximum force F*(MAX) with processing time. Experimental texture changes were obtained during frying of French fries and potato chips at different temperatures, while literature data for blanching/cooking of potato cubes have been considered. A satisfactory agreement between experimental and predicted values was observed, with root mean square values (RMSs) in the range of 4.7% to 16.4% for French fries and 16.7% to 29.3% for potato chips. In the case of blanching/cooking, the proposed model gave RMSs in the range of 1.2% to 17.6%, much better than the 6.2% to 44.0% obtained with the traditional 1st-order kinetics. The model is able to predict likewise the transition from softening to hardening of the tissue during frying.
Procesamiento hidroté de arroz cá: Efecto de las condiciones de hidratació y cocció en el remdimiento, textura y propiedades té del grano elaborado [Doctoral thesis Comparison of water and infrared blanching methods for processing performance and final product quality of French fries
- Bello
- Mo
Bello MO. 2009. Procesamiento hidroté de arroz cá: Efecto de las condiciones de hidratació y cocció en el remdimiento, textura y propiedades té del grano elaborado [Doctoral thesis]. Universidad de Buenos Aires, Aregentina. Bingol G, Wang B, Zhang A, Pan Z, McHugh TH. 2014. Comparison of water and infrared blanching methods for processing performance and final product quality of French fries. J Food Engr 121:135–42.
Procesamiento hidrotérmico de arroz cáscara: Efecto de las condiciones de hidratación y cocción en el remdimiento textura y propiedades térmicas del grano elaborado
- Bellomo
Bello MO. 2009. Procesamiento hidrotérmico de arroz cáscara: Efecto de las condiciones de
hidratación y cocción en el remdimiento, textura y propiedades térmicas del grano elaborado
[Doctoral thesis].