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The effects of cutting and drying medium on the vitamin C content of rosehip during drying
Abstract
Kinetics of ascorbic acid degradation during air-drying of whole rosehip has been investigated. Changes of vitamin C content during drying have been affected by drying time, drying air temperature and as well as moisture content. Vitamin C degradation rates for whole fruits during drying have been satisfactorily described by first-order kinetics. Temperature dependency of the model has been described also by Arrhenius relationship. Activation energy and reaction rate constant have been determined as a function of moisture content and described as Ea = 38600 + 100M and k0 = exp(6.32 + 0.75M). In addition, rosehip has been pre-treated by cutting into pieces and drying experiments were conducted with air and with the atmospheres prepared with various ratios of air–CO2 mixtures. Cutting of the rosehips before drying accelerated the drying process and increased the retention of vitamin C. The loss of vitamin C was increased depending on the rate of the oxygen in the air–CO2 mixtures used as a drying medium.
... L'influence des paramètres du procédé, tels que le temps, la température, la nature et la concentration de la solution osmotique, l'humidité relative et la vitesse de l'air de séchage a été largement étudiée pour les procédés de déshydratation. Une augmentation de la température diminue de manière significative la teneur en acide ascorbique que ce soit lors de la DII (Heng et al., 1990 ;Vial et al., 1991 ;Jiokap-Nono et al., 2001a ;Jiokap-Nono et al., 2001b), lors du séchage convectif (Zanoni et al., 1999 ;da Silva et al., 2005 ;Erenturk et al., 2005 ;Goula et Adamopoulos, 2006 ;Mrkic et al., 2006 ;Marfil et al., 2008 ;Muratore et al., 2008 ;Azoubel et al., 2009 ;George et Cenkowski, 2009 ) ou lors du séchage infra-rouge (Timoumi et al., 2007). Par exemple, le Tableau I-4 montre que lors d'un séchage convectif de tomate à 40 °C, plus de 70% de l'acide ascorbique est retenu et seulement 26% à 80 °C, pour une même teneur en eau finale (Muratore et al., 2008). ...
... La même observation est réalisée lors du séchage du brocoli (Mrkic et al., 2006) : une augmentation de 50 à 75 °C est peu influente, mais elle devient déterminante de 75 à 100 °C . La dégradation de l'acide ascorbique lors d'un séchage convectif peut être généralement représentée par une cinétique d'ordre 1 et la relation entre la constante de vitesse et la température est décrite par la relation d'Arrhenius (Erenturk et al., 2005 ;Goula et Adamopoulos, 2006 ;Timoumi et al., 2007). ...
... L'épaisseur du produit affecte également la durée du séchage et détermine ainsi le contenu en acide ascorbique des produits séchés (Santos et Silva, 2008). Au-delà d'un simple effet sur la vitesse de séchage, la découpe détruit la compartimentation cellulaire et met en contact la PPO et les composés phénoliques (Erenturk et al., 2005). L'acide ascorbique étant impliqué dans la régénération des polyphénols oxydés, sa consommation sera donc augmentée (Rouet-Mayer et al., 1993 ;Robards et al., 1999 ;Erenturk et al., 2005 ;Marquès et al., 2006). ...
La consommation régulière de fruits, sous forme fraîche ou transformée, est largement préconisée pour son effet bénéfique sur la santé. Les polyphénols contenus dans les fruits suscitent un intérêt croissant de la part des nutritionnistes, des industriels et des consommateurs, du fait de leurs propriétés antioxydantes et de leur rôle dans la prévention de certaines formes de cancers et des maladies cardiovasculaires. La pomme est naturellement riche en polyphénols et sa consommation courante la rend très intéressante en termes d'apports journaliers. Néanmoins, l’impact des procédés de transformation sur le devenir des composés antioxydants est peu étudié.Au cours de cette thèse, deux procédés, la déshydratation-imprégnation par immersion (DII) et le séchage convectif, ont été examinés séparément et combinés. Différentes variétés de pommes de table (Belchard®, Royal Gala et Reinette grise du Canada) et de pommes à cidre (Avrolles, Guillevic et Marie Ménard) ont été sélectionnées, sur trois années consécutives. Pour chacun des procédés, les cinétiques de déshydratation et de dégradation de l’acide ascorbique et des différentes classes de polyphénols ont été suivies, les concentrations en antioxydants étant mesurées par CLHP-UV-BD ; pour la DII, deux températures (45 et 60 °C) ont été étudiées. L’évolution des teneurs en sucres (fructose, glucose et saccharose) au cours de la DII a également été mesurée, par CLHP-IR.Après avoir mis au point les méthodes analytiques permettant de quantifier l’acide ascorbique et les composés phénoliques sur produits sucrés, ces composés ont été suivis en fonction du temps de procédé. En DII, un impact significatif de l’année de récolte a été observé sur les transferts, plus important que celui attribuable à la variété. Les transferts s’intensifient avec la température qui a aussi un impact négatif sur la rétention en antioxydants. Toutefois, les résultats font ressortir des différences de comportement significatives entre les polyphénols et l’acide ascorbique. La perte en acide ascorbique est très rapide, essentiellement due à l’oxydation et l’entraînement par l’eau. En ce qui concerne les polyphénols, leur rétention diffère selon leur structure chimique. Les procyanidines, composés polymérisés et capables de créer des interactions avec les composés des parois cellulaires, subissent très peu de pertes. Par contre, les acides hydroxycinnamiques, substrats préférentiels de la polyphénoloxydase et de faible masse moléculaire, enregistrent une perte plus importante. Par comparaison, le séchage convectif préserve mieux l’acide ascorbique et les composés phénoliques, sans différences marquées selon leur structure chimique. De plus, la variété semble avoir une faible incidence sur les transferts. Lors de l’enchaînement de DII / Séchage proposé, la DII, même si elle ne représente que 10% du temps de traitement, est responsable d'environ la moitié des pertes finales en polyphénols, avec des différences entre composés similaires à celle déjà décrites en DII et en séchage convectif. L’imprégnation en saccharose peut être néanmoins intéressante pour masquer l’astringence des procyanidines et améliorer les qualités gustatives des pommes séchées.
... Processing is an excellent possibility to extend the shelf life, but on the other hand, it is associated with significant losses of many pro-health ingredients, including vitamin C, which is the least stable of all vitamins and is easily destroyed during processing. Very often, processing involves the use of high temperatures, aeration, exposure to light and oxygen, and these are the main factors causing adverse changes in the composition of processed fruits and vegetables [13][14][15][16][17][18][19][20][21]. These factors promote the oxidation of L-ascorbic acid to unstable L-dehydroascorbic acid [22], which, as a result of hydrolysis and opening of the lactone ring, transforms into vitamin-inactive 2,3-diketogulonic acid [23]. ...
... Current convective drying is used on a large scale in the food drying industry due to economic reasons and a well-known and controlled process. The disadvantage of this method is that it may cause an adverse effect on fruit quality [17,25,[41][42][43][44][45]. Convective drying is usually a long-lasting process, and high temperature used can lead to a significant reduction of a dried product's nutritional and sensorial quality induced by chemical, physical and biological reactions [19,[46][47][48]. ...
... Thermal damage of a product during drying was directly proportional to the processing time: the longer the remaining time in the dryer, the longer exposure time for fruits with hot air was obtained, and consequently, the higher nutrient degradation occurred. These relationships are also confirmed by studies conducted on another plant material: tomatoes [16], wild rose [17], cranberries [41], strawberry [20], and sour cherries [49]. In a study carried out with strawberries, a particularly visible effect of drying time on the retention of vitamin C was noted at the highest tested temperature of 70 • C, where after 1 h of the process, the retention was about 90% and after 7 h of drying only 40% of ascorbic acid was left. ...
Nowadays, thermal treatments are used for extending the shelf-life of vegetable and fruit products by inactivating microorganisms and enzymes. On the other hand, heat treatments often induce undesirable changes in the quality of the final product, e.g., losses of nutrients, color alterations, changes in flavor, and smell. Therefore, the food industry is opening up to new technologies that are less aggressive than thermal treatment to avoid the negative effects of thermal pasteurization. Non-thermal processing technologies have been developed during the last decades as an alternative to thermal food preservation. Processing changes the structure of fruit and vegetables, and hence the bioavailability of the nutrients contained in them. In this review, special attention has been devoted to the effects of modern technologies of fruit and vegetable processing, such as minimal processing (MPFV), high-pressure processing (HPP), high-pressure homogenization (HPH), ultrasounds (US), pulsed electric fields (PEF), on the stability and bioavailability of vitamin C.
... The vitamin C can be easily degraded, depending on several variables such as pH, temperature, light, and presence of enzymes, oxygen, and metallic catalysers. Thus, numerous studies on food processes utilise vitamin C as a quality indicator (Lin et al. 1998;Ramesh et al. 1999;Erenturk et al. 2005;Santos and Silva 2008;Pei et al. 2014;Silva-Espinoza et al. 2020;Demarchi and Giner 2020). ...
... Researches carried out on convective hot air drying agree that the presence of oxygen and high temperatures considerably affect the loss of vitamin C and, even to a higher extent, for cut or grinded products as more surface area is exposed to the drying medium (Mohamed and Hussein 1994;Erenturk et al. 2005;Wojdylo et al. 2009). However, Rovedo and Viollaz (1998) and Kaya et al. (2010) have suggested that this deteriorative effect may be hindered with increasing relative humidity of the drying air. ...
In the past, research and development in food drying had focused on the processes as much as on the products. The technology was aimed to extend the food shelf-life without paying due attention to retaining quality attributes. However, recently, considerable efforts have been made to study and develop dehydrated products with higher nutritional quality. In this regard, the concept of functional food appeared to describe the potential of foods to improve human health by providing essential nutrients as carbohydrates, lipids, proteins, and other substances present in small amount as vitamins, minerals and bioactive compounds, with a large variety of health benefits. This chapter has the purpose of finding the impact of drying processes on bioactives in foods. After conducting an extensive literature review, a conclusion has been drawn on that the interaction of factors during drying, the bioactives extraction procedures and the nature of the food matrix finally determine retention. Beyond the nutritional topic, organoleptic and economic parameters must be considered in applied research for the selection of a drying method, adding complexity to the practice. By combining experiments and mathematical simulation that considers all coupled factors acting simultaneously, the science and technology of bioactives, and their retention will improve from the present state of affairs.KeywordsCarotenoidsPhenolic compoundsVitamin CVitamin E
... It is an essential step to obtain high-quality powders, with proper nutritional and physicochemical characteristics. Erenturk et al., 2005;Djantou et al., 2011;Bas-Bellver et al., 2020a Freezing Vegetable wastes stored in freezing conditions prior to processing Different impacts on water activity values, depending on the food matrix. Maintains nutritional and sensory quality of products. ...
... When producing powders, a final milling stage is needed to obtain the desired particle size; nevertheless, particle size is also determined by the grinding applied prior to drying since it conditions the response of the food matrix to the drying step and, therefore, the structure of the dried material, which determines the grinding results. Therefore, milling as a pretreatment is an essential step to obtain highquality powders, with proper nutritional and physicochemical characteristics (Erenturk et al., 2005;Djantou et al., 2011;Bas-Bellver et al., 2020b). As for freezing, Ando et al. (2016) investigated the impact of the freeze-thaw process on the drying rates of carrot roots, obtaining that the frozen-thawed samples damaged by ice crystals had the highest drying rate. ...
Food waste is a worldwide concern as it represents a constant threat to the environment and a serious operational problem for the food industry. The by-products of fruits and vegetables being a valuable source of bioactive compounds have the potential to be reused and reintroduced in the agri-food chain. This circular approach contributes to a sustainable production system. In this context, a collaborative project with the primary sector for the integral valorization of the waste generated in the fresh-processing vegetable lines of an agricultural cooperative is currently being developed, particularly focused on cabbage, carrot, celery, and leek. The objective of this project is to transform vegetable wastes into functional powdered ingredients and be able to use them in food formulations in order to improve the nutritional profile of foods, contributing to the development of sustainable healthy diets. Through an exhaustive bibliographic review, this research studies the influence of pretreatments, drying and in vitro digestion on the bioactive compounds of vegetable residues, with the aim of identifying the appropriate production parameters to achieve an adequate functional and physicochemical profile of the final powders.
... Vitamin C is somewhat easily degraded, and in nutrient stability studies in foods, it is assumed that if vitamin C is well retained, then other nutrients will be just as well retained if not better. The degradation of vitamin C depends on moisture-, oxygen, light, and metal ion catalysis as well as temperature and pH [5,64]. An analysis of the metadata of processing was performed in this present review (data not shown). ...
... Although no studies looked into the effect of cutting the seaweed biomass, a study on rose hips showed that cutting would lead to a decrease in vitamin C content, which might also be the case for seaweeds [64]. ...
Seaweeds are indiscriminately said to contain significant amounts of vitamin C, but seaweeds are a diverse group, which may limit the ability to generalize. Several studies have been performed on vitamin C in seaweed, and this review covers these findings, and concludes on how much vitamin C is found in seaweeds. A systematic review of vitamin C in 92 seaweed species was conducted followed by analyzing the 132 data entries. The average vitamin C content was 0.773 mg g−1 seaweed in dry weight with a 90th percentile of 2.06 mg g−1 dry weight. The vitamin C content was evaluated based on taxonomical categories of green, brown and red seaweeds (Chlorophyta (phylum), Phaeophyceae (class), and Rhodophyta (phylum)), and no significant differences were found between them. The vitamin C content was compared to other food sources, and this showed that seaweeds can contribute to the daily vitamin C intake, but are not a rich source. Moreover, seasonal variations, analytical methods, and processing impacts were also evaluated.
... where M is the moisture content on dry basis (g/g) and the P i 's are constants [9]. ...
... Food Eng Rev (2019) 11:[1][2][3][4][5][6][7][8][9][10][11][12][13] Content courtesy of Springer Nature, terms of use apply. Rights reserved. ...
The combined effect of temperature and moisture (or water activity) on the rate of nutrients loss and other deteriorative chemical reactions in foods has been primarily studied in relation to drying. In long foods storage, changes in their temperature and/or moisture content are much slower and never as dramatic, but their effect can be similar in kind. Reported degradation reactions in foods mostly followed first- or other fixed-order kinetics. Hence, their progress under dynamic conditions primarily depends on the varying rate constant. Perhaps the most economic way to describe the rate constant’s variations pattern and magnitude is a two-parameter temperature-dependence model whose two coefficients are moisture dependent, each described by another two-parameter model, which brings the total number of adjustable parameters to four. Such a flexible model is the two-parameter exponential temperature-dependence term, a simpler substitute to the Arrhenius equation, whose two parameters’ moisture dependencies are also described by two similar exponential terms. This model’s flexibility is demonstrated with computer simulations of chemical degradation under varying temperature and moisture conditions. Testing a large number of products stored for long times by the traditional methods to determine a reaction’s kinetic parameters and their temperature and moisture dependencies can create logistic problems. Theoretically, they can be avoided by estimating the kinetic parameters directly from several successive concentration determinations during a single dynamic storage experiment whereby the monitored temperature and moisture are allowed to vary arbitrarily. The principle is demonstrated with simulated data having no or very small errors. However, its practical implementation might not be effective if the experimental concentration measurements have a substantial scatter.
... Indeed, a variety of constituents have been reported for rosehip, such as vitamins, carotenoids, tocopherols, phenolic compounds, minerals, and essential oils [14,15]. Moreover, different kinds of food products could be produced using rosehip, including tea, infusion, juice, nectar, jam, marmalade, dried layers of fruit pulp, and vinegar [16,17]. ...
Due to a turn toward to functional foods with improved nutritional value, rosehip could be an appropriate candidate to create formulations using a milk matrix. In the present study, the influence of bovine or almond milk fortification on the bioaccessibility and intestinal absorption of rosehip infusion phenolics, mainly catechin, were investigated by a combined method of an in vitro gastrointestinal digestion/Caco-2 cell culture model. The results indicated that bovine (IB) or almond milk (IA) fortification enhanced the retention of total phenolics (TPC; increase of 8.1% and 20.3% for IB and IA, respectively), while there was a decline in the total flavonoids (TFC; decrease of 64% and 17% for IB and IA, respectively) and antioxidant capacity measured by CUPRAC assay (decrease of 15% and 4% for IB and IA, respectively) throughout the gastrointestinal tract in comparison with the control sample (IC). Then, based on the cytotoxicity (SRB) assay, 1/5 times diluted digests were subjected to transepithelial transportation of Caco-2 cells. According to the results, the bovine milk matrix positively affected the transportation of phenolics across the epithelial cell layer. It could be concluded that it is possible to produce functional infusion drinks with improved stability, bioaccessibility, and absorption efficiency of rosehip phenolics in the formulations containing milk matrix.
... This phenomenon could also be explained by the rapid inactivation of oxidative enzymes and the reduction in drying time as temperature increases. Also, a decrease in vitamin C content with increased drying temperature was reported in dried mango [72], rosehip, pears and apple slices [73][74][75]. On the contrarily, an increase in vitamin C content was reported in bitter melon with rising temperature [76]. ...
In this study, the effect of different infrared (IR) drying temperatures (60, 80, 100, and 120 °C) on drying kinetics and quality attributes of shea fruit peel and pulp was investigated.The results showed that drying time decreased with an increase in temperature, with shorter drying time required for the peel at the same temperature than the pulp. The Logarithmic and Page models were the best in describing the drying process of the shea fruit peel and pulp, respectively. Moisture diffusivity increased from 1.01 × 10−9 to 3.56 × 10−9 m2/s and 1.10 × 10−9 to 4.75 × 10−9 m2/s for the peel and pulp, respectively, as the drying temperature increased from 60 to 120 °C. The activation energy was 23.47 kJ/mol for the peel and 27.19 kJ/mol for the pulp. The rehydration ratio (RR) and CIE-L*a*b* color values were influenced (p < 0.05) by the drying temperature with lower total color change (∆E) values observed at 60 °C and 80 °C. However, an increase in IR drying temperature did not significantly (p > 0.05) influence the calcium and magnesium contents of the dried shea fruit components. Drying of the peel and pulp above 80 °C reduced ß-carotene content, total phenol content (TPC), and total antioxidant activity (TAA) while the highest potassium, vitamin C, and total flavonoid content (TFC) retention were observed at 120 °C. The study suggests IR drying of shea fruit peel and pulp at 60 to 80 °C for efficient drying and maintenance of color, ß-carotene content, TPC, TAA, and higher RR. Where, fast drying, vitamin C and TFC are of interest, drying of shea fruit components at 120 °C is recommended.
... (Fauzi & Sarmidi, 2010;Rojas & Gerschenson, 2001). Erenturk et al. (2005) showed that the air drying of ripe rose hips leads to decreasing AA content, where the loss of AA was more in whole than that of cut hips when drying was completed. The amount of AA in R. arvenis hypanthium ranged between 6.33 and 9.60 mg/100 g fw, which was lower than previously published results (0.13-0.42 mg/g dw) (Nađpal et al., 2016). ...
In this study, the chemical composition, antioxidant, and hypoglycemic activity of Rosa arvensis Huds. leaves and fruits collected from Zlatibor, Stara Planina, Stolovi mountains and Pešter plateau (Serbia) were analysed. Phenolic and vitamin profiles, as well as in vitro antioxidant potential and enzyme inhibitory activity on α-amylase and α-glucosidase, were studied. Phytochemical analysis showed higher phenolic content in leaf extracts than in those obtained from fruits. Gallic, chlorogenic and syringic acids were the most abundant phenolic acids, while catechin was the major flavonoid compound. Furthermore, the highest level of α-tocopherol (1.94 mg/100 g fw) in achenes and ascorbic acid (9.60 mg/100 g fw) in hypanthium were quantified in the fruits sampled on the Veliki Krš Mt. High antioxidant capacity was observed for the leaf extracts. It was highly correlated with their chemical composition and primarily referred to the catechin content (r > 0.95, p < 0.01), while the quinic acid had the opposite effect (r > −0.97, p < 0.01). Leaf extracts also showed good α-glucosidase and moderate α-amylase inhibitory potential in contrast to hypanthium and achenes extracts with lower antidiabetic activity. The high phenolic content and noted antioxidative potential were strongly correlated with the α-glucosidase inhibitory activity (r > 0.80, p < 0.01), while the α-amylase inhibition was only moderately correlated with those compounds (r > 0.49, p < 0.01). Among the tested R. arvensis samples, those from Zlatibor Mt. contained the highest amount of target compounds and expressed the highest biological activity. The obtained results suggest that R. arvensis extracts present a new source of bioactive compounds that could be implemented as novel food ingredients.
... Drying at a lower temperature that will retain some essential vitamin at larger percentage (close to that of the fresh sample) is preferable during drying, and this characteristic is thought to indicate a good quality of the dried product [5]. Series of works have been conducted on the effect of drying condition on the degradation kinetics of Ascorbic acid (AA) and beta-carotene (BC) [6,7,8,9,10] in some food materials, but there is lack of information on those okro with respect to slices. Thus, this study was aimed to determine the degradation kinetics of AA of okro slices and BB as affected by the drying methods. ...
... The fruit of rosehips (Rosa canina), having a reddish color, is mainly used in the dried form due to its limited period of availability, low stability during storage and the slightly sour taste of the fresh fruit [1]. Moreover, a variety of products including tea, juice, nectar, jam, marmalade, pestil [2] and vinegar [3], can be produced using rosehip. The great nutraceutical features being recognized in folk medicine arise from its high bioactive content, including vitamin C, carotenoids, tocopherols, phenolic acids, flavonoids, proanthocyanidins and tannins [4], as well as the abundance of minerals (calcium, phosphorus, potassium), pectin and essential oils [5]. ...
In this study, the in vitro bioavailability of rosehip infusion phenolics, mainly catechin, as a response to conventional and non-thermal treatments by combining gastrointestinal digestion and a Caco-2 cell culture model, was investigated. After application of thermal treatment (TT, 85 °C/10 min), high pressure (HPP, 600 MPa/5 min) or pulsed electric field (PEF, 15 kJ/kg) processing, all samples were subjected to simulated gastrointestinal digestion. Then, the amount of maximum non-toxic digest ratio was determined by the cytotoxicity sulforhodamine B (SRB) assay. Next, Caco-2 cells were exposed to 1:5 (v/v) times diluted digests in order to simulate the transepithelial transportation of catechin. Results showed that non-thermally processed samples (5.19 and 4.62% for HPP and PEF, respectively) exhibited greater transportation across the epithelial cell layer compared to than that of the TT-treated sample (3.42%). The present study highlighted that HPP and PEF, as non-thermal treatments at optimized conditions for infusions or beverages, can be utilized in order to enhance the nutritional quality of the final products.
... One of the factors which affect the degradation of ascorbic acid is oxidation. Many authors have studied the effect of oxygen on the degradation of ascorbic acid (Erenturk et al., 2005;Hawlader et al., 2006;Lavelli et al., 1999;Ramesh et al., 1999). Creating a low oxygen environment improves the rate of ascorbic acid retention (Lavelli et al., 1999;Ramesh et al., 1999). ...
In the present study, the vacuum drying of the Kadam fruit was performed, and the functional properties of the Kadam fruit powder were estimated. The drying conditions were optimized using the Response Surface Methodology for minimum color change and maximum vitamin C retention. The functional properties of the Kadam fruit powder dried at the optimized conditions (bed thickness 3.67 mm, drying temperature 65 °C, drying pressure 160 mm Hg, and blanching temperature 100 °C) were observed as; tapping density 4.23 ml/g, oil retention capacity 5.7 ml/g, water retention capacity 16 ml/g, water‐solubility 0.5%, emulsion activity 0.5%, and emulsion stability 0.85 %. The optimum dried fruit powder had vitamin C content (508 mg/100g), color change (6.32), and effective moisture diffusivity (2.16 x 10‐7 m2/min). This study showed that the vacuum drying of the Kadam pulp minimized the thermal degradation of the color and Vitamin C.
... The protein breakdown to amino acids during drying process is the main reason for forming this flavor. [65] Microwave vacuum drying (MVD) may be prevent the oxidation of mushroom chemical compounds, [66] and maintain the natural colors, [67] and nutritional compounds such as A, B 1 and C vitamins, [68] and providing an expanded porous cellular structure. [58] The impacts of MVD on quality characteristics of shiitake mushrooms compared with VD, MD, and HAD were investigated. ...
Shiitake mushroom (Lentinus edodes) is one of the most precious edible mushrooms. It has a variety of nutritional and bioactive compounds consumed as both food and medicine. Several preservation approaches were applied to avoid the short shelf-life of fresh shiitake mushroom. The present review aimed to comprehensively discuss the latest development in different preservation methods including drying, modified atmosphere packaging (MAP), coating, irradiation and fumigation techniques, and the effect on physicochemical and microbiological properties of shiitake mushroom during storage period. Various influences have been observed in physicochemical properties of shiitake mushroom such as sensory properties, weight loss, respiration rate, nutritional compounds (vitamins, sugars and proteins) and non-nutritional compounds (polysaccharides, phenols and volatile components). Additionally, the microbiological counts, the aerobic mezophilic bacterial count, yeasts and molds count, were reduced. Quality attributes were better maintained by synergistically treatment of two or more preservation approaches. The development of potentially novel preservation approaches should be considered in future trends.
... Recently, dried fruit products have been favoured for not only novelty of taste but also their convenience. However, the use of the conventional drying method was found to reduce the quality of the final product including texture, colour, taste, and nutritional values due to the high processed temperature and extended drying time (Erenturk et al., 2005). Hence, the alternative approach to minimize the nutritional loss of the dried products has been increasingly gained attention from researchers. ...
Mango (Mangifera india L.) is a common fruit that has been found in a wide range of applications. However, the diversification of mango products has been limited. In this study, the manufacture of dried mango was attempted to process by adopting the cold drying technique. The response surface methodology was used to evaluate the simultaneous effects of cold drying temperature - CT (℃), ultrasonic power - UP (W) and slice thickness-ST (cm) on total polyphenol (TP) and total ascorbic acid (TA) content by using Box Behnken experimental design. The established model was considered suitable to describe the experimental data. The optimized drying parameters were determined at the temperature of 45.02℃, ultrasonic power of 312.22 W, and slice thickness of 0.96 cm. These conditions effectively resulted in the highest retention of TP values of 338.994 mg GAE/100 g and TA of 36.783 mg AA/100 g.
... Adding of synthetic ascorbic acid increases vitamin C content, influences color, flavor and constancy of the fruit juices, food products and beverages [20]. Ascorbic acid is widely acknowledged as a chemical addition in living being diets due to its anti oxidative properties [21]. Therefore, the present study was conducted to determine the role of ascorbic acid in sustaining the post harvest quality of persimmon in storage in order to reduce post harvest losses of persimmon and to develop new and effective post harvest strategies for handling of perishable fruits. ...
Ascorbic acid is eco-friendly, widely used anti-oxidant and supplemented in manufactured foods to preserve the products for long time. Persimmon fruits were treated with different concentrations of ascorbic acid (0%, 1%, 2%, and 3%). After drying the treated fruits were stored at room temperature (18-24Cº and relative humidity 50-70%) for (0, 10, 20, 30 and 40 days) and their qualitative attributes were examined. Results revealed that ascorbic acid and storage duration alone and combined significantly affected the studied parameters. Data analysis showed that 2% ascorbic acid resulted in minimum weight loss (6.4%), maximum fruit firmness (1.9 kg cm-2), and minimum disease incidence (8.7%) in persimmon fruits. However, maximum percent juice content (44.6%), total soluble solids (16.3 oBrix) and fruit volume (104 cm-3) were found in control (0% ascorbic acid treatment). Similarly, storage duration beyond 30 days decreased the quality attributes of persimmon and resulted in maximum weight loss (13.3%), juice content (56.4%), total soluble solids (17.7 ºBrix), and disease incidence (22.5%). While the highest fruit firmness (2.6 kg cm-2), fruit volume (106.9 cm-3), titratable acidity (0.82 %), dry matter (2.3 g) and minimum pH (3.4) was noted in fresh fruits (0 days storage). Regarding interaction both ascorbic acid and storage duration significantly affected the fruit firmness and fruit juice pH. It is concluded that ascorbic acid at 2% might be useful and can sustain the post harvest quality of persimmon up to 30 days in storage.
... However, its stability is compromised in food systems and is vastly dependent on the storage conditions, pH, processing temperature, photo-oxidation and the presence of enzymes and metal ions (Moser and Bendich 1991). Several authors have investigated the role of air temperature in degradation kinetics of vitamin C in various foods (Erenturk et al. 2005;Goula and Adamopoulos 2006;Kaya et al. 2010). ...
Recent interest among consumers to avoid added chemical additives/preservatives has led to the recognition of seaweed as a healthy source of fibers, minerals, and antioxidants. Currently, global seaweed aquaculture is valued over US$ 6 billion and is increasing at a steady rate of 8% annually. Moreover, as per NOAA Fisheries the US imports more than 80% of the seafood consumed. This provides huge economic and workforce development opportunities in the seaweed aquaculture industry of Maine. Consequently, farming sugar kelp (Saccharina latissima), a brown seaweed, is gaining momentum along the northeast US coast. Due to its seasonal availability and limited shelf life, seaweeds are sun-dried or using hot-air to remove moisture, preventing oxidation and microbial growth. The goal of this research is to solve the bottlenecks of drying seaweed in Maine by developing an innovative technology focused on a clean, energy-efficient and closed drying system for producing top-notch and local finished products for American consumers. For this project, the effect of drying and storage conditions (temperature, humidity) on the physical, chemical and thermal properties of the final product are studied. Also, a mathematical drying model is developed to understand the drying kinetics and rate of moisture removal in hot-air driers. Investigations carried out throughout this experiment shows controlled environment drying can improve the predictability of drying dynamics significantly for the preservation of health-beneficial components in sugar kelp. The developed model showed drying can be optimized to create a carbon negative and sustainable seaweed processing industry in Maine.
... This creates a diffusion gradient in the food that moves the water from the interior to the outer surface [10]. However, this process decreases the quality of the final product [11]. Moreover, dehydration causes damages in texture, color, taste and nutritional value of food due to the high temperatures and long drying times required in the process [12]. ...
Sugars, mainly fructose, glucose, maltose and sucrose ratios in the fresh red grape and raisins and in the fresh and dried apricot fruit were determined by High Performance Liquid Chromatography, HPLC, equipped with Ec 250/4.6 Nucleodur 100-5 NH2-RP column and Refractometer -RID as a detector. Each type of the four samples was separately homogenized after removing the seeds from the samples before crushing, and in this study the deionized water was used for extraction of sugars. The ratio of each sugar in the four investigated cultivars was compared as well as comparing the contents of total sugars between these types, and it became obvious that fructose and glucose recorded significant increase rather than sucrose and maltose in these cultivars. Comparison has also been conducted for determination of fructose, glucose, maltose and sucrose ratios between the fresh red grapes and raisins on one hand, and between the fresh apricot fruit and dried apricot on the other. The study showed that the raisins contain high level of fructose, glucose, maltose and sucrose compared to the fresh grapes. Moreover, the sugar content in the dried apricot was higher than the sugar contents in the fresh apricot fruit.
... Many researchers have also reported that drying fruits at low temperatures could have a beneficial impact on the preservation of the structure [46], flavor [14], protein [47], antioxidants [48], ascorbic acid [49,50], and total phenolic compounds [22,51]. Catalase is believed to be a key antioxidant enzyme in the human body's defense against oxidative stress [52]. ...
Mango has been described as a valuable source of nutrients and enzymes that are beneficial to human health. Drying at different temperatures not only affects the nutritional properties but can also contribute to the degradation of valuable enzymes in dried fruit. The novelty of this paper is to investigate the quality of hot air dried mango in terms of activity retention of the heat-sensitive enzymes (HSE). For this, HSE was first screened in fresh mango flesh of the variety Samar Bahisht (SB) Chaunsa. Later, the combined effect of different drying temperatures (40 ◦C, 50 ◦C, 60 ◦C, 70 ◦C, and 80 ◦C) and air velocities (1.0 ms−1 and 1.4 ms−1) on the activity retention of HSE in dried mango
slices of the varieties Sindri, SB Chaunsa, and Tommy Atkins were investigated. The results showed that the drying temperature had a significant impact on the degradation of HSE, while at the same time some influence of the air velocity was also observed. Drying at 40 ◦C and an air velocity of 1.4 ms−1 retained more HSE compared to those samples dried at higher temperatures. The least retention of HSE was found in samples dried at 80 ◦C.
... Also, the specific drying time was affected by temperature in an inverse relationship. The specific drying time was used to adjust the relationship between the volume unit per time unit and to give a total time of drying time as Grove et al. (1985) reported while drying the strawberry and Erenturk et al. (2005) during drying rosehips. ...
... 52 This phenomenal change in AA content has been attributed to longer time of exposure to hot convective drying air at increasing slice thickness at constant air velocity. 1 54 for dried rosehip at 50-80 • C; 1.67 ms −1 and 0.005 kg moisture kg −1 dry air constant air velocity and humidity ratio, respectively. The gross reduction in AA content of the tomato samples is attributed to oxidation reaction rather than thermal damage after comparison between the initial AA content of fresh tomato (2.69 ± 0.22 mg/g) and the dried samples. ...
This study presents the effects of process parameters on the energy demand for drying and quality indices of dried tomato slices. The experiment was designed and analyzed with the Box‐Behnken method of Design Expert and conducted for drying 1800 g batch of a local variety of tomatoes with a solar‐electric dryer. The study examined the impact of varying process parameters: air temperature (50°C, 60°C, and 70°C), sample thicknesses (10, 15, and 20 mm), and air velocities (1.0, 1.5, and 2.0 ms−1) on the total and specific energy requirements, drying time, lycopene content, ascorbic acid, nonenzymatic browning index, brightness, and ratio of redness to yellowness of dried tomato samples, with emphasis on process optimization and drying time. The prediction of the optimal process condition is obtained using the desirability index technique. The results obtained show that the total and specific energy requirements for a batch of tomato varied from 7.82 to 125.48 kJ h and 6.70 to 179.83 kJ h g−1. The results of the analysis of variance (ANOVA) indicate that all the studied process parameters were significant with P > .05; with the maximum (40.21%) and minimum (19.82%) percent energy contribution by air temperature and air velocity, respectively. The energy of activation varies between 20.26 and 39.35 kJ mol−1. At the optimum process conditions of 57.28°C, 14.08 mm, and 1.3 ms−1, the specific energy requirements, lycopene content, ascorbic acid content, nonenzymatic browning index, brightness, redness to yellowness ratio, and drying duration are obtained as 103.313 ± 2.35 kW h kg−1, 58.7 ± 2.19 mg/100 mg dry matter, 2.9 ± 0.26 mg/g, 0.51 ± 0.033 absorbance unit, 60.074 ± 1.44, 0.77 ± 0.021, and 61.88 ± 8.93 minutes, respectively. The results of the study are of immense benefit to the food drying industry, as it provides food industries with improved drying parameters for enhancing dried tomato quality, as well as increasing dryer energy efficiency and cost‐effectiveness. Sugestions on prospects for further studies were given. This article presents the influence of process parameters on drying energy requirements and quality indices of dried tomato slices using a solar‐electric dryer. The prediction of the optimal process condition is obtained by using the desirability index technique. The research reports the results of the total and specific energy requirements, analysis of variance, percent energy contribution by air temperature and air velocity respectively, activation energy, as well as the values of the specific energy requirements, lycopene content, ascorbic acid content, nonenzymatic browning index, brightness, redness to yellowness ratio, and drying duration at the optimum process conditions.
... Drying fruits rose hips can be carried out in several ways [3][4][5][6][7][8][9][10][11][12][13][14][15][16]: on the Sun (not highly recommended due to the large loss of vitamin C in the final product), in the convective, in the air, etc. Since these fruits are relatively large and hard, dehydration is in progress drying fruits rose hips is a complex process. ...
The article discusses a new vacuum infrared equipment for drying fruits of rose hips with preservation of ascorbic acid. We have studied the drying process of rose hips in various ways (solar, convective and vacuum IR drying), to determine the rational version of the drying process to check the preservation of the vitamin composition of the fruit, mainly ascorbic acid. Special plants designed and manufactured for the production of dry powders from rose hips using low-vacuum and low-temperature infrared drying have been developed and manufactured. The vacuum drying unit consists of: a vacuum chamber, an electrical system for IR irradiation and instrumentation. During the drying process, the operating temperature was maintained at 65 ° C, the pressure inside the chamber was-0.8 atm and the drying time was 4 hours. With these parameters, the dogrose is dried effectively and vitamins are well preserved in its composition. In appearance, you can determine that the color and taste have not changed. Laboratory experiments were also carried out aimed at chopping and separating rose hips. Continue drying, setting the operating parameters depending on the parameters of the object. After setting the parameters of drying and its implementation, wild fruits rose hips is dehydrated to a moisture content of 12%, while the preservation of vitamins is provided in the fruit composition. As a result of an experimental study of the influence of vibration on the drying process, it has been established that the efficiency of dehydration increases to 4-5% under continuous heating conditions-at a certain frequency and amplitude. It is shown that the preservation of ascorbic acid in the composition of the pulp of the fruits rose hips with vacuum infrared drying is up to 0.77 mg%. The optimum thickness of the product layer is about 1-1.5 cm, the optimal wavelength is 3 microns, while the dehydration time of the products is an acceptable value, and the temperature of the fruits does not exceed 65 °C, the vacuum is-0.8 atm.
... In a study, stated that degradation of ascorbic acid depends on several factors, which include oxygen, metal ion catalysis, light, temperature and moisture content [3]. The absence of air during drying may inhibit oxidation, and therefore, color and nutrient content of products can be largely preserved the solubility of vitamin C in water and heat sensitivity of it compared to most other nutrients may cause problems during the preservation of foods. ...
Citrus waste is solid residue that remains after fresh fruits are squeezed for their juices. Pakistan is among the top ten citrus producing countries in the world. Pakistan is contributing 2.16 million tons per annum in fruit waste generation. Fresh food waste is often used locally to feed animals as milk enhancer. When fresh fruit are squeezed, a solid residue is produced which is commonly known as citrus waste. Fresh citrus waste has a natural acidity, but it is still a perishable product due to its high moisture content and soluble sugar. Dehydration method is usually applied for the removal of moisture content up to less than 10 % to increases the shelf life for easy handling and transportation. The present study enables the design of a rotary-hot air dryer having an internal rotating body. The drying efficiency increased with the increase in the internal temperature and the air flow rate in the rotary drum, while the drying efficiency decreases with increasing the drum speed. The drying process provided the optimal results with respect to drying time and Vitamin C concentration. The present designed hot-air dryer provides fundamentals for fruit pulp industry who can easily adopt this technology. This dryer can be installed within pulp industry and waste can be processed at source point. The dehydration process increases the shelf life of citrus fruit waste and it will be available throughout the year around the country. The dehydrated material can enhance the milk quantity of animal.
... Air drying in general enhances the drying rate, while direct exposure to the sun can have a deleterious effect on the quality of the dried product. Changes of vitamin C content during drying have been affected by drying time, drying air temperature and moisture content [9,10]. Yam contains vitamin C as a bioactive compound, which has strong antioxidant activity. ...
This work evaluates the yam (Dioscorea rotundata) drying performance of solar adsorption drying (SAD) compared to solar drying (SD) and open sun drying (OSD). The evaluation concerns the drying cycle for batches of yam, the effect on vitamin C, color and composition. As SAD can be applied during the night, by using air dehumidified by passing through a bed of silica gel, the cycle time for drying batches of yam can be reduced over 20–25% compared to SD and halved compared to OSD. SAD is thereby most effective during the first nights of drying when the driving force is the highest. Composition was not affected by drying methods but did affect vitamin C content. Vitamin C retention is not significant different for SD and SAD, but with a slight preference for SD. For three yam cultivars (‘Pona’, ‘Lilii’ and ‘Dente’), ‘Lilii’ dried fastest and ‘Dente’ drying slowest. SAD maintained 16 the whitish color of yam better than the other drying methods.
... where M is the moisture content on dry basis (g/g) and the P i 's are constants [9]. ...
The Bĕlehrádek/Ratkowski, also known as the square root model, was originally developed to describe and quantify the temperature dependence of organisms’ growth rate, in terms of a simple power-law expression that contains a threshold growth temperature. The model’s original version implied that the rate rises monotonically with temperature. Therefore it has been modified to account for peak growth at the organism’s optimal temperature, by adding a falling multiplying factor. The modified model has been extended to post-peak growth temperatures, and all the way to where growth turns into thermal inactivation. In principle, the model can also be extended to low temperatures where growth not only ceases, as the original model implies, but turns into mortality, albeit at a much slower pace. The performance of the original and extended model’s versions can be visualized with three freely downloadable interactive Wolfram Demonstrations available on the Internet. The three versions can be combined into a single temperature-dependence model that covers the entire temperature range from lethal cold to death by heat. This combined model can be incorporated into a general dynamic (non-isothermal) growth/mortality model, in the form of a differential rate equation, which can describe oscillations between growth, no growth, and mortality modes during a population’s thermal history. All the Bĕlehrádek/Ratkowski model’s variants can be replaced by a single continuous algebraic expression that eliminates the need to have “If statements” in their equations. The continuous version too can be incorporated into a dynamic rate model to describe growth, no growth, and mortality, and transitions between them.
... The vitamin C degradation rate constant can be expressed by the Arrhenius equation (Equation 12; Erenturk, Gulaboglu, & Gultekin, 2005). ...
In this study, the kinetics of vitamin C degradation is simulated by the development of a model based on the numerical approach of heat and mass transfer processes and the degradation rate of vitamin C during the dehydration of tomato slices at 45, 60, and 75°C. The results achieved by experimental data were consistent with those obtained by the numerical model (R ² > 0.88 and RMSE < 0.27). So, it is concluded that the rate of vitamin C degradation was increased at the beginning of the dehydration process when the temperature of the inner sample layers was raised and then its value decreased with the reduced moisture content at the stable temperature conditions. During the dehydration process, the highest concentrations of vitamin C were obtained at the surface layer of the tomato slice with the least moisture content and the lowest of its value was obtained at the sample center with the highest moisture content.
Practical Applications
Some of the essential nutrients are degraded during the dehydration process. Understanding factors effective on nutrient degradation is important to optimize the dehydration conditions to produce healthy food. Since vitamin C is an indicator for determining the health food, modeling of its degradation kinetics is an efficient method for understanding the effective factors of retaining nutritional components during the dehydration operation. In this research, a novel method developed to simulate the vitamin C degradation in different layers of a tomato slice during a thermal process. The result of this method is used to interpret the factors affecting on degradation of food component. After the dehydration process, the concentration of vitamin C at the surface node was approximately 47.9, 22.1, and 9.9% higher than its value at the center node at 45, 60, and 75°C, respectively. The effective moisture diffusivity was the most sensitive parameter in the modeling of vitamin C degradation kinetics.
... Among them, vitamin C is the compound whose degradation is the most rapid in this study. Retention in Vitamin C is often used as an estimate for the overall maintenance of nutrients in food products, as it is by far the least stable nutrient [30]. It is highly sensitive to oxidation and leaching into water-soluble matrices during storage [31]. ...
... The spray drier is a drying technology used to produce pharmaceutical drugs [1] by converting the liquid material into small powdered particles [2]. The technology uses drying air temperatures above 100°C [2][3][4][5][6][7]. ...
This study explores a combination of spray drying and refrigeration systems on production of vitamin B1, which is known to be heat-sensitive. It analyzes the effect of drying air temperature on vitamin B1 levels and notes the related influence on production levels. In addition to temperature, productivity is influenced by moisture and drying airflow rates. In this study, air temperatures were set at 80, 110, and 140°C. Air humidity variations were carried out by changing the humidifier's outlet air temperature to 10, 15, and 20°C. The airflow rate varied at 150, 300, and 450 lpm. High Performance Liquid Chromatography (HPLC) testing methods was used to test the level of damage to vitamin B1 products. By setting the temperature of air passing through the evaporator at 10°C, the drying temperature at 140°C, and airflow rate at 450 lpm, damage to vitamin B1 can be minimized by 7.69%. The drying productivity with the refrigeration system is even 3 times larger than the result of the drying productivity with conventional methode. These results indicate that the combination of spray drying and refrigeration systems with low evaporator temperatures can have a significant positive impact on the production quality of vitamin B1.
... Drying also reduced the vitamin C content in other food products. The content of vitamin C reduced by 25 to 35% in rosehips (Erenturk et al., 2005), and by 20 to 50% in pineapples (Rodríguez et al., 2017). Fig. 7 presents the relative content of total carotenoids in the pretreated mangoes samples compared to the untreated dried mango. ...
High intensity pulsed UV Light is a non-thermal treatment used in sanitization of fruits and vegetables. In this work, we have applied high intensity pulsed UV light as a pretreatment for convective air-drying evaluating the benefits of the pretreatment to the drying process and to the nutritional quality of the dried product. Mangoes were subjected to pulses of UV light. The pretreated samples were further dried in a convective oven-drier until 90% of the initial water content has been removed. Drying kinetics, water apparent diffusivity, vitamin B, vitamin C content and total carotenoids content were analyzed. Pulsed UV light showed to be an interesting pretreatment for mangoes given the higher nutritional content of the dried product. Keywords: mango; drying; ultraviolet; vitamins; kinetics
... Drying also reduced the vitamin C content in other food products. The content of vitamin C reduced by 25 to 35% in rosehips (Erenturk et al., 2005), and by 20 to 50% in pineapples (Rodríguez et al., 2017). Fig. 7 presents the relative content of total carotenoids in the pretreated mangoes samples compared to the untreated dried mango. ...
High-intensity pulsed UV light is a non-thermal treatment used in the sanitization of fruits. As a secondary effect to sanitization, the energy of the pulses is absorbed by the fruit and converted into internal energy, which results in partial evaporation of the water of the fruit. In this work, we have applied high-intensity pulsed UV light as a pretreatment for convective air-drying evaluating its advantages and disadvantages on the drying process and nutritional quality of the dried product. Mangoes were subjected to pulses of UV light and dried in a convective oven-drier. The pulsed UV light pretreatment reduced the water content in the samples but did not affect the kinetics or apparent water diffusivity of the subsequent drying process. The concentration of vitamin C and carotenoids in dried mangoes subjected to fluences between 3.6 and 10.8 J/cm² in the pretreatment were between 10 and 40% higher than the untreated dried mango. The concentration of vitamins B1, B3 and B5 increased by 10 to 25% in dried mangoes subjected to fluences between 3.6 and 7.2 J/cm², in comparison with the untreated dried mango. Vitamin B6 was highly affected by pulsed UV light decreasing by 40 to 50% in the pretreated mangoes.
... The cutting pretreatment can change the shape parameters of materials, so it may also affect drying rate and retention of organic matter and nutrients. The kinetics of ascorbic acid degradation during air-drying of whole rosehip has indicated that cutting pretreatment could accelerate the drying process and improve the retention of vitamin C (Erenturk, Gulaboglu, & Gultekin, 2005). The drying time and drying quality of agricultural products were significantly influenced by the cutting pretreatment and drying method. ...
Results of an experimental study were presented and discussed for hot air drying with horizontal cut (HC-HA) or vertical cut (VC-HA) at 55, 60, 65, 70, 75, and 80 °C, respectively, and heat pump drying with HC (HC-HP) or VC (VC-HP) at 40, 50, 60, and 70 °C, respectively, on drying characteristic, colour quality, chemical compositions (vitamin C, chlorophyll, total phenolic and polysaccharide) and antioxidant capacity (2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl radical scavenging capacity and oxygen radical absorbance capacity (ORAC)) of okra samples. Results showed VC had shorter drying time than that of HC both during HA and HP. The effective moisture diffusivity determined by Weibull distribution function ranged from 0.992 × 10⁻⁹ m²/s to 4.409 × 10⁻⁹ m²/s for HA, and 1.915 × 10⁻⁹ m²/s to 5.291 × 10⁻⁹ m²/s for HP. The drying activation was 37.00, and 35.91 kJ/mol for the samples of HC-HA and VC-HA, 29.25, and 21.40 kJ/mol for HC-HP and VC-HP, respectively. A comprehensive evaluation of quality attributes indicated that HP was more suitable for okra drying as it improved drying rate and drying quality compared with HA. The optimal sample quality (higher contents of chemical compositions and better colour quality) was found in okra treated with VC-HP at 50 °C.
... to a las muestras envasada en polietileno. Este fenómeno es atribuible a una menor permeabilidad al aire y una mayor opacidad del material trilaminado que no permite que la luz catalice la reacción de oxidación de la vitamina C. Existen numerosos investigadores que estudiaron la retención de vitamina C durante el proceso de deshidratación osmótica (Asami et al., 2003;Nicoleti et al.,2004;Erenturk et al., 2005;Orikasa et al., 2008;Ramallo y Mascheroni, 2010). ...
En el presente trabajo se fortificaron cubos de papas con calcio y vitamina C, por osmodehidro-congelación. Se trata de un proceso combinado en el que se produce una deshidratación parcial del producto al sumergirlo en una solución acuosa concentrada de solutos comestibles y posterior congelación. Por consiguiente, se reduce la formación de cristales de hielo y se daña menos su estructura. Además la carga térmica a extraer es menor respecto del proceso de congelación sin dicho pretratamiento logrando un importante ahorro de energía y un producto de menor volumen y peso. La deshidratación osmótica con pulsos de vacío permitió impregnar con calcio y vitamina C el producto a concentraciones suficientes que permiten considerarlo como un alimento fortificado. El envasado con atmósfera modificada en bolsas de un material trilaminado posibilitó conservar las características nutricionales así como también su estabilidad al deterioro microbiano durante un lapso de 180 días. Abstract In this paper potato cubes were fortified with calcium and vitamin C by osmodehydrofreezing. This is a combined process in which a partial dehydration of the product by soaking it in an aqueous concentrated solution of edible solutes occurs, followed by a subsequent freezing. Therefore, the formation of ice crystals is reduced and less damage to the structure takes place. Besides, the thermal load is lower when compared to the freezing process without a pre-treatment, achieving significant energy savings and a lower volume and weight product. Vacuum pulse osmotic dehydration allowed to impregnate the product with calcium and vitamin C at high enough concentrations as consistent to consider it a fortified food. The modified atmosphere packaging bags of tri-laminate material allowed to retain the nutritional characteristics as well as their stability to microbial spoilage during a period of 180 days.
... In a study, stated that degradation of ascorbic acid depends on several factors, which include oxygen, metal ion catalysis, light, temperature and moisture content [3]. The absence of air during drying may inhibit oxidation, and therefore, color and nutrient content of products can be largely preserved the solubility of vitamin C in water and heat sensitivity of it compared to most other nutrients may cause problems during the preservation of foods. ...
Citrus waste is solid residue that remains after fresh fruits are squeezed for their juices. Pakistan is among the top
ten citrus producing countries in the world. Pakistan is contributing 2.16 million tons per annum in fruit waste
generation. Fresh food waste is often used locally to feed animals as milk enhancer. When fresh fruit are squeezed,
a solid residue is produced which is commonly known as citrus waste. Fresh citrus waste has a natural acidity, but
it is still a perishable product due to its high moisture content and soluble sugar. Dehydration method is usually
applied for the removal of moisture content up to less than 10 % to increases the shelf life for easy handling and
transportation. The present study enables the design of a rotary-hot air dryer having an internal rotating body. The
drying efficiency increased with the increase in the internal temperature and the air flow rate in the rotary drum,
while the drying efficiency decreases with increasing the drum speed. The drying process provided the optimal
results with respect to drying time and Vitamin C concentration. The present designed hot-air dryer provides
fundamentals for fruit pulp industry who can easily adopt this technology. This dryer can be installed within pulp
industry and waste can be processed at source point. The dehydration process increases the shelf life of citrus fruit
waste and it will be available throughout the year around the country. The dehydrated material can enhance the
milk quantity of animal.
Wild garlic is a well-known and highly valued herbal plant. It is used fresh, unprocessed, and in the form of dried plants. The paper presents the results of the impact of the applied convection drying conditions at 30, 40 and 60°C on the parameters of the drying process as well as selected properties and composition of dried garlic obtained from wild garlic. It has been unequivocally shown that the increase in drying temperature significantly affects the content of thermally labile compounds, especially low-molecular weight antioxidants, including polyphenols and vitamin C. The analysis of the results clearly indicates that the dried plants obtained at 30°C contain relatively the highest amounts of antioxidant components and show the most volatile compounds profile similar to fresh wild garlic. However, the analysis of the parameters of drying process revealed that the temperature of the process significantly affects the time needed for the completion of drying process. The recommended of the most favourable process conditions should be based on an extended analysis and optimization of the entire process, taking into account not only the quality parameters of the dried material, but other parameters such as energy inputs and labour costs.
Edible wild-grown mushrooms, plentiful in resources, have excellent organoleptic properties, flavor, nutrition, and bioactive substances. However, fresh mushrooms, which have high water and enzymatic activity, are not protected by cuticles and are easily attacked by microorganisms. And wild-grown mushroom harvesting is seasonal the harvest of edible wild-grown mushrooms is subject to seasonality, so their market availability is challenging. Many processing methods have been used for postharvest mushroom processing, including sun drying, freezing, packaging, electron beam radiation, edible coating, ozone, and cooking, whose effects on the parameters and composition of the mushrooms are not entirely positive. This paper reviews the effect of processing methods on the quality of wild and some cultivated edible mushrooms. Drying and cooking, as thermal processes, reduce hardness, texture, and color browning, with the parallel that drying reduces the content of proteins, polysaccharides, and phenolics while cooking increases the chemical composition. Freezing, which allows mushrooms to retain better hardness, color, and higher chemical content, is a better processing method. Water washing and ozone help maintain color by inhibiting enzymatic browning. Edible coating facilitates the maintenance of hardness and total sugar content. Electrolytic water (EW) maintains total phenol levels and soluble protein content. Pulsed electric field and ultrasound (US) inhibit microbial growth. Frying maintains carbohydrates, lipids, phenolics, and proteins. And the mushrooms processed by these methods are safe. They are the focus of future research that combines different methods or develops new processing methods, molecular mechanisms of chemical composition changes, and exploring the application areas of wild mushrooms.
In this study, effect of vacuum modification (VM) on wheat bread containing rosehip extract (RE) and encapsulated rosehip extract (EnRE) was investigated in terms of the color parameters, textural properties, total phenolic content and antioxidant activity of breads. Analyzing starch crystalline structure and microstructure of breads were performed by X-ray diffraction and scanning electron microscopy. Rosehip extract was encapsulated using sodium alginate by ionic gelation method. Baking was conducted by conventional baking (CB, 220°C-17 min) and VM (220°C-12 min at atmospheric pressure and modification until −90 kPa vacuum pressure by 60 s time intervals at −30, −50, −70, and −90 kPa). PCA results showed that textural properties were the main distinctive feature with even harder texture of EnRE breads. VM led to have lower hardness for EnRE breads with the average hardness value of 781.51 ± 119.62 g than that of 1232.2 ± 83.83 g for conventional counterparts. Total phenolic content and antioxidant activity of EnRE breads were the highest after CB and VM. EnRE breads had more crystalline structure and less gluten aggregation after CB and VM processes. Results showed that vacuum modification is prominent technique to obtain softer texture of capsule containing breads with a high bioactivity.
Over the last few decades, many researchers have investigated in detail the characteristics of bioactive compounds such as polyphenols, vitamins, flavonoids, and glycosides, and volatile compounds in fruits, vegetables and medicinal and aromatic plants that possess beneficial properties, as well as consumer acceptance and preference. The main aim of this article is to provide an updated overview of recent research endeavors related to the effects of the drying process on the major bioactive/effective compounds in agricultural products. Particular emphasis was placed on details related to the changes occurring in vitamin C, polyphenols, flavonoids, glycosides and volatile compounds, as well as the antioxidant activity. An analysis of the degradation mechanisms of these compounds showed that vitamin C, phenols, flavonoids and glycosides react with oxygen during the convective drying process under high drying temperatures, and the reaction rate results in degradation in such bioactive compounds due to high reducibility. On the other hand, high temperature results in a short drying time, thus minimizing the degradation of bioactive compounds. The reviewed research works addressing this trend revealed that the ideal drying temperatures for retaining vitamin C, polyphenols, flavonoids, glycosides, volatile compounds and their antioxidant activity were 50-60 • C, 55-60 • C, 60-70 • C, 45-50 • C, 40-50 • C and 50-70 • C, respectively. In conclusion, to maintain plant bioactive components, convective drying at relatively low drying temperatures is strongly recommended.
This study aimed to investigate the effect of hawthorn berry saturation with a sucrose solution and preservation with various methods (freezing, air-drying, and freeze-drying) on the extractability of color compounds and antioxidative substances during liqueur production. The finished products were evaluated for color; turbidity; contents of total polyphenols, total flavonoids, phenylpropanoids, phenols, flavonols, and anthocyanins; antioxidative activity against ABTS and DPPH radicals and as ferric reducing antioxidant power (FRAP); polyphenolic profile and vitamin C content. Hawthorn fruit saturation with a sucrose solution had a significant effect on the color parameters (lower: L*, a*, b* values; and higher: C and h◦ values) and contributed to higher contents of the analyzed bioactive compounds except for caffeic acid and quercetin, whose contents were significantly higher in the liqueurs produced from non-saturated fruits. The freeze-drying proved best in fruit preservation and contributed to the most satisfactory extraction of bioactive compounds to the finished product.
Rosehip fruit, which is widely and naturally grown in many European countries as well as in Rosehip fruit, which is widely used in Turkey as well as in European countries and grows naturally, is a very rich species in terms of vitamin C value. Due to its benefits to human health, its consumption is increasing and its use in different forms is becoming widespread. In this study, the colour, effective diffusion-activation energy, phytochemical properties and thin-layer drying patterns of rosehip fruit of the ‘Yıldız’ variety were investigated after drying in a convective dryer at different temperatures (40, 50, 60 and 70°C). In the study, it was determined that 70°C temperature was statistically more suitable in terms of measured and calculated colour values. It has been determined that the effective diffusion value is affected by the drying temperature and the increase in temperature also increases the effective diffusion value. It has been determined that the effective diffusion value varies between 1.35×10-7-5.92×10-6 m2/sec. The activation energy value of dried rosehip samples was calculated as 69,41 kJ/mol. When the chemical analysis values were examined, when the SÇKM, total phenolic, total antioxidant substance and vitamin C values were evaluated together, it was found that the most appropriate drying temperature was 70°C statistically. Among all drying models, Midilli-Küçük and Yağcıoğlu models (R2: 0.9999) estimated the drying data best.
Strawberry is one of the most important soft fruit in food industry. With its flavor and antioxidant content, it is widely used mainly in confectionery and beverage industry. Strawberries are perishable and this limits their usage in foods. For that reason, drying is one of the solutions to make them durable. The aim of this study is to analyze certain quality parameters and headspace volatiles of hot air-dried 'Florida Fortuna' and 'Osmanlı' strawberries (Fragaria xananassa) at 50, 60 and 70°C. The results showed that drying the strawberry samples at high drying temperature caused a decrease in acidity and bulk density and a deterioration in ascorbic acid content. However, total phenolic contents and total color difference values of both of strawberry samples increased with drying process. A total of 24 headspace volatiles were detected in dried strawberries. The most abundant volatiles were dimethyl sulfide, acetic acid and acetone. The highest number of compound groups were aldehydes, acids, esters and sugar degradation products, respectively. The highest retention of fresh strawberry volatiles and minimum formation of sugar degradation products were obtained by drying at low temperature.
Dehydration, using hot air or heated surfaces, removes water from foods and reduces their water activity, which inhibits microbial growth and enzyme activity to extend their shelf life. Drying can cause deterioration of both the organoleptic quality and the nutritional value of foods, and the design and operation of dehydration equipment aim to minimise these changes. The chapter first describes psychrometrics, the theory of drying and calculation of drying rates. It then summarises the many different types of hot air and heated surface drying equipment, and methods used to control their operation. The chapter concludes by describing rehydration and the effects of dehydration on microorganisms, and the quality of foods.
This study aimed to determine the effect of different drying methods namely, hot air drying (HAD), freeze-drying (FD), vacuum drying (VD), and ultrasound-assisted vacuum drying (USVD) on drying kinetic, total bioactive compounds, lycopene and β-carotene, phenolic composition and color quality of rosehip. Drying times of the rosehips for USVD, VD, and HAD were 180, 300, and 1140 min, respectively, indicating that USVD significantly reduced drying time of rosehip. The results of total bioactive compounds, lycopene and β-carotene, phenolic composition showed that FD resulted the highest bioactive compounds, followed by VD, USVD, and HAD. DPPH and CUPRAC results showed that FD dried samples showed highest antioxidant activity than fresh and all dried samples while HAD showed lowest antioxidant activity. USVD and FD exhibited a lower ΔE value than HAD and VD, indicating that they had similar color properties to the fresh sample. USVD resulted in lower drying time and color change than VD and HAD, while USVD showed lower bioactive compounds retention than VD. This study suggested that USVD could be used as an alternative to HAD due to its lower drying time and higher bioactive compound and color retention than HAD.
Retention of quality attributes during drying of fruit and vegetables is a prime concern since the product’s acceptability depends on the overall quality; particularly on the nutritional, color, and physical attributes. However, these quality parameters deteriorate during drying. Food quality changes are strongly related to the drying conditions and researchers have attempted to develop mathematical models to understand these relationships. A better insight toward the degradation of quality attributes is crucial for making real predictions and minimizing the quality deterioration. The previous empirical quality models employed kinetic modeling approaches to describe the quality changes and therefore, lack the realistic understanding of fundamental transport mechanisms. In order to develop a physics based mathematical model for the prediction of quality changes during drying, an in-depth understanding of research progress made toward this direction is indispensable. Therefore, the main goal of this paper is to present a critical review of the mathematical models developed and applied to describe the degradation kinetics of nutritional, color, and texture attributes during drying of fruit and vegetables and microbial growth model during storage. This review also presents the advantages and drawbacks of the existing models along with their industrial relevance. Finally, future research propositions toward developing physics-based mathematical model are presented.
In this study, the goal was to evaluate the ascorbic acid degradation in basil, purslane and celery leaves during microwave drying. The effects of microwave output power and sample amount on ascorbic acid loss in basil, purslane and celery leaves were investigated. The method for the determination of ascorbic acid content was based on the reaction between ascorbic acid and 2,6-dichloroindophenol and was successfully applied to basil, purslane and celery leaves. Increasing microwave output power and decreasing sample amount led to higher degradation rates in basil, purslane and celery leaves. Ascorbic acid degradation kinetics in basil, purslane and celery leaves during microwave drying followed a first-order reaction. The activation energy values were also calculated using an exponential expression based on Arrhenius equation for degradation of ascorbic acid.
Background:
Combination drying is recognized as an energy-efficient method utilized for dry product processing, and proper order of combination is a critical factor determining the effectiveness of the technique. In this study, hot air-drying (HD), vacuum freeze-drying (VFD), and combination drying with different orders (HD-VFD and VFD-HD) are performed to whole Lentinula edodes and pre-cutting (half-cut and quarter-cut) L. edodes. The effects of various cutting and drying approaches on drying characteristics, physicochemical properties and microstructures of dried L. edodes were investigated.
Results:
The longest processing time required to dry the whole L. edodes by VFD was 25 h. In contrast, the pre-cutting treatment and combination drying certainly shortened the drying time. Compared with HD, VFD-HD and VFD significantly decreased the shrinkage ratio, hardness, and discoloration of dried products but increased the rehydration capacity, nutrient retention, and porous microstructure. Interestingly, switching the order of combination drying provoked entirely different drying effects. Specifically, HD-VFD triggered negative effects on the shrinkage and color of dried mushrooms, and its appearance color was similar to HD-treated samples. Moreover, pre-cutting dramatically enhanced the protein content of HD-treated mushrooms, and the quarter-cut samples obtained the highest level (21.69 g kg-1 dry base) among the three types of cutting.
Conclusions:
The dried L. edodes processed through pre-cutting and combination drying (VFD-HD) have optimal industrial quality, accompanied by shorter processing time. This article is protected by copyright. All rights reserved.
In connection with the state policy of import substitution and fortification of food products, in the Russian Federation, the search, study and introduction of new types of domestic non-traditional plant materials into the food industry are relevant. The purpose of the study is comparative analysis of the size and weight characteristics of cynarodies (fruits) of rosehips undergoing introduction tests in the arboretum of the N.V. Tsytsin Main Botanical Garden of Russian Academy of Sciences, to find out the possibilities and advantages of their industrial and domestic use. The objects of the study are mature infructescences of hips growing abundantly in the conditions of Moscow region: Rosa amblyotis C.A. Mey, Rosa maximowicziana Regel and Rosa oxyodon Boiss. The determination of the length, diameter, weight of cynarrodies, the content of absolutely dry substances in them, as well as the statistical processing of the research results were carried out according to standard methods. The reliability of interspecies differences of analyzed traits were established according to criteria of Student and Fisher. The superiority of the most variable fresh and air-dried cynarrodies of R. oxyodon in length, diameter and weight (2.02×1.18 cm and 1.08 g, respectively) was revealed, compared to the smallest and least changeable infructescences of R. maximowicziana (0,86×0.90 cm and 0.34g), as well as of R. amblyotis fruits which are intermediate in terms of these characteristics (1.06 x1.22 cm and 0.74 g). However, infructescences of R. amblyotis, containing an increased percentage of absolutely dry substance (94%), turned out to be no less promising than larger ones due to the significant water content of R. oxyodon cynarrodies (90%). For final determination of industrial significance of investigated rosehips infructescences, the size and weight study we have undertaken is not enough; further biochemical analysis is required.
In this study, the kinetic change of the antioxidant properties were determined during apple chips production using three different cultivars. Using a rotary forced‐air dryer, apple slices were dried at three different temperatures (65, 70, and 75°C). The ascorbic acid content, total phenolic content (TPC), total flavonoid content (TFC), Oxygen Radical Absorbance Capacity (ORAC) and Trolox Equivalent Antioxidant Capacity (TEAC), and hydroxymethylfurfural content were analyzed. Phenolic compounds of apple chips were also identified by chromatographic separation. Thermal degradation of ascorbic acid was fitted to first‐order reaction kinetics. TPC, TFC, ORAC, and TEAC values, and hydroxymethylfurfural content increased with drying time and temperature where the data were fitted to first‐order and zero‐order reaction kinetics. Reaction rate constants were influenced by temperature, based on the Arrhenius model. The primary phenolic compounds of apple chips were gallic acid, chlorogenic acid, catechin, caffeic acid, epicatechin, and rutin.
Practical applications
Dietary antioxidants with health benefits have increased attention on fruit and vegetable products. The processing of fruits and vegetables affects their antioxidant properties as well as their quality. Apple chips are dehydrated, ready to eat, fruit‐based snacks with desirable sensory properties. The results of this article will contribute to an understanding of the thermal kinetics of antioxidant properties and phenolic content during apple chip production. The kinetic results may be useful for the design of dryers and optimization of the drying conditions.
The effects of fresh and dried rosehip addition on the physicochemical and microbiological properties of fermented meat model system were investigated. Addition of fresh and dry rosehip significantly decreased thiobarbituric acid reactive substances (TBARS) and pH values compared to control group (P<0.05). While higher L* values were determined in batter with 10% fresh rosehip compared to other treatment groups at the beginning of the fermentation (P<0.05). The addition of rosehip in batter showed non-significant effects on moisture, protein, fat and ash levels in batters after fermentation (P>0.05). The addition of rosehip did also not affect yeast, mold, total mesophilic aerobic and coliform counts (P>0.05). The results of this study demonstrated that rosehip can be used in fermented meat model system to inhibit lipid oxidation without posing any quality problems.
Spray drying is a method of preservation that is widely used in food and pharmaceutical industries. Nevertheless, the drying temperature in spray drying is the common problems faced during the drying process. Drying in high temperature inevitably caused damages to the material, especially for heat-sensitive material including vitamin C. Vitamin C is more sensitive than other vitamins. In tomatoes, it may be browning due to high temperature in drying process. To get around this, the spray dryer is then combined with a dehumidifier system. The aim of this study is to know the safe drying temperature and also to know the specific energy consumption when using a combination system. Testing was performed using vitamin C from tomatoes and vitamin C essence. Based on research result, the temperature of drying air is not recommended to exceed 90°C, because the vitamin C content will be degraded at that temperature. The lowest ratio of specific energy consumption (RSEC) when the drying air temperature at 90 °C is obtained at the highest drying air flow rate with the lowest drying air specific humidity with a value of 0.45.
Vacuum microwave drying of carrot slices was compared to air drying and freeze drying on the basis of rehydration potential, color, density, nutritional value, and textural properties. Vacuum microwave dried (VMD) carrot slices had higher rehydration potential, higher α-carotene and vitamin C content, lower density, and softer texture than those prepared by air drying. Carrot slices that were air dried (AD) were darker, and had less red and yellow hues. Less color deterioration occurred when vacuum-microwave drying was applied. Although freeze drying of carrot slices yielded a product with improved rehydration potential, appearance, and nutrient retention, the VMD carrot slices were rated as equal to or better than freeze dried (FD) samples by a sensory panel for color, texture, flavor and overall preference, in both the dry and rehydrated state.
The influence of low oxygen concentrations on lipid oxidation during storage of cream powder was studied. The powder was packed with oxygen concentrations of 209 mL/L, 17 mL/L, 8.3 mL/L, 3.4 mL/L, 1.5 mL/L, 0.7 mL/L and 0.6 mL/L and stored in darkness at 30 °C for 29 weeks. To follow oxidation, the formation of volatile oxidation products and oxygen consumption were measured. After 7 weeks of storage a significant (P<0.01) hexanal development was already seen in all the samples, and the hexanal content was directly related to the initial oxygen content, with one exception, the 0.6 mL/L sample, which had a slightly (but not significantly,P>0.05) higher hexanal content than the 0.7 mL/L sample. There were only small differences in hexanal formation between the samples packed with oxygen concentrations below 3.4 mL/L. This could be due to a more pronounced influence of oxygen diffusion at these low levels of oxygen, leading to a diffusion-controlled oxidation. Other volatiles, not produced by lipid oxidation, also increased during storage. The formation of Strecker aldehydes was found to be oxygen-dependent, whereas the formation of 2-alkanones was not. Measurement of oxygen consumption was not sufficient to detect differences in oxidation rate between the samples packed with 17 mL/L oxygen and less.
The kinetics of ascorbic acid degradation were studied in an intermediate moisture model food system as a function of water activity (0.69-0.90) and temperature (61-105°C). The disappearance of ascorbic acid in each case followed a zero order kinetic model. Rates of ascorbic acid degradation ranged from 1.5-10.5 mg/100g solids/min, while the activation energy was in the range of 14—17 Kcal/mole. It is suggested that dissolved oxygen concentration was limiting above 92°C, resulting in a rate decrease between 92 and 105°C. Rates of ascorbic acid degradation were found to increase with increasing aw, except at 105°C, where the opposite was observed. An equation derived from the integrated zero order rate law was used to predict ascorbic acid losses during an unsteady state heating process approximating a linear temperature rise, with good results. The same equation was much less accurate (predictions were 2-4 times larger), when used to predict ascorbic acid losses during extrusion processing, most likely due to the difficulty in obtaining an accurate temperature history of the extruded product.
The stability of reduced and total ascorbic acid in a low moisture dehydrated model food system was determined as a function of water activity, moisture content, oxygen and temperature. Ascorbic acid degradation rates were satisfactorily described by first-order kinetics and were dependent on water activity and temperature. Rate constants obtained for the model system stored with a large excess of oxygen (303 cans) were compared with those reported previously for the case of limited gaseous oxygen (TDT cans). At all conditions of temperature and water activity the degradation of ascorbic acid was greater for the condition of excess oxygen (303 cans). This effect is interpreted as reflecting the consumption of oxygen dissolved in the moisture of the product and the continuous dissolution of excess molecular oxygen present in the 303 cans. The significance of this oxygen effect is further manifested by the change in activation energies for RAA and TAA destruction at 0.1 aw from 7.0 kcal/mole limited oxygen to 10.7 kcal/ mole in excess oxygen conditions. These data suggest that dissolved and gaseous oxygen are primary factors in the storage stability of ascorbic acid in dehydrated food systems.
An accelerated method for determining the kinetic model which describes the loss of ascorbic acid during air drying was developed. The method is based on tests conducted under dynamic conditions, i.e. ascorbic acid loss is studied in the course of the dehydration process during which temperature and moisture content are changing continuously. The results are used to determine the form of the kinetic model and the kinetic parameters relating rate of loss to moisture content, temperature, and reactant concentration. The method successfully predicted the kinetic model describing the loss of ascorbic acid in a simulated air drying process. This approach may eliminate the necessity for time-consuming experiments conducted at each of several combinations of temperature and moisture content and may be applicable to other deteriorative reactions.
ABSTRACTA kinetic model representing ascorbic acid degradation in potatoes as a function of moisture content and temperature was used to find optimal dryer-temperature control paths for minimizing ascorbic acid loss during air drying of potato disks. Optimal dryer-temperature control was also determined for minimizing drying time given a specified minimum retention of ascorbic acid. Constraints were placed on the final moisture content and the air temperature. Optimization was achieved using a simulation-optimization approach based on the complex method.
Ripe, fresh tomato halves of Rita cultivar were dried in a pilot-plant cabinet air dryer at 80 and 110°C. During drying the variation in loss of weight and tomato temperature was continuously measured, and tomato samples were taken to make a visual evaluation of color and to determine the lycopene, ascorbic acid and 5-hydroxymethyl-2-furfural (HMF) contents. Color, ascorbic acid and HMF contents indicated severe oxidative heat damage during drying. Conversely, lycopene had a high stability during drying. The lycopene content decreased to a maximum of 10% after drying at 110°C and did not change during drying at 80°C.
The influence of different non-electrolytes (fructose, xylitol, glucose/mannitol mixture) and electrolytes (NaCl, KCl) on anaerobic L-ascorbic acid (AA) degradation in an aqueous model system (pH 3.5, aw 0.94) was studied to assess the effect on that reaction of substances commonly used to diminish the water activity of fruit or vegetable juices, as well as its relation with non-enzymatic browning (NEB) development, at processing (70, 80, 90 °C) and storage (24, 33, 45 °C) temperatures. AA degraded as a function of time with a behaviour that could be described by first-order kinetics at all temperatures studied, and activation energies could be calculated using the Arrhenius law. The presence of humectants enhanced AA destruction, with D-fructose promoting the fastest L-ascorbic acid destruction and browning development at processing temperatures. The influence of humectants on NEB seemed to determine differences between their influence on AA degradation. Water activity decrease by humectant addition produced higher AA stability in solution at storage temperatures. The differential effect of each humectant used to decrease the water activity seemed to be related to its influence on solvent structure.© 2001 Society of Chemical Industry
This work presents a two-dimensional diffusional model to predict the simultaneous mass transfer and shrinkage during drying of solids with prolate spheroidal shape, considering that the changes in volume of solid are equal to the volume of evaporated water. The resulting equations are numerically solved, using the finite-volume method. This model was used to study numerically the effect of the air-drying conditions and shrinkage on the drying kinetic of banana peel for six experiments, considering the natural shape of this fruit. Here, it was treated as an ellipsoid of revolution. Several results are shown and analyzed such as the comparison between numerical and experimental data; the dimensionless shrinkage parameters; the relationships of length, superficial area and volume; the moisture content distribution and finally the mass transfer and diffusion coefficients.
The effect of air conditions (air temperature, air humidity and air velocity) and characteristic sample size on drying kinetics of various plant materials (potato, carrot, pepper, garlic, mushroom, onion, leek, pea, corn, celery, pumpkin, tomato) was examined during air drying. A first-order reaction kinetics model was used, in which the drying constant is function of the process variables, while the equilibrium moisture content of dried products within the range of 0.10–0.90 water activity at two temperatures (30 and 70 °C) was fitted to GAB equation. The parameters of the model considered were found to be greatly affected by the air conditions and sample size during drying. In particular the temperature increment increases the drying constant and decreases the equilibrium moisture content of the dehydrated products.
This study, using vitamin C (ascorbic acid) as ‘marker’, allowed a direct comparison of the nutritional quality of fresh vegetables at various stages of distribution and storage, with the same vegetable commercially quick-frozen and stored deep frozen for up to 12 months. The nutrient status of frozen peas and broccoli was similar to that of the typical market-purchased vegetable and was superior to peas that have been stored in-home for several days. Fresh peas and broccoli retained their quality for up to 14 days when stored under chill conditions. The nutrient status of frozen whole green beans and frozen carrots, with no loss on freezing, was similar to the fresh vegetable at harvest. Frozen spinach also compared reasonably well with the harvested fresh vegetable and was clearly superior to all market produce.
During the last years the nutritional importance of antioxidants in food, e.g. carotenoids, tocopherols and vitamin C, has been recognized because of their possible role in the prevention of human diseases such as cancer, atherosclerosis and immune depression. During normal industrial processing – including cutting, blanching, drying and storing – vegetables usually suffer distinct losses in these components, resulting in a significant quality decrease. Applying low oxygen conditions during critical processing steps yields products of better quality. Results of a comparative study of atmospheric and inert gas processing of three vegetables are presented.
Agricultural food products and specially root vegetables undergo several physical and structural modifications during the drying process. Shrinkage of root vegetables during drying is important not only from the viewpoint of material end-use but also for simulation problems. In this paper the shrinkage of root vegetables is studied in a pilot-scale, inert medium fluidized bed dryer. Cylindrical carrot samples were utilized as the test media, providing simulants for high moisture content food systems. The effects of various parameters such as air temperature, air humidity, sample diameter, sample initial moisture content, existence of inert particles and air velocity were investigated. It was found that the shrinkage of root vegetables during drying in a fluidized bed could be well correlated with moisture content of the sample during drying. Air velocity, temperature and presence of inerts did not show significant effects on shrinkage in this system.
Drying is an indispensable process in many food industries. The drive towards improved drying technologies is spurred by the needs to produce better quality products. Improvement in quality of most food products translates into significant increase in their market value. The recent development of new hybrid drying technologies to improve food quality is in line with the present trend of ‘quality’ enhancement with reduced environmental impact. This review paper summarises some recent developments in hybrid drying technologies of interest to food industry. Numerous emerging technologies are listed and discussed in detail. The potential application areas for these hybrid drying technologies in product quality enhancement are identified.
Vitamin C, including ascorbic acid and dehydroascorbic acid, is one of the most important nutritional quality factors in many horticultural crops and has many biological activities in the human body. The content of vitamin C in fruits and vegetables can be influenced by various factors such as genotypic differences, preharvest climatic conditions and cultural practices, maturity and harvesting methods, and postharvest handling procedures. The higher the intensity of light during the growing season, the greater is vitamin C content in plant tissues. Nitrogen fertilizers at high rates tend to decrease the vitamin C content in many fruits and vegetables. Vitamin C content of many crops can be increased with less frequent irrigation. Temperature management after harvest is the most important factor to maintain vitamin C of fruits and vegetables; losses are accelerated at higher temperatures and with longer storage durations. However, some chilling sensitive crops show more losses in vitamin C at lower temperatures. Conditions favorable to water loss after harvest result in a rapid loss of vitamin C especially in leafy vegetables. The retention of vitamin C is lowered by bruising, and other mechanical injuries, and by excessive trimming. Irradiation at low doses (1 kGy or lower) has no significant effects on vitamin C content of fruits and vegetables. The loss of vitamin C after harvest can be reduced by storing fruits and vegetables in reduced O2 and/or up to 10% CO2 atmospheres; higher CO2 levels can accelerate vitamin C loss. Vitamin C of produce is also subject to degradation during processing and cooking. Electromagnetic energy seems to have advantages over conventional heating by reduction of process times, energy, and water usage. Blanching reduces the vitamin C content during processing, but limits further decreases during the frozen-storage of horticultural products.
The effect of ethyl oleate on the drying rates for corn was investigated in a pilot plant air-dryer. Corn was air dried in controlled mention the drying conditions without treatment or after dipping in a cold solution of ethyl oleate. Dipping in a solution of 2% (w/w) ethyl oleate and 4% (w/w) potassium carbonate (AEEO) resulted, in most cases, in an increase in the drying rate of corn kernels. The Hunter colour scale parameters (lightness, redness and yellowness) were measured to quantify the colour changes. The shorter drying times and best quality dried product were obtained with corn kernels dipped in the solution of ethyl oleate. The single exponential equation and the Page equation were used to determine the thin-layer drying characteristics. Both the equations fitted well to the experimental data. The Page equation was found to better describe the thin-layer drying of corn than the single exponential equation. The effective diffusivity was determined to be 9.488×10−11 to 1.768×10−10 m2/s for the untreated corn and 1.424×10−10 to 2.716×10−10 m2/s for treated samples in the temperature range of 55–75 °C. The activation energies for diffusion were calculated to be 29.56 kJ/kg mol (for untreated) and 30.56 kJ/kg mol (for treated).
Nutrients and technological properties were determined in developing Rosa canina L. fruits (rosehips) from Konya (Hadim) and Kastamonu to investigate potential uses. Completely ripe fruits contained ash, crude oil, crude energy, crude fiber, crude protein, ascorbic acid, dimethyl sulfite (DMS), and minerals including K, P, Mg, Ca and Fe. Also, technological properties such as length and width of fruit, weight of 1000 fruits, projected area, porosity, bulk density, hectoliter weight, skin break resistance were measured. In general, dry matter, crude energy, crude protein, ascorbic acid, water-soluble extract, acidity, DMS, Na, K, P, Mn and Mg contents of Kastamonu rosehip fruits were higher than those of Hadim fruits. Ascorbic acid was also present at high concentrations in the rose fruits. Also, length of fruit, width of fruit, weight of 1000 fruits, projected area and fruit bulk of Kastamonu rose fruits were found to be higher than those of Hadim fruits. Results of the static and dynamic coefficients of friction for both rose fruits were found to be similar.
The growing proportion of processed foods in the average daily diet in industrialized countries is considered as a challenge to the food industry, not only to provide more variety to the food assortment, but also to cope with high nutritional quality standards. Industrial handling of food therefore includes the monitoring of numerous operations and conditions from the agricultural source, through processing, packaging and distribution. Various types of food raw materials are processed by different kinds of technological treatments, the main objectives being to guarantee wholesomeness, taste, nourishment and convenience. New processing methods combined with the cold chain distribution reduce micronutrient losses to a certain extent. We shall examine some of the critical technological operations with regard to losses of vitamins and minerals in representative examples of foods like milk, leafy vegetables, potatoes, etc. and compare the classical food preservation with more modern food handling. With the increasing demand of pre-prepared fresh, refrigerated or frozen foods, the contribution of the maintained micronutrients is of interest, especially with reference to modern eating habits, i.e. lowering the total food intake and improving the nutrient density in the normal diet plan.
A new colorimetric technique for the estimation of ascorbic acid by using Folin phenol reagent has been developed. The absorption maximum of the color developed by the interaction of ascorbic acid with Folin reagent is 760 nm. The technique obeys the Beer-Lambert law up to a concentration of 45 μg ascorbic acid as shown by the standard curve. The color developed has been found to be stable up to 18 h. Recovery experiments showed that the technique is almost 100% efficient. The development of the color is not obstructed by glucose, glutathione, bovine serum albumin, urea, cysteine, adenine, guanine, cytosine, uracil, sulfosalicylic acid, thymol, or oxyhemoglobin, which are compounds suspected of interfering in routine analysis. The technique is simple, quick, and efficient and can be employed for the estimation of ascorbic acid in a wide variety of biological materials.
Folate concentrations in rosehips and commercial rosehip products and factors affecting folate retention during drying were investigated. On the basis of the raw material studied during 3 years, rosehips were shown to be a rich folate source, 400-600 microg/100 g based on dry matter and 160-185 microg/100 g based on the fresh weight (edible part). Rosehips are not often consumed fresh; therefore, drying to produce stable semimanufactures is a crucial step. The degradation of folate was shown to be dependent on the drying time until the water activity was below 0.75. The required drying time was reduced by cutting the rosehips in slices and to some extent also by increasing the temperature. Retention of folate and ascorbic acid was affected by the same factors, and high content of ascorbic acid could provide a possible protection for folate degradation.
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- Artik
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All rights reserved. doi:10.1016/j.jfoodeng.2004.07.012 * Corresponding author. Tel.: +90 442 2314561; fax: +90 442 2360957. E-mail address: serenturk@yahoo.com (S. Erenturk). www.elsevier.com/locate Influence of oxygen concentra-tion on the storage stability of cream powder
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