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The effect of air-drying, freeze-drying and storage on the quality and antioxidant activity of some selected berries
Abstract
The aim of this study was to analyze the effects of air-drying and freeze-drying and subsequent storage of dried products on the content of polyphenols, anthocyanins and the antioxidant properties of selected berry fruits. The material was raspberry (Rubus ideaus L.), strawberry (Fragaria ananassa Duch) and bilberry (Vaccinum myrtillus). Despite exposure to atmospheric oxygen, the stored freeze-dried fruit retained the properties of the raw material better than the air-dried product. In the case of the latter, there were considerable differences in the retention of total polyphenolic and anthocyanin content as well as antioxidant properties in the three fruit species examined. In particular, bilberry maintained a high polyphenol and anthocyanin content and high antioxidant potential despite the greatest losses of these compounds.
Consumer demand for food with health-promoting qualities is increasing. The food industry has intensified its efforts to provide high quality, semi-processed products that fulfil this requirement. The results presented in this work indicate that even after long-term storage and despite exposure to atmospheric oxygen, freeze-dried berries retain the antioxidant properties of the raw material to a very high degree. Therefore, lyophilisates can satisfy this particular need. Air-dried berries are much less stable during long-term storage. The dynamics of the changes occurring during the storage of both kinds of product are presented in detail.
... Anthocyanins usually give a red (Michalczyk, MacUra, & Matuszak, 2009), purple-red (Ersus Bilek, Yılmaz, & Özkan, 2017, or blue color (Aishah, Nursabrina, Noriham, Norizzah, & Mohamad Shahrimi, 2013). The color of anthocyanins changes (Choi, Kim, & Lee, 2002;Sadilova, Carle, & Stintzing, 2007;Sui, Bary, & Zhou, 2016) from red to blue or to pale blue (Noh, Jung, Choe, & Yoon, 2015) or from dark red to blue and purple (Aishah et al., 2013) depending on the pH of the water. ...
... In recent studies, natural red colorants based on anthocyaninshave been obtained by freeze-drying fruits such as raspberry (Bustos, Rocha-Parra, Sampedro, De Pascual-Teresa, & León, 2018;Michalczyk et al., 2009;f Si, Chen, Bi, Wu, Yi, Zhou & Li, Z., 2016), strawberry (Michalczyk et al., 2009), Andesberry (Estupiñan, Schwartz, & Garzón, 2011), and Murtilla berry (Reyes et al., 2010). Sanchez, Baeza, and Chirife (2015)prepared a red colorant from cherry, while Tepić, Vakula, Pavlić, Jokanović, Malbaša et al. (2018) used cornelian cherries, Bustos et al. (2018) redcurrants andCoklar, Akbulut, Kilinc, Yildirim, andAlhassan (2018) hawthorn. ...
... In recent studies, natural red colorants based on anthocyaninshave been obtained by freeze-drying fruits such as raspberry (Bustos, Rocha-Parra, Sampedro, De Pascual-Teresa, & León, 2018;Michalczyk et al., 2009;f Si, Chen, Bi, Wu, Yi, Zhou & Li, Z., 2016), strawberry (Michalczyk et al., 2009), Andesberry (Estupiñan, Schwartz, & Garzón, 2011), and Murtilla berry (Reyes et al., 2010). Sanchez, Baeza, and Chirife (2015)prepared a red colorant from cherry, while Tepić, Vakula, Pavlić, Jokanović, Malbaša et al. (2018) used cornelian cherries, Bustos et al. (2018) redcurrants andCoklar, Akbulut, Kilinc, Yildirim, andAlhassan (2018) hawthorn. ...
Background
Natural food colorants obtained from plants are of growing interest, as they are safe and healthy and positively affect the color of the food; in addition, they may have further positive effects on its properties. Many studies have shown different methods of obtaining natural food colorants. To date, there are some review studies on natural food colorants, but there are no studies describing the process of the freeze-drying method and the pretreatments used.
Scope and approach
In this review, we describe the freeze-drying methods and pretreatments used in the measurement of the quality of the obtained food colorants. In addition, we review studies describing natural sources of colorants and examples of their applications in food. Future trends in the research related to natural food colorants have also been reviewed.
Key findings and conclusion
The most commonly used procedure for obtaining natural colorants consists of several basic steps: extraction, filtration, concentration, and freeze-drying. Freeze-drying is one method which can yield good quality product from whole or part plants, including without the addition of color stabilizers. Some interesting future techniques could be the use of industrial waste, fruit peels, or petals of various flowers in the production of natural pigments. The freeze-drying technique could be ideal for functional additives that combine several functions (color, fiber, minerals, and vitamins). The determination of antiseptic properties of natural colorants obtained by freeze-drying is also valuable.
... Similar findings were also observed in jujube (Gao et al., 2012), blueberry (Kwok et al. 2004), and stinging nettle leaves (Garcìa et al. 2021). On the other hand, phenolic contents of pomelo peels (Rahman et al. 2018), mango, papaya, andwatermelon (Shofian et al. 2011), pineapple (Izli et al. 2018), black grape (Çoklar & Akbulut 2017), bilberry and raspberry (Michalczyk et al. 2009) have decreased after freeze-drying. The same observation was noted in this study where the TPC in bignay pomace decreased after freeze-drying. ...
... The findings of Michalczyk et al. (2009) on strawberry is consistent with the trend observed for bignay pomace where freeze-drying increased the total anthocyanin content. Çoklar and Akbulut (2017) also observed higher individual anthocyanins in the freeze-dried grape than in the fresh sample. ...
Bignay pomace is a processing byproduct that can be a source of bioactive compounds. However, a suitable dehydration method should be considered to efficiently valorize this waste material into high-value food ingredient and maximize its health-promoting properties. Bignay pomace was subjected to convection oven-drying and freeze-drying to investigate the effect of these pre-processing techniques on the physicochemical, bioactives, and antioxidant properties of the samples. Both drying methods significantly ( p <0.05) changed the total phenolic and anthocyanin contents of bignay pomace while flavonoids and tannins were not significantly affected. Freeze-drying of samples resulted in higher phenolic content (1742 vs. 1273 mg gallic acid equivalent/100 g DW) and anthocyanin content (496 vs. 223 mg cyanidin-3-glucoside equivalent/100 g DW) than convection oven-drying. Freeze-drying also resulted in higher antioxidant properties based on DPPH, ABTS radical scavenging activity, and FRAP assays. B ignay pomace extract was analyzed through HPLC (with photo-diode array detector) for its phenolic profile and nine compounds were identified, with catechin and epicatechin as the dominant components. HPLC analysis also showed that while the drying process does not influence the phenolic profile of the samples, it significantly affected the concentration of phenolic compounds present. The results of this study showed that freeze-drying is a more viable method to retain the majority of bignay pomace’s functional properties compared to convection oven-drying.
Graphical Abstract
... Compared to traditional dry food cooking methods, air-dried pet food typically uses low drying temperatures (usually below 100 • C) with gentle airflow for a long drying time [55][56][57]. Freeze-drying is beneficial in retaining the properties of the raw material better than the air-dried product [58]. However, both options provide end products that are minimally processed to help maintain the nutritional value of the raw material, which can be lost in traditional manufacturing processes. ...
Simple Summary: The pet food industry is growing rapidly globally. Although new products continue to be developed, research into their palatability still largely uses traditional methods. Testing focuses on the amount of food consumed, but little consideration is given to why differences are observed and which ingredients are most important. This review will discuss the feeding behaviour and nutritional requirements of dogs and cats, the main types of pet foods produced currently, and the current methods used for assessing palatability. Finally, the opportunities to use better methods to develop foods that are more palatable and understand the nutritional factors responsible for driving intake are discussed. Abstract: The pet food industry is an important sector of the pet care market that is growing rapidly. Whilst the number of new and innovative products continues to rise, research and development to assess product performance follows traditional palatability methodology. Pet food palatability research focuses on the amount of food consumed through use of one-bowl and two-bowl testing, but little understanding is given to why differences are observed, particularly at a fundamental ingredient level. This review will highlight the key differences in feeding behaviour and nutritional requirements between dogs and cats. The dominant pet food formats currently available and the ingredients commonly included in pet foods are also described. The current methods used for assessing pet food palatability and their limitations are outlined. The opportunities to utilise modern analytical methods to identify complete foods that are more palatable and understand the nutritional factors responsible for driving intake are discussed.
... As regards flavonoids, they are an important class of polyphenols with diverse biological activities [23,24]. Its content is also higher in the peel than in the orange pulp. ...
The large amount of waste generated by the orange juice industry has sparked the interest of many researchers in incorporating recycling systems and following a much more sustainable circular economy model. This work proposes the valorization of the co-product generated in the orange juice extraction industry after freeze-drying for its subsequent reuse as a natural ingredient in the food industry. In addition, the possible protective effect of gum Arabic and corn starch esterified with octenyl succinic groups, in proportions optimised in previous studies 0.25 and 0.45 g/g orange co-product dry solutes, on the main bioactive compounds of orange peel during the freeze-drying process has been studied. The samples were characterised for their content of vitamin C (ascorbic and dehydroascorbic acids), flavonoids (hesperidin and narirutin), total phenols and total carotenoids, as well as their antioxidant capacity (DPPH and FRAP assays). In addition, samples were digested, mimicking the human enzymatic oral gastro-intestinal digestion process, and the bioaccessibility of the bioactive compounds was evaluated. It was observed that the addition of both biopolymers improved the stability of the hydrophilic compounds during freeze-drying. This conservative effect was more remarkable for higher biopolymer concentrations. However, no protective effect on carotenoid compounds was observed. This trend was reflected in the antioxidant activity of the different samples. In addition, the incorporation of biopolymers improved the bioaccessibility of the bioactive compounds studied. In conclusion, the results supported the feasibility of the freeze-dried orange juice co-product as a natural, sustainable source of health-promoting compounds.
... This will increase the exposure time of anthocyanins to heat and thus increase their degradation [47]. Meanwhile, powders of FD-J exhibited better preservation of anthocyanins (>90%) due to the low drying temperature, which has also been reported in previous studies [48,49]. ...
The most widely-used wall materials for spray-dried microencapsulation have limitations in cost-effectiveness, health benefits and sustainability. Wood hemicelluloses, by-products of the forestry industry, including galactoglucomannans and glucuronoxylans have the potential to be utilized as innovative wall materials. This study investigated the applicability of galactoglucomannan and glucuronoxylan and their mixtures with carboxymethylcellulose as wall materials for microencapsulation of bilberry juice, in comparison to gum arabic. The results indicated that galactoglucomannan and glucuronoxylan have a relatively high anthocyanin encapsulation efficiency (71–73%), which was similar to that of gum arabic (76%). The addition of carboxymethylcellulose reduced the encapsulation efficiency of wood hemicelluloses to 46–54%. Microencapsulated powders prepared with wood hemicelluloses were considerably higher in total phenolic content and antioxidant activities than those prepared with gum arabic, and mixtures of wood hemicelluloses with carboxymethylcellulose. The results indicate that wood hemicelluloses are efficient wall materials for spray-dried microencapsulation of bioactive compounds.
... Anthocyanin degradation was positively affected by air temperature and got reduced by 60 to 70% after drying (Mussi et al., 2015). Freeze dried products retained the properties of raw material as compared to the air dried products (Michalczyk et al., 2009). It indicated that low temperature and vacuum helps in retaining the anthocyanin during drying operation. ...
Java plum seeds and skin wastes recovered after passing fruits through a pulper were separated manually and dried in tray/fluidised bed drier at 50, 70 and 90˚C or in freeze drier at-55°C at 4.4 torr. Drying behaviour of java plum seeds and skin followed falling rate period and described adequately by Page's model. Drying rate constant was higher for fluidized bed drier varying from 0.00163 to 0.255406 h-1 for seeds and 0.002042 to 0.004258 h-1 for skin followed by tray and freeze drier. Anthocyanin content of freeze dried java plum skin was 1944 mg/100 g dry basis but high drying temperature resulted in lower anthocyanin retention in tray and fluidized bed driers. 'L' and 'b' value of java plum seeds increased but 'a' value decreased. Free radical scavenging activities of fresh java plum seeds and skin were 92.41 and 93.42%, respectively which decreased after drying.
... Other method with good ability to preserve this type of compounds is vacuum freeze-drying. Michalczyk et al. (2009), De Torres et al. (2010 and Valadez-Carmona et al. (2017) compared the effect of air-drying and freeze-drying on the content of polyphenols in different foods. These authors concluded that freezedrying is the most convenient technique to preserve these bioactives, since low temperatures and the practical absence of oxygen allow them to remain unchanged. ...
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
... Several problems of air-drying, such as slow process, insect infestation, low quality in nutritional composition, and hygiene, have revealed the need to develop alternative drying methods [15,16]. Freezedrying (FD) or lyophilization is the protection technique that takes place through a process called sublimation for the drying of the material [17]. The water contained in the sample is frozen first, and the iced water is removed by sublimation. ...
... Flower petals have multicolored pigments, which attract manufacturers for the production of natural food colorants [1][2][3][4]. Anthocyanins are pigments found in fruits, flowers, and other plant structures [5], and provide a red or blue color [6,7]. Previous studies have shown that flowers that have an intense red or blue color have a high content of these pigments [8,9]. ...
Although the health benefits of cornflower extracts are known, their application in food production has not been widely investigated. This study assessed microencapsulated red powders (RP) prepared from the aqueous extract of blue cornflower petals. Microencapsulation was performed by freeze-drying using various stabilizers, such as maltodextrin, guar gum, and lecithin. The microencapsulated RP were characterized by spectral (FT-IR and FT-Raman), mineral, structural, and antioxidant analyses. The FT-IR and FT-Raman band related to guar gum, lecithin, and maltodextrin dominated over the band characteristic of anthocyanins present in the cornflower petal powders. The main difference observed in the FT-Raman spectra was attributed to a shift of bands which is reflection of appearance of flavium cation forms of anthocyanins. The microencapsulated RP had total phenolic content of 21.6–23.4 mg GAE/g DW and total flavonoid content of 5.0–5.23 mg QE/g. The ABTS radical scavenging activity of the tested powders ranged from 13.8 to 20.2 EC50 mg DW/mL. The reducing antioxidant power (RED) of the powders was estimated at between 31.0 and 38.7 EC50 mg DW/mL, and OH• scavenging activity ranged from 1.9 to 2.6 EC50 mg DW/mL. Microencapsulated cornflower RP can be valuable additives to food such as sweets, jellies, puddings, drinks, or dietary supplements.
... According to the knowledge of the authors, the comparative studies concerning the antioxidant properties of the dried and lyophilised E. umbellata berries have not been carried out until now. Similarly as in the present study, the lyophilised berries protected more strongly from the oxidative processes in comparison to the dried fruits in the case of wild rose (Rosa rugosa), strawberry tree (Arbutus unedo), [26], raspberry (Rubus ideaus L.), strawberry (Fragaria ananassa) and blueberry (Vaccinum myrtillus) [27]. ...
Fruits of autumn olive (Elaeagnus umbellata) are the abundant source of
antioxidative substances such as carotenoids, polyphenols, flavonoids, fat-soluble
vitamins and Vitamin C. The conducted study was aimed at the selection of the optimum
method for extraction of berries. To this end, two methods for preservation of the berries
were compared: drying at 60°C and freeze-drying (lyophilisation) and two types of
solvent, employed in the extraction: water and methanol. The results showed that the
methanol extracts produced from lyophilized fruits were characterized by the highest
antioxidative activity
... After soaking the freeze-dried goji berries into warm water, it can be observed that dried goji berry absorbs water easily and quickly restore to the original state, then the flesh floating on the surface of the water. [70] Overall, the advantage of freeze-drying goji berry is that the original shape, taste, flavor, and nutrition of the berries are preserved quite well compared with other drying methods and in addition, [71] the final consumers can discover a very different dried goji berry product with crispy structure, which may open new business opportunities for goji processors. However, the frail and crumbling texture can also become a disadvantage, because dried goji berries keep their original shape and size, meaning that they might require extra transportation and storage space and also special package. ...
Goji berry, as a kind of typical and special agricultural material, has high water content, high sugar content, thin epidermis with waxy covering, and dense fleshy cell structure, which makes the drying process more complex than the dehydration of other bio-materials. To obtain high drying efficiency and the high quality products, most researchers have paid much attention on the different kinds of pretreatment and drying technology. This study aimed to examine all the corresponding published data in the literature and to compare the drying characteristics and quality of wolfberry dried by conventional and advanced wolfberry drying methods as well as different drying parameters. We conclude that heat pump drying with simultaneous control of temperature and humidity could replace traditional hot air drying in commercial production to increase the drying efficiency and quality of wolfberry. Infrared drying and microwave drying can be combined with other drying methods to improve drying efficiency; freeze drying, pulsed vacuum drying and electro-hydrodynamic drying are conducive to maintain the appearance and nutrients as well as higher rehydration ratio because of more porous microstructure compared with hot air drying. In addition, this study gives some suggestions and new horizons for directed wolfberry drying development both on the research and application in the future. © 2022 Chaojing Cui, Dandan Zhao, Jin Huang and Jianxiong Hao. Published with license by Taylor & Francis Group, LLC. © 2022, Published with license by Taylor & Francis Group, LLC.
... Of, these, freeze-drying has been claimed to be the most beneficial, due to its viability in preserving nutrients and aroma compounds, but, at the same time, it is the most expensive method. Therefore, air-drying is still in use, as it is relatively inexpensive, and because the dried material does not require any special storage conditions, unlike the freeze-dried one [8,12], even though it often modifies the composition and sensory traits of the dried material. ...
The leaves, inflorescences, and fruits of hawthorn have long been known for their therapeutic properties. A wide range of hawthorn products, including liqueurs, are manufactured, due to the technological potential of the raw material as well as the richness of its volatile compounds. This study aimed to determine the effect of the liqueur production method and various methods of fruit preservation on the quantitative and qualitative composition of volatile compounds in the liqueurs produced. Hawthorn fruits saturated with sucrose and non-saturated with sucrose, fresh or preserved through one of three methods: freezing, air-drying, and freeze-drying, were used for liqueur preparation. The samples were analyzed using a gas chromatograph–mass spectrometer. They were found to contain 54 volatile compounds classified into 12 groups of chemicals. All 54 identified volatile compounds were detected in the liqueur made from hawthorn fruits non-saturated with sucrose and preserved by freeze-drying. In this liqueur type, 12 of the identified volatile compounds occurred in the highest concentration when compared to the other treatments. Among all volatiles, the following compounds were present in the analyzed liqueurs in the highest concentrations: dodecanoic acid ethyl ester (11.782 g/100 g), lactones (6.954 g/100 g), five monoterpenes (3.18 g/100 g), two aromatic hydrocarbons (1.293 g/100 g), isobensofuran (0.67 g/100 g), alcohol—2-methyl-2-propanol (0.059 g/100 g), and malonic ester (0.055 g/100 g). Among all analyzed liqueurs, the one made from the fruits non-saturated with sucrose and frozen was characterized by the smallest diversity of volatiles, which were present in the lowest concentrations in that liqueur.
... A significantly higher AO activity was determined in the fresh raspberry than in strawberry, which is well correlated with literature data (Beekwilder et al., 2005;Michalczyk et al., 2009;Milivojević et al., 2011Milivojević et al., , 2013. Interestingly, although strawberry demonstrated a significantly higher content of the AA compared to raspberry (67.36%), a significantly higher AO was recorded in raspberry fruits. ...
The effects of different freezing methods and long‐term frozen storage on quality of strawberry and raspberry were investigated, i.e. the retention of initial property and free radical scavenging (AO) activity after Individual Quick Freezing (IQF) and conventional (discontinuous) freezing. The physicochemical properties, vitamin C and AO activity were more affected by long‐term frozen storage than by freezing itself; however, their better retention was obtained after IQF. Moreover, AO activity was found to be higher in frozen samples compared to fresh fruits, but significant decrease was detected after 8 months of frozen storage. Despite the significantly higher initial content of vitamin C in strawberry, it demonstrated a lower AO activity than raspberry. Sensory attributes were significantly affected by the freezing; the most considerable changes were recorded on their texture/firmness, especially after conventional (slow) freezing. Therefore, IQF can generally be suggested as a more suitable method of preserving these delicate fruits than slow freezing.
... In particular, the samples D 50 and D 100 showed an anthocyanin retention after drying of 9.7 ± 2.2 and 27 ± 2.5% respectively, when compared to the initial anthocyanin content, while in the D Control sample it was only 7.0 ± 1.7%. The degradation of anthocyanins depends, among other factors, on polyphenol oxidase activity, organic acid content, pH and temperature [45,46]. Anthocyanins are also easily susceptible to the degradation during storage and especially during heat processing [47,48]. ...
Novel products that carry concrete and relevant health benefits, with texture and flavor not substantially different from already available products, are generally well accepted by consumers. Vacuum impregnation is a non-thermal technology that allows the enrichment of fruit with different ingredients in solution. The characteristic of the resulting product is a combination of both the solid matrix and the impregnation solution. This work aimed at: (i) evaluating the effect of trehalose on anthocyanin retention after drying of apple snacks vacuum impregnated with blueberry juice; (ii) modelling the air-drying kinetic, proposing an image analysis approach to monitor the drying process. Four mathematical models successfully fitted the drying experimental data, obtainingequations that could be used in the implementation of this process at industrial scale. The drying kinetics of samples impregnated with blueberry juice and trehalose were faster when compared to the control sample. Samples impregnated with blueberry juice and 100 g/kg of trehalose retained nearly four times more anthocyanin after drying when compared to the control.
... mg QE/100 g in G. pedunculata. The loss of flavonoids during drying may be due to the process conditions, in particular, the temperature and duration (Michalczyk et al., 2009;Schieber et al., 2001). Effect of slice thickness, drying methods and their interaction were significant for flavonoid content. ...
Aim: The present study was undertaken to establish a suitable drying process for Garcinia cowa and Garcinia pedunculata fruits for maximum retention of their nutritional qualities. Methodology: Slices of three different thickness with 0.3, 0.6, 0.9 cm of G. cowa and G. pedunculata fruits were dried by sun drying, solar drying and by cabinet drying at three different temperatures (50°C, 70°C and 90°C). Results: The mean crude fat and ash content were higher in G. cowa than G. pedunculata while later was found rich in crude protein and Fe contents. Total phenol content ranged between 881.31-888.65 and 719.00-736.74 mg gallic acid equivalent 100 g-1, total flavonoid content between 89.21-90.06 and 51.00-52.54 mg quercetin equivalent 100 g-1 and mean HCA contents ranged between 3.13-3.92% and 1.84-1.99% for G. cowa and G. pedunculata, respectively. The methanolic extracts exhibited significant antioxidant activity. With lower IC50 values, G. cowa had higher antioxidant activity than G. pedunculata. Interpretation: Oven drying at 50°C and 0.9 cm slice thickness for drying resulted in better retention of total phenolic and flavonoid contents with better antioxidant activities.
... The results revealed a high VC and TP stability after freeze-drying. The fact that the FDP samples had higher values than the P can be justified by assuming an easier extraction of the compounds in the freeze-dried products, related to their higher porosity (Michalczyk, MacUra, & Matuszak, 2009). ...
Dehydrated fruit puree may be a convenient way to promote the healthy consumption of fruit based foods. Drying carriers, highly used by the food industry to stabilize dried fruit products, may show a potential encapsulating capacity of the biocompounds, that could also limit their bioaccesibility. This study analyzed the impact of gum Arabic (GA), bamboo fiber (BF), native corn starch, starch substituted with octenylsuccinic groups, pea fiber, and maltodextrin on the in vitro bioaccessibility of vitamin C (VC), total phenols (TP), and β-carotene, as well as on the antioxidant capacity during the freeze-drying and in vitro digestion of an orange puree. Amongst the formulations studied, GA+BF was the most effective for phytochemicals protection of the freeze-dried orange puree during the intestinal stage of digestion, resulting in a higher TP and VC bioaccessibility (59% and 36%, respectively).
... Moreover, the quantity of anthocyanins can be affected by process conditions. Our study confirms, as has been shown in research that the freeze-drying method is the best method to protect phenolics and anthocyanins, it has been reported in many studies before [20,21]. Freeze drying is a useful method to preserve color, flavor, and nutrient compounds due to the lack of water, low pressure and temperature [22]. ...
Natural phytonutrients in foods, including anthocyanins, can play an important role in human health. Anthocyanins have been reported to cause many various useful effects, such as reducing cancer cell proliferation, regulating blood pressure, preventing tumor formation, and preventing diabetes. In this study, we aimed to reveal the qualitative anthocyanin content, antiproliferative and antimicrobial effects of different extracts derived from Vaccinium myrtillus, Vaccinium corymbosum, Sambucus nigra and Aronia melanocarpa. The anthocyanin content of the plants mentioned in the study was characterized after the freeze-drying process. MTT assay was chosen to determine the antiproliferative effect of extracts on colorectal cancer cells. Antimicrobial effects of extracts were studied on typical and clinical strains of five different bacteria. As a result, it was determined that the anthocyanin content in the extracts obtained by the freeze-drying method was acceptable, and some extracts were found to have a strong antiproliferative effect on colorectal cancer cells and have an antibacterial effect on typical and clinical strains. Conclusionally, it has been shown that anthocyanins, which are reported to have many beneficial effects, are very promising when prepared with a relatively new method, and this study is a pioneer study for possible future pharmacological and in vivo studies.
... The most significant damages were observed in bilberries, for which a sharp decrease in polyphenols was observed up to the sixth month (freeze-dried and air-dried fruit), as well as in anthocyanins, up to the second month of storage (freeze-dried fruit). During the following storage stages of bilberries and other fruit, the changes progressed gradually [36]. ...
Chokeberry fruit exhibits a high level of pro-health potential, associated with a significant amount of polyphenol content and antioxidant activity. The fruit is easily perishable and therefore needs to be processed in short order to ensure its availability throughout the year. For this purpose, the fruit is dried, which has an impact on the preservation of bioactive components such as polyphenols. In the study, chokeberry fruit was influenced by a suspension of spices, including clove and cinnamon, and subsequently dried using the freeze-drying, convection, and microwave radiation methods. Freeze-drying was concluded to be the most desirable method of drying, which preserves the largest amount of polyphenols while soaking fruit in a suspension of cinnamon or cloves accelerated the loss of anthocyanins during the storage period. The obtained test results may constitute a valuable source of information for manufacturers in designing new products with increased pro-health potential, whose properties result from the high content of polyphenols and other plant additives.
... Also, the quantity of anthocyanins can be affected by process conditions. As in our study, the freeze-drying method is the best method to protect phenolics and anthocyanins, it has been reported in many studies before [14,15]. Freeze drying is one of the useful methods to preserve colour, flavour, and nutrient compounds due to the lack of water, low pressure and temperature [16]. ...
Natural phytochemicals in foods, including anthocyanins, can play an important role in human health. Anthocyanins have been reported to cause many various useful effects, such as reducing cancer cell proliferation, regulating blood pressure, preventing tumour formation, improving eyesight, and preventing diabetes. In this study, we aimed to reveal the qualitative anthocyanin content, antiproliferative and antimicrobial effects of different extracts derived from Vaccinium myrtillus, V. corymbosum, Sambucus nigra and Aronia melanocarpa. The anthocyanin content of the plants mentioned in the study was characterized after the freeze-drying process. MTT assay was used to determine the antiproliferative effect of extracts on cancer cells. Antimicrobial effects of extracts were studied on typical and clinical strains of 5 different bacteria. As a result, the anthocyanin content in the extracts obtained was determined to be quite good with the freeze-drying method, and it was also determined that the extracts had various levels of antiproliferative and antibacterial effects.
... This explanation was also supported by Mrad et al. [56]. However, Michalczyk et al. [57] reported that the antioxidant capacity of dried berries was retained during prolonged storage to a remarkably high degree, which is in contrast with the results from this present study. ...
This study investigated the effect of hot-air and freeze-drying on the physicochemical, phytochemical and antioxidant capacity of dried pomegranate arils during long-term cold storage (7 ± 0.3 • C, with 92 ± 3% relative humidity) of whole fruit over a single experiment. Extracted arils were processed at monthly intervals during 12 weeks of cold storage of whole fruit. After the 12-week storage period, hot-air and freeze-dried arils showed the least (3.02) and highest (23.6) total colour difference (TCD), respectively. Hot-air dried arils also contained 46% more total soluble solids (TSS) than freeze-dried arils. During the storage of pomegranate fruit, total phenolic content (TPC) steadily increased from 20.9 to 23.9 mg GAE/100 mL and total anthocyanin content (TAC) increased from 6.91 to 8.77 mg C3gE /100 mL. Similarly, an increase in TPC and TAC were observed for hot-air (9.3%; 13%) and freeze-dried arils (5%; 5%), respectively. However, the radical scavenging activity (RSA) reduced by 8.5 and 17.4% for hot-air and freeze-dried arils, respectively, after 12 weeks of cold storage. Overall, the parameters such as colour, TPC and TAC as well as the lower degradation in RSA stability during storage showed distinct differences in quality when using the freeze-drying method, which is, therefore, recommended.
... Fresh black plum fruits were processed into juice based on the methodology outlined by Skrede et al. (2000) and dried plums according to Michalczyk et al. (2009) to assess the impact of processing on their functional properties. Black plum fruits (20 g) were crushed and the juice was removed by squeezing with a muslin cloth. ...
Influence of drying, juice processing, and simulated enteric digestion on bioactive constituents and bioactivity of Syzygium caryophyllatum fruit was assessed and compared with fresh blueberry (Vaccinium angustifolium). Methanolic extracts of fresh fruits and processed products and digesta at different digestion phases were analyzed for phenolics, flavonoids, anthocyanin, β‐carotene, lycopene, and ascorbic acid contents, and antioxidant activities. The results indicated that fresh black‐plum possesses higher bioactives content and antioxidant activities compared to processed black plum. The contents of bioactives and antioxidant activities reduced gradually due to gastrocolic digestion. Bioaccessibility and bioavailability of bioactives from blueberry, black‐plum, and its products showed significant variations. These results highlighted that the alterations in contents of bioactives and antioxidant activities of black‐plum due to drying, juice processing, and gastrocolic digestion could potentially influence on bioaccessibility and dialysis or potential bioavailability of bioactives found in black‐plums.
Practical applications
The present research produced a comprehensive cognition regarding alterations in the contents of bioactive constituents and antioxidant activity of black plum due to drying, juice processing, and gastrointestinal digestion, which can function as a new source of functional food.
... Lyophilization is a more costly and slower technique compared to oven-drying because it needs a vacuum and it could take several days to reduce the water content in the pomace to the desired level (Galanakis 2012). Due to the low temperature conditions, however, this technique could protect the phenolic compounds from thermal degradation, retaining the high-degree antioxidant activity in the substrate (Michalczyk et al. 2009). For instance, mango peel and kernel residues subjected to freeze-drying showed superior phenolic content and antioxidant activity to samples treated with oven, cabinet, vacuum and infrared-drying techniques (Sogi et al. 2013). ...
Phenolic antioxidants have increasing attention in the food industry as functional food additives or as alternative preservatives. Plant residues, including various food processing wastes, can contain such chemicals in high amount, but most of them are in glycosidic form having reduced bioavailability. Numerous studies have reported that the solid-state fermentation with cellulolytic fungi and the carbohydrase-assisted extraction are exploitable techniques for mobilization of phenolics from glycosides. The extracted phenolic compounds can enhance the stability and shelf life of food products, increase their antioxidative capacity, and inhibit the growth of a range of microorganisms. This chapter aims to highlight the relevance of fermentation and enzyme-catalyzed approaches in bioactive phenolics production from plant materials. In line with this, antioxidative plant residues as potential phenolics sources, as well as fermenting fungi and enzymes suitable for the high yield production have been presented in detail. Factors determining the effectiveness of treatments, some combination studies with conventional extraction procedures, and possibilities for the ecofriendly production of carbohydrase cocktails have been discussed.
... The most popular fruit in Poland is the strawberry (Gajdoš Kljusurić et al., 2016). Also, chokeberry and elderberry are becoming more and more popular due to their antioxidant properties (Michalczyk et al., 2009). The chokeberry in particular exhibits such potential (Lipińska et al., 2017). ...
... The higher content of these bioactive compounds in the freeze-dried products may be due to the lack of oxygen and the low drying temperature during freeze-drying, which largely prevented the degradation reactions and/or enzymatic reactions (Ratti, 2001). The degradation reaction was mainly related to factors such as air and temperature, which are inhibited under freeze-drying conditions (Macura and Matuszak, 2009). The enzymatic reaction was mainly initiated by polyphenol oxidase, which lost its activity at low ...
The effect of three different drying methods (hot-air, combined hot-air-microwave, and vacuum-freeze) on the sensorial, textural, nutritional, and other quality characteristics of persimmon chips was compared. The result showed that the freeze-dried chips had the best nutritional and quality features. However, persimmon chips processed by combined hot-air-microwave and freeze-techniques had the same sensory score (85.40 points), which were higher than that of hot-air dried samples (70.51 points). Additionally, persimmon chips dried with aid of hot-air technique had the lowest chewability value and hardly met the panelists’ requirements. These disadvantages could be avoided by using a combined hot-air-microwave drying method with lower power consumption compared with the others. The optimized combining microwave and hot-air drying conditions were as follows: 1 mm thickness of persimmon slice, a temperature of 70 °C at an air velocity of 1.0 m/s of initial hot-air drying system until the moisture content of persimmon samples reached 10% (about 150–160 min) and 10.7 Wg⁻¹ of the following microwave-drying system. It was concluded that the combined hot-air-microwave drying technique could be used for processing persimmon chips with high quality and nutritional values as well as low operating costs.
... However, as the storage period progressed, the retention of total phenolic compounds became distinctly higher in the air-dried product. Several studies have found that freeze-drying results in superior retention of phenolic compounds than air-drying in a variety of dried and stored fruits and vegetables (Korus, 2011;Michalczyk et al., 2009;Tseng and Zhao, 2012). However, Tseng and Zhao (2012) reported that losses during storage were smallest in air-dried wine grape pomace and that the highest final content of phenolic compounds in freeze-dried products was mainly due to the small losses occurring during the freeze-drying process. ...
... However, as the storage period progressed, the retention of total phenolic compounds became distinctly higher in the air-dried product. Several studies have found that freeze-drying results in superior retention of phenolic compounds than air-drying in a variety of dried and stored fruits and vegetables (Korus, 2011;Michalczyk et al., 2009;Tseng and Zhao, 2012). However, Tseng and Zhao (2012) reported that losses during storage were smallest in air-dried wine grape pomace and that the highest final content of phenolic compounds in freeze-dried products was mainly due to the small losses occurring during the freeze-drying process. ...
Background:
In stored freeze-dried orange carrots, carotenoids are not stable compounds. The aim of the work was to evaluate the stability of carotenoids in products obtained from polyphenol-rich purple carrots which additionally contain anthocyanins.
Methods:
This study compares the effect of air-drying and freeze-drying as well as 6-month storage on the content of carotenoids, anthocyanins and total phenolics in dried products obtained from purple carrot.
Results:
The phenolic compounds found in the greatest amounts in carrot were ferulic acid cyanidin 3-xylosylglucosylgalactoside, p-coumaric acid cyanidin 3-xylosylglucosylgalactoside, chlorogenic acid, and caffeic-quinic acid. Freeze-drying did not significantly reduce levels of carotenoids and anthocyanin content, while air-drying led to substantial losses of carotenoids, anthocyanins and polyphenols. 6-month storage of freeze-dried products caused losses of carotenoids, anthocyanins and total polyphenols of 42%, 33% and 53% respectively when compared with the raw material. In air-dried products, the losses were 66%, 33% and 36%, respectively.
Conclusions:
The results indicate that the combined effect of freeze-drying and 6-month storage was reduced losses of carotenoids compared to traditionally dried products.
... The glycosides of anthocyanidins produce a red color under acidic conditions (Khoo, Azlan, Tang, & Lim, 2017;Rababah, Ereifej, & Howard, 2005). The most abundant anthocyanins in raspberries, in a descending order by weight, are cyanidin-3-sophorosid, cyanidin-3-glucoside, and cyanidin-3-rutinoside (Michalczyk, Macura, & Matuszak, 2009). Raspberries also contain ascorbic acid (AA), an important antioxidant with a wide variety of health-promoting properties (Cetojević- Simin et al., 2015;Martí et al., 2018). ...
Foamed fruit purees can be dried and consumed as snacks. This study compares the characteristics of foamed raspberry puree dried via microwave-assisted freeze drying and conventional freeze drying. The effect of potato protein (PP) (as a foaming agent), maltodextrin (MD) (as a foam stabilizer), and microwave power on the product characteristics was investigated. The puree contained 18%–20% higher content of anthocyanins and ascorbic acid than unprocessed raspberries. The retention of ascorbic acid and anthocyanins increased with increasing concentrations of MD and PP. Both drying methods resulted in 66%–81% retention of ascorbic acid and 53%–84% retention of total anthocyanins. The higher drying rates obtained at higher maltodextrin concentrations resulted in higher ascorbic acid and anthocyanin retention. The total color difference was significantly
higher for the foam with 30% MD (w/w) at 2.0Wg−1, accounting for the formation of hot spots. Protein concentration did not have a considerable effect on product color. Increasing the maltodextrin concentration yielded a harder foam structure, while increasing the protein concentration had the opposite effect. Overall, microwave-assisted freeze drying was found to be a promising alternative to conventional freeze drying, as it offers a more efficient drying process with comparable product quality.
... These results suggest that changes depend on sample characteristics and on the native compounds found in its fresh form. Michalczyk et al. (2009) reported that freeze-drying in raspberry (Rubus ideaus L.), strawberry (Fragaria ananassa Duch), and bilberry (Vaccinum myrtillus) retained the raw material properties in storage better than the air-dried products. This was especially true for total phenolics and anthocyanin contents as well as for antioxidant properties, despite the great losses of these compounds by processing. ...
Polyphenol compounds are synthesized in plants as secondary metabolites in response to ecological and physiological stresses such as adverse climate, insect attack, UV radiation, and wounding. The basic structural feature of phenolic compounds is an aromatic ring bearing one or more hydroxyl groups. Plant polyphenols are classified as simple phenols or polyphenols based on the number of phenol units in the molecule. Thus, plant polyphenols comprise simple phenols, coumarins, lignins, lignans, condensed and hydrolyzable tannins, phenolic acids, and flavonoids.
Plant foods (including fruits, cereal grains, legumes, and vegetables) and beverages (including tea, coffee, fruit juices, and cocoa) are major sources of polyphenols in the human diet. However, processing of foods and food ingredients often exerts a major effect on their constituents. For instance, most of the vegetables that we consume are cooked by being boiled in water or microwaved. These processes bring about a number of changes in the physical characteristics and chemical composition of vegetables. Sahlin et al. (2004) showed that boiling and baking had a small effect on the ascorbic acid, total phenolics, lycopene, and antioxidant activity of tomatoes, while frying significantly reduced the ascorbic, total phenolic, and lycopene contents of tomatoes. Additionally, Rocha-Guzmán et al. (2007) reported that processes such as pressure-cooking affected not only
the total polyphenols concentration, but also their distribution in the different effluents of the process (e.g., bean seeds and cooking water).
For this reason, we summarize the information on some common processes used for food products and their effect on polyphenols based in the current scientific literature.
... A similar fall was observed for anthocyanin on samples. [96] Neither IR nor freezing rate had significant effect on the polyphenol content of VFD Murtilla berries. [97] Pressure and sample size where found to have a negative effect, while IR did not reach significance on polyphenol content of blueberries after FD. ...
The aim of this paper is to review the effects of several different types of freeze-drying processes on some nutritional properties of foodstuff. Both the vacuum freeze-drying (VFD) process and the atmospheric freeze-drying (AFD) process have been considered, as well as the possibility of accelerating both using ultrasound (US), microwave (MWD), infrared (IR) heating, and other techniques. The effects of these processes on ascorbic acid, phenolic compounds, and total antioxidant capacity have been extensively reviewed in this paper, as these molecules were widely investigated in the literature. Finally, a summary of effects on other less recurrent studied compounds is also presented. It appears that for vitamin C, VFD most of the time gives the best results; MWD and IR combined processes with VFD seem to be able to decrease processing time, while having a mild effect on product quality. With respect to phenolic compounds and total antioxidant capacity, VFD and AFD seem to have fairly similar effects, with a mild effect of IR and US.
... It is thought that these differences may be attributable to several factors, including the genetic characteristics and growing conditions of the pomegranate, the different drying and storage conditions of pomegranate peel, and the different production steps of foodstuffs related to such aspects as heating conditions, drying conditions, etc. (Fang & Bhandari, 2011;Korus, 2011;Lohachoompol, Srzednicki, & Craske, 2004;Michalczyk, Macura, & Matuszak, 2009;Toledo & Burlingame, 2006;Zilic, Kocadağli, Vancetovic, & Gökmen, 2016). ...
Pomegranate (Punica granatum) peel is known as a good source of biologically active food components, and in this research, the potential use of pomegranate peel in muffin cakes was studied. Wheat flour was partially (5, 10, and 15%) substituted with pomegranate peel powder. Pomegranate peel powder increased apparent viscosity values of cake batters. Pomegranate peel addition caused a significant (p < 0.05) increase in insoluble and total dietary fibers, total phenolics, Mg, Ca, and K contents, and total antioxidant activity values. It was found that crumb and crust Hunter L and b values and crust Hunter a value decreased (p < 0.05) by increasing the amount of pomegranate peel. Specific volume, symmetry index and uniformity index values of all cakes were similar. The addition of pomegranate peel significantly (p < 0.05) increased hardness and decreased springiness values. Control cakes and cakes having 5 and 10% pomegranate peel received similar scores in smell and flavor.
Practical applications
In this study, significant increases were determined in insoluble and total dietary fibers, total phenolics, Mg, Ca, K contents, and total antioxidant activity values of cakes by adding pomegranate peel to the formulations. But increasing the pomegranate peel level in cakes caused increasing in hardness values in texture analysis, and decreasing in crumb cell structure and chewiness scores in sensory analysis. So, we can suggest to increase liquid phase ratio in cake batters for cakes having pomegranate peel. When we take into account that increasing the pomegranate peel to 15% caused significant reductions in smell, flavor, and color scores, it is advisable not to exceed 15% in pomegranate peel addition. The results show that using pomegranate peel in muffin cakes will be a good alternative for increasing the nutritional and functional properties of cakes, and pomegranate peel may also be considered as a potential functional ingredient in other food products.
... Most berries are rich in carbohydrates, amino acids, polyphenols, anthocyanins, with bioactive function of anti-virus, anti-cancer, antioxidant, anti-fatigue, and improve hypertension. The fresh berries are highly susceptible to various mechanical damages and physical-chemical changes in harvest, storage, and transportation processes, due to the characteristic of the juiciness, soft texture, and high temperature of harvest season [28][29][30]. The sensory quality and nutritional value of the berries were seriously affected, resulting in discoloration, decay, and moldiness [31][32][33]. ...
Fresh berries containing in bioactive compounds are perishable under natural conditions. Drying is one of the most effective processing techniques to extending the shelf life of berry products, and the nutrients and active components of berries can be retained to a great extent. However, the flavor and texture of the final product considerably correlate with drying techniques. Therefore, the present reviewed work summarizes the research progress of berry drying technology by the perspectives of traditional drying technology and innovative drying concepts and explores the research situation of convective drying, freeze drying, vacuum drying, microwave drying and innovative drying technology for berry drying. The dehydration mechanism, pretreatment methods, and drying technology of various berries were summarized. And the effects of different drying treatments on nutritional components of berry drying were presented; application status of mathematical modeling employed in berry drying was also discussed. Moreover, the research direction and development trend of berry drying techniques in the future were pointed out, which are aimed at improving the drying efficiency of berries, preserving the active components of berries to the greatest extent, and promoting the processing utilization of berries and economic benefits in the future to provide a reference for further research and utilization of drying technology.
... Our study showed that different drying methods applied on C. nutans had significant effects on the composition of phytochemical contents in the samples. Evidently, the loss of TPC during drying was due to the drying conditions, in particular the temperatures and duration used (Michalczyk et al., 2009). According to Davey et al. (2000), the drying process can affect the phytochemical contents by thermal breakdown. ...
Background: Clinacanthus nutans, also known as ‘Sabah snake grass’ or ‘Belalai gajah’, is a herb well known locally for its medicinal values. The primary chemical constituents of the leaves are schaftoside, vitexin, isovitexin, orientin and isoorientin, and antiviral activity is shown by two glycoglycerolipids. Despite the importance of C. nutans, complete information with respect to commercial production and postharvest handling of the herb in the local herbal industry is still lacking. Thus, the objective of this study was to determine the optimum postharvest handling processes that could retain the phytochemicals quality of C. nutans. Materials and Methods: The flavonoid compounds of C. nutans were analysed by using ultra fast liquid chromatography (UFLC). Total phenolic content and antioxidant activity were determined using a spectrophotometer. Results: The total phenolic compounds and antioxidant activity in C. nutans were found to be higher in the young vegetative stage than in the mature vegetative stage. Flavonoid compounds (schaftoside, isovitexin, vitexin and orientin) were also found to be highest in the young vegetative plant compared to the mature vegetative plant. All of the assayed phytochemicals and flavonoid compounds levels were found to be highest in oven dried samples compared to the sun, air and solar dried samples. Conslusion: This study suggests that oven-drying young vegetative C. nutans plant material is the optimum method to retain postharvest quality.
... Asami, Hong, Barett, and Mitchell (2003) and Wojdyło et al. (2009) found that freeze-dried strawberry preserved highest levels of total phenolic contents in comparison with other drying methods. Michalcayk et al. (2009) studied the effects of air-drying, freeze-drying and storage on the quality and antioxidant activity of raspberry, strawberry and bilberry. Their study showed the freeze-dried fruits retained the properties of the raw material better than the air-dried samples. ...
The effects of hot-air drying (AD), freeze drying (FD) and Refractance Window drying (RWD) on the retention of anthocyanins, phenolics, flavonoids, vitamin C and B, and antioxidant capacity (ORAC) in blueberries, tart cherries, strawberries, and cranberries, as well as organic acids and proanthocyanins in cranberries and chlorogenic acid and catchins in blueberries were evaluated. Changes in color, glass transition, specific heat, and surface morphology of the dried fruits were also evaluated. The quality retention in the dried fruits was found to be product and drying method specific. The FD products exhibited a better retention of vitamin C, ORAC, anthocyanins, and phenolics than the AD and RWD fruits. The RWD produced samples with a less effective ORAC, anthocyanins, and phenolics retention, but a higher total vitamin B retention compared to the FD products. The AD-dried fruits displayed significantly lesser quality retention in most of the quality indexes measured in the study.
... There are some studies regarding the amount of phenolic antioxidants in the berry fruit teas [8,9]. However, there are not enough studies which determine the chemical composition mainly in bioactive molecules and selected microelements and to demonstrate the antioxidant potential of the infusions prepared and ingested by people [10]. ...
Antioxidant activity was measured by ferric reducing ability of plasma (FRAP) assay in seven types of infusions prepared from commercial dried berry fruit products: Rosa canina, Vaccinium vitis-idaea, Hiphophae rhamnoides, Hibiscus sabdariffa and three fruit mixtures. Total polyphenols (TP), total anthocyanins and the polyphenolic compounds were determined by HPLC equipped with diode array detector. To estimate the amount of elements released from fruits into the water extracts, levels of Fe, Mn, Zn and Cu in dried samples and in infusions were determined by flame atomic absorption spectrometry. The correlation between polyphenols content and the antioxidant activities and the microelements in the infusions and the antioxidant activities were estimated using the Pearson’s correlation test. The results showed a high, positive and significant correlation (r = 0.9465) between the FRAP values and TP content, meaning that the concentration of phenolic compounds may be a good indicator of the reducing capacity in the infusions. Correlations varied (positive, negative and weak) between antioxidant and mineral extractability of berry infusions. Among the polyphenolic compounds, gallic acid contributed particularly to the antioxidant capacity of the studied samples (r = 0.563). The correlation of antioxidants, total polyphenols with mineral extractability showed the influence of antioxidant compound on mineral bioavailability.
... It was observed that k value was higher for cultivar with high initial total phenol content. Michalczyk et al. (2009) found that the polyphenolic and anthocyanin contents in bilberries were increasingly reduced with long exposure time and high temperatures. Mrad et al. (2012) reasoned that damage to the membrane ultrastructure caused by cutting pears in parallel-epipedic pieces, permits rapid oxidation of phenolics compounds leading to degradation. ...
The effect of shelf storage under ambient conditions of cut apple dices on degradation of bioactive compounds such ascorbic acid, total phenols, antioxidant activity (% DPPH inhibition) and PPO activity were investigated. The results indicated that antioxidant activity declined significantly over 80 min storage of diced apples at ambient temperature. Similar trend was observed for ascorbic acid, total phenols and PPO activity. Ascorbic acid, total phenols and antioxidant activity degradation followed first-order kinetics where the rate constant (k) was found to be in range for all the thirteen cultivars, though initial ascorbic acid and phenol content varied in different apple cultivars. The reaction rate constant (k) for first order degradation ranged from 1.16 to 1.97, 0.89 to 1.29 and 0.37 to 1.54 for antioxidant activity, total phenols and ascorbic acid, respectively. This explains that antioxidant activity degrades at higher rate than total phenols and ascorbic acid, which also corroborates that antioxidant activity is affected by both total phenols and ascorbic acid content. In general, total antioxidant activity for apple dices kept for 80 min under ambient conditions exhibited lower values as compared to control.
... During drying operation could be activated some oxidative and hydrolytic enzymes, which may lead to the losses of phenolic compounds. Other authors also report that more significant losses occur when phenolic compounds are exposed to long times at high temperatures (Mejia-Meza et al., 2008;Michalczyk, Macura, & Matuszak, 2009). These results were already expected, since it is known that thermal processing of fruits reduces their bioactive compound content (Mrad et al., 2012) 3.4 | Antioxidant activity The antioxidant activity is initially little affected by the temperature. ...
The aim of this study was to describe the drying kinetics of Bunchosia glandulífera pulp, as well as the changes in its phenolic compounds, carotenoid content, and antioxidant activity. The experiments were performed in a drying oven with forced air at 45, 65, and 85 °C, until the equilibrium moisture was reached. An increase in the mass transfer rate was observed at the highest temperature, with a subsequent decrease in the drying time. The drying curves exhibited a period of fast decline and an exponential trend was observed in all of them, validated using Page's mathematical model. The concentration of phenolic compounds and carotenoids decreased during the first minutes of drying. Bioactive compounds were the most sensitive to high temperatures and the antioxidant activity was mainly affected by the drying time.
The lipid profiles of the truffles with different treatments were determined by ultra-high-performance liquid chromatography-Quadrupole-Exactive Orbitrap mass spectrometry (UHPLC-QE Orbitrap/MS/MS) and the volatile organic compounds (VOCs) were identified by purge-and-trap-gas chromatography-mass spectrometry (P&T-GC-MS). A total of 37 lipid molecular species and 28 VOCs were tentatively identified. Lysophophatidylcholine (LPC), triacylglycerol (TG) and sphingomyelin (SM) in heat-drying truffles, phosphatidic acid (PA) in freeze-drying and fresh truffles might be the key lipids that bound VOCs. Furthermore, the correlation between lipids and VOCs were analyzed by 19 differential lipids and 7 VOCs. The findings indicated that TG 18:2/18:2/18:2 and Cardiolipin (CL) 16:0/16:0/18:2/18:2 might be the key lipid molecule species for the formation of 2-methoxyphenol. The study helps to understand the effect of different treatments on the lipid profiles and provides the mechanistic insights to the relationship between the lipids and VOCs of truffles.
Five types of drying methods were demonstrated to dry corn silks and their effects on the constitution of phenolic and antioxidant capacities were analyzed, so as to identify the best method to preserve the quality factors of corn silk including phenolic, flavonoid and antioxidant activity. According to the results, drying can improve the level of phenolic and flavonoid in corn silk by 2.5‐3.2 folds and 1.6‐3.6 folds, respectively. Drying in shade (MCS‐shade) had the highest content of total phenolics and flavonoids. Eight kinds of phenolic were detected by HPLC and ferulic acid was the main component. MCS‐shade also showed the highest PSC value and CAA value (no wash). Overall, MCS‐shade (silks treated by shade‐drying) showed the best performance and the quality of dry corn silks affected greatly by different drying methods.
In recent years, polyphenols have attracted considerable attention due to their diverse potential health-beneficial effects on humans. Polyphenols are widely distributed in natural plants, and therefore play an important role in human food. Thermal processing, irradiation, fermentation, high pressure, microwave, and drying are several popular food processing methods. However, polyphenols are instable in food processing, which easily degrade and react with other components because of their polyhydroxy characteristic. Traditional and advanced technologies have been used to characterize the stability of polyphenols. The main influence factors of stability of polyphenols such as pH, temperature, light, oxygen, enzymes, metal ions, as well as macromolecules, are summarized. Besides, thermal processing greatly promoted the degradation of polyphenols. Thermal degradation mechanisms and products of some polyphenols, such as quercetin and rutin, have been intensively demonstrated. Nevertheless, the structural changes of polyphenols caused by food processing, may lead to different bioactivities from the obtained results based on unprocessed polyphenols. Therefore, to maximize the beneficial effects of polyphenols ingested by human from processed food, the stability of polyphenols in food processing must be thoroughly investigated to assess their real bioactivities. In addition, some available technologies for improving the stability of polyphenols in food processing have been proposed.
This study aimed to determine the effect of different drying methods, namely hot air drying (HAD), vacuum drying (VD), ultrasound‐assisted vacuum drying (UAVD), and freeze‐drying (FD) on drying kinetic, total phenolic antioxidant activity, anthocyanin profile, invitro‐ bioaccessibility of phenolic and color quality of raspberry samples. The drying time of the raspberry was 540 min, 720 min, and 1140 min for UAVD, VD, and HAD, respectively, indicating that UAVD showed a significantly lower drying time than VD and HAD. The results of anthocyanin profile, TPC, CUPRAC, and DPPH analysis showed that FD had higher bioactive compound retention than other methods, followed by UAVD. Cyanidin 3‐O‐sophoroside and Cyanidin 3‐O‐glucoside were found as the most abundant anthocyanin in raspberry samples. In the content of cyanidin 3‐O‐sophoroside, a loss of 78.33%, 15.41%, 4.63% was observed in HAD, VD, and UAVD, respectively. In vitro‐bioaccessibility of the VD and UAVD were higher than FD and HAD. While the recovery value of TPC (%) was found for fresh raspberry as 3.09%, it was found as 6.79, 9.42, 8.46, and 5.58% for HAD, VD, UAVD, and FD, respectively. Color quality was significantly affected by drying methods (p<0.05), and UAVD showed the lowest DE value. SEM analysis showed that less shrinkage and cell damage were observed in FD and UAVD dried samples. This study suggested that UAVD could be used as an alternative drying method since it showed lower drying time and shrinkage, higher bioactive compounds, and color retention than VD and HAD.
Powdered ingredients from maqui wastes were produced and the effect of drying method (air- and freeze-drying) and particle size on physicochemical and bioactive properties was investigated. Among the particulate systems of smaller particle size that showed the most balanced insoluble to soluble fiber ratio and the best hydration and oil absorption properties, the freeze-dried ones presented the best retention of polyphenols, anthocyanins, and antioxidant capacity. These powders could be used as ingredients in premixes for the development of foods for diabetes or gluten-free diets. The powders of higher granulometry presented excellent flowability and more dispersed particle size distribution, being more adequate for the development of composite foods or nutraceutics.
Sušenje je jedan od najstarijih i najekonomičnijih procesa produljenja trajnosti hrane. Osušeni proizvodi imaju manju masu i volumen što olakšava i smanjuje troškove pakiranja, skladištenja i transporta. Nedostatci prilikom konvencionalnog sušenja prehrambenih sirovina su toplinska razgradnja nutritivno vrijednih sastojaka, boje, mogući gubitci arome, nepoželjne promjene oblika i teksturalnih svojstava te enzimsko posmeđivanje. Ti nedostatci se mogu značajno smanjiti sušenjem u vakuumu. Konvencionalno vakuum sušenje i mikrovalno vakuum sušenje te sušenje zamrzavanjem u vakuumu su najpoznatiji procesi sušenja u vakuumu. Prednosti sušenja u vakuumu su niže temperature sušenja što rezultira većim očuvanjem hranjivih tvari proizvoda odnosno boljom kvalitetom sušenog proizvoda.
The aim of this work was to study the effect of three drying methods, namely convective drying (CD), vacuum-microwave pretreatment with convective drying (CMWV), and freeze-drying (FD), on the bioactive compounds, antioxidant activity, color, and sensory attributes of red-fleshed apple cubes. Different drying methods considerably affected the quality factors of the product. The highest concentration of remaining phenolics was observed in the FD apples. Chlorogenic acid constituted the main phenolic compound, representing 60% of all phenolics in fresh and dried red-fleshed apples; cyanidin-3-galactoside was the major anthocyanin. The amounts of anthocyanins were considerably reduced using all three procedures for drying. However, the CD apple cubes exhibited the highest antioxidant activity while the CMWV samples had the lowest. Substantial differences in color were observed. The FD apple cubes had about 20% higher values for L*(lightness) and a* (red parameter), and they had better sensory attributes of color and odor than the other dried samples.
Besides limiting microbiological and chemical activity in fruits, drying is a practical method that provides healthy snacks nowadays, when culture of nutrition with snacks is increasingly common. It is very important to choose a method that preserves both nutritional values and physical and sensory properties of foods in the drying process. In this study, the comparison of quality characteristics of dried avocados using vacuum dryer and fluidized bed dryer was investigated. Avocados with initial moisture content of 72±09 % were dried until their moisture content reached 13±1 %. The drying process in the fluidized bed dryer was completed at 50 °C, 60 °C and 70°C with 1.5 m/s speed in 8 hours, 7 hours and 6 hours respectively, while the vacuum drying process was completed at 10 Kpa pressure at 50 °C, 60 °C and 70 °C temperatures in 10 hours, 9 hours and 8 hours respectively. In order to compare the physical, chemical and sensory properties of dried avocados, color, water activity, rehydration capacity, shrinkage rate, pH, antioxidant activity, total phenolic content measurements and sensory analysis tests were conducted. (p<0.05). In the result of this study, it has been revealed that vacuum drying is a method that better preserves the physical and chemical properties of avocados as well as their sensory properties.
Ce travail avait pour objectif l'étude de l'impact des deux procédés : la déshydratation imprégnation par immersion (DII) et le séchage convectif menés séparément ou combinés sur les transferts couplés d'eau et de saccharose et les principaux critères de qualité de fruit (écart de couleur, teneur en phénols totaux (PT), teneur en acide ascorbique (AA), retrait volumique, activité de l'eau) en prenant la poire Conférences comme modèle. L'effet des procédés sur les morceaux de poire a été appréhendé selon deux approches : (i) une étude globale de l'impact des variables de commandes sur la qualité du produit fini et (ii) une étude cinétique des composés d'intérêt nutritionnel et de la qualité (couleur, retrait, activité de l'eau).Un plan d'expériences composite centré à quatre facteurs et cinq niveaux a été établi (concentration en saccharose de la solution osmotique : 25-65%, température de DII : 20-60 °C, durée de la DII : 0,5-6,5 h, température du séchage convectif : 30-70 °C) pour étudier l'effet global des procédés sur le produit fini. En DII, les paramètres « °Brix, « durée » et « la température de la solution » ont un effet significatif (p < 0,01) sur les pertes en eau, le gain en soluté et les attributs de qualité de morceaux de poire. Les pertes en AA sont plus élevées que les pertes en PT et sont essentiellement dues à l'oxydation et à l'entraînement par l'eau. Durant le séchage convectif, les pertes en PT et en AA dépendent plus de la durée du procédé que de la température d'exposition. Elles atteignent respectivement 80% et 34% après 10 h de séchage à 30 °C. Le changement de couleur de morceaux de poire dépend de la durée et de la température de traitement et est plus prononcé en fin de séchage. Des modèles quadratiques prédictifs ont été proposés pour relier les variables de réponse (aw, différence de couleur, perte en PT et durée totale de traitement) aux paramètres opératoires des deux procédés étudiés. Cependant, la perte en AA décroit linéairement avec la durée de DII. Une optimisation multicritères en utilisant la méthodologie des surfaces de réponse (MSR) a été proposée (pertes minimales en PT et en AA, durée totale du traitement et différence de couleur réduites et une aw inférieure à 0,6) pour la combinaison DII/séchage. Les conditions optimales sont : solution osmotique à 28°C et 25°Brix, une durée de DII de 30 min et un séchage convectif à 60 °C. Par ailleurs, les effets de la température (30, 45 et 60 °C) et de l'imprégnation en saccharose par DII (10 et 65 min, 70°Brix, 30 °C) sur les isothermes de désorption et sur la température de transition vitreuse (Tg) de morceaux de poires, de pommes et d'abricots ont été déterminés. L'imprégnation en saccharose du tissu végétal atténue l'influence de la température sur sa capacité de sorption. Elle engendre un effet dépresseur de l'activité de l'eau et une augmentation de l'hygroscopicité de la poire, la pomme et l'abricot à température élevée. Les isothermes de désorption des abricots frais et enrichis en saccharose présentent un croisement des courbes marquant l'inversement de l'effet de la température sur les isothermes. La Tg dépend de la température, de la teneur en saccharose et de la teneur en eau des fruits. Pour une teneur en eau constante, l'augmentation de la température et la durée de DII se traduisent par l'augmentation de la Tg. Les digrammes de phase (Tg=f(X) et Tg=f(aw)) des fruits ont été établis à 30, 45 et 60°C et les teneurs en eau critiques ainsi que les activités d'eau critiques ont été déterminées. Une teneur en eau en fin de séchage inférieure ou égale à 0,02 g/g M.S. est recommandée pour l'obtention de morceaux de fruit stables aux niveaux microbiologique, physicochimique et rhéologique.
Cherry laurel fruit is a good source of phenolics together with considerable antioxidant activity. However, it is only available for a short period of time during the year. Drying could offer long-time preservation however it harms the bioactive compounds due to the high temperatures applied during the process. The aim of this study is to determine the most proper drying method for cherry laurel in terms of preserving its bioactive compounds. The phenolics contents, antioxidant and antibacterial activities, and color properties of cherry laurel dried via lyophilization, vacuum drying, and fan oven-drying were compared. Lyophilized cherry laurel had the highest phenolics content (315.51 Gallic acid equivalent mg/100 g dried cherry laurel) and color intensity (C*). The antioxidant activity was determined using both DPPH and ABTS assays. The highest antioxidant activity (6.16 mM TE/g in DPPH and 28.83 mM TE/g in ABTS) thus, the lowest half-maximal inhibitory concentration (IC50) was detected for lyophilized samples in both DPPH and ABTS assays in methanolic (1.59 mg dried cherry laurel) and aqueous (0.30 mg dried cherry laurel) extracts, respectively. In general, vacuum- and fan oven-dried cherry laurel presented similar phenolics contents and antioxidant activities. None of the dried cherry laurel extracts showed antibacterial activity against the selected bacteria. Although lyophilization is a high-cost technology, it could be applied as an alternative method in the drying of cherry laurel since it provides high-quality products while maintaining its bioactivity.
Berry powders are popular as ingredients in a range of food products, where they naturally provide flavor, color, texture, polyphenols, fiber, and other nutrients. The choices regarding processing techniques and conditions influence the quality attributes of berry powders. The aim of this study was to study the effects on bilberry powder functionalities of applying different preprocessing techniques (purée mixing and juice pressing vs. untreated whole berries) prior to hot air drying and milling. Drying of press cake reduced the drying time by 72% and increased the total apparent phenolic content of the final powder by 44%, as compared to the powder of dried whole berries. The press cake powder showed an easier flowing behavior than the powders from whole berries and puréed berries. Dispersibility (in water and dairy cream) was 60% higher for powders from whole berries and puréed berries, as compared to press cake. The total phenolic content of the dispersed powders was highest for whole berries and puréed berries. Bilberry powder functionality can be modulated through the selection of an appropriate preprocessing technique before drying and milling. This tailors the powder properties into food ingredients ready for different applications, without the need for additives.
In this study, the effect of grape (Vitis labrusca L.) pomace dried by different methods on the functional properties of yoghurt was examined. Oven- and freeze-dried pomaces were added to the yoghurts at the ratios of 1, 3 and 5%. The freeze-dried pomace had the highest levels of bioactive components, with 34.959 mg GAE/g of total phenolics and 12.586 mg/L DPPH of radical scavenging activity, followed by the pomace oven dried at 80 °C (p < 0.001). At the beginning of the storage period, the yoghurt that contained oven dried, powdered pomace had higher levels of antiradical activity and total phenolics than the yoghurt containing lyophilized pomace (p < 0.05). The total phenolic content, radical scavenging activity, pH, acidity and whey separation decreased, and viscosity increased, during storage for 21 days at 4 °C. Microbiological analysis showed that the amount of lactic acid bacteria did not change significantly (p > 0.05) in yoghurt samples during storage. The sensory analysis done at the end of the storage revealed that the yoghurt samples containing pomace dried in the forced air oven were mostly liked by consumers. This study showed that Isabella grape (V. labrusca L.) pomace can be used as a functional food ingredient in yoghurt production.
The stability of pelargonidin 3-glucoside, pelargonidin 3-sophoroside and pelargonidin 3-sophoroside 5-glucoside acylated with malonic and cinnamic acids was determined at varying water activities. Model systems, containing purified anthocyanin in pH 3.4 citrate buffer and glycerol, were stored at 25°C in the dark for 242 days. Changes in pigment, degradation index, and anthocyanin profile, as monitored by high-performance liquid chromatography (HPLC), were studied. In general, anthocyanin degradation followed first order kinetics and the degree of anthocyanin degradation increased with water activity. Half lives of the anthocyanins ranged from 56 to 934 days. Changes in the chromatographic profile showed hydrolysis of pelargonidin 3-sophoroside to pelargonidin 3-glucoside and production of malonic acid from the acylated anthocyanin.
Temperature, pH, and oxygenation of extracted blueberries were examined to determine how processing may affect the antioxidant capacity of blueberry food products. Extraction of fruit at 60 °C resulted in higher recovery of anthocyanins and antioxidant capacity, compared to extracts obtained at 25 °C. Subsequent room temperature storage resulted in losses in anthocyanins and antioxidant capacity only in those extracts obtained at 60 °C. Antioxidant capacity was greatest in pH 1 extracts, compared to extracts at pH 4 and 7. Oxygenation was detrimental to both anthocyanins and antioxidant capacity. Antioxidant capacity of processed products was positively correlated with anthocyanin (R = 0.92) and phenolic content (R = 0.95), and negatively correlated with % polymeric color (R = -0.64). In general, products that had experienced less processing had a higher antioxidant capacity. Simple colorimetric tests for anthocyanins and phenolics proved to be useful indicators of antioxidant capacity in processed products.
The objective of this work is to develop and validate mathematical models based on heat and mass transfer principles for freeze-drying of vegetable slices. Carrot samples of 1, 2 and 3 mm thickness were freeze dried to obtain drying curves. Developed mathematical models were tested against experimental data to establish that the freeze-drying process is mass transfer controlled. Average values of mass diffusivity were also obtained for samples of three different thicknesses. Capsicum was freeze-dried using two types of circular disk samples obtained from whole capsicum using a cork borer. In one set of samples the natural protective outer membrane was left as it is and in another set the layer was removed prior to freeze-drying. The resulting difference in drying behaviour was insignificant. The drying process was also found to be very slow for capsicum. Mushroom samples on the other hand showed a drying behaviour very similar to 2 mm thick carrot samples.
A predominantly plant-based diet reduces the risk for development of several chronic diseases. It is often assumed that antioxidants contribute to this protection, but results from intervention trials with single antioxidants administered as supplements quite consistently do not support any benefit. Because dietary plants contain several hundred different antioxidants, it would be useful to know the total concentration of electron-donating antioxidants (i.e., reductants) in individual items. Such data might be useful in the identification of the most beneficial dietary plants. We have assessed systematically total antioxidants in a variety of dietary plants used worldwide, including various fruits, berries, vegetables, cereals, nuts and pulses. When possible, we analyzed three or more samples of dietary plants from three different geographic regions in the world. Total antioxidants was assessed by the reduction of Fe(3+) to Fe(2+) (i.e., the FRAP assay), which occurred rapidly with all reductants with half-reaction reduction potentials above that of Fe(3+)/Fe(2+). The values, therefore, expressed the corresponding concentration of electron-donating antioxidants. Our results demonstrated that there is more than a 1000-fold difference among total antioxidants in various dietary plants. Plants that contain most antioxidants included members of several families, such as Rosaceae (dog rose, sour cherry, blackberry, strawberry, raspberry), Empetraceae (crowberry), Ericaceae (blueberry), Grossulariaceae (black currant), Juglandaceae (walnut), Asteraceae (sunflower seed), Punicaceae (pomegranate) and Zingiberaceae (ginger). In a Norwegian diet, fruits, berries and cereals contributed 43.6%, 27.1% and 11.7%, respectively, of the total intake of plant antioxidants. Vegetables contributed only 8.9%. The systematic analysis presented here will facilitate research into the nutritional role of the combined effect of antioxidants in dietary plants.
Recent studies show that edible berries may have potent chemopreventive properties. Anti-angiogenic approaches to prevent and treat cancer represent a priority area in investigative tumor biology. Vascular endothelial growth factor (VEGF) plays a crucial role for the vascularization of tumors. The vasculature in adult skin remains normally quiescent. However, skin retains the capacity for brisk initiation of angiogenesis during inflammatory skin diseases such as psoriasis and skin cancers. We sought to test the effects of multiple berry extracts on inducible VEGF expression by human HaCaT keratinocytes. Six berry extracts (wild blueberry, bilberry, cranberry, elderberry, raspberry seed, and strawberry) and a grape seed proanthocyanidin extract (GSPE) were studied. The extracts and uptake of their constituents by HaCaT were studied using a multi-channel HPLC-CoulArray approach. Antioxidant activity of the extracts was determined by ORAC. Cranberry, elderberry and raspberry seed samples were observed to possess comparable ORAC values. The antioxidant capacity of these samples was significantly lower than that of the other samples studied. The ORAC values of strawberry powder and GSPE were higher than cranberry, elderberry or raspberry seed but significantly lower than the other samples studied. Wild bilberry and blueberry extracts possessed the highest ORAC values. Each of the berry samples studied significantly inhibited both H2O2 as well as TNF alpha induced VEGF expression by the human keratinocytes. This effect was not shared by other antioxidants such as alpha-tocopherol or GSPE but was commonly shared by pure flavonoids. Matrigel assay using human dermal microvascular endothelial cells showed that edible berries impair angiogenesis.
Regulation of the matrix metalloproteinases (MMPs), the major mediators of extracellular matrix (ECM) degradation, is crucial to regulate ECM proteolysis, which is important in metastasis. This study examined the effects of 3 flavonoid-enriched fractions (a crude fraction, an anthocyanin-enriched fraction, and a proanthocyanidin-enriched fraction), which were prepared from lowbush blueberries (Vaccinium angustifolium), on MMP activity in DU145 human prostate cancer cells in vitro. Using gelatin gel electrophoresis, MMP activity was evaluated from cells after 24-hr exposure to blueberry fractions. All fractions elicited an ability to decrease the activity of MMP-2 and MMP-9. Of the fractions tested, the proanthocyanidin-enriched fraction was found to be the most effective at inhibiting MMP activity in these cells. No induction of either necrotic or apoptotic cell death was noted in these cells in response to treatment with the blueberry fractions. These findings indicate that flavonoids from blueberry possess the ability to effectively decrease MMP activity, which may decrease overall ECM degradation. This ability may be important in controlling tumor metastasis formation.
Regulation of the matrix metalloproteinases (MMPs), the major mediators of extracellular matrix (ECM) degradation, is crucial to regulate ECM proteolysis, which is important in metastasis. This study examined the effects of 3 flavonoid-enriched fractions (a crude fraction. an anthocyanin-enriched fraction, and a proanthocyanidin-enriched fraction), which were prepared from lowbush blueberries (Vaccinium angustifolium), on MMP activity in DU145 human prostate cancer cells in vitro. Using gelatin gel electrophoresis, MMP activity was evaluated from cells after 24-hr exposure to blueberry fractions. All fractions elicited an ability to decrease the activity of MMP-2 and MMP-9. Of the fractions tested, the proanthocyanidin-enriched fraction was found to be the most effective at inhibiting MMP activity in these cells. No induction of either necrotic or apoptotic cell death was noted in these cells in response to treatment with the blueberry fractions. These findings indicate that flavonoids from blueberry possess the ability to effectively decrease MMP activity, which may decrease overall ECM degradation. This ability may be important in controlling tumor metastasis formation.
V. myrtillus is a deciduous small shrublet belonging to the Ericaceae family and growing on hilly and mountainous regions of Europe, Asia and Northern America. Fruits and leaves have been traditionally used in folk medicine of several European countries. In the last decades, some components of the fruits received particular interest due to their pharmacological properties. In particular, anthocyanosides have been investigated for their effect on blood vessels and in ophthalmology. At present, pharmaceutical proprietary products containing standardized extracts from V. myrtillus fruits are available for the therapy of alterated conditions of capillary fragility and permeability and for the normalization of some ophthalmological disorders.
Previous studies in our laboratory have demonstrated the inhibitory effects of freeze-dried strawberries and black raspberries on N-nitrosomethylbenzylamine (NMBA)-induced tumorigenesis in the rat esophagus. In addition, organic extracts from strawberries and black raspberries were shown to inhibit benzo[a]pyrene-induced transformation of Syrian hamster embryo (SHE) cells in vitro. In the present study, we evaluated blueberries for their ability to inhibit NMBA tumorigenesis in the rat esophagus. Blueberries, like strawberries and black raspberries, contain multiple cancer preventive agents, and are among the most heavily consumed berries in the American diet. They differ from strawberries and black raspberries, however, in that they contain only small amounts of the chemopreventive agent ellagic acid. Two weeks prior to NMBA treatment, animals were placed on a control diet or diets containing 5 and 10% freeze-dried blueberries. The animals were fed berry diets or control diets for the duration of the study. NMBA treatment was once per week for 15 weeks. At 25 weeks, 5 and 10% blueberries produced no significant differences in tumor incidence, multiplicity, or size when compared to NMBA-treated controls. In addition, blueberries did not reduce the formation of NMBA-induced O6- methylguanine adducts in esophageal DNA when fed at 10% of the diet. Blueberries appear to lack components that inhibit the initiation and progression of NMBA-induced tumorigenesis in the rat esophagus.
The stability of pigment in freeze-dried carotenoid powder during dark storage at 4, 25, or 45°C, or under light at 25°C was studied. Carrot pulp waste was used as raw material for processing carotenoid powder by freeze-drying. The various carotenoids were analyzed by HPLC with photodiode-array detection. Results showed that the amounts of all-trans forms of all three compounds, α-carotene, β-carotene and lutein, decreased with increasing storage temperature or illumination time. The major isomers formed during dark storage were 13-cis-α-carotene, 13-cis-β-carotene and 13-cis-lutein, while 9-cis-α-carotene, 9-cis-β-carotene and 9-cis-lutein were favored during illumination. The degradation rate of the total amount of all-trans plus cis forms of each pigment fits a first order model, and the highest rate constant (day−1) was found for β-carotene, followed by α-carotene and lutein. Both the Hunter L and b values of the powder decreased with increasing storage time and temperature, while the Hunter a value showed insignificant change (p>0.05).
Total polyphenols, total anthocyanins, and reduced ascorbic acid were evaluated in berries belonging to the genera Rubus, Ribes, and Aronia by means of spectrophotometric and high-performance liquid chromatography (HPLC) techniques. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity of the fruit extracts was tested. Total polyphenols ranged from 140.6 to 888.5 mg/100 g fresh weight (FW), total anthocyanins ranged from 22.0 to 460.5 mg/100 g FW, and reduced ascorbic acid ranged from 12.4 to 153.8 mg/ 100 g FW. The average EC50 values for Aronia melanocarpa, Ribes nigrum, Ribes rubrum, Rubus fruticosus, and Rubus idaeus were 1.8, 2.8, 5.3, 6.4, and 8.2 mg FW, respectively. The results indicate that the fruits tested are good sources of natural antioxidants.
Saskatoon berries (Amelanchier alnifolia Nutt., cv. Thiessen and Smoky) were dehydrated using freeze-drying (FD), vacuum microwave drying (VMD), air-drying (AD), and a combination of air-drying and vacuum microwave drying (CD) methods. All processed berries had significantly reduced (P < 0.05) total phenolics and anthocyanin contents in addition to reduced antioxidant activities, as compared with fresh frozen (FF) berries. FD berries rendered the highest amount (P < 0.05) of anthocyanin and antioxidant activities, followed by VMD berries. The CD dehydration resulted in intermediate results between VMD and AD. The substantial decrease in both total phenolics and anthocyanin content in berries was corresponded to significant (P < 0.05) losses in antioxidant capacities measure in different model systems.
The antiradical activities of various antioxidants were determined using the free radical, 2,2-Diphenyl-1-picrylhydrazyl (DPPH*). In its radical form. DPPH* has an absorption band at 515 nm which dissappears upon reduction by an antiradical compound. Twenty compounds were reacted with the DPPH* and shown to follow one of three possible reaction kinetic types. Ascorbic acid, isoascorbic acid and isoeugenol reacted quickly with the DPPH* reaching a steady state immediately. Rosmarinic acid and δ-tocopherol reacted a little slower and reached a steady state within 30 min. The remaining compounds reacted more progressively with the DPPH* reaching a steady state from 1 to 6 h. Caffeic acid, gentisic acid and gallic acid showed the highest antiradical activities with a stoichiometry of 4 to 6 reduced DPPH* molecules per molecule of antioxidant. Vanillin, phenol, γ-resorcylic acid and vanillic acid were found to be poor antiradical compounds. The stoichiometry for the other 13 phenolic compounds varied from one to three reduced DPPH* molecules per molecule of antioxidant. Possible mechanisms are proposed to explain the experimental results.
Retention of ascorbic acid (vitamin C) in dried guava during storage was studied. The effects of storage temperature: 30°C, 40°C, 50°C and water activity (aw): 0.43, 0.75, 0.84, 0.97 were investigated. The degradation of ascorbic acid follows a pseudo-first-order reaction. The rate constant increased about four to six fold when storage condition was changed from aw=0.43–0.97. The rate constants and corresponding water activities are related by a second-order polynomial equation. The effect of temperature on the rate constant followed the Arrhenius relationship. The activation energy of ascorbic acid degradation is found to be in the range 3.4–11.0 kcal/mol. An empirical equation, based on temperature, water activity and rate constant, is developed to predict shelf life of dried guava in respect of ascorbic acid retention.
The objective of this research is to evaluate drying methods that have the potential of adding value to green asparagus especially for use as ingredient in instant foods or as a nutraceutical product. Five drying methods were used: namely, tray drying (TD), spouted bed (SB) drying, combined microwave and spouted bed drying (MWSB), Refractance Window (RW) drying and freeze-drying. Asparagus spears with diameters between 9 and 12 mm were blanched in 85°C water-bath for 3 min, sliced into 2–4 mm thickness (or pureed for RW drying), then dried to moisture content less than 0.1 db. MWSB drying produced asparagus particles with good rehydration and color characteristics, and was the fastest among the methods where heated air was used. When using MWSB drying, the power level of 2 W/g and 60°C heated air resulted in highest retention of total antioxidant activity (TAA). TAA of asparagus was enhanced after RW and freeze-drying, with the TAA values being significantly higher than for heated air-drying methods. In all cases, the tip portion of asparagus retained more TAA after drying than either middle or basal parts. The highest amount of ascorbic acid was retained in the product after RW drying, followed by freeze-drying, MWSB and SB drying. TD resulted in the least retention of ascorbic acid.
In this study, carrots were treated with ascorbic acid (0.1%) in a glucose (1.0%) solution (AA-Glu), and then freeze-dried and hot-air-dried to investigate the effects on their antioxidant content after 30 days of storage. The antioxidant components were extracted from the carrot samples using methanol. To assess antioxidative properties, tests measured the samples’ reducing power, α,α-diphenyl-β-picrylhydrazyl (DPPH) radical scavenging activity, and ferrous ion chelating power. The above antioxidative properties of carrot extracts were compared with α-tocopherol and butylated hydroxyanisole (BHA). The analysis of antioxidant compounds included the total amount of ascorbic acid, total amount of phenolics, total amount of flavonoids, and carotenoids. The analysis showed that the samples immersed in AA-Glu solution prior to drying exhibited a higher antioxidative property than those not immersed.
Sugar solutions with different sugar composition and concentration were used to reconstitute freeze-dried strawberries. The mass transfer between fruit pieces and solution during the rehydration process and the physicochemical characteristics of the reconstituted products were evaluated. The results indicated that by varying the concentration of the sugar solution and reconstitution time it was possible to obtain from the same freeze-dried product, rehydrated fruit pieces with different and peculiar characteristics such as water activity, freezing point, amount of freezable water and firmness. In addition, these characteristics were linearly correlated with soluble solids content in the rehydrated products. Using the above method, the reconstituted freeze-dried strawberries are able to be used as an ingredient in formulated foods at different levels of water activity and also in frozen dessert or ice cream.
Different cultivars of four Vaccinium species [Vaccinium corymbosum L (Highbush), Vaccinium ashei Reade (Rabbiteye), Vaccinium angustifolium (Lowbush), and Vaccinium myrtillus L (Bilberry)] were analyzed for total phenolics, total anthocyanins, and antioxidant capacity (oxygen radical absorbance capacity, ORAC). The total antioxidant capacity of different berries studied ranged from a low of 13.9 to 45.9 micromole Trolox equivalents (TE)/g of fresh berry (63.2-282.3 micromole TE/g of dry matter) in different species and cultivars of Vaccinium. Brightwell and Tifblue cultivars of rabbiteye blueberries were harvested at 2 times, 49 days apart. Increased maturity at harvest increased the ORAC, the anthocyanin, and the total phenolic content. The growing location (Oregon vs Michigan vs New Jersey) did not affect ORAC, anthocyanin or total phenolic content of the cv. Jersey of highbush blueberries. A linear relationship existed between ORAC and anthocyanin (r(xy) = 0.77) or total phenolic (r(xy) = 0.92) content. In general, blueberries are one of the richest sources of antioxidant phytonutrients of the fresh fruits and vegetables we have studied.
Fresh strawberries (Fragaria x ananassa Duch.), raspberries (Rubus idaeus Michx.), highbush blueberries (Vaccinium corymbosum L.), and lowbush blueberries (Vaccinium angustifolium Aiton) were stored at 0, 10, 20, and 30 degrees C for up to 8 days to determine the effects of storage temperature on whole fruit antioxidant capacity (as measured by the oxygen radical absorbing capacity assay, Cao et al., Clin. Chem. 1995, 41, 1738-1744) and total phenolic, anthocyanin, and ascorbate content. The four fruit varied markedly in their total antioxidant capacity, and antioxidant capacity was strongly correlated with the content of total phenolics (0.83) and anthocyanins (0.90). The antioxidant capacity of the two blueberry species was about 3-fold higher than either strawberries or raspberries. However, there was an increase in the antioxidant capacity of strawberries and raspberries during storage at temperatures >0 degrees C, which was accompanied by increases in anthocyanins in strawberries and increases in anthocyanins and total phenolics in raspberries. Ascorbate content differed more than 5-fold among the four fruit species; on average, strawberries and raspberries had almost 4-times more ascorbate than highbush and lowbush blueberries. There were no ascorbate losses in strawberries or highbush blueberries during 8 days of storage at the various temperatures, but there were losses in the other two fruit species. Ascorbate made only a small contribution (0.4-9.4%) to the total antioxidant capacity of the fruit. The increase observed in antioxidant capacity through postharvest phenolic synthesis and metabolism suggested that commercially feasible technologies may be developed to enhance the health functionality of small fruit crops.
The quantitative and qualitative evolution of the anthocyanins and volatile compounds of four raspberry cultivars (cvs. Heritage, Autumn Bliss, Zeva, and Rubi) growing in Spain were analyzed raw, just frozen, and during long-term frozen storage at -20 degrees C for a 1 year period. HS-SPME coupled with GC-MS and HPLC techniques were employed to study the evolution of the volatile compounds and the individual anthocyanins, respectively. The volatile aroma composition changes produced by the freezing process and long-term frozen storage were minimal. Only a significant increase in extraction capacity was obtained for alpha-ionone (27%) and for caryophyllene (67%) in Heritage at 12 months of storage. The stability of anthocyanins to freezing and frozen storage depends on the seasonal period of harvest. Heritage and Autumn Bliss (early cultivars) were less affected by processing and long-term frozen storage (1 year), and the total pigment extracted showed the tendency to increase 17 and 5%, respectively. Rubi and Zeva (late cultivars) suffered a decreased trend on the total anthocyanin content of 4% for Rubi and 17.5% for Zeva. Cyanidin 3-glucoside most easily suffered the degradative reactions that take place during processing and the storage period.
The ellagic acid, total phenolic, and vitamin C contents in four raspberry cultivars (Heritage, Autumn Bliss, Rubi, and Zeva) grown in Spain were detected and quantified by HPLC in fresh, just frozen, and stored fruits at -20 degrees C for a one year period. Ellagic acid [207-244 mg kg(-)(1) of fresh weight (fw)], total phenolic (137-1776 mg kg(-)(1) of fw), and vitamin C (221-312 mg kg(-)(1) of fw) contents in raw material were higher in the late cultivars Zeva and Rubi than in the early cultivars Autumn Bliss and Heritage. The freezing process slightly affected the values of extracted ellagic acid, total phenolic, and vitamin C content. At the end of long-term frozen storage (12 months), no significant change of total phenolic content extracted was observed, but significant decreases of 14-21% in ellagic acid and of 33-55% in vitamin C were quantified. Free radical scavenging capacity measured as antiradical efficiency (AE) depends on the seasonal period of harvest. Late cultivars, Rubi (6.1 x 10(-)(4)) and Zeva (10.17 x 10(-)(4)), showed higher AE than early cultivars, Heritage (4.02 x 10(-)(4)) and Autumn Bliss (4.36 x 10(-)(4)). The freezing process produced a decrease of AE values in the four cultivars ranging between 4 and 26%. During the frozen storage, the AE values reached after the freezing process remained unchanged.
Recent studies are emphasising the importance and putative modes of action of specific flavonoids as bioactive components of the diet in in vivo and in vitro models. Thus, it is important to have a clear idea of the major phenolic families of which fruit and vegetables are comprised and the levels contained therein. Regularly consumed fruit and vegetables of mixed varieties available on the UK market were analysed for the composition of the major individual phenolic components. The total phenolic content (applying the Folin assay) and the vitamin C levels were also determined. The antioxidant capacities of aqueous/methanolic extracts were comparatively assessed using the TEAC (Trolox Equivalent Antioxidant Capacity), the FRAP (Ferric Reducing Ability of Plasma) and ORAC (Oxygen Radical Absorbance Capacity) assays, which comprise contributions from polyphenols, simple phenols and the ascorbate component. The results were calculated in terms of 100 g fresh weight (FW) uncooked portion sizes. Fruit and vegetables rich in anthocyanins (e.g. strawberry, raspberry and red plum) demonstrated the highest antioxidant activities, followed by those rich in flavanones (e.g. orange and grapefruit) and flavonols (e.g. onion, leek, spinach and green cabbage), while the hydroxycinnamate-rich fruit (e.g. apple, tomato, pear and peach) consistently elicited the lower antioxidant activities. The TEAC, FRAP and ORAC values for each extract were relatively similar and well-correlated with the total phenolic and vitamin C contents. The antioxidant activities (TEAC) in terms of 100 g FW uncooked portion size were in the order: strawberry> raspberry = red plum > red cabbage >grapefruit = orange > spinach > broccoli > green grape approximately/= onion > green cabbage > pea > apple > cauliflower tomato approximately/= peach=leek > banana approximately/= lettuce.
Previously, we showed that blueberry (BB) supplementation reversed the deleterious effects of aging on motor behavior and neuronal signaling in senescent rodents. We now report that BB-fed (from 4 months of age) APP + PS1 transgenic mice showed no deficits in Y-maze performance (at 12 months of age) with no alterations in amyloid beta burden. It appeared that the protective mechanisms are derived from BB-induced enhancement of memory-associated neuronal signaling (e.g. extracellular signal-regulated kinase) and alterations in neutral sphingomyelin-specific phospholipase C activity. Thus, our data indicate for the first time that it may be possible to overcome genetic predispositions to Alzheimer disease through diet.
Epidemiological studies have noted a consistent association between the consumption of diets rich in fruits and vegetables and a lower risk for chronic diseases including cancer and cardiovascular disease. There is accumulating evidence that much of the health-promoting potential of these plant foods may come from phytochemicals, bioactive compounds not designated as traditional nutrients. In strawberries, the most abundant of these are ellagic acid, and certain flavonoids: anthocyanin, catechin, quercetin and kaempferol. These compounds in strawberries have potent antioxidant power. Antioxidants help lower risk of cardiovascular events by inhibition of LDL-cholesterol oxidation, promotion of plaque stability, improved vascular endothelial function, and decreased tendency for thrombosis. Furthermore, strawberry extracts have been shown to inhibit COX enzymes in vitro, which would modulate the inflammatory process. Individual compounds in strawberries have demonstrated anticancer activity in several different experimental systems, blocking initiation of carcinogenesis, and suppressing progression and proliferation of tumors. Preliminary animal studies have indicated that diets rich in strawberries may also have the potential to provide benefits to the aging brain.
The purpose of this investigation was to report on the total phenolics, anthocyanins, and oxygen radical absorbance capacity (ORAC) of strawberry, peach, and apple, the influence of dehydration and ascorbic acid treatments on the levels of these compounds, and the effect of these treatments on fruit color. Results showed that fresh strawberry had the highest levels for total phenolics [5317.9 mg of chlorogenic acid equivalents (CAE)/kg], whereas lower levels were found in fresh apple and peach (3392.1 and 1973.1 mg of CAE/kg, respectively), and for anthocyanins (138.8 mg/kg), whereas lower levels were found in fresh apple and peaches (11.0 and 18.9 mg/kg, respectively; fresh strawberry had an ORAC value of 62.9 mM/kg Trolox equivalents. The fresh apple and peach were found to have ORAC values of 14.7 and 11.4 mM/kg of Trolox equivalents, respectively. The color values indicated that the addition of 0.1% ascorbic acid increased the lightness (L) and decreased the redness (a) and yellowness (b) color values of fresh strawberry, peach, and apple, sliced samples, and the puree made from them. Also, results showed that dehydration is a good method to keep the concentrations of total phenolics and anthocyanins and ORAC values at high levels.
A blueberry extract (A) and two anthocyanin-derived extracts (B and C) were prepared. The contents of polyphenols, flavonoids, anthocyanins, and anthocyanin-derived pigments of the extracts were determined for the first time. The pigment profile of blueberry extract A corresponded to 15 anthocyanins, whereas extract B was mainly composed of anthocyanin-pyruvic acid adducts of the blueberry original anthocyanins and extract C was mainly composed of the respective vinylpyranoanthocyanin-catechins (portisins). The extracts' abilities to inhibit lipid peroxidation, induced by 2,2'-azobis(2-methyl-propanimidamide) dihydrochloride in a liposomal membrane system were examined. The antioxidant capacities of the extracts were evaluated through monitoring oxygen consumption and by measuring the formation of conjugated dienes. All of the extracts provided protection of membranes against peroxyl radicals by increasing the induction time of oxidation. This effect increased with the polyphenol content and with the structural complexity of the anthocyanin-derived pigments of the extracts. The pigments present in extract C seemed to induce a higher protection of the liposome membranes toward oxidation. In addition, the antiradical properties and the reducing power of the extracts were determined by using DPPH and FRAP methods, respectively. The results from these assays were in agreement with those obtained with the liposome membranes.
Characterisation and measure-ment of anthocyanins by UV – visible spectroscopy Systematic screening of total antioxidants in dietary plants
- M M Giusti
- R G Wrolstad
- Ny
- B L Halvorsen
- K Holte
- M C W Myhrstad
- I Barikmo
- E Hvattum
- S F Remberg
- A B Wold
- K Haffner
- H Baugerød
- L F Andersen
GIUSTI, M.M. and WROLSTAD, R.G. 2001. Characterisation and measure-ment of anthocyanins by UV – visible spectroscopy. In Current Protocols in Food Analytical Chemistry, (R.E. Wrolstad and S.J. Schwartz, eds.) pp. F1.2.1–F1.2.13, John Wiley and Sons, New York, NY. HALVORSEN, B.L., HOLTE, K., MYHRSTAD, M.C.W., BARIKMO, I., HVATTUM, E., REMBERG, S.F., WOLD, A.B., HAFFNER, K., BAUGERØD, H., ANDERSEN L.F., et al. 2002. Systematic screening of total antioxidants in dietary plants. J. Nutr. 132, 461–471.
Blueberry fla-20 M. MICHALCZYK, R. MACURA and I. MATUSZAK vonoids inhibit matrix metalloproteinase activity in DU145 human pros-tate cancer cells
- M D Matchett
- Mac Kinnon
- S L Sweeney
- M I Gottschall-Pass
- K T Hurta
MATCHETT, M.D., MAC KINNON, S.L., SWEENEY, M.I., GOTTSCHALL-PASS, K.T. and HURTA, R.A.R. 2005. Blueberry fla-20 M. MICHALCZYK, R. MACURA and I. MATUSZAK vonoids inhibit matrix metalloproteinase activity in DU145 human pros-tate cancer cells. Biochem. Cell Biol. 83, 637–643.
Blueberry supplementation enhances signaling and prevents behavioral deficits in an Alzheimer disease model
- JOSEPH