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Citrus fruits, regarded as a prominent fruit crop, are cultivated extensively around the globe and orange (Citrus sinensis L.) is a widely cultivated popular member of the citrus family. Dried oranges have gained recognition as a healthy snack option among consumers and worldwide markets due to the absence of additional ingredients such as sugar and chemicals, whilst yet containing significant natural beneficial components. The drying method is very intriguing due to its ability to facilitate the efficient production, packaging, storage, and transportation of dried oranges at a cost-effective price. In this study, the effects of microwave pretreatment (Mpt) (90 W, 30 min) on hot air drying (HTAD-MW) (60, 70, and 80°C) were investigated, along with the effects on the drying kinetics, rehydration capacity, and quality properties of the orange snack including phenolic compounds (vanillic acid, gallic acid, epicatechin, hesperidin, naringenin, chlorogenic acid, sinapic acid, and o-coumaric acid), antioxidant capacities (with DPPH, FRAP, and CUPRAC methods), and ascorbic acid contents. For modeling the kinetics of orange snack drying in all tests, logarithmic, Wang and Singh's, diffusion approach, two term, and Wang and Sing's models performed best. Hot air drying (HTAD) at 70°C applied orange snacks showed the lowest △E ∗ ab value, and the color values were close to those of fresh orange slices. The levels of total and individual phenolics, antioxidant capacity (AC), and ascorbic acid (AA) in dried orange snacks were found to be significantly lower (p < 0.05) than in the fresh orange slices. Results also showed that HTAD-MW-applied orange snacks contained more total phenolic (TP) content, individual phenolic content, and AC but lower AA than HTAD-applied samples. The highest amount of phenolic compound was hesperidin for fresh and dried orange snacks. The method that best preserves the TP content and AC of dried orange snacks was found at the drying condition of HTAD-MW at 60°C. As a conclusion, it was suggested that the use of microwave and hot air combination is a promising method to introduce a new functional healthy snack to the dried product market with high quality. [ABSTRACT FROM AUTHOR]

The dehydration behavior of turkey berries was analysed in a fluidized bed dryer at various inlet air velocities (0.8, 2.1, and 3.4 m/s) and temperatures (50, 60, and 70°C). The drying parameters and physiochemical values of fruits were extensively studied, as were the moisture content, rate of drying, moisture diffusivity of the sample, shrinking percentage, color variations, retention of vitamin C, β-carotene, antioxidant capacity, and total phenolic content. The activation energy varies between 36.82 and 45.63 kJ/mol under different bed conditions. According to the experimental results, it has been observed that the maximum moisture diffusion rate was 2.898 × 10−10 m2/s and maximum retention rates of vitamin C, β-carotene, antioxidant capacity, and total phenolic content were 1.91 mg/100 g d.m, 184 μg/100 g d.m, 21.34 mg AAE/100 g d.m, and 513 mg GAE/100 g, during the drying of the sample at 70°C and 3.4 m/s. The minimum shrinkage (49.1%) and color variation (ΔE = 11.08) were detected at 3.4 m/s and 70°C. The Midilli et al. model was fitted, which is the most preferable model for predicting the dehydration characteristics of turkey berries. [ABSTRACT FROM AUTHOR]

Stevia rebaudiana has grown in popularity and consumption across the world as an excellent natural sweetener due to its 300 times sweetness than sugar. Since Stevia leaves are often used in their dried state, the drying process has an inevitable effect on the attributes of finished product. In this study, Stevia leaves were microwave dried at five different levels of powers ranging from 180 to 900 W to evaluate the influence of power levels on moisture ratio (MR), drying rate and time, effective moisture diffusivity, specific energy consumption (SEC), color, and biochemical characteristics. Among the five selected thin layer models for evaluating the drying behavior, the semiempirical page model described the drying kinetics very well with R2 > 0.997. The effective diffusivity increased from 3.834 × 10 − 11 to 1.997 × 10 − 10 m2/s with increasing microwave power, while SEC first increased till 320 W to a value of 9.77 MJ/kg and then followed a decreasing trend. Furthermore, multilayer feed forward (MLF) artificial neural network (ANN) using backpropagation algorithm was used to predict the moisture ratio of Stevia leaves during microwave drying. The result showed that the ANN model with 15 neurons in 1 hidden layer could predict the MR with a high R2 value (0.999). Thus, ANN modelling can successfully be used as an effective tool for predicting drying kinetics of samples. Furthermore, the color properties showed significant differences between fresh and dried samples except for the hue angle, and the variation in their values was not affected by the microwave dryer's power output. At 720 W power level, the highest content of stevioside (11.84 mg/g) and rebaudioside A (7.11 mg/g) along with maximum retention of ascorbic acid (∼86%) was observed, while the highest total phenol content (56.98 mg GAE/g) and antioxidant capacity (74.22%) was reported in microwave dried samples at 900 W. [ABSTRACT FROM AUTHOR]

An experimental study was conducted to assess the drying kinetics of lemongrass shreds, dried using two different drying methods and retention of bioactive compounds in the dried lemongrass. Convective drying (CD) was carried out at 45°C for 7 h, whereas during pulsed microwave drying (PMD), lemongrass shreds were exposed to microwaves at 1350 W for 3‐3‐2‐1‐min pulsed intervals with a 30‐s pulse gap. Experimental data were fitted to three drying models, namely Lewis, Henderson and Pabis, and Page models, to determine the moisture ratio as a function of drying time. The bioactive compounds were analyzed before and after drying to assess the changes during the drying process. Pulsed microwave dried samples showed maximum retention of total chlorophyll: 13.85 mg/g, ascorbic acid: 17.80 mg/100 g, flavonoids: 2.64 mg/g, and highest antioxidant capacity of 74.02%. Moreover, microwave‐assisted hydrodistillation (MAHD) of these samples yielded 1.54% essential oil with a specific gravity of 0.89. Novelty impact statement: The synergistic influence of PMD and MAHD process on the quality of dried lemongrass shreds has not been investigated earlier.Polynomial fit‐MR and polynomial fit‐lnMR for moisture ratio were found to have the highest R2 values for both drying methods.Retention of bioactive compounds was observed to be higher in PM dried samples compared with convective dried samples. [ABSTRACT FROM AUTHOR]

A vacuum concentration method was established to produce pear paste using fresh pear juice in this study. The optimal condition was determined by comparing the quality indexes, contents of total phenol and flavonoid, and antioxidant properties of the pear paste produced by traditional heating concentration and vacuum concentration. Electronic nose and electronic tongue were introduced in this study to provide digital smell and taste indicators. The results showed that the best vacuum concentration temperature was 65°C, which led to the best sensory evaluation score and pear paste quality. The browning degree and soluble quinones were the lowest in all tested temperatures, and the content were 60.12% and 72.88% compared with the heating method, respectively. While the values were 148.29%, 209.44%, 310.86%, 120.37%, 106.24%, and 181.26% of total phenol, total flavonoid, vitamin C, 1,1-diphenyl-2-trinitrophenylhydrazine (DPPH) and hydroxyl (·OH) radical scavenging rates, and total reducing power, respectively. The electronic nose could effectively distinguish the vacuum-concentrated pear paste from the traditional heating-concentration pear paste and could provide quality guidance on their flavor differences through characteristic sensors. The electronic tongue tests showed that the vacuum-concentrated pear paste had larger freshness and richness kurtosis. The pear paste made by the optimized vacuum concentration method had higher retention of nutritional and functional components and higher antioxidant capacity, which could be clearly differentiated from the traditional process, thus this method had an applicable potential. [ABSTRACT FROM AUTHOR]

Microalgae are one of the most important sources of natural bioactive compounds, especially those revealing antioxidant activity such as β‐carotene. Thus, this study was to compare the effects of dietary Vitamin C (L‐ascorbic acid) or Vitamin E (α‐tocopherol) with β‐carotene extracted from Arthrospira platensis on Nile tilapia (Oreochromis niloticus) on growth, feed utilization, blood indices, antioxidant activity, non‐specific immunological indices and related gene expression. Three hundred and sixty apparent healthy Nile tilapia (5.80 ± 0.286 g) were randomly distributed into four groups. Four isonitrogenous and isoenergetic diets were performed. A control diet was compared against three experimental diets supplemented with Vitamin C (0.5 mg kg−1 diet), Vitamin E (1 g kg−1 diet) or β‐carotene (0.5 g kg−1 diet) for 10 weeks. According to the results, there was no significant difference in feed intake (p > 0.05) between experimental diets. Dietary Vitamins C and E and β‐carotene significantly (p < 0.05) enhanced the weight gain, final body weight, protein efficiency ratio, specific growth rate and apparent protein utilization in all groups, whereas the best FCR (p = 0.017) and the highest weight gain (p = 0.007) were detected in the β‐carotene diet. Fish survival rates differed significantly (p < 0.05) amongst treatments, whilst fish fed a diet supplemented with β‐carotene recorded the highest survival rate. The supplemental diet with β‐carotene boosted the values of the biochemical and haematological parameters (p < 0.05) compared with the control diet. The activities of catalase, superoxide dismutase (SOD) and total antioxidant capacity (T‐AOC) in the liver (p = 0.0560; p = 0.0032; p = 0.0353 respectively) and tilapia muscles were higher in fish fed either β‐carotene or Vitamin E (p = 0.0579; p = 0.1494; p = 0.2145 respectively) than other groups. The highest values of SOD, CAT and immune globulin M‐2 gene expression (p < 0.05) were found in fish fed a diet enriched with β‐carotene. These results suggested that the dietary incorporation of β‐carotene had a superior impact on growth performance, haemato‐biochemical and immune‐oxidative stress biomarkers in addition to the associated gene expression of Oreochromis niloticus. [ABSTRACT FROM AUTHOR]

As an agro‐food by‐product, pomegranate peel is a potential source of bioactive compounds with preservative properties. Ultrasound‐assisted extraction (UAE) is a green extraction method that is useful in increasing extraction yields and reducing extraction time without using toxic solvents. This study aimed to optimize the UAE of a pomegranate peel for its use as a preservative using water as the solvent, maximizing its antioxidant potential for its particular application to chicken burgers. A Box–Behnken design was applied using extraction time, extraction temperature, and ultrasound amplitude as independent variables. The response surface methodology (RSM) results showed that the highest concentration of the phenolic compound is obtained at amplitude—50%, temperature—38°C, and time—15 min. The extracts with RSM conditions at a concentration of 0.8% indicated that the extracted preservative exerts the ability to delay meat oxidation on days 1, 2, 4, and 7, even better than ascorbic acid. Practical applications: The waste and elimination of agro‐industrial by‐products generate significant environmental impacts and critical economic losses. Today, a sustainable paradigm it seeks to add extra value to these by‐products by giving them a new application in the production chains, thus favoring the circular economy. The ultrasound‐assisted process is an excellent tool to obtain green compounds that cover the recent concern from the industry and consumers for healthier foods. In this case, the application of the pomegranate peel extract is presented as an alternative to synthetic preservatives due to its great antioxidant capacity. [ABSTRACT FROM AUTHOR]

Application of weak acid and preservatives on tomatoes has the potential to reduce the loss of functional properties during drying. The effects of using sodium metabisulphite (SMB) and citric acid (CA) to control the degradation of nutraceuticals in dried tomatoes were studied. The following treatments: T0 (control, no additives), T1 (1% w/v CA), T2 (0.5% w/v CA +0.5% w/v SMB), and drying methods (dehydration, sun, and solar) were used. The T2 pretreated samples, dried using the sun, solar, and dehydration had total soluble solids (TSS) (5.10%), total sugar (TS) (7.32 g/100 g), and rehydration ratio (RR) (2.0) and β‐carotene (30.0 mg/100 g), lycopene (51.3 mg/100 g), ascorbic acid (14.1 mg/100 g), respectively. The T2 pretreated and dehydrated samples had a high Trolox equivalent antioxidant capacity (TEAC) and 2,2‐diphenyl‐1‐picrylhydrazyl radical scavenging activity. By using T2 treatment and dehydration, the tomato had the best functional properties, which would be used as optimal conditions for preserving tomatoes. Novelty impact statement: Hybrid Amukela Plus tomatoes pretreated with 0.5% w/v CA +0.5% w/v SMB and dried ‐in a food dehydrator preserved ‐further degradation of nutraceutical compounds and resulted in a β‐carotene (30.0 mg/100 g), lycopene (51.3 mg/100 g), and ascorbic acid (14.1 mg/100 g) content during storage. These treatments produced dried tomatoes with over 50% Trolox equivalent antioxidant capacity (TEAC) and 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging activity. Solar and sun‐drying treatments have significant damage on the nutraceutical compounds in the dried hybrid tomatoes. [ABSTRACT FROM AUTHOR]

Effect of vacuum impregnation (VI) times on quality and healthy potential attributes of fresh‐cut apples was modeled, determining optimal processing times. Mild VI treatments (67.7 mbar vacuum pressure, 30 oBrix sucrose osmotic solution containing citric and ascorbic acids) were applied with vacuum (tv) and relaxation (tr) times of 1.14 to 14 min through a central composite design. After VI, respiration rate decreased as tv increased but increased with tr. Bioactive compounds and antioxidant capacity increased with both processing times. Optimal tv and tr obtained for minimizing respiration rate and maximizing the attributes related to sensory quality were 6.18 and 1.14 min. Otherwise, optimal tv and tr for minimizing the respiration rate, maximizing the related sensory properties, and the health potential of fresh‐cut apples were longer (10.18 and 6.21 min). Mild VI, with an antioxidant solution at appropriate VI times, is an adequate technology for obtaining fresh‐cut apples with improved fresh‐like quality and healthy characteristics. Novelty impact statement: This study showed that mild vacuum impregnation treatment with an antioxidant solution is an adequate technology for processing fresh‐cut apples with improved healthy potential. The optimal vacuum and relaxation times improve the fresh‐cut apple qualities and its health potential after 7 days of storage at 1.5°C if both are suitably selected. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the effect of high hydrostatic pressure (HHP) (250 or 400 MPa/5 min) and storage conditions (2 or 27℃/24 hr) on polyphenols, ascorbic acid, antioxidant capacity, polyphenol oxidase (PPO), and color in fresh‐cut cashew apple. The association of HHP and storage decreased ascorbic acid (14%–49%), soluble polyphenols (13%–43%), and antioxidant capacity (41%) and modified phenolic acids profile. Protocatechuic acid was detected in samples after cut and storage. The association of HHP and storage at 27℃ led to hydrolysis of conjugated cinnamic acid, but did not change the flavonoids profile. PPO activity was enhanced after treatment of 250 MPa. Storage at room temperature changed all color parameters and HHP treatment promoted great color differences. Processing at 400 MPa followed by storage at 2℃ seems to be more suitable to fresh‐cut cashew apple since it was less detrimental to ascorbic acid, phenolics, and antioxidant capacity. Practical applications: Cashew apple is a fruit, which is rich in bioactive compounds, ascorbic acid, and polyphenol oxidase, but despite its nutritional content it undergoes fast deterioration, so that HHP could be an alternative to increase its shelf life and consumption. Treatment at 400 MPa and low storage temperature retains ascorbic acid, phenolic compounds, and antioxidant capacity of fresh‐cut cashew apples. The outcomes could help the food industry apply HHP associated with adequate storage temperature to the cashew apple food products to meet the quality standards. [ABSTRACT FROM AUTHOR]