Food Engineering
Fakhreddin Salehi; Moein Inanloodoghouz; Sara Ghazvineh; Parisa Moradkhani
Abstract
IntroductionSour cherries (Prunus cerasus L.) are relatively diverse and broadly distributed around the world, being found in Asia, Europe, and North America. Sour cherries have unique anthocyanin content, and rich in phenolic compounds. The fruits are generally used for processing purposes, such as ...
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IntroductionSour cherries (Prunus cerasus L.) are relatively diverse and broadly distributed around the world, being found in Asia, Europe, and North America. Sour cherries have unique anthocyanin content, and rich in phenolic compounds. The fruits are generally used for processing purposes, such as for production juice and jam. The fruits of sour cherries can also be frozen and dried. One of the best methods for the preservation of agricultural product is drying, which involves removing water from the manufactured goods. Dried sour cherries have a long shelf life and therefore may be a fine alternative to fresh fruit all year round. There are no reports on the effect of microwave pretreatment on the hot air drying kinetics of sour cherries in the literature. Hence, the purpose of this study was to estimate the impacts of microwave pretreatment on the total phenolics, drying time, mass transfer kinetic, effective moisture diffusivity, total color difference index, shrinkage and rehydration of sour cherry. In addition, the moisture ratio changes of sour cherry during drying were modeled. Material and MethodsSour cherries were purchased from the market at Bahar, Hamedan Province, Iran. The average diameter of fresh sour cherries was 1.6 cm. In this study, the water content of fresh and dried sour cherries was calculated using an oven at 103°C for 5 h (Shimaz, Iran). In this research, the effect of microwave time on the drying time, effective moisture diffusivity coefficient and rehydration of sour cherries was investigated and drying kinetics were modeled. To apply the microwave pretreatment on the sour cherries, a microwave oven (Gplus, Model; GMW-M425S.MIS00, Goldiran Industries Co., Iran) was used under atmospheric pressure. In this work, the influence of the microwave pretreatment time at five levels of 0, 30, 60, 90, and 120 s (power=220W) on the cherries was examined. After taking out the treated sour cherries from microwave device, the samples were placed in the hot-air dryer (70°C) as a thin layers. The dehydration kinetics of sour cherries were explained using 7 simplified drying equations. Fick's second law of diffusion using spherical coordinates was used to calculate the moisture diffusivity of sour cherries at various hot-air drying conditions. The rehydration test was conducted with a water bath (R.J42, Pars Azma Co., Iran). Dried sour cherries were weighed and immersed for 30 min in distilled water in a 250 ml glass beaker at 50°C. Results and DiscussionThe results showed that microwave treatment led to an increase in moisture removal rate from the sour cherries, an increase in the effective moisture diffusivity coefficient, and, consequently, a decrease in drying time. By increasing the microwave time from 0 to 12 s, the average drying time of sour cherries in the hot-air dryer was decreased from 370 min to 250 min (p<0.05). The average effective moisture diffusivity coefficient calculated for the samples placed in the hot-air dryer was 4.25×10-10 m2/s. Increasing the microwave time from 0 to 120 s increased the average effective moisture diffusivity coefficient by 85%. The maximum amount of phenolic was related to the sample treated with microwave for 90 seconds. Microwave treatment time had no significant effect on the rehydration of dried sour cherries. ConclusionKinetic modeling of weight changes of sour cherries during drying was carried out using models in the sources, followed the Page model was selected as the best model to predict moisture ratio changes under the selected experimental conditions. The mean values of sum of squares due to error, root mean square error, and r for all samples ranged from 0.001 to 0.007, 0.005 to 0.017, and 0.997 to 0.999, respectively. Generally, 120 s pre-treatment by microwave is the best condition for drying sour cherries.
Hadis Cheraghi; Fardin Ghanbari; Mehdi Saidi
Abstract
Introduction: Button mushroom (Agaricus bisporus L.) is one of the most popular and widely consumed edible mushrooms that is grown all over the world. However, button mushrooms have a short shelf life of about 3 to 4 days after harvest and lose their commercial value within a few days due to browning ...
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Introduction: Button mushroom (Agaricus bisporus L.) is one of the most popular and widely consumed edible mushrooms that is grown all over the world. However, button mushrooms have a short shelf life of about 3 to 4 days after harvest and lose their commercial value within a few days due to browning of the tissue, water loss, aging and microbial attack. Tissue browning is caused by the activity of polyphenol oxidase (PPO) in plastids on phenolic compounds in the vacuoles as a substrate. Therefore, enzymatic browning is intensified by the loss of membrane integrity due to aging and tissue deterioration and as a result of physical connection between the enzyme and the substrate. The use of some techniques such as the chemicals and physical treatments gives promising results in delaying Browning and increasing the shelf life of edible mushrooms. Cinnamic acid (CA) is an organic acid that occurs naturally in plants and has low toxicity and a wide range of biological activities. Cinnamic acid and its derivatives are widely used in food industry. This compound acts as an inhibitor of polyphenol oxidase activity. On the other hand, cinnamic acid in low concentration has been proposed as an activator of the antioxidant system and its positive effects on reducing the effects of environmental stresses in various plants have been proven in several experiments. Therefore, in the present study, the effect of cinnamic acid treatment on reducing the browning of the tissue and maintaining the quality of white button mushrooms in the post-harvest period has been investigated. Materials and Methods: Treatments included exogenous application of cinnamic acid at four levels (control, 100, 200 and 400 μM trans cinnamic acid) and storage time at five times (0, 4, 8, 12 and 16 days after storage). Cinnamic acid treatment at the mentioned concentrations was applied by top application 24 hours before mushroom harvest. Distilled water was used for control treatment. At the time of picking, infected, very large and small mushrooms were removed and the same mushrooms with a cap diameter of 40 to 45 mm were collected for each experimental treatment. After harvesting, the mushrooms were placed in a polyethylene box covered with cellophane and after weighing, they were transferred to an incubator at 4°C. In the post-harvest period, different traits were measured with a four day interva. Results and Discussion: The results showed that by increasing storage time, the activity of polyphenol oxidase and peroxidase increased and consequently the browning of the tissue also had an increasing trend. Also, with increasing storage time, weight loss percentage, hydrogen peroxide and malondialdehyde increased and total phenol and total antioxidant capacity were decreased. The use of cinnamic acid treatment in all three concentrations (100, 200 and 400 μM) reduced the activity of peroxidase and polyphenol oxidase activities and reduced tissue browning. The application of cinnamic acid also improved the quality traits of edible mushrooms such as total phenol, total antioxidant capacity and visual quality index. These findings suggest that application of cinnamic acid, especially at a concentration of 400 μM, could have the potential of inhibiting tissue browning and thus maintaining the mushrooms quality at the postharvest period
Rohollah Pashaei Bahram; Sodeif Azadmard Damirchi; Javad Hesari; Seyed Hadi Peighambardoust; Samad Bodbodak; , Boukaga Farmani
Abstract
Introduction: Cornelian cherry is one of horticultural crops in Iran. There are about 1094.26 hectares of cornelian cherry orchards in Iran and 2329.36 ton cornelian cherry fruit are produced annually based on statistics of the Ministry of Agriculture-Jahad. Cornelian cherry fruit is usually consumed ...
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Introduction: Cornelian cherry is one of horticultural crops in Iran. There are about 1094.26 hectares of cornelian cherry orchards in Iran and 2329.36 ton cornelian cherry fruit are produced annually based on statistics of the Ministry of Agriculture-Jahad. Cornelian cherry fruit is usually consumed in fresh form, but it products are also used in form of dried fruit, jam, pickles, sauce, juice, jelly, marmalade, vinegar, fruit roll-ups (Golriz et al., 1996; Demir and Kalynoco, 2003; Gulcin et al., 2005) and syrup (Damir et al, 2003; Jayaprakasam et al., 2006). Cornelian cherry fruit is a rich source of antioxidant compounds and has different benefits such as nutritional, medicinal value, profitability and export values (Panatelidis et al., 2006).Total anthocyanins content of most varieties of Cornus are 15-10 times higher than other fruits more that are used as anthocyanins source (Vareed et al., 2007). Although it is obvious that bioactive compounds of cornelian cherry fruit are valuable, but there is little information about changes of their composition and activity during postharvest storage. Some parameters such as Storage temperature, light and exposure to oxygen have great influence on the stability of the composition during postharvest storage of the fruits (Kalt et al., 1999). Since cornelian cherry is a climacteric fruit, the aim of the research was studying the effect of storage and transport of cornelian cheery in ambient temperature on physicochemical properties and bioactive compounds. Two ways of cornelian cherry preservation are included storage of cornelian cherry at room temperature and storage in dried form.
Materials and methods: Cornelian cherry fruit is supplied from an orchard in the city Horand in east Azerbaijan Province from a high yielding tree. After picking, fruits were sorted and held in incubator (25 ˚C) for 9 days and were sampled at intervals of 24 hours up to 9 days and physico-chemical parameters of samples such as pH, acidity, dry matter, Total ash and loss of their bioactive compounds (total phenols, total flavonoids, total anthocyanin, vitamin C and antioxidant capacity) were evaluated. In this research, the effects of storage time on the physicochemical properties and bioactive compounds contents of cornelian cherry fruit during storage at room temperature (25 ˚C) were analyzed by means repeated measurements in time method in three replications. The results obtained were analyzed by using analysis of variance and mean comparison using the least squares (p≤0.05).
Results and discussion: The results showed that pH and acidity significantly increased and decreased during storage time respectively. It could be attributed to consumption of organic acids in the respiration pathways as a substrate and use of them by mold. It gradually led to an increase of pH and improved the condition for yeast growth. The results showed that after 9 days storage at 25 ˚C the amount of Vitamin C decreased from 1385 to 354 (mg/100 gd. b). It could be ascribed to oxidation of Vitamin C during storage in presence of air. Total anthocyanins decreased from 379 to 195 (mg/100 gd. b) which is the result of degradation of the compounds in presence of oxygen and condensation of them with tannin and protein compounds during storage at ambient condition) PiljacZegarac et al., 2011). The amount of total phenols increased from 1237 to 2067 (mg/100 gd. b) During 9 days of storage at ambient conditions. The increase of phenolics compounds could attributed to release of them from protein and carbohydrate complexes (Doshi & Adsule, 2008). Prior et al. (2005) concluded that increase of phenolic compounds during storage of fruits could be the result of moisture decrease and reducing sugar content increase and their interaction with folin ciocalteu reagent. Also flavonoid content of cornelian cherries increased from 491 to 943 (mg/100 gd. b) During storage which probably is due to release of flavonoid compound during ripening process in postharvest storage time. Also, the antioxidant activity was reduced to 33%. According to the results, it could be concluded that storage of cornelian cheery fruit in ambient condition significantly decreased the bioactive compounds. Therefore it was recommended that cornelian cheery should be stored in low temperature condition and consumed in fresh form in short time after harvesting in order to remain nutritional properties and bioactive compounds.
