Food Technology
Karim Mandahakki; Hamid Hassanpour
Abstract
IntroductionDue to the high rate of respiration, strawberry is prone to water loss, mechanical damage and fungal decay post-harvesting, which may reduce its shelf life (Yan et al., 2019). Food waste is an important global challenge that estimated about 30% of the world's agricultural land. Every year, ...
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IntroductionDue to the high rate of respiration, strawberry is prone to water loss, mechanical damage and fungal decay post-harvesting, which may reduce its shelf life (Yan et al., 2019). Food waste is an important global challenge that estimated about 30% of the world's agricultural land. Every year, about 9.5 million tons of food is lost in the post-harvest phase of agriculture crops (Bishop et al., 2021). Post-harvest storage of strawberry at low temperature without using other combined treatments may reduce its shelf life due to its highly perishable nature. Therefore, in addition to low temperature storage, other post-harvest techniques have also been reported to increase the shelf life of strawberry fruits after harvest. One of these techniques is using chemicals (Kahramanoglu et al., 2019).Glutathione is present in various plant tissues in concentrations of 2 to 3 mM and plays an important role in many cellular processes such as cell differentiation, enzyme regulation, cell signaling and cell death and acts as an antioxidant. (Diaz-Vivancos et al., 2015). During the experiment, spraying GSH on strawberry plants increased the amount of total flavonoids and ascorbic acid in the harvested fruits, and the results showed that the application of GSH can increase the shelf life of strawberries. (Ge et al., 2019). It has been reported that application of glutathione after harvesting okra has reduced browning and prevented its weight loss, which has created a suitable market for it, also GSH has increased the level of total phenol and the activity of ascorbate peroxidase enzyme and reduced the level of ROS and malondialdehyde, which can increase the shelf life of okra in cold storage after harvesting (Li et al., 2023).Materials and MethodsSabrina strawberry fruit was obtained from a commercial greenhouse located in Urmia in the full maturity stage. The fruits were transported to the laboratory of Horticultural Sciences Department of Urmia University, observing the necessary precautions to prevent mechanical damage. The fruits were separated in terms of size and uniformity, so that the fruits were divided into 5 groups of 15, one group as a control group and 4 groups treated with different concentrations of L-glutathione (4, 16, 32 and 64 mM respectively). After drying, the treated fruits were placed in zipped nylon bags and stored for 15 days in a cold room at ± 0.5 °C and a relative humidity of 90-95%. Also, three biological replicates at each time interval were included in the analysis. Samples obtained at each of specified time were placed to evaluate skin color, titratable acidity, soluble solids, taste index, pH, weight loss, total antioxidant capacity, total phenol content, and polyphenol oxidase enzyme activity.Results and DiscussionThe results of variance analysis showed that the effect of GSH treatment after harvesting, the effect of storage and the interaction between them differently affect each of the studied indicators. In terms of color, no significant effect was found. The effect of storage (p≤0.01) and post-harvest treatment (p≤0.05) were significant on TA trait and its highest value was observed in 10 days of storage with 32 mM. In terms of antioxidant capacity (p≤0.05) and PPO activity (p≤0.01), the effect of GSH treatment after harvest was significant, and the highest amount was observed in 16 and 64 mM treatment, respectively. Also, the effect of storage time (p≤0.05) and the effect of GSH treatment after harvesting (p≤0.01) were significant in the trait of total phenol content, and the highest amount was observed in 15 days of storage and 64 mM treatment. However, both the storage (p≤0.01) and the post-harvest GSH treatment (p≤0.05) effects on fruit weight reduction were significant and the lowest weight loss was observed in 5 days of storage and 64 mM treatment. There were no significant changes in indices such as TSS, taste index and pH.ConclusionAccording to the obtained results, the treatment of 64 mM GSH is the best concentration of GSH to increase the shelf life of harvested strawberry fruits in cold storage.Author ContributionsManda-Hakki: conceptualization, data management, financing, research and review, resources, validation, visualization, writing-main draft, Hassanpour: formal analysis, methodology, project management, software, supervision, Writing - review and editingFunding SourcesPart of this project was financially supported by Urmia University.AcknowledgementWe appreciate and thank all those who were with us in this project, especially the officials of Horticulture Laboratory, Faculty of Agriculture, Urmia University.
Food Chemistry
Zahra Khodakaramifard; Hannan Lashkari
Abstract
Introduction
The date palm (Phoenix dactylifera L.) plays an important social, environmental, and economical role for many people living in arid and semiarid regions of the world. Date fruit is one of the major agricultural crops in the East Asia region, where about 90% of the world's dates are cultivated. ...
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Introduction
The date palm (Phoenix dactylifera L.) plays an important social, environmental, and economical role for many people living in arid and semiarid regions of the world. Date fruit is one of the major agricultural crops in the East Asia region, where about 90% of the world's dates are cultivated. Dates are rich in certain nutrients and provide a good source of rapid energy, due to their high carbohydrate content (70–80%). Moreover, date fruits contain fat (0.20–0.50%), protein (2.30–5.60%), dietary fibre (6.40–11.50%), minerals (0.10–916 mg/100 g dry weight), and vitamins (C, B1, B2, B3, and A) with very little or no starch. In addition to the direct consumption of the fruit, various industrial products are also extracted derived from this product, including date juice, date honey, liquid sugar, vinegar, alcohol, caramel, date paste and date chocolate. The annual production of one million and 400 thousand tons of dates in Iran has made Iran the second pole of date production in the world after Egypt. Zarin Dasht region is located in Fars province, and the annual production of dates in this region reaches more than 1000 tons. The aim of the present work was to investigate the chemical composition, carbohydrate, and antioxidant capacity of two cultivars of Zarin Dasht dates.
Materials and Methods
After collection, all date fruits were washed with tap water, and the seeds were then removed, and the flesh were shade dried at room temperature. The dimensions and area of the imaged surfaces were measured by the physical properties measurement device in 100 repetitions. The working principle of this device is based on image processing technique. By placing the product in three different positions and perpendicular to each other, pictures of the date samples were taken individually. Date mass was obtained using a sensitive digital scale with an accuracy of 0.01 g. The displaced water method was used to determine the volume and density of each date seed. Bulk density, date porosity, geometric mean diameter, sphericity coefficient and surface area of the samples were determined. The amount of moisture was determined by weight method, ash by burning in an electric furnace, titratable acidity based on malic acid and pH of the samples were measured by a digital pH meter. To measure the amount of total phenol in the fruit, Folin–Ciocalteu reagent was used and the absorbance of the reaction mixture was read at 750 nm by a spectrophotometer. The amount of total phenol was reported in terms of gallic acid. The antioxidant capacity was determined through the neutralization of free radical 2 and 2 diphenyl 1-picrylhydrazyl (DPPH). To measure the sugar of all samples, first a standard curve was drawn from the glucose solution in different concentrations, then the sugar content of the samples was measured in milligrams per gram of fresh weight at 490 nm using the sulfuric phenol method. The amount of crude fibre was calculated according to the standard method of AOAC-991/43. The amount of fat was obtained with the Universal Extractor E-800 device for 3 hours at a suitable temperature and in 250 cc of n-hexane solvent. Finally, the statistical analysis of the data was done factorially and in the form of a completely random design in 3 replications using SAS 4, 9 software and the comparison of the means was done using the LSD test at a probability level of 1%.
Results and Discussion
According to the results of this research, there was a significant difference in all qualitative traits except pH (P<0.01). In comparing the characteristics of the palms of two cultivars, it was observed that the highest amount of fibre (1.78 %), titratable acid (0.59 %), ash (1.64 %) and fat (0.85 %) is related to Shahani cultivar,and the highest amount of total phenol (8.1 mg/gFW), DPPH inhibitory property (13 %), moisture (18.7%), sugar (63.8 %), protein (0.29 %) and pH (5.74) belonged to Khassui cultivar. Also, comparing the kernel characteristics of two cultivars, it was observed that the highest amount of ash (3.17 %), total phenol (10.8 mg/gFW), antioxidant property (72 % DPPH inhibition), protein (2.55 %), pH (6.11) and fat (9.20 %) related to the kernel of Shahani variety and the highest amount of fibre (26.2 %), moisture (5.26 %), sugar (15.8 %) and titratable acid (0.38 %) belonged to the kernel of Khassui cultivar. Overall, the kernel of Shahani variety had more DPPH inhibitory power among all the samples.
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
