A. A. Shokouhian; F. Letafatti; B. Fathi Achachelooee; A. Asghari; R. Olfatti
Abstract
Introduction: Grape is a non-climacteric fruit. Its ripening is associated with increased sugars, decreased acidity and development of color and flavor. Edible films and coatings could be used as a selective protection method to extend storage life of fruits. Edible coatings reduce the absorption amount ...
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Introduction: Grape is a non-climacteric fruit. Its ripening is associated with increased sugars, decreased acidity and development of color and flavor. Edible films and coatings could be used as a selective protection method to extend storage life of fruits. Edible coatings reduce the absorption amount of brine, osmotic solution and frying oil into foods, improve mechanical properties, facilitate displacement and storage strengthen food structure, reduce spoilage and increase its shelf-life. The coatings provide a protective layer for fresh fruits and act as like as modified atmosphere packaging, change the composition of internal gases, and increase the storage-life of fruits by reducing respiration rate. Zein, is an important protein in corn seed and consists about 45 - 50% of the corn proteins. This protein contains a group of Prolamines found in the corn endosperm. Zein has unique properties for preparing edible films and coatings in comparison to other plant proteins due to its high percentage of nonpolar amino acids. Gluten is an insoluble in water protein of wheat that its disulfide bonds play an important role in the establishment of gluten films. Prepared films from wheat gluten are pure and transparent, but commercial gluten produces an opaque film due to gelatinization of its existing starch. Wheat gluten-based films have satisfactory mechanical resistance and very low oxygen permeability. Gluten can encapsulate flavors, colors, or medicines, providing slow-release materials. Bacteria, fungi, or other pest- or weed-control agents can be encapsulated in gluten granules that are then coated with oil to slow drying and maintain vitality. Materials and Methods: This study was carried out to investigate the effects of gluten and zein coatings on postharvest quality of grape cultivars in a factorial arrangement based on randomized completely design with application of corn’s Zein coating treatments at four levels (control, 2, 4 and 6% w/w) and also wheat gluten at four levels (control, 2, 4 and 6% w/w) were performed in the grape cultivars (Meshkin cultivar). Grape fruits were harvested from the gardens of Meshkin city and moved to the laboratory in the University of Mohaghegh Ardabili. Then, after applying the treatments, fruits were kept at 0° C and humidity of 90-95% in cold storage. In this study, pH, total soluble solids, total acidity, starch, anthocyanin, firmness, taste, fruit storage-life, TSS/TA, weight loss, appearance and vitamin C content of fruits were measured in 30 days after applying the treatments. Results and Discussion: The results of analysis of variance showed that using of zein as grape coating had significant effect on total soluble solids, vitamin C, taste and weight loss (p < 0.01) and on the TSS /TA attribute (p < 0.05).The use ofgluten also had a significant effect on total soluble solids, anthocyanin, weight loss and vitamin C (p < 0.01) and also on the fruit starch (p < 0.05). Interaction effect of gluten and zein treatments were significant on total soluble solids, vitamin C (p < 0.01) and fruit weight loss (p < 0.05). Based on the obtained results, the highest starch content, anthocyanin, maturity index and taste were achieved by using of gluten at 4 and 6% and the lowest amount of these substances was related to control treatment. A higher amount of anthocyanin (2.45 mg / 100 g) was retained in 6% gluten treatment, Moreover, in the fruit ripening index, the best result (41) was obtained from 6% zein treatment. The taste of the fruit was also more attractive in the 6% zein treatment without gluten consumption with a score of 8.5. Also, the best results in preservation of vitamin C (17.9), soluble solids (24 brix), fruit appearance (9.5 points) and the least weight loss of fruit (6.5%) were obtained from the combination of gluten and 6% zein treatment. Comparison of the means showed that vitamin C and soluble solids were better preserved by combined using of 4 and 6% gluten with 6 and 4% zein in storage period. These results showed that vitamin C and soluble solids had the lowest stability under control conditions. Also, the control treatment had the highest weight loss and the lowest score in the fruit preservation index. In overall, the best results in most of the studied parameters were obtained from the treatment combination of 6% gluten and zein. Conclusion: Based on the obtained results, gluten and zein coatings in comparison to control treatment at levels of 6%, had significant positive effects on post-harvest quality and storage of grapes.
Mohammadreza Asghari; Hojjat Khalily
Abstract
Because of the harmful effects of chemicals on human health and environment, the use of these compounds in postharvest technology of horticultural crops is highly restricted. Current study was done to evaluate the effect of Aloe vera gel on postharvest quality and storage life of fruit cultivar Siahe-Mashhad. ...
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Because of the harmful effects of chemicals on human health and environment, the use of these compounds in postharvest technology of horticultural crops is highly restricted. Current study was done to evaluate the effect of Aloe vera gel on postharvest quality and storage life of fruit cultivar Siahe-Mashhad. Fruit were treated with Aloe vera gel of 25 and 33% for 5 min at 22 °C. Control fruit were treated with distilled water at 22°C. After drying the surface moister of fruit at ambient temperature. Fruit were divided into different groups of 25 fruit in each group and were transferred to cold storage of 1±0.5°C with 85-95% RH. Fruit quality attributes including marketing, total acidity, total phenolics, pH, weight loss and polyphenoloxidase enzyme activity were evaluated at first day and after 15 and 30 days of cold storage. 33% Aloe vera gel effectively preserved marketability, total acidity and total phenolics content and prevented increase in pH, polyphenoloxidase enzyme activity and decrease in fruit weightduring 30 days of cold storage. The results showed that Aloe vera gel could be used as commercial compound as a good alternative to chemicals in postharvest technology of cherry fruit cultivar Siahe-Mashhad.
M.R. Asghari; F. Asghari
Abstract
The effect of different concentration of salicylic acid (0, 1 and 2 mmolL-1) and chitosan (0, 0.5 and 1 percent) on postharvest life and quality of Selva strawberry fruit during storage at 2.5±0.5°C with 85-95% RH for 7 and 14 days was studied. Decay incidence, marketability, total soluble solids, ...
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The effect of different concentration of salicylic acid (0, 1 and 2 mmolL-1) and chitosan (0, 0.5 and 1 percent) on postharvest life and quality of Selva strawberry fruit during storage at 2.5±0.5°C with 85-95% RH for 7 and 14 days was studied. Decay incidence, marketability, total soluble solids, total acidity, vitamin C content and total antioxidant activity were evaluated during storage. chitosan 1% significantly decreased decay incidence and maintained fruit marketability. 1mmolL-1 of salicylic acid in combination with 1% chitosan significantly retained fruit soluble solids, vitamin C content and total antioxidant activity and was more effective on total antioxidant activity during first week of cold storage. 1 and 2 mmolL-1 salicylic acid retained total acidity.
M. Babalar; marjan Hosseini; Mohammadali askari; S. Davarpanah
Abstract
Pears are among the most important fruits in all the temperate regions in about 50 countries of the world. "Shahmiveh" and "Spadona" pears, sprayed at three stages at harvest with different concentrations putrescine (0, 0.5, 1 and 2 mM) and post harvest dipping at the same concentrations putrescine and ...
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Pears are among the most important fruits in all the temperate regions in about 50 countries of the world. "Shahmiveh" and "Spadona" pears, sprayed at three stages at harvest with different concentrations putrescine (0, 0.5, 1 and 2 mM) and post harvest dipping at the same concentrations putrescine and also dip into heat treatment (40 and 50 °C and control). Fruits were stored at 0±1 °C for 5 month. The factorial experiment was conducted using a completely randomized design of three replications. During the storage period, Sampling were carried out every three weeks and some of the qualitative and quantitative traits such as surface color, weight loss, firmness, pH, titrable acidity, total soluble solids, flavor index and vitamin C were measured. Results showed in Shahmiveh ratio to Spadona cultivar was upper firmness, pH and flavor index. Hue angle, lightness, weight loss, TA and TSS in Spadona cultivar was higher than Shahmiveh cultivar. 1 and 2 mM putrescine treatments showed maximum firmness and minimum pH, TSS and flavor index in both cultivars. Heat treatment at 40 and 50 °C respectively in Shahmiveh and Spadona increased TSS and fruit flavor index. In total, Spadona with suitable quality and quantity properties for the purpose of marketing and keeping in store is better than Shahmiveh.
