Ali Akbar Shokouhian; Farzad Letafatti; Bahram Fathi Achachelooee; Ali Asghari; Robab 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.
Ali Akbar Shokouhian; Ali Asghari; Hadi Mahmoodi
Abstract
Introduction: Kiwifruit (Actinidia Sp) is one of the fruits that it is considered as an appropriate food source, because it is rich in vitamins, especially vitamins c, E, A, B1 and also in the form of potassium. Humic substances are contained nutrients that improve the soil nutrients and are increases ...
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Introduction: Kiwifruit (Actinidia Sp) is one of the fruits that it is considered as an appropriate food source, because it is rich in vitamins, especially vitamins c, E, A, B1 and also in the form of potassium. Humic substances are contained nutrients that improve the soil nutrients and are increases the availability of food and therefore plant growth and yield. Studies have shown that adding certain amount of humic acid fertilizer can improve the growth of root, stem and leaves of plants and enhances yield and quality of products and increases the efficiency of nitrogen fertilizer consumption. According to pervious findings, recent research was performed aimed to achieving the best combination of humic acid and its application method for improving yield and organic fruits production in Kiwifruit cv. Hyvard.
Materials and methods: In order to investigate the effects of humic acid concentration and application method on nutrient uptake and quality and quantity of fruit indices, of Kiwifruit CV Hyvard an experiment based on complete block design with four replications was conducted during 2015-2016 in Talesh city, Gilan province. Experimental treatments included soil drenching method and foliar spraying of different levels (control, 2, 4 and 6 kg. ha-1) of humic acid. In this study traits such as absorption indexes of nutrient elements consisting nitrogen, potassium, phosphorus, calcium, zinc, magnesium, manganese, copper and iron content of leaves and quantitative and qualitative traits of fruit (yield, Tissue firmness, vitamin C, total soluble solids of fruits and leaf area and leaf chlorophyll content) were measured. Phosphorus was measured by spectrophotometer at 430 nm and potassium was measured by flame photometer. Atomic absorption was used to determine the amount of calcium (at wavelength of 422.7 nm) and magnesium (at wavelength of 285.2 nm). Nitrogen was also measured by Kjeldahl method. Micro elements were determined by flame atomic absorption method. Standard samples and treatments were cloudy with a blue acetylene flame and the adsorption of iron, manganese, zinc and copper were read at wavelengths of 243/3, 288.5, 213.9, 327.7 nm, respectively. This study was carried out in a randomized complete block design with seven treatments (0%) and application of humic acid at concentrations of 2, 4, 6 kg.ha-1 as spraying on leaves and soil application on Hayward cultivar with four replications. Data from this study were analyzed by using Jmp statistical software and graphs were drawn using Excel 2013 software.
Results and Discussion: Results of analysis of variance showed that different concentration of humic acid had significant effect on nutrient uptake and quality and quantity of fruit indices at 1% probability level. Results of this research indicated that using of humic acid caused increasing in nutrient elements uptake and improving the quality and quantity of fruit in Hyvard cv. of Kiwifruit. Comparison of means showed that the highest value of nitrogen (1.8%) of foliar application of 2 kg.ha-1 and 4 kg.ha-1 to soil of humic acid, phosphorus (0.3%) obtained by foliar application of 2 and 4 kg.ha-1, calcium (3.5%) by foliar and soil application of 4 kg.ha-1. The highest value of potassium (1.92) with soil application of 6 kg.ha-1, manganese (0.33%) and copper (12.8 Mg.Kg Dw-1) of foliar application of 4 kg.ha-1,iron (226 Mg.Kg Dw-1) of soil application 6 kg.ha-1 humic acid and the highest value of magnesium (34.7 Mg.Kg Dw-1) uptake index obtained from adding 6 kg.ha-1 humic acid to soil. The results indicated that foliar spraying of 2 kg.ha-1 humic acid had higher efficiency for zinc uptake (21.7 Mg.Kg Dw-1). Comparison of means showed that the lowest value of measured elements obtained in control treatment. Based on the results, the concentration of four kilograms per hectare of humic acid with soil and leaf application methods had the highest effect on quantitative and qualitative indices of kiwifruit.
Conclusion: Results showed that application of humic acid caused increasing in absorption of nutrients and improving the quality and quantity of fruit in Hyvard CV of Kiwifruit. Comparison of meanings showed that the application, soil application of 4 kg.ha-1 of humic acid, was more effective in absorption indices of nitrogen elements, phosphorus, calcium and quantitative and qualitative indices of kiwifruit. Treatment of 6 kg.ha-1 soil increased the adsorption of manganese and iron elements and soil treatment of 2 kg ha-1 humic acid had the highest absorption of magnesium. Data analysis showed that zinc and copper elements were more adsorbed in humic acid by 2 and 4 kg.ha-1 in spray application. In this study the lowest value of measured elements obtained in control trait.
