جستجوی مقالات مرتبط با کلیدواژه « عمر قفسه ای » در نشریات گروه « زراعت »

Modeling of calcium ascorbate effects on characteristics of button mushroom was investigated by Genetic Algorithm–Artificial Neural Network (GA-ANN). Calcium ascorbate is effective in maintaining the quality and reducing the waste of agricultural products after harvest.  In this study button mushrooms were treated by calcium ascorbate solutions in 45°C temperature at three levels of 0, 0.4 and 0.8 %, and after drying at room temperature, kept at 1°C and 90% relative humidity. Qualitative characteristics of button mushroom during postharvest period were evaluated after 0, 10, 15, 20 and 25 days. Modeling of calcium ascorbate effects on button mushroom characteristics were undertaken by GA-ANN method with 2 inputs (calcium ascorbate concentration and shelf life) and 9 output (weight loss, firmness, TDS, pH, chroma, hue angle, ΔE, browning index and total phenol) using multi-layer perceptron. The results showed that networks with 12 neurons in a hidden layer using tangent activation function could predict effect of calcium ascorbate on button mushroom characteristics with correlation coefficient equal to 0.95. Results of sensitivity analysis by optimum neural network (2-12-9), was defined shelf life as the most effective factor in predicting button mushroom attributes during postharvest period.

Peach fruit has a short storage life due to high water content and respiration rate. In this study the effect of polyethylene (PE) and nano-composite (nano-C) packaging films on quality and postharvest life of peach fruit cv. Alberta was evaluated. Peach fruits were stored at 2°C and 90% RH for 6 weeks. Some properties such as weight loss, fruit firmness, pH, TSS, TA, color indexes, browning, microbial contamination and polyphenol oxidase activity were evaluated weekly. Results showed that both films could maintain fruit qualitative and quantitative properties better than the control. Application of nano-C and PE films led to delay in fruit softening, decrease in weight loss, fruit color darkness, internal browning and polyphenol oxidase in compression with the control. Application of both films resulted in low changes in TA, TSS and pH when compared control. Nano-C film caused a decrease in microbial contamination, whereas the highest microbial contamination observed in polyethylene one. Results also showed that the effect of nano-C film on the maintenance of fruit quality properties such as lightness index, chroma, hue, TA, browning, microbial contamination and polyphenol oxidase activity were more than PE film. In general, application of nano-C may be a useful way for the reduction of fruit weight loss and maintenance of peach quality during cold storage.

Banana as one of the climacteric fruits which is sensitive to postharvest fungal diseases has a short shelf life. Applications of salicylic acid as antimicrobial and anti-ethylene compound and mentha extraction as antimicrobial compound can be effective to increase postharvest life of banana.In order to evaluate the effect of salicylic acid and mentha extraction on some quantitative and qualitative post-harvest traits of banana, an experiment in a completely randomized block design with two factors, salicylic acid in three levels of 0, 2 and 4 (mM) and mentha extraction in four levels of 0, 100, 150, 200 (mg. l) with three replication was performed. Different parameters including the percentage of weight reduction, fungi rot, total soluble solids, reduced sugar, ascorbic acid, starch and quality were measured. The result showed that all of the treatments especially salicylic acid (2 mM) in combined to 150 or 200 (mg. l) of mentha extraction improved the quality of fruit and decreased the lesions of crown and stem end rot compared to control treatment. All of treatments decreased the percentage of weight loss, total soluble solids and reduced sugar but increased ascorbic acid and starch in treated fruits. Thus, it is suggested that 2 mM of salicylic acid together with 150 mg/L of mentha extraction can be used to increase the postharvest life and quality of banana.

The market sales of ready to use fresh cut fruits have grown rapidly in recent decades. Kiwi fruit is an important fruit that its marketing as fresh cut has increased in recent years. The main limiting factors in shelf life of fresh cut fruits are microbial spoilage, drastic softening and browning. In this study, the effects of oxalic and citric acids, both at 0, 2, 4 and 6 mM concentrations, with or without ultra-sonic treatment were investigated on the increasing the shelf life of fresh cut kiwi fruit. After treatments, the fresh slices were stored at 2°C for 7 or 14 days and assessed for several traits and analyzed. Results showed that, oxalic and citric acid treated slices, in comparison to the control, had greater marketability, as well as higher flesh firmness, titrable acidity, ascorbic acid content, total phenol content and antioxidant capacity and smaller bacterial forming colony unit (CFU). Among the treatments, 2, 4 and 6 mM oxalic acid and 6 mM citric acid treatments were found more appropriate than the reaming treatments. Application of ultra-sonic treatment, despite the reduction of microbial load and maintaining antioxidant capacity, had no effects on marketability of fresh cut kiwi fruit. Hence, application of organic acid treatments as dipping can be used to increase the shelf life of fresh cut kiwi fruit.