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In this research, the effect of vacuum pressure and storage time were investigated on the postharvest quality of tomato and carrot. Three levels of vacuum pressure, 0.6, 0.4 and 0.2 bar were considered and during 12 days of carrot storage every three days and during 20 days of tomato storage every five days the sampling were performed. The effects of these treatments on the factors such as weight loss, firmness, soluble solids, titrable acidity and pH in carrots and tomatoes were investigated as factorial test based on Completely Randomized Design. Analysis of variance results showed that the effect of vacuum pressure and storage time on all mentioned factors were significant. Weight loss of both products was low at vacuum pressure of 0.4 bar. Also, tirable acidity and pH of these products were preserved better at vacuum pressure of 0.4 bar. The highest firmness was observed at vacuum pressure of 0.4 bar. Based on the results, storage of these two products at high vacuum pressure (0.6 bar) reduced the quality. In general, vacuum pressure of 0.4 bar was resulted in higher storage time of tomato and carrot.

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  Freshness of vegetables and fruits in the short term and long term is one of the important challenges of postharvest process. In this research, the effects of packaging type, modified atmosphere and temperature on the post harvest quality of tomato were investigated during storage. The treatments were considered as modified atmosphere packaging (passive and active) with two gas combinations (4%O₂+8%CO₂+88%N₂ and 8%O₂+4%CO₂+88%N₂), two types of package (polypropylene and polyethylene films) and two storage temperatures (4±1) and (20±2)ºC. The effects of above mentioned treatments were investigated using Completely Randomized Design with three replicates on the weight loss, firmness, soluble solids, titratable acidity and pH of tomato during 20 days storage. Analysis of variance results indicated that the effects of all treatments on the measured factors were significant (p<0.01). Tomatoes stored in polypropylene due to less thickness and more O₂ permeability preserved the quality of tomatoes better than those of polyethylene film.Also,storage temperature of(4±1)ºC maintained the quality of tomato much better than (20±2)ºCdue to slow down metabolic activities. The first gas combination (4%O₂+8%CO₂+88%N₂) was suitable due to higher CO₂ and respiration reduction. Tomatoes stored in polypropylene film and first gas combination at (4±1)ºC had the best quality after 20 days storage. In general, storage of products in the packages with modified atmosphere resulted in preserving quality and shelf life.  

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High efficiency and uniformity of water and fertilizer application are usually, considered as the ultimate goals of an appropriate design and management of irrigation and fertigation systems. The objective followed in this paper was to present a simulation-optimization model for alternate vs. conventional furrow fertigation. Two simulation models (surface fertigation and SWMS-2D models) along with an optimization approach (genetic algorithm) were employed. Inflow discharge, irrigation cutoff and start times as well as duration of fertilizer injection were chosen as decision variables to be optimized for maximizing two objective (fitness) functions based on water and nitrate application efficiency plus uniformity. Experiments were conducted to collect field data (soil water content, soil nitrate concentration, discharge and nitrate concentration in runoff, as well as advance and recession times) in order to calibrate the simulation models. The simulation-optimization model indicated that variable and fixed alternate furrow fertigations benefited from higher water and nitrate efficiencies than the conventional furrow fertigation. However, minor differences were observed between these types of furrow irrigation regarding water and nitrate uniformity. This approach substantially improved water and nitrate application efficiency as well as uniformity, taking into account the field experimental conditions. Water and nitrate application efficiencies ranged from 72 to 88% and from 70 to 89%, respectively. Christiansen uniformity coefficients for water and nitrate varied between 80 and 90% and from 86 to 96%, respectively. A higher improvement was observed in conventional furrow fertigation than those in both alternate furrow fertigation treatments. The potential of the simulation-optimization model to improve design and management of furrow fertigation is highlighted.

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The aim of this study was to investigate the antimicrobial and antioxidant effects of chitosan edible film containing nanoemulsion of Melissa officinalis L. extract and Bunium persicum essential oil on Listeria monocytogenes inoculated into camel meat. The studied films were prepared using 2% chitosan and 2.5% and 5% of nanoemulsion of Bunium persicum essential oil and 4% of Melissa officinalis L. extract. The antimicrobial and antioxidant effects of coated camel meat during 16 days of storage at 4 °C with a 4-day interval (0, 4, 8, 12, 16) were evaluated. The coated portions were chemically evaluated. Most of the essential oil compounds include: cuminaldehyde (24.37%), γ-Terpinene (19.99%), and P-cymene (9.71%). The MIC of Melissa officinalis L. extract and Bunium persicum essential oil against L. monocytogenes were 1% and 0.25%, respectively. The antioxidant effects of films by DPPH method showed that the addition of essential oils and extracts increases the antioxidant properties of films. The antimicrobial effect of films by disk diffusion method, the largest diameter of growth inhibition zone (17.15 ± 0.16) was related to chitosan film containing 5% Bunium persicum essential oil and 4% Melissa officinalis L. extract. The average count of L. monocytogenes in the control treatment was higher than the other treatments. The results of TBARS showed that the antioxidant properties of films containing Bunium persicum essential oil and Melissa officinalis L. extract was higher than the control sample. The pH level in the samples coated with chitosan film containing 5% Bunium persicum essential oil and 4% Melissa officinalis L. extract was lower than the other treatments. In general, the prepared films have good antimicrobial and antioxidant properties against L. monocytogenes, which increase with the addition of plant compounds.

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Today, the use of active packaging containing natural antimicrobial compounds such as essential oils and plant extracts has increased to increase the shelf-life of food  products. The purpose of this study is to investigate the effect of gelatin coating containing Citrus sinensis peel extract on increasing the shelf life of rainbow trout meat. Gelatin (4%) coating was prepared with different levels of Citrus sinensis peel extract (2% and 4%). After preparing the pieces of rainbow trout meat, all the pieces were coated and examined for chemical properties (pH, TVB-N, TBARS), microbial (TVCs and TPCs) and sensory properties (odor, color, texture and overall acceptance) were evaluated for 16 days at 4°C with a 4-day interval (0, 4, 8, 12, 16). The results of the investigation of the antimicrobial effect showed that in the samples coated with 2% and 4% levels of Citrus sinensis peel extract, the average count of mentioned bacteria was significantly lower than the control and gelatin alone (p < 0.05). The results of examining the chemical properties of the samples showed that pH, TVB-N and TBARS increased during the period, but this increase occurred at a slower rate in the samples coated with different levels of Citrus sinensis peel extract. In the evaluation of sensory characteristics, at the beginning of the study, all the samples had the highest acceptance limit, and with the passage of time and the appearance of signs of spoil, the scores decreased, especially in the control. Generally, the results showed that gelatin coating along with different levels of Citrus sinensis peel extract has a positive effect on increasing the shelf life of fish meat and these compounds can be used together to increase the shelf life of protein foods.