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Consumption of fresh pistachios is very important today due to its health and high nutritional value, and since the metabolic activities of fresh pistachios continue in the post-harvest period, it has a short post-harvest life. In this study, in the first experiment, the effect of edible coating type in combination with thyme essential oil and ventilated and unventilated packaging film on fresh pistachio storage was investigated. Factors include 3 factors of edible coating (alginate, carrageenan, chitosan, carboxymethylcellulose and hydroxypropyl methylcellulose) in the amount of 1.5%, packaging film (polyethylene without holes, polyethylene with 3 fine holes, poly propylene and polypropylene with hole had 3 tiny holes, polyethylene terephthalate without holes and polyethylene terephthalate with 3 tiny holes) and storage time (week zero, week one, week two, week three and week four).The thickness of the films was 100 μm and the diameter of the holes was 150 μm. Samples were stored at ambient temperature (20± 2 °C). The best ambient temperature coatings (alginate and chitosan) were used for refrigeration temperature (3 ± 2 ° C). Measured parameters include product weight loss, oil content changes, soluble carbohydrates, free fatty acids, peroxide value, hull color, shell color, skin firmness, chlorophyll a, chlorophyll b, carotenoids, total count, mold and yeast, and sensory evaluation (taste, odor, texture, fresh hull color, and shell color) were evaluated by sensory panelists (n = 10). In the second experiment, in order to investigate the possibility of increasing the shelf life, fresh pistachios of Akbari cultivar with cluster, using modified atmosphere packing method (MAP), in two gas ratios N2 88% + CO210% + O22 % (Gas ratio No. 1) and N283% + CO215% + O22% (gas ratio No. 2), in three types of packaging materials including polyethylene, metallized multilayer, and both films with alcohol paper (which is considered an active packaging), packaged and stored at refrigerator temperature (5 ±1 °C) for three months. During storage, quantitative and qualitative parameters such as moisture content, weight loss, respiration rate, pH, and texture were evaluated. In the third experiment, 100 grams of fresh pistachios without clusters were harvested from Ohadi and Akbari cultivars for each experiment and fresh pistachio samples were collected by different treatments including control (distilled water) and nano-silver at concentrations of 120, 150 and 180 mg / l for 10 Immersed for a minute. Then it was placed in two temperatures of refrigerator (4 ± 2 ° C) and laboratory temperature (20 ± 2 °C). Weight loss, fat percentage and soluble carbohydrate were measured every 10 days for 30 days. This factorial study was performed based on a completely randomized design with 3 replications. The results of immersion of fruits in different cover treatments (first experiment) showed that after the storage period of fresh pistachios, the appearance and chemical properties of fresh pistachios change and the use of oral coating of sodium alginate and chitosan 1 % enriched with Zataria multiflora essential oil 0.3% and 0.5% in polyethylene terephthalate containers with 3 holes, in comparison with other treatments, significantly prevented the appearance and chemical changes of the fruit and maintained fruit quality. Also, application of sodium alginate and chitosan enriched with thyme essential oil was significantly effective in reducing the growth of bacteria, mold and yeast. The results of the second experiment showed that the quality of packages with gas composition number 2 was better than packages with gas composition number 1. The quality of the packages containing both gaseous compounds was better than the quality of the packages containing the alcoholic adsorbent, and the quality of the packages of all three above packages was better than the control samples (packages without gaseous compound, and without alcoholic paper). The quality of the packages consisting of metallized multilayer film was better than polyethylene. Therefore, freshly packed pistachios in metallized multilayer film with gas composition No. 2 with three months of storage is the best treatment in this study. Based on the results of the third experiment, the treatment contained a concentration of 150 mg / l nano-silver compound at refrigerator temperature with the lowest weight loss (21.49%) and the highest amount of soluble carbohydrates (0.25%) and fat (54.25%) has been selected as the best treatment in this experiment. In general, the use of edible coating of sodium alginate and chitosan 1% enriched with Zataria multiflora essential oil 0.3% and 0.5% in polyethylene terephthalate containers with 3 holes for pistachios without spikes and metallized multilayer film with gas composition No. 2 (83% nitrogen, 15% carbon dioxide and 2% oxygen) are recommended to increase the shelf life of fresh pistachios with spikes.
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