Introduction: Peach fruit is considered to be a part of the fragrance fruits in terms of respiratory behavior, which is why it quickly becomes corrosive at normal temperature. Shelf life of peach is limited because of weight loss due to water loss and physiological abnormalities such as browning and tissue alteration. The Aloe Vera gel is a polyester coating and has an elastic property that is easily soluble in water and covers the entire area around the product to a similar extent. This gel acts as a protective layer on the product and protects the cells below the protective layer against mechanical damage and also prevents the loss of juices. Polyamines are a group of low-molecular-weight, naturally-occurring compounds with linear nitrogen groups found in almost all organisms and play a role in a wide range of physiological processes in plants, animals and microorganisms. The purpose of this experiment was to investigate the effect of Putrescine and Aloe Vera gel on the prolongation of the post-harvest life of peach fruit.
Materials and methods: Peach fruits (Prunus persica L.), the redtop cultivar at commercial maturing stage, when 80-50% of the fruits were painted, Harvested from the gardens of Moghan Agro Industry & Industry Co., located in Pars Abad city and after transferring to the laboratory, coating treatments as factorial based on completely randomized design with coating treatments in four levels of Putrescine (0, 2, 4, and 6 milli molar) and Aloe-vera gel treatments in four levels (0%, 15%, 30%, and 45%) in three time periods (15, 30 and 45 days) and three replicates with total of 144 experimental units was carried out. The fruits at -1° C and humidity of 95-90% were kept in cold storage. The pH of the juice were measured by a Digital pH Meter, soluble solids at room temperature was read by hand-made refractometer on a graded column. To measure total acid, titration was performed using 0.1% sodium hydroxide solution and the results were expressed in grams of malic acid in 100 grams of fresh weight. Measurement of vitamin C was done by titration with Decolor phenol Indole Phenol and Meta phosphoric acid and its amount expressed as mg of ascorbic acid in 100 grams of sample. The total phenol content was measured by the Folin- Sioculto method. The acetone method was used to measure carotenoid. Flavonoids were measured by acid ethanol method. The data of this study were analyzed using SPSS (9.1.3) and comparison of mean of treatments with LSD-test at probability level of 5%. Charts were also drawn using Microsoft Excel software.
Results & Discussion: Based on the analysis of variance table, the triple effects of Putrescine, aloe vera and time treatments in all indices had a significant effect at 1% probability level. Analysis of variance showed the lowest pH at combined treatment of 6 mM putrescine and 30% Aloe-vera gel. Also, the most titratable acidity was observed at combined treatment of 6 mM putrescine and 15% Aloe-vera gel and the most total soluble solids was observed at combined treatment of 2 mM and 45% Aloe-vera gel. Highest levels of vitamin C were observed at combined treatment of different levels of Aloe-vera gels at 6 mM putrescine. The most carotenoid levels was for combined treatment of 6 mM putrescine and 30% Aloe-vera gel and the most flavonoids was for combined treatments of 6 mM putrescine and 45% Aloe-vera gel. The pH peach juice increased during storage, due to the breakdown and decomposition of organic acids in the respiration process. The organic acids during storage are low due to their consumption during respiration and have a downward trend. The amount of soluble solids in fragrance fruits, such as peaches, increases during storage, when using putrescin significantly reduced the changes in soluble solids. The treatment of polyamide fruits slowly reduces the amount of total soluble solids that can be delayed in the production of ethylene and the ripening of fruit. It seems that the effect of polyamide treatments on their ability to maintain acidic conditions and the total acid content of the fruit extract, is related to their ability to compete with ethylene and delay in the ripening process. The amount of phenol over time has been increased. Phenol content of fruits and vegetables can be reduced or increased, which depends on storage conditions. With increasing maintenance period, the activity of PEL enzymes increases in different stages of harvesting, so that it has the highest amount at the time of commercial maturation. Based on the results of this study, it was observed that co-application of Putrescin coated treatments with aloe vera gel maintains biochemical parameters in terms of storage of peach fruit. Generally, the combination of 6 μM Putrescin and 30% Aloe Vera combination therapy had the best effect among other treatments in maintaining the traits in tomato fruit.