effect of pressure infiltration of putrescine on postharvest quality of two table grape cultivars (vitis vinifera l.)

this experiment was designed to study the effect of putrescine on quality of table grapes during storage. table grapes cvs, rishbaba and olhoghi were dipped in putrescine solutions (0, 1 and 2mm) by the method of pressure-infiltration. the results indicated that after 55 day of storage putrescine 1 mm in rishbaba and at 2mm in olhoghi cultivars were the most effective treatments in maintaining the firmness with means of 0.28 and 0.56 kgf, respectively. on the other hand, these treatments showed the lowest weight loss compared to control at the end of experiment period. in respect to the microbial activity, putrescine at 2mm decreased the infection about 3.59 cfu g-1 compared to control. untreated fruits showed the reduction in total phenolic compounds, antioxidant activity, titratable acidity, color indices, but increment in weight loss, ph, total soluble solids and ripening index. all these changes delayed significantly by putrescine treatments.