Quality improvement and shelf life extension of persimmon fruit (Diospyros kaki)

Persimmon (Diospyros kaki) is an important fruit in Japan, China, Europe and Italy and is also gaining popularity in the Mediterranean countries. It is normally marketed as fresh fruit, but processing of this fruit is of great interest due to its important biologically active compounds (different types of carotenoids and vitamin C) and astringency associated with unripe hard fruit. As a result of encouragement from a series of previous experiments, the present work of treating persimmon with nitrogen and carbon dioxide gas atmosphere for 48 h followed by storage at ambient conditions (20–25 °C) for three weeks was conducted for removing astringency, improving quality and extending shelf life for export purpose. On the 1st day after 48 h treatment total phenols varied from 1.41% (nitrogen treated samples) to 1.93% (control), leucoanthocyanidine content ranged from 6.58 (nitrogen atmosphere) to 8.58 ΔA550/g (control) and procyanidine content from 4.08 (nitrogen atmosphere) to 6.46 ΔA550/g (control). There was no effect of treatments on weight loss, however, it increased as the storage time increased. Both treatments of nitrogen and carbon dioxide maintained well the texture, nutritional and sensory qualities after three weeks storage period. It was further observed that nitrogen treated fruits got maximum score (7.5) for appearance and carbon dioxide treated fruits for flavor (7.5).