رفع كسي ميوه خرمالوي ژاپني DIOSPYROS KAKI L. با تيمار اتمسفر اشباع از دي اكسيد كربن و تاثير آن بر برخي از ويژگي هاي مهم ميوه

Astringency removal of Japanese persimmon fruit (Diospyros kaki L.) by CO2 enriched atmosphere and its effects on some important fruit characteristics

Astringency of persimmon fruit is due to soluble tannins. Polymerization of these tannins by induced acetaldehyde produced during deastringency treatments, results in removal of astringent taste in fruits. In this study Japanese persimmon fruits cv. Karaj, were harvested at three different stages and were used for astringency removal process by saturated CO2 atmosphere inside closed polyethylene bags at two time levels of 24 and 36 hours. After induction of acetaldehyde production, for completion of astringency removal process, fruits were exposed to two time periods of 24 and 48 hours in ordinary atmosphere. Both 24 and 36 hours of CO, treatments significantly reduced soluble tannin concentration compared to control and the astringent taste disappeared. Astringency removal treatments by CO, and relative ambient conditions inside bags reduced fruit firmness and titrable acidity and increased color index and pH compared to control. Also CO, treatments resulted in decrease the SSC of fruits. Astringency removal treatments by CO, had no effect on ethylene production, therefore changes in fruit characters were due to CO, treatment itself or acetaldehyde and ethanol production by this treatment.