Changes during storing and astringency removal of persimmon fruit (Diospyros kaki L.)

Physiological changes during ripening, storing and astringency removal of p ersimmon fruits were traced. The fruits were stored under normal (NA), cont rolled (CA) and vacuum atmospheres (VA). The fruits were stored for 100 day s and analysed for firmness, acetaldehyde and ethanol content and soluble t annins, both before and after storing. The same analyses were done during t he deastringency treatment carried out with a high CO2 concentration (99.99 %) for 20 h at 20 degrees C . The persimmon fruits stored under NA, CA, VA or treated with high CO2 for 20 h accumulated acetaldehyde and ethanol in t he fruit tissue. CA conditions caused the highest acetaldehyde accumulation ; vacuum conditions the lowest. Ethanol content increased 20 fold during st orage; the highest accumulation was observed in vacuum stored fruit followe d by CA (3% CO2-2% O-2 and 0.5% CO2-2% O-2) conditions. Astringency removal treatment caused an immediate increase of acetaldehyde and ethanol, nearly to the same extent as in conventionally ripened or stored fruit. The amoun t of soluble tannins, the main cause of an astringent taste, decreased duri ng storage, and it did much faster during deastringency removal at the same level. The sensory evaluation test revealed that fruit treated with high C O2, was preferred to conventionally ripened fruit.