REDUCTION OF CHILLING INJURY IN THE SWEET PERSIMMON FUYU DURING STORAGE BY DRY AIR HEAT-TREATMENTS

Sweet persimmon fruit (Diospyros kaki cv. Fuyu L.) were heat-treated w ith dry air at 34-50 degrees C for durations of 0.5-10 h, cooled immed iately, and stored for 6.5 weeks at 0 degrees C in air. After storage, fruit were held for 3 days at 20 degrees C, and evaluated for quality . Extreme chilling injury (flesh gelling) was observed in non-heated f ruit. Associated with development of chilling injury was increased eth ylene production 1 day after removal from storage, and decreased fruit firmness, juiciness, titratable acidity, and colour (L value, hue and chroma) 3 days after removal from storage. Increasing the temperature of the hot air heat treatment (HT) progressively reduced flesh gellin g and alleviated chilling injury. However, external and internal brown ing increased with greater HT temperatures and duration. Least chillin g injury and external browning were observed at 47 degrees C for 0.5-3 h. However, the levels of browning observed in these treatments are l ikely to be commercially unacceptable. Thus, although hot air HTs conf er significant protection against low temperature damage to persimmon fruit, heat damage needs to be reduced before such benefits can be rea lised commercially. (C) 1997 Elsevier Science B.V.