STORAGE OF ´PINK LADY®´ APPLES: QUALITY AND BIO-PATHOLOGICAL ASPECTS

Abstract

For three years 'Pink Lady®' apples were picked, at different stages of maturity (early, commercial and late harvest), ripened immediately at 20°C or stored in air at 0°C for 60, 120 and 180 days and kept at 20°C after removal from storage. The best storability and quality were attained after 60-120 days of storage with fruit harvested with the following maturity indices: light green-yellow ground colour (L* 69÷71; a* -9 ÷ -11; b* 40÷43), firmness 7.5÷8 kg f ; starch degradation 2.8-3.2 (scale 1-5), SSC 15% and titratable acidity 1-1.3 meq/10 ml. Internal browning seemed to be the main postharvest disorder of 'Pink Lady' apples. The incidence of this disorder, observed in the 2 nd and 3 rd year of experimentation, increased with the stage of maturity at harvest and the period of storage. Superficial scald was high (after 120-180 days of storage) only in fruit harvested too early. The susceptibility to fungal diseases increased with the period of storage. Sourness, vegetative aroma and chewiness, which characterised the fruit at harvest, decreased after 60-120 days of storage and during ripening at 20°C, leading to a more balanced fruit flavour and less hard texture. Fruit quality declined after 180 days of storage, due to loss of juiciness, crispness and fruitiness and increase in mealiness. Texture and flavour attributes of 'Pink Lady' apples with values lower than 6 kg f for firmness, 15% for SSC and 0.7 meq/10 ml for titratable acidity were not appreciated by a trained panel. 'Pink Lady' apples seemed to be suitable to 7-14 days of shelf-life at 20°C.