KEEPING QUALITY OF COLD-STORED PEACHES USING INTERMITTENT WARMING

Firm-breaker and firm-mature mid-season peaches (Prunus persica L. Bat sch cultivar 'Paraguayo') were stored for up to four weeks at 2 degree s C or subjected to intermittent warming cycles of one day at 20 degre es C every six days at 2 degrees C. Several quality parameters were mo nitored during normal ripening at 20 degrees C and weekly during stora ge, with and without three days of subsequent ripening at 20 degrees C . After three cycles, intermittent warming avoided or strongly allevia ted chilling injuries (particularly woolliness and lack of juiciness) especially in breaker fruit. Low temperature induced abnormal ripening in control fruit, which was detectable when chilling injury was alrea dy irreversible. In comparison to sound fruit, injured fruit showed an increased total soluble solids/titratable acidity ratio, a decrease i n flesh firmness and in Hue angle flesh color during storage and an ex cessive loss of acidity in fruit of advanced maturity. Hue angle was a good maturity index only for sound fruit. Intermittent warming appear s to maintain the quality of peaches by acclimatizing chilled fruit to subsequent periods of chilling by allowing a gradual ripening of the fruits (softening, enhancement of ground and flesh color, and maintena nce of juiciness). (C) 1998 Canadian Institute of Food Science and Tec hnology. Published by Elsevier Science Ltd. All rights reserved.