INTERMITTENT WARMING DURING COLD-STORAGE OF PEACHES PACKED IN PERFORATED POLYPROPYLENE

Finn-breaker peaches (Prunus persica L. Batsch cv. 'Paraguayo') were s tored for up to 3 weeks at 0.5 degrees C in perforated polypropylene ( PPP) bags and/or subjected to intermittent warming (IW) of three cycle s of 1 d at 20 degrees C every 6 d of storage at 0.5 degrees C in PPP. Flesh firmness, pH, total soluble solids, titratable acidity, colour, taste and total losses were monitored. The reduction in ethylene emis sion observed in conventionally stored fruit supports the hypothesis t hat the ethylene-synthesizing system is impaired during the latency pe riod of chilling injury. The transient peak in respiration activity ob served in IW fruit after 12 h warming was probably associated with the restoration to normal metabolism. Both PPP and PPP + IW maintained fr uit freshness and prevented chilling injuries and weight losses. PPP f ruit required a post-storage ripening period. Although IW slightly inc reased senescence, the shelf-life was extended and the peaches were pr eferred for colour and taste PPP + IW might be a useful commercial met hod for maintaining quality and extending shelf-life of peaches. (C) 1 998 Academic Press Limited.