Intermittent warming during cold storage of peaches packed in perforated polypropylene

Finn-breaker peaches (Prunus persica L. Batsch cv. 'Paraguayo') were stored for up to 3 weeks at 0.5 degrees C in perforated polypropylene (PPP) bags and/or subjected to intermittent warming (IW) of three cycles 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 emission observed in conventionally stored fruit supports the hypothesis that the ethylene-synthesizing system is impaired during the latency period of chilling injury. The transient peak in respiration activity observed in IW fruit after 12 h warming was probably associated with the restoration to normal metabolism. Both PPP and PPP + IW maintained fruit freshness and prevented chilling injuries and weight losses. PPP fruit required a post-storage ripening period. Although IW slightly increased senescence, the shelf-life was extended and the peaches were preferred for colour and taste PPP + IW might be a useful commercial method for maintaining quality and extending shelf-life of peaches. (C) 1998 Academic Press Limited.