Quality improvement of peaches by intermittent warming and modified atmosphere packaging

Peaches (Prunus persica L. Batsch cv. Paraguayo) were stored at the firm-breaker stage of maturity for 3 weeks at 0.5 degrees C. A factorial design, involving three cycles of intermittent warming (IW) for 1 day to 20 degrees C every 6 days of storage at 0.5 degrees C, and modified-atmosphere packaging (MAP) were applied. During storage, respiratory activity, ethylene emission, flesh firmness, titratable acidity (TA), total soluble solids content (TSS) and pH were monitored. The factorial design made it possible to evaluate the effects of interactions between these factors on fruit behaviour. The different behaviours induced by IW and MAP account for the different patterns of ethylene emission, flesh firmness, TSS and TSS . TA(-1). IW had a prolonged effect on ethylene emission, which continued to be stimulated after the first and second warmings. Intermittently warmed fruits also had the best quality attributes at the end of storage. However, IW did not improve ripening sufficiently when applied in combination with MAP. Both IW and MAP prolonged shelf-life by about 1 week more than did conventional cold storage. Fruits that were packaged in a modified atmosphere needed more than 3 days of subsequent ripening before the optimum level of eating quality was reached.