QUALITY IMPROVEMENT OF PEACHES BY INTERMITTENT WARMING AND MODIFIED ATMOSPHERE PACKAGING

Peaches (Prunus persica L. Batsch cv. Paraguayo) were stored at the fi rm-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 modifie d-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 factori al design made it possible to evaluate the effects of interactions bet ween these factors on fruit behaviour. The different behaviours induce d by IW and MAP account for the different patterns of ethylene emissio n, flesh firmness, TSS and TSS . TA(-1). IW had a prolonged effect on ethylene emission, which continued to be stimulated after the first an d second warmings. Intermittently warmed fruits also had the best qual ity attributes at the end of storage. However, IW did not improve ripe ning sufficiently when applied in combination with MAP. Both IW and MA P prolonged shelf-life by about 1 week more than did conventional cold storage. Fruits that were packaged in a modified atmosphere needed mo re than 3 days of subsequent ripening before the optimum level of eati ng quality was reached.