Juice characteristics related to woolliness and ripening during postharvest storage of peaches

The effect of up to three cycles of intermittent warming (IW) for one day a t 20 degrees C every 6 days of storage at 0.5 degrees C on the development of woolliness and on the changes in juice characteristics during post-stora ge ripening of "Paraguayo" peaches at two ripening stages was studied. By s ubjecting the peaches to IW, woolliness was strongly reduced concomitantly with a sudden reduction in flesh firmness due to normal fruit ripening. Dur ing post-storage ripening, extractable juice and juiciness only decreased i n conventionally stored (CS) fruit as a result of woolliness. However, the liquid phase of the juice extracted (clear juice) decreased in IW but not i n woolly CS fruit. Clear juice reduction appeared to be related to normal a dvanced ripening, with differences between woolly and sound fruit associate d with the ripening stage during storage. The technological and physiologic al implications of these quality indices, mainly related to ripening, senes cence, and woolliness, are discussed. These results support the hypothesis that IW maintains cellular membrane integrity and helps the recovery of pec tolytic enzymatic activity. It has been stated that the incidence of woolli ness was more closely related to the juice release mechanism than to the cl ear juice content.