Role of pectolytic enzymes in the development of woolliness in peaches

Abstract

SummaryThe role of pectolytic enzymes in the development of woolliness in peaches (Prunus persica, cv. Peregrine), stored at different temperatures, was studied. All peaches became woolly during a ripening period of 12 days at 10°C following storage at 2°C, whereas 75% of those stored at –0.6°C developed this disorder. Only 6% of fruit showed symptoms of woolliness after 48 h at 23°C prior to storage. The sugar content, as well as the viscosity of soluble pectin, of peaches stored after the delay period reached a maximum during the 15th day of cold storage, after which it decreased until the end of the ripening period. In peaches stored immediately, however, the maximum sugar content and viscosity was reached during the ripening period. Pectinesterase (PE) activity fluctuated between the different treatments and its possible role in the development of woolliness is not clear. The polygalacturonase (PG) activity of those peaches which became woolly after being stored directly at either temperature was markedly lower over the first 21 days’ storage than peaches which were initially subjected to delay before storage. A sharp increase in PG-activity of the peaches which developed woolliness was observed during the ripening period.