Woolliness Control and Pectin Solubilization of 'Douradão' Peach after Heat Shock Treatment

Peach fruit ripens and senesces rapidly at room temperatures. The use of cold storage is limited by chilling injury which results in internal breakdown where internal browning and woolliness are the symptoms, and it is difficult to extend their storage life. In this study, the effect of high and moderate temperatures on incidence of woolliness and changes of pectin solubilization of 'Douradao' peach fruit during cold storage were investigated. The treatments were: heating at 50°C during 1 and 2 hours (50°C/1h and 50°C/2h); heating at 20°C during 48 hours (20°C/48h) and non treated fruit (control). Fruit were stored at 1°C for 30 days and were analyzed every 10 days (plus 3 days at 25°C). Treatments with high temperature (50°C) advanced the onset of woolliness symptoms when compared with the control treatment. The treatment with heating at 20°C/48h reduced the woolliness symptoms, but induced greater solubilization of pectin and consequently high loss of firmness. The heat shock treatment appears problematic for the extension of the postharvest storage life of peach fruits.