Development of Skin Burning Discoloration On Peach and Nectarine Fruit in Response to High pH Solutions During Postharvest Operations

A high level of a new skin damage incidence related to exposure to high pH during the brushing-waxing postharvest operations has been observed recently on some peaches and nectarine cultivars. As the causes that trigger this skin discoloration are different than those that cause traditional field inking previously reported, we have called this blemish as skin burning disorder. In this work, we have studied the combination of factors that could lead to skin burning discoloration in. Different susceptibility to skin burning was observed after screening 22 different peach and nectarine cultivars. A classification of the 22 studied cultivars depending on the rate of pH-related skin burning susceptibility has been suggested. Additionally, the role of phenolic compounds from the skin of peach and nectarine fruits in the skin burning development has been studied. The stability of the skin phenolic extracts to pH in the range 7-10 was studied with the aid of ultraviolet spectroscopy. This study demonstrates that fruit skin phenolic compounds are not stable to high pH, and that the transformations they suffer with high pH are time-dependant and non-reversible.