Compositional modifications of bioactive compounds and changes in the edible quality and antioxidant activity of 'Friar' plum fruit during flesh reddening at intermediate temperatures.

Flesh reddening of 'Friar' plum (Prunus salicina Lindl.) fruit developed rapidly during storage at intermediate temperatures of 5 and 15 °C in comparison to flesh turning yellow at 25 °C and almost no colour change at 0 °C. Thus, modifications of phytochemicals and antioxidant activity during flesh reddening were investigated. Anthocyanins accumulated rapidly in reddening flesh tissue and cyanidin-3-O-glucoside was identified as the absolutely predominant individual anthocyanin. Anthocyanins contributed greatly to the antioxidant activity at 5 °C, and especially at 15 °C by combining with non-anthocyanin phenolics, including protocatechuic, syringic, trans-p-coumaric and caffeic acids. Storage at 15 °C impeded the hydrolysis of sucrose to glucose and fructose, while storage at 5 °C maintained sucrose and accumulated fructose. Intermediate temperatures altered organic acid compositions helping to produce reasonable SSC/TA ratios. These results would provide a postharvest approach for fruit to meet the consumer's demand for diverse tastes and health promoting effects.