[Effect of processing on the antioxidant capacity of the plum (Prunus domestica)]

Fruits are considered sources of antioxidant compounds whose properties could impair due to processing. The objective of this work was to determine the effect of blanching and osmotic dehydration on the total polyphenols content, tannins and antioxidant capacity of plums (Prunus domestica) in yellow and red varieties. The total phenolic content in plums was determined according to the Folin-Ciocalteu assay and tannins were determined by vanillin assay. The antiradical efficiency (AE) and ferric reducing power (FRP) were used to estimate the total antioxidant capacity. The content of total polyphenols and tannins were higher in the red plum. The content of polyphenols in the pulp was higher that the peel while for tannins the opposite was observed in both varieties. The red plum had higher antioxidant capacity. The AE was low and slow kinetics for the two varieties. There was a linear correlation between polyphenols and tannins with antiradical efficiency; however, there was no correlation with the reducing power. The total polyphenols content was increased with blanching, while the tannins and the AE decreased, ferric reducing power is unaffected. For osmotic dehydration, the tannins and the AE were decreased, while the total polyphenols content and ferric reducing power are unaffected. It is recommended the blanched as an alternative to consumption and conservation in the plum.