Effects of Anti-Browning Agents on Polyphenoloxidase Activity and Total Phenolics as Related to Browning of Fresh-Cut ‘Fuji’ Apple

The objective of this study was to study the influences of anti-browning agents on the correlation between phenolics, and PPO activity and browning of fresh-cut ‘Fuji’ apple. Fresh apples were washed with distilled water, peeled, cut in to 1.5 cm cubes, and treated with distilled water (WC), chlorinated water (CW, 0.01%, v/v), cysteine solution (CS, 0.5%, w/v) and ascorbic acid solution (AA, 0.5%, w/v). The WC treatment was considered as a control. All samples were stored in the dark at 4oC and RH 90% for 7 days. Color, browning index, total phenolics, and PPO activity of the samples were evaluated. PPO activity and browning index of all samples increased during storage. For total phenolics, WC and CW treatments did not show observed changes during storage, although CS and AA treatments showed an increase. Browning index of WC and CW treatments during storage was found to be highly correlated with PPO activity and color degradation, as indicated by changes in color parameters, but CS and AA treatments were not. Total phenolics of fresh-cut apples during storage were found to be moderately correlated with browning index and not correlated with color degradation.