EFFECT OF HARVEST TIME AND L-CYSTEINE AS AN ANTIOXIDANT ON FLESH BROWNING OF FRESH-CUT CHERIMOYA (Annona cherimola Mill.)

Abstract

Browning development is the most important factor limiting the quality of fresh-cut cherimoya (Annona cherimola Mill). However there is little information available about its causes and methods of control. The effectiveness of L-cysteine (0.125. 0.25 and 0.5%) in fresh-cut cherimoya harvested on two occasions (October and November) and stored for 6 and 12 days at 0 degrees C was studied. In order to understand the biological basis of browning, polyphenol oxidase (PPO) enzyme activity and total phenolic content in fresh-cut pieces were measured. Quality measurements and sensory analysis indicated that 0.5% L-cysteine was somewhat effective in reducing browning development, without affecting other quality attributes. In terms of physiological parameters, PPO activity did not show differences between mature (at harvest) and ripe fruit (at processing) in both harvest times, but cherimoya fruits picked in November presented lower PPO activity than fruit from October. In general, PPO activity and total phenolic content of L-cysteine treated fruits did not show consistent differences with untreated fruit at 6 or 12 days at 0 degrees C. PPO activity analyses demonstrated that PPO activity was higher in the outer part of cherimoya flesh compared to the middle or inner sector. These results would support the possibility of using L-cysteine as a postharvest treatment to reduce browning development in fresh-cut cherimoya.