Impact of hot water soaking on antioxidant enzyme activities and some qualities of storage tomato fruits

Mature-green tomato fruits were soaked in hot water for 10 minutes at 35, 40, 45 or 50°C and then stored at 13°C for 20 days. Untreated fruits were soaking with tap water (22°C). The study showed that exposing fruit to hot water influenced peroxidase (POD) and catalase (CAT) activities. Activity of the two enzymes increased with the increasing of soaking temperature, except for the 50°C treatment. Decay of tomato fruits reduced concurrently with increasing of POD and CAT activities. Polyphenol oxidase (PPO) activity in all hot water treatments decreased when compared to control and slightly increased at the end of storage period. Hot water treatment did not alter qualities of tomato fruits in terms of total soluble solids, titratable acidity and ascorbic acid. From the study, hot water treatment of tomato fruits at 40°C for 10 minutes before storage at 13°C was the most effective in activating antioxidant enzymes and reducing fruits decay.