Putrescine treatment suppresses PPO activity and retards fruit browning during ambient storage of pear

Abstract

The efficacy of putrescine (PUT) application in regulating the polyphenoloxidase (PPO) and peroxidase (POD) enzymatic activity and internal fruit browning of “Punjab Beauty” pear (Pyrus spp. cv. Punjab Beauty) was examined during the ambient storage. Postharvest dip treatments of PUT (1mM, 2mM or 3mM) were given for 5 min to the pear fruit. Control fruit were dipped in distilled water only. Fruit were kept at ambient conditions (31 ± 2°C, 78 ± 5% RH) for 15 days. Fruit were analyzed for physical and enzymatic observations on 0 day (before treatment) and at 3, 6, 9, 12 and 15 days of storage. PUT @ 3 mM effectively retained the higher total phenols content (TPC) and POD activity, while lowered the carotenoids content of fruit during storage. Moreover, 3mM PUT significantly delayed the PPO activity along with a reduction in the internal browning of fruit. As compared to the control, PUT treatment maintained the peel colour (L*, a* and b*) and ‘chlorophyll a and b’ content of pear fruit for a longer duration. The present findings exhibited the potential of PUT dip treatment as an effective tool to maintain the postharvest quality by enhancing the TPC, POD and carotenoids content, while reducing the PPO activity and internal browning of pear fruit during ambient storage.