Postharvest application of L‐cysteine to prevent enzymatic browning of “Stanley” plum fruit during cold storage

Abstract

Low temperature (1°C) storage causes internal browning (IB) in plum (Prunus domestica L.) fruit. Consequently, any treatment with beneficial effect on decreasing these symptoms would achieve promising attention. For this purpose, L-cysteine (0.1, 0.2, and 0.5%) treatments were applied on “Stanley” plum, and investigated IB, antioxidant capacity, electrolyte leakage (EL), malondialdehyde (MDA), internal content of anthocyanin, flavonoids, phenols, and ascorbic acid and some antioxidant enzymes. The results showed that L-cysteine at 0.5% concentration could significantly alleviate IB in plum fruit by enhancing antioxidant capacity and inhibiting polyphenol oxidase activities. In addition, 0.2 and 0.5% L-cysteine improved the activity of antioxidant enzymes (i.e., superoxide dismutase, catalase, and ascorbate peroxidase) and decreased hydrogen peroxide content. Moreover, L-cysteine maintained membrane integrity as manifested by reduced EL and MDA accumulation. L-cysteine-treated fruit showed higher ascorbic acid, anthocyanin, flavonoids, and phenol contents, and total antioxidant activity higher than the control fruit during low temperature storage. In conclusion, L-cysteine postharvest treatment could act as promising and safe method for preserving nutritional quality of plum during low temperature storage. Practical applications Low temperature storage is considered as an effective way to slow down respiration and senescence processes and then extending the postharvest life of plum. However, low temperature storage results in chilling injury (e.g., IB) and causes requisite of complementary treatment(s) to reduce the injury. Considering the present results, L-cysteine treatment could be spotted as an encouraging approach to reduce browning and preserve nutritional quality of plum during low temperature storage.