Changes in postharvest quality and antioxidant characteristics of "Dargazi" pear fruit influenced by L-cysteine

Pear ( Pyrus spp.), belonging to the family Rosaceae, has a pleasant taste and is world-renowned for its taste, flavor, high digestibility, nutritional value and significant economic implications. However, pear fruit is prone to spoilage during storage. Therefore, in this study, we aim to reduce the storage spoilage of this fruit during the cold storage period, and we hypothesized that L-cysteine could be a suitable option to reduce this storage spoilage. Therefore, L-cysteine (Cys) (0, 0.1, 0.2 and 0.5 mM) was used to improve biochemical characteristics and antioxidant enzyme activities of pear cv. Dargazi fruits under cold storage for days (30, 60 and 90) were considered and several traits were measured. Our findings showed that Cys treatment at different concentrations prevented weight loss (0.4 %) and fruit firmness (1.2 N) compared to the control and caused maintenance or increase in titratable acidity (TA) (5.53 g.100.ml -1 ), total phenol content (TP) (643 mg Cat 100 g -1 FW), total flavonoid content (TF) (643 mg Cat 100 g -1 FW), antioxidant capacity (49.47 µmol. g -1 FW), ascorbic acid (15 mg 100 g -1 FW) and phenylalanine ammonialyase (PAL) (579.11 nmol/g/min), glutathione reductase (GR) (278.18 U g -1 FW) and ascorbate peroxidase (APX) (29.30 U kg -1 FW) enzymes activities. Also, Cys treatment decreased pH (4.47), total soluble solids (TSS) (16.05), malondialdehyde (MDA) (0.56 mM kg -1 FW) and polyphenol oxidase (PPO) enzyme activity (154.0 U kg -1 FW) compared to the control. Cys treatments did not affect the amount of ion leakage, but the effect of storage time (0.489 %) on the amount of ion leakage was significant. Therefore, based on our results, Cys may be useful for increasing storage life and improving the post-harvest quality of pear fruit.