Glutathione application delays surface browning of fresh-cut lotus (Nelumbo nucifera Gaertn.) root slices during low temperature storage

Abstract

Fresh-cut slices of lotus roots are prone to rapid surface browning during post-cut storage conditions. In the present work, the impact of glutathione [(GSH) 0, 0.25%, 0.5% and 1%)] was studied on lotus root slices (LRS) at 5 ± 1 ºC for 8 d. Results exhibited that 1% GSH concentration was the best among the used treatments. The 1% GSH delayed the increase in browning index, browning degree, soluble quinones, superoxide anion, electrolyte leakage, malondialdehyde and hydrogen peroxide compared with untreated LRS. In addition, 1% GSH treatment stimulated total phenols accumulation owing to enhanced phenylalanine ammonia lyase activity and suppressed polyphenol oxidase and peroxidase activities. It was observed that 1% GSH application showed higher catalase and superoxide dismutase activity in comparison with untreated group. In the same way, 1% GSH stimulated ascorbate peroxidase, glutathione reductase as well as dehydroascorbate and monodehydroascorbate reductase activity having higher ascorbic acid, glutathione and oxidized glutathione contents in treated LRS. The levels of total aerobic bacteria and yeasts and molds remained substantially lower in 1% GSH treatment. In conclusion, 1% GSH could be used as an anti-browning treatment for fresh-cut LRS under cold storage.