Effects of Pullulan-Based Coatings Incorporating ɛ-Polylysine and Glutathione on the Preservation of Cowpeas (Vigna unguiculata L.) Postharvest

Abstract

Pullulan has a fine-coating-forming ability, ɛ-polylysine has an antibacterial activity, and glutathione has both a potent antioxidant activity and polyphenol-oxidase-inhibiting ability. This study explored the effects of pullulan-based coatings incorporating ɛ-polylysine and glutathione (1% pullulan + 0.2% ɛ-polylysine + 0.3% glutathione) on the preservation of cowpeas (Vigna unguiculata L.) during refrigerated storage. Pullulan-based coatings incorporating ɛ-polylysine and glutathione decreased the weight loss, decay and rust spot indices, respiratory rate and malondialdehyde by 49.01%, 60.38%, 91.09%, 69.09% and 49.23%, respectively, and increased soluble solid content by 34.21% compared with the control group after 15 days of refrigerated storage (p < 0.05). Results show that pullulan-based coatings incorporating ɛ-polylysine and glutathione treatment may be practical materials for the preservation of cowpeas during refrigerated storage.