Blueberries are a highly economically valuable crop worldwide; however, conventional preservation strategies are insufficient to reduce postharvest losses. This study evaluated the efficacy of γ‐polyglutamic acid (γ‐PGA), a natural microbial biopolymer, in preserving the postharvest quality and antioxidant properties of rabbiteye blueberries ( Vaccinium ashei ). Blueberries were immersed in 50 mg·L −1 γ‐PGA or in sterile distilled water (as a control) and stored at 4 °C for 28 days. γ‐PGA‐treated fruits exhibited significantly delayed senescence and improved visual appearance compared with those in the control group. Fruit firmness was notably higher and weight loss was markedly lower in the γ‐PGA‐treated group than in the control group. γ‐PGA treatment significantly enhanced the activities of antioxidant enzymes, including superoxide dismutase (SOD), peroxidase, ascorbate peroxidase, and glutathione S ‐transferase. In addition, γ‐PGA treatment enhanced the activity of phenylalanine ammonia lyase, a key enzyme involved in phenolic metabolism, and modulated polyphenol oxidase (PPO) activity. Additionally, γ‐PGA‐treated fruits exhibited reduced accumulation of the oxidative stress indicators malondialdehyde, hydrogen peroxide, and superoxide anion. These results suggest that γ‐PGA is a promising, safe, and eco‐friendly coating agent for maintaining fruit quality and delaying senescence.
Min et al. (Thu,) studied this question.