Synergistic Utilization of ε-Polylysine and p-Coumaric Acid as Natural Preservatives for Enhancing the Shelf Life of Fresh-Cut Green Bell Peppers

The utilization of natural preservatives presents a promising avenue for mitigating the spoilage of fresh-cut fruits and vegetables induced by microorganisms, enzymatic browning, and water loss. We have developed an innovative method for preserving fresh-cut green peppers using the combined effects of epsilon-polylysine (epsilon-PL) and p-Coumaric acid (p-CA). Through concentration screening experiments, we determined that the optimal concentrations of epsilon-PL and p-CA were 25 mg/L and 10 mg/L, respectively (epsilon-p-CA). Treatment with epsilon-p-CA significantly improved the quality of fresh-cut green peppers. It effectively reduced hardness and weight loss, preserving the texture and appearance of the peppers. Furthermore, epsilon-p-CA treatment delayed the increase in respiratory rate, electrolyte leakage, and ethylene production, thereby maintaining the structural integrity. Meanwhile, epsilon-p-CA treatment effectively inhibited the malondialdehyde (MDA) content increase and maintained DPPH radical scavenging activity. The microbial analysis demonstrated the epsilon-p-CA-treated peppers also showed lower total bacterial, mold, and yeast counts, which prolonged the freshness of fresh-cut peppers. In addition, epsilon-p-CA treatment improved the retention of phenolics and vitamin C without significantly affecting the color and soluble sugar content of green peppers. Overall, the epsilon-p-CA treatment showed promise as a natural preservative for extending the shelf life of fresh-cut green peppers.