Inhibitory Effect of Honeysuckle (Lonicera japonica Thunb.) Extract on the Melanosis and Quality Deterioration of Pacific White Shrimp (Litopenaeus vannamei) During Cold Storage

The effect of <i>Lonicera japonica</i> Thunb. (LJT) extract on melanosis and quality deterioration of Pacific white shrimp (<i>Litopenaeus vannamei</i>) during cold storage was evaluated, using 4-hexylresorcinol (4-HR), a commercial melanosis inhibitor, as a positive control. The results showed that LJT inhibited polyphenol oxidase (PPO) activity and complexed copper ions in a dose-dependent manner (LJT < 16 mg/mL), indicating that LJT has the potential to inhibit shrimp melanization. Visual image and grayscale value analysis revealed that LJT and 4-HR effectively alleviated melanosis and delayed deterioration of shrimp quality stored at 4 °C, with LJT exhibiting a superior effect. LJT samples displayed a lower total number of colonies, total volatile base nitrogen value, and thiobarbituric reactive substance value than the others (<i>p</i> < 0.05), suggesting that LJT exerted the most potent inhibition on microbial growth and lipid oxidation in shrimps during cold storage. Consequently, LJT effectively retarded the melanosis and quality deterioration of shrimps.