Blackening and blackening control of litopenaeus vannamei during storage at low temperature

Litopenaeus vannamei easily blackens during cold storage. To inhibit blackening and improve the storage quality of prawns, in this study, konjac glucomman (KGM)-epigallocatechin gallate (EGCG) topological microgel was formed and used for storage and preservation of prawns to improve their antioxidant properties. The effect of KGM-EGCG topological microgel on inhibiting shrimp blackening was studied by measuring the sensory evaluation score, pH value, TVB-N value, K value, PPO activity, and the effect of changes in the total number of bacteria of KGM-EGCG-treated prawns during storage. SEM and FTIR results showed that during the KGM-EGCG binding process, the number of hydrogen bond connections and the intermolecular force increased. Results also showed that the KGM microgel can effectively embed EGCG and enhance its stability to achieve a better controlled release effect. Compared with the EGCG group and untreated group, KGM-EGCG microgel has better anti-PPO activity and can better maintain the organoleptic quality and inhibit bacterial growth of Litopenaeus vannamei. Therefore, the KGM-EGCG microgel could slow down the increase in pH value, the production of volatile base nitrogen, and the increase in K value, and effectively extend the shelf life of Litopenaeus vannamei from 3 d to 6 d, providing a theoretical basis for the research of KGM functional gel and a reference for the deep processing and value enhancement of green tea and shrimp.