Effect of chitosan coating and organic acid salts on quality and shelf life of black tiger shrimp stored at 0° C

Abstract

This study investigated the extension of the shelf life of black tiger shrimp stored at 0 °C by applying treatments with organic acid salt solutions combined with chitosan preservation coatings. Four shrimp samples were included: the control sample, the sample treated with 2.5% sodium citrate solution, the sample treated with 2% chitosan solution, and the sample treated with 2.5% sodium citrate solution followed by 2% chitosan. Sensory, chemical, and microbiological quality factors were monitored over 17 days of storage using quality indices such as the quality index (QI) from the quality index method, hypoxanthine, trimethylamine nitrogen (TMA‐N), total volatile basic nitrogen (TVB‐N), and total viable count (TVC) to assess the shrimp's freshness. As a result, QI and hypoxanthine levels increased linearly with storage time in all shrimp samples. TMA‐N and TVB‐N values exhibited two‐phase linear changes corresponding to the autolysis and decomposition stages of the shrimp. The shelf life was determined to be 8 days for the control sample, 12 days for the citrate sample, 13 days for the chitosan sample, and 15 days for the citrate/chitosan sample. Linear regression equations between the indices and storage time, as well as between the quality indices for each sample, were identified.