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.