Formulation Optimization of a Composite Biological Preservative for Scophthalmus maximus

Based on the study of single biological preservative, a composite biological preservative composed of pullulan, e-polylysine and protamine was developed using orthogonal array design. The quality of Scophthalmus maximus during cold storage was evaluated based on the parameters of Total Bacterial Counts (TBC), pH, Total Volatile Basic Nitrogen (T-VBN) and Trimethylamine (TMA). The significance of various factors on cold storage was in the order of pullulan, e-polylysine and protamine and the optimum ratio was 1.5% pullulan, 0.6% e- polylysine and 0.6% protamine. The Linnaeus treated with this biological preservative of storage at (4±1)°C showed better results of TBC, pH, T-VBN and trimethylamine than the untreated control group. The shelf-life of Linnaeus was prolonged for 4~5 days, indicating a good fresh-keeping effect.