Abstract: This study aimed to lower the water activity of ready-to-eat Scophthalmus maximus and consequently to prolong its storage life. Glycerol, sodium lactate and maltitol were used as water activity-lowering agents. The water activity-lowering effect of each of these compounds was determined by one-factor-at-a-time experiments. Combinations of the water activity-lowering agents were optimized by response surface methodology based on a three-variable, three-level Box-Behnken design. Furthermore, storage experiments were carried out on samples with and without water activity-lowering agents. The optimum combination obtained was 4.1 mL/100 g glycerol, 1.5 mL/100 g sodium lactate and 4.0 g/100 g gmaltitol. Under this condition, the water activity of the product with 40% water was 0.781. After seven days of storage at 37 ℃, total bacterial count was 4.04 (lg(CFU/g)), total volatile basic nitrogen (TVB-N) content was 12.47 mg/100 g, and thiobarbituric acid (TBA) value was 1.48 mg/100 g, which were all below the national standard limits. Accordingly, it was proved that the water activity-lowering agents could effectively improve the preservability of ready-to-eat Scophthalmus maximus and prolong its storage life.

Key words: ready-to-eat Scophthalmus maximus, water activity, water activity-lowering agent, response surface methodology, preservation