The Optimization of Sodium Tripolyphosphate Treatment Conditions on the Weight of Giant Freshwater Prawns (<i>Macrobrachium rosenbergii</i>) during Frozen Processing

During the frozen processing of giant freshwater prawns (<i>Macrobrachium rosenbergii</i>), the average weight loss after thawing is high. Overcoming this problem will be an economic benefit and has a significant implication for its large-scale production for seafood producers and traders. Sodium tripolyphosphate (STPP) is a common additive and is irreplaceable for retaining water in seafood products. Identifying optimal STPP treatment conditions for frozen <i>M. rosenbergii</i> to minimize weight loss is important to the seafood processing industry. In this study, we examined the effect of STPP on the weight of frozen <i>M. rosenbergii</i>. STPP treatment included the following factors: (1) time (min), (2) temperature (°C), and (3) concentration (%). The factors were optimized by response surface methodology using a centered second-order rotation model (central composite design) to gain the lowest weight loss rate of <i>M. rosenbergii</i> during frozen processing. The results indicated that with an STPP concentration of 3.56%, a temperature of 15.8°C, and a time of 54 min, the lowest weight loss of <i>M. rosenbergii</i> was 6.4%. The chemical composition of STPP-treated giant freshwater prawns after thawing were as follows: water content 82.3%, NH₃ content 6.3%, and total nitrogen 3.8% (the composition of the original raw materials were 77.7%, 6.7%, and 4.9%, respectively).