Application Of Mungbean Trypsin Inhibitor In The New Antistaling Agent For Aquatic Products

Sea foods are widely consumed because of their high valued nutrients including proteins,bioactive peptides,poly-unsaturated fatty acids and so on.Protein denaturation,drip losing,meat loosing,color changing and other problems always appear during the thawing process of the frozen aquatic products.Such problems led to the bad appearance of the goods,decreased their quality and cause economic losses.Aquatic products such as fish and shrimp are rich in sarcoplasmic and myofibrillar proteins,which are easily degraded by endogenous proteinases,and is the main cause for the bad quality.Therefore,it is necessary to develop a new type antistaling agent using natural proteinase inhibitors combined with other water retention agents.In the present study,a simplified process including acid extraction,heating and activated carbon treatment was established for the purpose to obtain mung bean trypsin inhibitor(MBTI)in large amount for the preparation of antistaling agent.The final product was discolored with less smell and could meet the need for application in sea food processing industry.In this paper,the shelled fresh shrimps were soaked in the solution of trehalose and MBTI.Trehalose could improve the quality of shrimp with the increment of weight gain and meat yield,reducing salt soluble protein losing,suppress the decreasing of Ca2+-protein ATPase activity,decreasing the loss rate of cooking droplets.Addition of sodium alginate combined with water retention could improve the meat yield.Thus,these reagents could be as applied in frozen shrimp for water retention.The water retention agent combined with MBTI,sodium alginate,trehalose was used to treat the shrimp and compared the result treated with traditional antistaling agent.The shape of shrimp individual treated with antistaling agent was full,bright,with incarnadine color.Furthermore,the shrimp showed good appearance and quality without blackening caused by oxidization.The shrimp revealed good water holding capacity,fresh gloss surface and the consistent crimp degree.The part connected to the head was good and loose condition was not observed.Furthermore,treatment of tilapia fillets by soaking in the solution of trehalose with concentration of 0.4 %,the fish fillets revealed springness,good appearance,full and white body and greater hardness.The best water retention agent formula was 0.52% trehalose,1.4%trisodium phosphate,and 0.44% MBTI.The fish fillets thus treated was full in shape,homogeneous,bright,stretchy and most of the nutrients were kept.The new antistaling agents have been applied to production by Xiamen Maillard Food Science and Technology Co.and obtained high praise by the customers.