Effects And Mechanism Of ?-Polyglutamic Acid Combined With Transglutaminase On The Functional Properties Of Chicken Myofibrillar Protein

As a common food material,chicken has great demand in the world market,and its gelatine products are rich in protein,fresh and tender,light and refreshing,and it is widely welcomed by consumers.Gelatin formation of chicken protein is mainly salt soluble myofibrillar proteins,the gelatine strength and springiness of chicken myofibrillar protein are poor,and water holding capacity and slicing capacity of the chicken processing products are also poor,it seriously restrict the industrialization development of chicken products.With the improvement of living standards,low sodium salt meat products are becoming more and more popular and sought after,but the effect on the gelatine ability are negative if the single reduction in salt content,how to reduce the sodium salt content while maintaining product quality is the key to the development of low sodium salt meat products.In order to provide theoretical reference and application basis for the improvement of gelatine properties and developing functional meat products,the effects and mechanism of ?-polyglutamic acid and transglutaminase on the functional properties of chicken myofibrillar protein in different system conditions was investigated,the basic formula of low sodium chicken surimi gelatine was studied.The main results are as follows:1.?-polyglutamic acid had a significant effect on the functional properties of chicken myofibrillar protein.With the increase of the concentration of ?-polyglutamic acid,myofibrillar protein solubility,emulsification,gelatine hardness and springiness were first increases and then decreased,and respectively reached the maximum when the concentration of ?-polyglutamic acid was 0.6‰,but ?-polyglutamic acid on gelatine whiteness had little effect;cooking loss first decreased and then increased,and it reached the minimum when the concentration of ?-polyglutamic acid was 0.6‰.The change of rheological properties indicated that ?-polyglutamic acid can reduce the thermal denaturation temperature of the protein forming gelatine and improve the formation ability of the gelatine.SDS-PAGE studies indicated that the cross-linking reaction between ?-polyglutamic acid and myofibrillar protein to form macro-molecularsubstances.Comprehensive consideration from costs and processing effects,the concentration of ?-polyglutamic acid was 0.6‰.2.When the pH value was 5.5-7.0,with the increase of pH value,the solubility,emulsifying and gelatine hardness of myofibrillar protein with ?-polyglutamic acid treatment were increased,cooking loss and gelatine whiteness were decreased,gelatine springiness were first increases and then decreased.When the concentration of NaCl was 0.3-0.6 mol/L,with the increase of NaCl concentration,the solubility,emulsifying,gelatine hardness and springiness of myofibrillar protein with ?-polyglutamic acid treatment were gradually increased,and respectively reached the maximum when the concentration of NaCl was 0.6 mol/L,cooking loss and gelatine whiteness were gradually decreased,and reached the minimum when the concentration of NaCl was 0.6mol/L.when the concentration of TPP was 0-0.45%,with the increase of TPP concentration the solubility and emulsification of myofibrillar protein with?-polyglutamic acid treatment were first increased and then decreased,gelatine hardness and springiness were increased,the cooking loss and gelatine whiteness were first decreased and then increased.The functional properties of myofibrillar protein with?-polyglutamic acid treatment were improved under the same pH,NaCl concentration and TPP concentration.Considering the effects of ?-polyglutamic acid treatment under different system conditions,the suitable conditions for the effect of ?-polyglutamic acid were pH value 6.5,NaCl concentration 0.6 mol/L,TPP concentration 0.15%.3.There is a synergistic effect between ?-polyglutamic acid and transglutaminase,?-polyglutamic acid combined with transglutaminase treatment on the gelatine properties of chicken myofibrillar protein is obviously better than the single use of?-polyglutamic acid or transglutaminase,and the concentration of transglutaminase was0.5%,the concentration of ?-polyglutamic acid was 0.6‰,gelatine hardness and springiness reached the maximum and the cooking loss reached the minimum;gelatine whiteness reached the minimum,when the concentration of transglutaminase was 0.7%,the concentration of ?-polyglutamic acid was 1.2‰.The chemical force analysis showed that after ?-polyglutamic acid and transglutaminase treatment,hydrophobic interaction and non-dissulfide covalent bond were major factors in maintaining the stability of three-dimensional structure of the gelatin;ionic bonds,hydrogen bonds and disulphide bonds were the secondary factors,and disulphide bonds were mainly formed during heating.SDS-PAGE studies indicated that ?-polyglutamic acid can make MHC bands and Actin bands decreased;transglutaminase can catalyze the cross-linkingreaction between MHC and Actin is not involved in the process;?-polyglutamic acid combined with transglutaminase treatment can enhance the degree of protein cross-linking,and then improve the gelatine properties of protein.4.When the pH value was 5.5-7.0,with the increase of pH value,the solubility,gelatine hardness and springiness of myofibrillar protein with ?-polyglutamic acid and transglutaminase treatment were increased,emulsification was first increases and then decreased,cooking loss and gelatine whiteness were gradually decreased.When the concentration of NaCl was 0.3-0.6 mol/L,with the increase of NaCl concentration,the solubility,emulsifying,gelatine hardness and springiness of myofibrillar protein with?-polyglutamic acid and transglutaminase treatment were gradually increased,cooking loss and gelatine whiteness were gradually decreased.when the concentration of TPP was 0-0.45%,with the increase of TPP concentration,the solubility,emulsification and gelatine springiness of myofibrillar protein with ?-polyglutamic acid and transglutaminase treatment were first increased and then decreased,and gelatine hardness was gradually increased,and the cooking loss and gelatine whiteness were first decreased and then increased.Considering the effects of ?-polyglutamic acid combined with transglutaminase on the functional properties of myofibrillar protein treatment under different system conditions,the suitable conditions for the effect of?-polyglutamic acid combined with transglutaminase were pH value 6.5-7.0,NaCl concentration 0.5 mol/L,TPP concentration 0.15%.5.With the increase of NaCl concentration,the gelatine strength and water holding capacity of chicken minced were gradually increased,and reached the maximum when the concentration of NaCl was 1.25%,cooking loss and gelatine whiteness were gradually decreased,and reached the minimum when NaCl concentration was 1.25%.With the increase of ?-polyglutamic acid concentration,the gelatine strength and water holding capacity of chicken minced were first increased and then decreased,and reached the maximum when the concentration of ?-polyglutamic acid was 0.6‰;cooking loss and gelatine whiteness were gradually decreased,and reached the minimum when ?-polyglutamic acid concentration was 0.6‰.With the increase of transglutaminase concentration,the gelatine strength and water holding capacity of chicken minced were increased,and reached the maximum when the concentration of transglutaminase was 0.5%;cooking loss and gelatine whiteness were gradually decreased.In the case of 1.0% KCl instead of NaCl,The response surface method for the optimal formulation of chicken meat gelatine of low sodium salt was NaClconcentration 1.25%,?-polyglutamic acid concentration 0.65‰,and transglutaminase concentration 0.57%.