将不同浓度的γ-聚谷氨酸(γ-polyglutamic acid,γ-PGA)和谷氨酰胺转氨酶(Transglutaminase,TGase)复合后添加到鸡肉肌原纤维蛋白中,通过测定肌原纤维蛋白热诱导凝胶硬度、弹性、保水性、白度值及凝胶中化学作用力的变化,以研究γ-PGA复合TGase对鸡肉肌原纤维蛋白凝胶特性的影响。结果表明:γ-PGA和TGase对鸡肉肌原纤维蛋白凝胶特性都具有明显的改善作用,但将二者复合使用后对凝胶特性的改善作用更为明显,且在TGase浓度为0.5%、γ-PGA浓度为0.6‰时,凝胶硬度、弹性和保水性都达到最大值;在TGase浓度为0.7%、γ-PGA浓度为1.2‰时凝胶白度值最小。化学作用力分析表明,经γ-PGA和TGase处理后,疏水相互作用和非二硫共价键是维持凝胶三维结构稳定性的主要因素,离子键、氢键和二硫键是次要因素。通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(sodium dodecyl sulfate-polyacrylamide gel
electrophoresis,SDS-PAGE)图谱结果表明,TGase能够催化γ-PGA-蛋白质和蛋白质-蛋白质之间发生交联反应、形成大分子物质。
Different
concentrations of γ-polyglutamic acid and transglutaminase were added to
chicken myofibr- illar protein, in order to study the effects of γ-polyglutamic
acid combined with transglutaminase on the myofibril- lar protein heat-induced
gelatin properties, the changes of hardness, springiness,
water holding capacity, whiteness and the chemical force in the gelatin
were measured. The results showed that the γ-polyglutamic acid and transg-
lutaminase had obvious effect on the gelatin properties of chicken myofibrillar
protein. However, the improvement of gelatin properties was more obvious after
the γ-polyglutamic acid and transglutaminase compounds were used, and when the
concentration of transglutaminase was 0.5%, the concentration of γ-polyglutamic
acid was 0.6‰, gelatin hardness, springiness, water
holding capacity reached the maximum; when the concentration of transgluta-
minase was 0.7%, the concentration of γ-polyglutamic acid was 1.2‰, gelatin
whiteness value reached the minimum. The chemical force analysis showed that
after the γ-polyglutamic acid and transglutaminase treatment, hydrophobic
interaction and non-disulfide covalent bond were major factor in maintaining
the stability of the three-dimensional structure of the gelatin, ionic bonds,
hydrogen bonds and disulphide bonds were the secondary factors. SDS-PAGE
studies indicated that transglutaminase could catalyze the cross-linking
reaction between γ-polyglutamic-protein and protein-protein to form
macromolecular substances.