添加谷氨酰胺转氨酶对糙米蛋糕品质的影响

研究在糙米蛋糕的蛋黄糊和蛋清中分别添加不同量的谷氨酰胺转氨酶(transglutaminase,TGase)对蛋糕烘焙品质的影响,并分析比较了TGase添加前后蛋黄糊和蛋清理化特性的变化。结果表明:添加TGase能显著提高糙米蛋糕的比容和弹性,降低其硬度,在蛋黄糊和蛋清中分别添加10和2 U/g TGase时,糙米蛋糕比容达到最大值6.0 mL/g。添加TGase后,蛋黄糊的黏度和乳化稳定性分别提高62.27%和3.86%,蛋清打发后的泡沫稳定性提高8.43%。通过测定发现蛋黄糊中的游离巯基含量明显减少,傅里叶变换红外光谱(fourier transform infrared spectroscopy,FTIR)和体积排阻高效液相色谱(size exclusion high performance liquid chromatography,SE-HPLC)的分析表明,添加了TGase的蛋黄糊中蛋白质β-折叠的比例显著增加,无规卷曲、β-转角的比例下降,并形成了更多大分子质量的蛋白质聚集体。这表明添加TGase促进了蛋黄糊和蛋清中的蛋白形成更多的交联,使蛋白质网络更加紧密,从而改善糙米蛋糕的质构。

Effect of transglutaminase addition on the quality of brown rice cake

The effect of transglutaminase(TGase)addition to the egg yolk batter and egg white on the baking quality of the brown rice cake was investigated,and the physicochemical properties of the yolk batter and egg white were compared before and after the addition of TGase.The results showed that the addition of TGase significantly increased the specific volume,elasticity and reduced the hardness of the brown rice cake.When 10 and 2 U/g TGase were added to egg yolk batter and egg white,the specific volume of brown rice cake reached the maximum value of 6.0 mL/g.After adding TGase,the viscosity and emulsion stability of egg yolk batter increased by 62.27%and 3.86%,respectively,and the foam stability of egg white after whipping increased by 8.43%.The egg yolk batter was further analyzed by free sulfhydryl content determination,Fourier transform infrared spectroscopy(FTIR)and size exclusion high performance liquid chromatography(SE-HPLC),which showed that the content of free sulfhydryl groups was significantly lower after adding TGase,and theβ-sheet ratio increased significantly,the random curl andβ-turn ratio decreased,and more protein mass aggregates were formed in the protein of the egg yolk batter.This indicated that the addition of TGase enhanced the protein network more compactly due to the formation of more cross-linking in the egg yolk batter and egg white,resulting the improvement of the texture of brown rice cake.