反复冻融对麦谷蛋白结构及其功能性质的影响

Effect of the Freeze-thaw Cycles on Glutenin Structure and Functional Properties

冷链流通过程中温度的波动对于速冻水饺的品质有重要影响。为了探究其对品质的影响机理,以饺子皮中的主要成分-麦谷蛋白为研究对象,对其进行冷冻-解冻循环处理,研究其结构及功能性质的变化。结果表明,反复冻融使得乳化性、起泡性及表面疏水性增加,溶解性降低;麦谷蛋白的游离巯基含量下降,HMW发生降解,测得的二级结构无规卷曲,α-螺旋较冻融前分别减少了8.25%和18.67%,说明蛋白质的结构发生了变化。试验表明,反复冻融会破坏饺子皮中的麦谷蛋白结构,降低其功能特性,从而影响饺子皮的品质,这为研究速冻水饺的品质变化机理提供了理论依据。

In order to explore the change mechanism of frozen food quality in cold chain circulation, the glutenin in the dumpling wrapper was objected to analyze the changes of physicochemical and functional properties under the freeze- thaw cycles from -40℃ to 25 ℃. The result showed that emulsification and foaming ability increased, the solubility de- creased while the surface hydrophobicity raised by freeze-thaw cycles; the free thiol contents dropped and HMW degrad- ed, and the decreasing of random coil and a-helix were 8.25%, 18.67% respectively. All of these showed that the structure of protein was broken and functional properties reduced under the freeze-thaw cycles, which provided the refer- ence for the study in mechanism of dumplings quality.