碱、盐存在下添加小麦球蛋白对面条加工品质的影响及其机制探讨

Effect of wheat globulin addition on noodle processing quality in the presence of alkali or salt and the discussion on its mechanism

为了探究小麦球蛋白在面条加工中的功能和结构特性,在碱(Na_(2)CO_(3))和盐(NaCl)存在下,研究添加小麦球蛋白对面条质构和拉伸特性的影响,并通过测定二硫键、表面疏水性和傅里叶变换红外光谱探讨球蛋白与面筋蛋白分子间的相互作用。结果表明:单独添加球蛋白能够提高面条的硬度、最大拉伸阻力以及拉伸距离;在碱存在下,添加球蛋白后面条品质显著提高,面条的弹性也得到明显改善,而在盐存在下这种促进作用并不显著。进一步对面条蛋白分子结构进行分析发现:单独添加球蛋白后,球蛋白与面筋蛋白间的疏水和二硫键作用有所增强;在盐存在下,添加球蛋白后疏水作用减弱,而氢键作用得到改善;而在碱存在下,添加球蛋白后蛋白分子间氢键作用进一步显著增强,且加速了分子间二硫键交联。综上所述,与单独添加球蛋白相比,碱存在下添加球蛋白能显著提升面条加工品质,这与碱存在下蛋白分子间相互作用的增强密切相关。

In order to explore the structure and function characteristics of wheat globulin in noodle processing, the effect of wheat globulin addition on the quality of cooked noodles was investigated under alkali(Na;CO;) and salt(NaCl) conditions. And the interaction between globulin and gluten protein was further explored. The texture and tensile properties of cooked noodles were measured with texture profile analysis. The results showed that the hardness and springiness of cooked noodles with the addition of globulin were significantly improved under alkaline condition. While, the boost from salt was not obvious. Further analysis of the molecular structure of the noodle protein was performed. When globulin was added alone, the number of disulfide bonds increased. In addition, the increase of disulfide bonds was greater under alkali condition, indicating that the protein aggregation with disulfide bonds during cooking occurred, and the synergistic effect of globulin and alkali accelerated the disulfide bonds cross-linking in the gluten-globulin complex, while the effect of salt was not obvious. In addition, Fourier infrared spectrometry was conducted to analyze the protein secondary structure. The results showed that the β-sheets and α-helixes reduced and the β-turns increased when only globulin was added;under alkali induction, the β-sheets were significantly increased, meanwhile, the α-helixes and β-turns were significantly decreased. Under salt induction, the β-sheets increased and the β-turns decreased after globulin addition, while the changes were slighter than those under alkali induction, in addition, the change of random coils and α-helixes were not obvious. The results showed that the hydrogen bonding interaction between the proteins was significantly enhanced under alkali induction. Furthermore, the fluorescence spectroscopy was conducted to explore the protein surface hydrophobicity. The results showed that the protein surface hydrophobicity decreased when globulin was added alone;under alkali induction, the decrease of the protein surface hydrophobicity was significantly smaller after globulin addition. However, under salt induction, the protein surface hydrophobicity was increased. These results indicated that the hydrophobic interaction between globulin and gluten protein was further weakened under alkali and salt induction. In conclusion, the alkali induced obvious enhancement of hydrogen and disulfide bond interactions between globulin and gluten protein, which promoted the aggregation of the protein network and then significantly improved the noodle processing quality.