Zhao Gai-Ming, Zhang Gui-Yan, Bai Xue-Yuan, Yin Feng, Ru Ang, Yu Xiao-Ling, Zhao Li-Jun, Zhu Chao-Zhi
College of Food Science and Technology, Henan Agricultural University, Zhengzhou 450002, PR China; Henan Key Lab of Meat Processing and Quality Safety Control, Henan Agricultural University, Zhengzhou 450002, PR China.
College of Food Science and Technology, Henan Agricultural University, Zhengzhou 450002, PR China; Henan Key Lab of Meat Processing and Quality Safety Control, Henan Agricultural University, Zhengzhou 450002, PR China.
Food Res Int. 2022 Sep;159:111599. doi: 10.1016/j.foodres.2022.111599. Epub 2022 Jul 10.
Although collagen is widely used as an emulsifier in the food industry, its emulsifying properties are strongly influenced by processing conditions. This research investigated the effects of NaCl on the emulsifying properties of type I collagen after heating. Before heating, the solubility, emulsifying activity index (EAI), emulsifying stability index (ESI), and viscosity of type I collagen initially increased after adding NaCl (0.2 M), after which decreased with increasing NaCl concentration (0.4 M and 0.6 M) due to salt-in effect and the salt-out effects of the protein. While after heating (90℃, 30 min), the collagen became more soluble, with improved EAI and ESI, viscosity, and reduced particle size in response to increasing NaCl concentrations. It was found that NaCl increased the EAI of type I collagen twice after heating, and the EAI reached its maximum at 0.6 M NaCl concentration. We concluded that the improved emulsifying properties may due to thermal denaturation of the protein, resulting in an unfolded and disordered structure with increase of hydrogen bonds with water, rupture of disulfide bonds, and exposure of hydrophobic groups, leading to the increase of adsorption at the oil/water interface. Meanwhile, the Raman spectra analysis and Atomic Force Microscope (AFM) images showed that unfolding of the collagen triple helix was gradually destroyed after NaCl addition and heating, with emulsifying properties improved. The specific outcomes of present study can be adapted towards the requirements to improve the quality of emulsified meat products in the food industry.
尽管胶原蛋白在食品工业中被广泛用作乳化剂，但其乳化性能受到加工条件的强烈影响。本研究调查了氯化钠对加热后I型胶原蛋白乳化性能的影响。加热前，添加氯化钠（0.2 M）后，I型胶原蛋白的溶解度、乳化活性指数（EAI）、乳化稳定性指数（ESI）和粘度最初有所增加，之后随着氯化钠浓度的增加（0.4 M和0.6 M）而下降，这是由于蛋白质的盐溶效应和盐析效应。而加热后（90℃，30分钟），随着氯化钠浓度的增加，胶原蛋白的溶解性增强，EAI、ESI和粘度提高，粒径减小。研究发现，加热后氯化钠使I型胶原蛋白的EAI提高了两倍，在氯化钠浓度为0.6 M时EAI达到最大值。我们得出结论，乳化性能的改善可能是由于蛋白质的热变性，导致结构展开和无序，与水的氢键增加，二硫键断裂，疏水基团暴露，从而导致在油/水界面的吸附增加。同时，拉曼光谱分析和原子力显微镜（AFM）图像显示，添加氯化钠并加热后，胶原蛋白三螺旋的展开逐渐被破坏，乳化性能得到改善。本研究的具体成果可根据食品工业中改善乳化肉制品质量的要求进行调整。
