College of Food and Biological Engineering, Zhengzhou University of Light Industry, Henan Collaborative Innovation Center of Food Production and Safety, Henan Key Laboratory of Cold Chain Food Quality and Safety Control, 5 Dongfeng Road, Zhengzhou 450002, PR China.
College of Food and Biological Engineering, Zhengzhou University of Light Industry, Henan Collaborative Innovation Center of Food Production and Safety, Henan Key Laboratory of Cold Chain Food Quality and Safety Control, 5 Dongfeng Road, Zhengzhou 450002, PR China.
Ultrason Sonochem. 2020 Oct;67:105149. doi: 10.1016/j.ultsonch.2020.105149. Epub 2020 Apr 28.
The effect of ultrasonic-assisted freezing (UAF) on the water distribution of dough and molecular structure of gluten was in-situ monitored by low field nuclear magnetic resonance (LF-NMR) and micro-miniature Raman spectroscopy in this research. The results showed that UAF treatment increased the bound water content between 5 min and 30 min, and weakened the signal intensity of hydrogen protons due to the ultrasound enhanced heat and mass transfer during the freezing process. In-situ Raman spectra analysis indicated that UAF delayed the transition from embedded to exposure of tyrosine and tryptophan residues during the freezing process. Meanwhile, UAF reduced the number of hydrogen bonds, gauche-gauche-gauche (g-g-g) conformation breakage, the degree of α-helix to random coil conversion and damage to the gluten network during the freezing process. UAF treatment reduced the water mobility and breakage of non-covalent bonds, which prevented a dramatic shift in the protein advanced conformation during the freezing process, thereby improving the quality of frozen dough.
本研究采用低场核磁共振（LF-NMR）和微小型拉曼光谱技术，原位监测超声辅助冷冻（UAF）对面团水分分布和谷朊分子结构的影响。结果表明，UAF 处理在 5 分钟至 30 分钟内增加了结合水含量，并由于冷冻过程中超声增强的传热和传质而削弱了氢质子的信号强度。原位拉曼光谱分析表明，UAF 延缓了酪氨酸和色氨酸残基在冷冻过程中从嵌入到暴露的转变。同时，UAF 减少了氢键数量、gauche-gauche-gauche（g-g-g）构象断裂、α-螺旋向无规卷曲的转化程度以及冷冻过程中对谷朊网络的破坏。UAF 处理降低了水的流动性和非共价键的断裂，防止了蛋白质高级构象在冷冻过程中的剧烈变化，从而提高了冷冻面团的质量。
