腊肉加工过程中肌原纤维蛋白结构的变化

Changes of the Construction of Myofibrillar Proteins in Chinese Traditional Bacon During Processing

【目的】解析肌原纤维蛋白在腊肉加工过程中主链构象及微环境的变化。【方法】运用拉曼光谱,对酰胺Ⅰ、Ⅲ带及S-S、C-C、C-N伸缩振动谱带进行分析,比较I760、I850/I830的强度变化。【结果】在加工过程中,肌原纤维蛋白α-螺旋的含量显著下降,β-折叠的最终含量显著增加,β-转角及无规则卷曲含量无明显变化,主链C-C的α-螺旋及C-N伸缩振动强度减弱,二硫键天然构象的谱带强度也显著下降;I760归一化强度在干腌2d后显著降低,而后在风干过程中又显著上升,I850/I830的比值在同时期显著下降。【结论】肌原纤维蛋白的主链及二级结构在整个加工过程中发生了变化,氨基酸残基的疏水性在风干过程中得到了增强。

[Objective] The objective of the study was to analyze the： configuration and microenvironment changes of the myofibrillar proteins in Chinese traditional bacon at different processing points. [Method] Raman spectroscopy was used to analyze the changes of amide I, Ⅲ belt and S-S, C-C and C-N stretching vibration bands and compare the intensity changes of 1760, 1850/1830, respectively. [Result] The content of α-helix decreased significantly accompanied by an final increase in β-sheet during the processing period, while the β-turns and random coil had no obvious change. The intensity of main chains of C-C （a-helix） and C-N stretching vibration was weaken. The intensity of native conformation of disulfide bond decreased during the processing. The normalized intensity of 1760 decreased significantly after 2 days when samples were dry-cured, and then increased significantly during the drying process, while the 1850/1830 ratio was a significantly decreased. [Conclusion] The main chain and secondary structure of myofibrillar proteins changed during the whole process period, but the hydrophobicity of amino acid residues was enhanced just in the drying process.