CaCl_(2)对小麦粉面筋蛋白聚集特性及二级结构的影响

Effects of CaCl_(2)on aggregation characteristics and secondary structure of wheat flour gluten

为了从分子水平上探究CaCl_(2)对小麦粉面筋蛋白聚集及结构特性的影响机制,以中筋小麦粉为原料,研究CaCl_(2)不同添加量对小麦粉面筋蛋白聚集特性、二级结构及面团质构特性的影响。结果表明:随着CaCl_(2)添加量的增加,小麦粉面筋蛋白的峰值最大时间显著缩短,峰值扭矩增加;面团的硬度、弹性和咀嚼性随CaCl_(2)添加量的增加而显著降低,回复性随CaCl_(2)添加量的增加变化不显著,黏附性随CaCl_(2)添加量的增加先显著增加再降低之后趋于平缓;面筋蛋白的二级结构中无规则卷曲和β-转角含量增加,β-折叠含量降低,α-螺旋含量无显著性变化。整体来看,添加CaCl_(2)能加快面筋的形成,缩短面筋的聚集时间,弱化面团的质构特性,降低面筋结构的稳定性,从而导致面制品品质下降。

To explore the influence of CaCl_(2)on aggregation and structural characteristics of wheat flour gluten at the molecular level,wheat flour was used as the raw material.The effects of CaCl_(2)addition on the aggregation characteristics of wheat gluten,the textural characteristics of wheat dough,the extractability and secondary structure of dough gluten were studied.Firstly,the influence of different CaCl_(2)additions on gluten aggregation characteristics of wheat flour was analyzed by Gluten Peak Tester.The results showed that the maximum peak time of flour decreased significantly(from 75.67 s to 30 s),and the maximum torque increased significantly with the increase of CaCl_(2)additions(from 50 GPU to 74.67 GPU).Secondly,the texture analyzer was used to analyze the influence of different CaCl_(2)additions on the textural characteristics of wheat dough.The results showed that the hardness,springiness and chewiness of dough decreased significantly with the increase of CaCl_(2)additions.The resilience did not change significantly with the increase of CaCl_(2)additions,adhesion increased first and then decreased and then to be stable.Thirdly,the influence of different CaCl_(2)additions on gluten extractability of wheat dough was analyzed by fluorescence spectrophotometer.The results showed that the fluorescence intensity of gluten protein decreased as CaCl_(2)additions decreased(0.2%and 0.4%),indicating that wheat gluten extractability decreased significantly(P<0.05).With the further increase of CaCl_(2)additions(0.8%-3.2%),the fluorescence intensity of gluten protein did not change significantly,indicating that wheat gluten extractability did not change significantly.Finally,the influence of different CaCl_(2)additions on the secondary structure of dough gluten was determined by fourier transform infrared spectroscopy.The results showed that the peak positions and trends of FTIR spectra of gluten proteins with different CaCl_(2)additions were basically the same,indicating that the addition of CaCl_(2)could not change the specific groups of gluten,but changed the content of secondary structure of gluten.The addition of CaCl_(2)significantly decreased the content ofβ-sheet,increased the con-tent of random coil andβ-turn,but did not significantly change the content ofα-helix.Overall,the addi-tion of CaCl_(2)accelerated the formation of gluten,shortened the aggregation time of gluten,weakened the textural characteristics of dough,and reduced the stability of gluten structure,which reduced the quality of wheat product.Furthermore,these results also provided a theoretical guidance for the flour product process-ing industry.