麦麸超微粉碎对面团流变学特性与网络结构的影响

Effect of superfine-grinding of wheat bran on the rheological property and gluten network of dough

为阐明麦麸粒度影响全麦产品品质的内在机理,将不同粒度的麦麸(粗麦麸、细麦麸和超微麦麸)以20%的添加量添加于低筋和中筋面粉中。利用Mixolab测定面团的流变学特性,采用低场核磁(LF-NMR)分析面团中水分的存在状态,运用傅里叶红外(FT-IR)分析面筋蛋白二级结构和扫描电镜(SEM)观察面团面筋网络微观结构。结果表明,与粗麦麸和细麦麸相比,添加超微麦麸后,面团的吸水率、峰值黏度和淀粉热凝胶稳定性显著增加,面团形成时间减少;随着麦麸粒径的减小,面团T_2弛豫时间显著缩短,自由水含量逐渐降低;减小麦麸粒径,蛋白质二级结构中α-螺旋和β-折叠含量上升,β-转角和无规则卷曲含量下降;面团微观结构观察显示,随着麦麸粒径的减小,面筋网络的连续性和致密性得到改善。

In order to investigate the mechanism of wheat bran particle size on the quality of whole wheat products, wheat bran with different particle sizes(coarse, medium and superfine, respectively) was added into low and medium protein flours at the addition level of 20%. The rheological property, water fluidity, protein secondary structure and gluten network of dough were investigated by Mixolab, LF-NMR, FT-IR and SEM, respectively. Compared to coarse and medium bran, the results showed that the addition of superfine bran into white wheat flours could significantly increase the water absorption, peak viscosity, starch hot-gel stability and decrease the development time of dough. With the reduction of wheat bran particle size, the T2 and free water content of dough were significantly decreased. The decrease of wheat bran particle size also resulted in higher content of α-helix and β-sheet and lower content of β-turn and random coil in dough. SEM results showed that with the reduction of wheat bran particle size, the continuity and compactness of dough gluten network were improved.