小麦抗冻蛋白对面筋蛋白冻融稳定性的影响

    The effect of wheat antifreeze proteins on the freeze-thaw stability of gluten proteins

    • 摘要: 为探究小麦抗冻蛋白(WAFPs)对面筋蛋白冻融稳定性的影响,将WAFPs添加至面团中(未添加者为对照组),经2、4、6、8、10次冻融循环后,测定面筋蛋白的持水性、持油性、乳化性等功能特性,并结合其二级结构、水分分布、游离巯基含量、微观结构、流变学特性及SDS-PAGE亚基分析进行综合评价。结果表明:WAFPs可显著缓解冻融循环引起的面筋蛋白劣变;与对照组相比,WAFPs减少了疏水基团的暴露,抑制了持水性的下降与持油性的上升,改善了乳化性及其稳定性;WAFPs通过氢键和疏水作用与面筋蛋白结合,使无规卷曲和α-螺旋结构的降幅减小,自由水与结合水含量的变化幅度减弱,游离巯基含量显著降低,网络结构更为规整,弹性模量与黏性模量增大,部分大分子量蛋白亚基的解离减少。综上,WAFPs在冻融循环过程中对小麦面筋蛋白具有多方面的保护作用,为改善冷冻面团制品品质提供了潜在应用价值。

       

      Abstract: This study investigates the protective effect of wheat antifreeze proteins (WAFPs) on the freeze-thaw stability of gluten proteins. WAFPs were added to dough with samples without WAFPs serving as the control. Both sample sets underwent 2, 4, 6, 8, and 10 freeze-thaw cycles, each comprising 2 h of freezing at -40 ℃, 20 h of storage at -20 ℃, and 2 h of thawing at 25 ℃. Following the freeze-thaw treatments, gluten proteins were extracted by washing with distilled water. The measured parameters included water-holding capacity, oil-holding capacity, emulsifying capacity, emulsification stability, secondary structure (analyzed by Fourier-transform infrared spectroscopy), water distribution (assessed by low-field nuclear magnetic resonance), free thiol content, microstructure (observed via scanning electron microscopy), rheological properties (elastic modulus G', viscous modulus G″, and loss tangent tanδ), and SDS-PAGE subunit composition. The results indicate that WAFPs significantly mitigate freeze-thaw-induced degradation of gluten proteins. Compared with the control, WAFPs reduced the exposure of hydrophobic groups, inhibited the decline in water-holding capacity and the increase in oil-holding capacity, and enhanced emulsifying properties and stability. Furthermore, WAFPs bind to gluten proteins via hydrogen bonding and hydrophobic interactions, leading to a smaller reduction in random coils and α-helices, less variation in free and bound water content, a significant decrease in free thiol content, a more regular network structure, increased elastic and viscous moduli, and reduced dissociation of certain high-molecular-weight protein subunits. In summary, WAFPs exert multifaceted protective effects on wheat gluten proteins during freeze-thaw cycling, demonstrating potential for improving the quality of frozen dough products.

       

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