小麦粉吸水速率与其蛋白组成特性的关系

蛋白质理化特性的差异会导致小麦粉吸水速率的不同。本文以不同吸水速率的小麦粉为研究对象,测定面粉中粗蛋白含量、面筋蛋白含量、湿面筋含量、面筋指数、沉降值、谷蛋白溶胀指数、氨基酸含量及观测面团内部微观网络结构。结果表明,当粗蛋白含量13.25%降低到6.98%时,小麦粉的吸水速率从0.17 g/s增大到3.87 g/s;当麦醇溶蛋白含量从4.02%下降到1.53%及麦谷蛋白含量从5.28%下降到2.77%时,因形成的面筋膜的质量下降使小麦粉的吸水速率增大。同时吸水速率随湿面筋含量的减小而显著性增大,面筋指数对吸水速率无显著性影响。沉降值从69.50m L降到32.50 mL,谷蛋白溶胀指数从5.24%下降到3.33%,均与吸水速率呈显著性负相关(p0.05)。半胱氨酸含量从0.14%降低到0.04%,导致二硫键含量下降,使蛋白质间的分子作用力下降。当面团内部面筋网络结构紧密时,面粉成团时的阻力越大,其吸水速率越小。本研究表明蛋白质性质与小麦粉吸水速率呈负相关。

Study on the Relationship between Water Absorption Speed and Protein Composition Characteristics of Wheat Flour

The difference in the physical and chemical properties of protein causes the difference in the water absorption speed of wheat flour. Taking the wheat flours with different water absorption speed as research objects, the crude protein content, gluten protein content, wet gluten content, gluten index, sedimentation value, gluten swelling index, amino acid content and the internal micro network structure of the dough were measured in this paper. Results showed that the water absorption speed of wheat flour increased from 0.17 g/s to 3.87 g/s when the crude protein content was reduced from 13.25% to 6.98%. Besides, when the gliadin content decreased from 4.02% to 1.53% and the glutenin content decreased from 5.28% to 2.77%, the quality of the gluten membrane decreased, making the dough easier to shape, and increasing the water absorption speed of wheat flour. Meanwhile, the water absorption speed increased significantly with the decrease of wet gluten content, and the gluten index had no significant effect on the water absorption speed. The sedimentation value decreased from 69.50 mL to 32.50 mL, and the gluten swelling index decreased from 5.24% to 3.33%, both of which were significantly negatively correlated with the water absorption speed (p<0.05). The amino acid content affected the molecular force of the protein. The cysteine content was reduced from 0.14% to 0.04%, resulting in a decrease in the formation of disulfide bonds, and thereby affecting the protein structure. When the internal micro network structure of the dough was tight, the greater the resistance of the flour to agglomespeed, the lower the water absorption speed.The results showed that there was a negative correlation between protein properties and water absorption speed of wheat flour.