甜荞与主粮作物蛋白营养功能特性比较研究

Comparative Study on Nutritional Functional Characteristics of Protein Between Common Buckwheat and Staple Crops

本实验采用碱溶酸沉法提取甜荞、小麦、玉米和水稻4种作物的籽粒蛋白质,并对其蛋白及氨基酸含量、蛋白颗粒形态、溶解性、泡沫特性、乳化特性、持水性、持油性、热特性等营养特性和功能特性进行对比研究。结果表明,4种作物籽粒蛋白的营养特性及理化性质存在一定差异。甜荞和小麦蛋白微观结构较为相似,均呈现疏松多孔,且表面有尖锐状突起,而玉米和水稻蛋白结构紧致,局部有小孔。甜荞清蛋白和球蛋白质量分数为21.81%和19.07%,高于小麦、玉米、水稻;而醇溶蛋白和谷蛋白含量与比值显著低于主粮作物。甜荞蛋白质中8种必需氨基酸评分最好,蛋白溶解性、持水性、起泡能力分别为31.32%、5.075 g/g、36.73%,显著高于其他3种主粮作物。4种作物蛋白变性温度都达到了80℃以上,热稳定性良好,甜荞蛋白变性温度为86.1℃,显著高于小麦和玉米。甜荞蛋白质比3种主粮作物蛋白具有更好的营养价值以及食品加工特性。

In this experiment, the protein was extracted from the grains of four crops, that is, common buckwheat, wheat, maize and rice, by using the method of alkali solution and acid precipitation, and its nutritional and functional characteristics such as protein and amino acids content, protein particle morphology, solubility, foam characteristics, emulsification properties water holding capacity, oil holding capacity and thermal properties were compared and researched. The results showed that there were some differences in the nutritional and physicochemical properties of grain protein among the four crops. The protein microstructure of common buckwheat and wheat was similar, both of which were loose and porous, with sharp protrusions on the surface, while the protein structure of maize and rice was compact, with local small holes. The mass fraction of albumin and globulin of buckwheat were 21.81% and 19.07%, respectively, higher than that of wheat, maize and rice. However, the content and ratio of gliadin and glutenin were significantly lower than those of staple crops. The score of eight essential amino acids in common buckwheat protein was the best, with the protein solubility, water holding capacity and foaming capacity of 31.32%, 5.075 g/g and 36.73%, respectively, which were significantly higher than those of the other three staple crops. The denaturation temperature of the protein of the four crops all reached above 80 ℃, with good thermal stability;The denaturation temperature of common buckwheat protein was 86.1 ℃, which was significantly higher than that of wheat and maize. In conclusion, common buckwheat protein has better nutritional value and food processing characteristics than the protein of other three staple crops.