籽瓜种子蛋白质的持水及持油性研究

Study on Water and Fat Absorption of Seed-watermelon's Seeds Protein

以籽瓜种子为原料,采用碱溶酸沉法提取籽瓜种子蛋白质。测定并比较籽瓜种子蛋白和大豆浓缩蛋白的持水及持油性。探究蛋白质、氨基酸组成及含量、表面疏水性及蛋白质的超微结构与持水及持油性的关系。结果表明：籽瓜种子蛋白的持油性是大豆浓缩蛋白的1.1-1.2倍,持水性较差,仅是大豆浓缩蛋白的0.65-0.7倍;籽瓜种子蛋白以球蛋白和难溶蛋白为主,分别占总蛋白的58.79%和24.15%,球蛋白对持油性不利,难溶蛋白则能增强持油性;籽瓜种子蛋白具有较高的表面疏水性,其疏水指数为440,大豆浓缩蛋白较低为354,较高的表面疏水性能有益于持油性,降低持水性;结构疏松、存在空洞缝隙的海绵状蛋白结构对持水性和持油性有利。

Protein has been extracted from seed -watermelon＇s seeds by alkali extraction and acid precipitation method in the paper. The retention and fat absorption of seed - watermelon＇s seeds protein have been evaluated and the soybean protein concentrate were also compared. The relationship of composition, count of protein and amino acid, surface hydrophobicity, ultrastructure of proteins and the retention and fat absorption of protein were studied respectively. The results showed that the fat absorption of seed - watermelon＇s seeds protein could be 1.1 - 1.2 times of that of soybean protein concentrate, but the retention was not as well as the fat absorption, which was only 0.65 - 0.7 times ; protein of seed -watermelon＇s seeds mainly included globulin and insoluble protein, which accounted for 58.79% and 24. 15% of total protein respectively. The existence of globulin had a passive effect on fat absorption, while insoluble protein increased the fat absorption; protein of seed - watermelon＇s seeds had high surface hydrophobieity of 440, while the soybean protein concentrate was only 354. The relatively higher surface hydrophobicity increased the fat absorption while reduced the reten- tion; the protein with a loose spongy structure was satisfied for retention and fat absorption of protein.