【作者】 孟岩；

【导师】 郭顺堂；

【作者基本信息】 中国农业大学 ， 食品科学， 2004， 硕士

【摘要】 大豆蛋白质是优质的植物蛋白源，其主要组分为11S（glycinin）和7S（β-conglycinin）。11S（glycinin）是由酸性亚基A和碱性亚基B构成的，A和B形成五种复合体：Ⅰ(A_2aB₂，A_1bB_1b，A₂B_1a)和Ⅱ（A₅A₄B₃、A₃B₄）；7S（β-conglycinin）是由α’，α和β三个亚基构成的。 本研究以1624份大豆品种为材料，用SDS-PAGE电泳和western-blotting电泳的方法，对蛋白亚基的缺失情况进行了分析和鉴定。并进一步以缺少或缺失β亚基的大豆为原料，研究了β亚基对大豆加工特性的影响。 研究结果表明，我国的大豆品种有许多A₃、A₅、γ、β亚基缺少或缺失的天然变异的材料，其中我们首次发现了缺失β亚基的特异大豆品种。经western-blotting分析结果证实该品种大豆确实缺失β亚基。对其氨基酸分析结果表明，该品种含硫氨基酸含量非常丰富。 以β亚基含量不同的大豆为原料调制豆乳时，对其豆乳中蛋白质溶出状态的研究结果表明，β亚基缺失品种的豆乳中蛋白质粒子的相对含量明显高于普通大豆调制的豆乳，而且对Ca²⁺引起的凝聚反应较敏感；然而当β亚基含量增加时，豆乳中粒子含量逐渐减少。SDS-PAGE电泳分析β亚基含量不同的豆乳粒子构成表明，随着豆乳中β亚基含量的增加，粒子组成中β亚基的含量也增加，但碱性亚基的含量却减少。当蛋白浓度一定时，用富含β亚基的大豆蛋白调整豆乳中β亚基的含量，制成豆乳凝胶，然后分析其质构特性，结果表明，随着β亚基含量的增加，豆腐凝胶的硬度、弹性等质构特性均降低。对不同品种大豆分离蛋白的功能特性的研究结果表明，缺失β亚基的品种凝胶质构特性较差，乳化稳定性也较低。以上结果表明β亚基在大豆的加工过程中对蛋白质存在形态和凝胶网络结构的形成以及大豆分离蛋白的功能特性起着重要的作用。更多还原

【Abstract】 Soybean is a good dietary protein resource.11S (glycinin) and 7S (p-conglycinin) are major components in soybean. Glycinin is consisted of acidic subunits (A) and basic subunits (B), Acidic and basic subunits formed five complexes: group I (A1aB2, A1bB1b,A2B1a) and II(A5A4B3, A3B4), P-conglycinin is consisted of a’, a, and p subunits.The soybean protein subunit compositions of more than 1624 varieties were analyzed by SDS-PAGE and western-blotting methods in this study, and the lacking extent of the p subunits was analyzed and identified. The effect of p subunits on soybean process properties were used the low or lacking p subunits soybean as materials.The results, showed that there were many native aberrant materials which having low content of or lacking A3, A, γ,β subunits among the soybean varieties in China, and the special soy variety lacking p subunits was found for the first time. The results of the western-blotting analysis confirmed this result. The result of amino acid analysis of the variety lacking the p subunits showed that the suit-ammo acid content was high in this variety.The extraction states of protein in soymilk prepared with the varieties of different p subunit content were investigated. The results showed that the relative content of the protein particles in soymilks prepared with lacking p subunit was higher than the common obviously, and the protein particles were more sensitive to the coagulate. Reaction caused by the calciulmion and hydrogenion. However, as the increase of the content of p subunit, the protein particles in soymilk decreased gradually. The constitutes of protein particles in soymilks prepared with varieties containing different p subunit content were analyzed by SDS-PAGE, the results showed that the more p subunit in soymilks, the more p subunit content in protein particles, and the less basic subunit content. Keeping the protein concentration constantly, the p subunit content in soymilk was adjusted by soy protein riched p subunit, and the textural characteristics of tofu gel prepared with adjusted soymilk were analyzed, the results showed that the hardness and springiness of tofu gel decreased with p subunit content increasing, the whole texture characteristics such as the hardness and the flexibility of the tofu gel decrease. The functional properties of various SPI were investigated, the results indicated that the variety lacking p subunits showed the lower gel textural propeties and emulsified stability. As the results above, the p subunits have important effect on exist state of the protein and the gel network during the soybean process.更多还原