蛋白质对淀粉物料微波膨化的影响

研究了大豆分离蛋白（SPI）对淀粉物料微波加热效果，膨化过程及膨化产品的膨化率，质构的影响，结果表明：SPI的添加及添加方式不影响微波的加热效果，但会影响物料的膨化效果。与对照样比较，含蛋白质的淀粉物料的微波加热过程有三个阶段，物料的膨化过程也有三个阶段，即加热段，膨化段和固化段。加入SPI会使产品膨化率变小，且若微波膨化前SPI已变性，则产品的膨化率比含等量未变性SPI物料的小，随着SPI含量的增加，膨化产品中的孔隙逐渐变小，孔壁变薄，膨化前未变性的SPI可使孔隙细密均匀，而变性的SPI则会使产品组织结构粗糙，且孔隙尺雨随其含量的变化比较大。随着SPI含量的增加，膨化产品的孔隙率增大，硬度变大，色泽加深。

Effects of Protein on the Microwave Expansion of Starchy Materials

The effects of soy protein isolate (SPI) on the heating of microwave and the quality and the texture of starchy products expanded by microwave were investigated. The experimental results showed that SPI had no effects on microwave heating but affected the expanding of materials and the quality and texture of the products. The heating procedure of starch with SPI by microwave had three stages compared with the pure starch samples. Correspondingly, the expanding procedure of this kind of materials had three stages too, namely, the heating stage, the expanding stage and the solidifying stage. The addition of SPI led to the decreasing of expanding ratio (ER). If SPI was denatured before microwave expanding, the ER of products became smaller than that of the materials with the same weight and natural SPI. With the increasing of SPI content, the holes in the products became smaller, and the wall of holes became thinner. The holes of the materials with natural SPI before expanding were dense and even, while the structure of the materials with denatured SPI was rough and the size of the holes in products varied greatly with the SPI content. With the increasing of SPI content, the hole ratio of products increased and the products became harder and the color darker.