膨化过程中水分含量对菜籽粕蛋白性能的影响

Effect of different water content on properties of rapeseed protein in extrusion process

试验考察了挤压膨化过程中菜籽粕水分含量对其粗蛋白和17种氨基酸含量、体外蛋白质消化率及蛋白二级结构的影响。利用双螺杆挤压膨化机对调质水分含量为14.52%、16.10%、17.62%、19.10%、21.21%的菜籽粕原料进行膨化处理,测定了膨化处理前后菜籽粕的常规指标(水分含量、粗灰分、粗纤维、粗蛋白及17种氨基酸含量),体外蛋白消化率,并利用红外光谱测定了蛋白的二级结构,利用扫描电镜测定了微观结构。结果表明,经膨化处理后,菜籽粕蛋白体外消化率显著提高,且随着膨化过程中水分含量的增加,蛋白体外消化率先升高后降低;在菜籽粕蛋白的二级结构中,经膨化处理后菜籽粕蛋白中β折叠的含量减少,无规卷曲含量增加;据SEM结果,膨化处理后菜籽粕表面变为疏松多孔,该变化增强了养殖动物体内消化酶的作用。本研究探讨了菜籽蛋白在膨化处理过程中的变化,为通过膨化处理提高菜籽蛋白的营养价值提供了数据和理论支持。

This experiment was conducted tostudy the effect of the moisture content of rape-seed meal in the extrusion on its proteinand 17 varieties of amino acid content, in vitro proteindigestibility, and secondary structure of rape-seed meal protein. The rapeseed meal whichthe moisture content were 14.52%, 16.10%,17.62%, 19.10%, 21.21%, respectively after conditioning were extruded by, the TSE 65 typeTwin screw extruder. and then the conventional nutritional content, the in vitro protein digestibility were tested. The secondary structure of the protein was determined by infrared spectroscopy and the microstructure was observed by scanning electron microscopy.These results indicated that: with the increasing of moisture content, the in vitro protein digestibility of rapeseed meal increased gradually, and the in vitro protein digestibility increased first and then decreased with the increase of moisture content during the extrusionprocess. By SEM,it was found that after extrusion the surface of rapeseed meal particles becomes porous, which improve the digestibility of rapeseed meal of digestive enzymes. Based on the above results,it can be concluded that: extrusion treatment of rapeseed meal can improve the in vitro protein digestibility and the nutrient indexes,and water addition is necessary for obtaining high valuable extruded rapeseed meal.