响应面法优化米糠挤出工艺及其物性研究

采用响应面法对米糠挤出试验工艺条件进行优化。在单因素试验基础上，以米糠粒度、水分含量、挤出温度为响应因素，米糠可溶性膳食纤维得率为响应值，根据中心组合及Box-Behnken 试验设计原理采用三因素三水平的响应面分析法，确定最佳挤出工艺。结果表明：米糠粒度0.175mm(80 目)、水分含量33%、挤出温度164℃时，米糠可溶性膳食纤维得率为19.23%，与理论值较为接近，表明数学模型对优化挤出工艺可行，方差分析结果表明挤出过程中对可溶性膳食纤维得率影响程度由强到弱的因素为水分含量＞挤出温度＞物料粒度。挤出后米糠的膨胀力、持水力、结合水力、吸脂力均较挤出前有较大改善，综合物性值为挤出前的2.12 倍。

Optimization of Extrusion Technology of Rice Bran by Response Surface Methodology and Measurement of Its Physical Properties

In order to optimize the extrusion technology of rice bran, the effects of rice bran granule size, water content and extrusion temperature on the yield of soluble dietary fiber from rice bran were explored by response surface methodology on the basis of single factor experiments. The optimal extrusion conditions were determined to be: rice bran granular size, 0.175 mm; water content, 33%; and extrusion temperature 164 ℃. The yield of soluble dietary fiber from rice bran was 19.23% under these extrusion conditions, which was close to the theoretical value. The importance of the above three process conditions affecting the extraction rate of soluble dietary fiber from strong to weak was in an order of water content, extrusion temperature and rice bran size. The extruded rice bran exhibited a significant improvement in expansion power, water-holding capacity, water-binding capability and oil-absorbing capacity. Comprehensive material property value of extruded rice bran exhibited a 2.12-fold improvement. Therefore, the extrusion technology can greatly improve the content of soluble dietary fiber in rice bran and comprehensive material properties, which will provide theoretical references for the utilization of rice bran in food industry.