挤压变量对小米-豆粕复合挤压膨化产品蛋白体外消化率、脆性和颜色的影响  

Effects of Extrusion Variables on the Protein Digestibility in Vitro,Crispness and Color of Expanded Foxtail Millet- Soybean Meal Blends

作　　者：赵学伟[1] 张培旗[1] 王章存[1] 张华[1] 魏益民[2] 

机构地区：[1]郑州轻工业学院食品与生物工程学院,郑州450001 [2]中国农业科学院农产品加工研究所,北京100094

出　　处：《中国粮油学报》2015年第5期11-18,共8页Journal of the Chinese Cereals and Oils Association

基　　金：科技部农业科技成果转化资金(05EFN216900373)

摘　　要：添加豆粕可提高淀粉基挤压膨化食品的营养品质。以同向双螺杆挤压机处理小米-豆粕混合物料,采用中心组合试验设计,就挤压变量（挤压温度、物料水分、螺杆转速、喂料速度、物料配比）对产品特性（蛋白体外消化率、脆性指数、色差值）的影响进行响应面分析,并采用贡献率分析法分析了各变量对产品特性的贡献率。挤压后消化率提高至79.0%～90.5%,提高混合物料中豆粕的含量有利于提高蛋白消化率,高水分结合适当高温或低水分结合高温也有利于提高蛋白消化率;高温结合低水分、高螺杆转速结合低喂料速度有利于提高脆性指数;较低的挤压温度有利于降低色差值。温度是影响3个指标的最重要因素;水分对消化率及脆性也有较大影响;物料中豆粕含量对消化率的影响较大,但是对脆性和色差的影响较小。因此,挤压操作条件仍是决定产品特性的主要因素,这为通过改变操作条件而获得高营养的小米-豆粕挤压膨化产品提供了可能。Soybean meal supplementation increases the nutritional value of starch - based expanded snacks. Millet - soybean meal blends were extruded in a co - rotating twin - screw extruder. Response surface methodology using a central composite design was applied to evaluating the effects of process variables （ extrusion temperature, feed moisture content, screw speed, feed rate and millet- soybean meal blend ratio） on the characteristics （in vitro pro- tein digestibility index, crispness index and color difference） of the extrudates. Contribution analysis of each variable was performed. Protein digestibility of the extruded blends increased to 79.0%-90.5% after extrusion, got higher values at higher soybean meal level, and higher moisture content combined with mid - higher extrusion temperature or lower moisture content combined with higher extrusion temperature. Crispness index was higher at higher extrusion temperature combined with lower moisture content or higher screw speed combined with lower feed rate. Smaller color difference was obtained at lower extrusion temperature. The most important variable affecting all the three characteristics was extrusion temperature, which was followed by moisture content with respect to affecting the protein digestibility and crispness. The level of soybean meal, one major contributor to protein digestibility, contributed little to crispness and color difference. Therefore, extrusion operating variables were still the major factors dominating extrudate quality, which would make it feasible to manufacture nutritional extrusion expanded millet - soybean meal blend through manipulating extrusion operating conditions.

关 键 词：小米 豆粕 复合挤压 蛋白体外消化率 脆性 颜色 

分 类 号：TS213[轻工技术与工程—粮食、油脂及植物蛋白工程]