Abstract:

Soy protein isolate and potato starch were partially added to cold pressed soybean meal to develop high-moisture textured soy protein products by optimized extrusion technology and raw material system. The results showed that extrusion temperature, material moisture, content of soy protein isolate and potato starch had significant effects on product quality. The texturization degree, brilliance index, effective lysine content and water keeping ability were increased gradually with the increase of material moisture content and high forming temperature was needed at the same time, and the water binding capacity and tissue integrity were increased gradually with the addition of soy protein isolate as well. Starch was helpful to bond and extrusion moulding among textured soy protein, but the addition quantity should be strictly controlled, because high starch content would decrease the texturization degree of textured soybean protein. The optimum technology of raw material system and extrusion temperature was determined in this study as follows: soy protein isolate 20%, starch 5%, material moisture content 60%, and extrusion temperature 185 ℃.

Key words: soybean, textured protein, extrusion technology, raw material system