Veränderungen der Proteinqualität Getreideextrudaten mit und ohne Sojazusatz

The DC-PER was calculated based on the amino acid profile and proved to be a simple and reliable index to evaluate the protein nutritional quality. Response Surface Methodology was used to study the effect of extrusion cooking on the protein quality of wheat, rice with and without addition of soybean. Mathematical Models were established to describe the relationships between the DC-PER values and the extrusion parameters. For extrudates of wheat, rice as well as their mixture with addition of soybean, the Extrusion Temperature T d was the most important factor, which influenced the DC-PER values. The DC-PER of wheat and rice extrudates decreased intensively with rising of T d , while that of their mixture with addition of soybean increased. The Mass Moisture Content M c affected the DC-PER relatively gently. There were interactive effects between M c and T d , whose intensity changed with the sort of raw materials. Only as a minor factor the Screw Rotation Speed V s played an irrelevant role. Interactive effect between M c and V s for cereal extrudates was found to be much stronger for wheat than that for rice. The protein quality as well as the stability of wheat and rice extrudates were improved very significantly through addition of soybean during extrusion cooking