Effects Of Protein And Lipid Content On Yuba Film Forming

The study was performed to enhance the yuba production, improve its mechanical properties and increase its nutritional value. The traditional production process of the north and south yuba have been compared; 5 soybean cultivars were choesd in order to select the most suitable cultivar of soybean for yuba production. The relationships between ingredients of soybean and qualities of yuba were studied by means of simulated soymilk system. Based on the fuzzy binary contrast, we have taken special expertise investigation to find the priority of yuba sensory indicators for sequence.1. By dynamic tracking yuba production process, cold grinding and hot grinding process were used in yuba production respectively. We found that the process affect the protein and lipid content in the soybean milk, accordingly affect the quality of yuba. It is demonstrated that in comparison with the hot grinding yuba, the cold grinding yuba has higher yield, greater hardness, deeper color, higher protein content, and wider variety of flavor compounds. Hot grinding yuba has lower yield, higher resilience, whitish color, higher lipid content, and higher characteristic material content in the flavor substances.2.5 soybean varieties were selected to make yuba, respectively. Yuba made of Tianlong1 and Zhongdou 8 has higher film-forming rate; Yuba made of Zhongdou8 has greater hardness and Yuba made of Tianlong2 has higher resilience; Yuba made of Zhongdou8 has deeper color while Zhongdou39 has whitish color; Yuba made of Zhongdou8 has higher protein content and lower lipid content; Yuba made of Tianlong1 has higher lipid content and Zhongdou40 has lower protein content.3. The influence of protein and lipid in the film forming process was studied by simulated soymilk system. It presented that the improvement of soybean lipid content can improve film-forming rate, increase resilience and the protein and lipid content of yuba. But high levels of soybean lipid content would have certain inhibition on the above indicators. With the increase of soybean protein content, the film-forming rate, the hardness of the film and the protein content of yuba would increase while the lipid content firstly increased and then decreaed. It turns out that high protein denaturation degree could increase film-forming rate, improve the mechanical properties and nutritional value of the film. The change of protein components has little effect on the film-forming rate, but the change of 11S/7S has a direct impact on the mechanical properties of yuba.4. We get priorities for sensory quality evaluation criteria by expertise investigation method and fuzzy binary contrast method. The orders are as forllows:1. Resilience; 2.Taste; 3.Aroma; 4.Color; 5.Complete degree; 6.Hardness; 7. Smoothness; 8.Gumminess. Based on the results from sensory evaluation, more protein and lipid content of soybean varieties and the cold grinding process would contribute better yuba production.