Effect Of Cooking On The Protein Of Noodle And Edible Quality

Cooking noodle is the last step before eating noodle. And it's also the necessary step to produce the boiling noodle. When we cook noodle, content and structure of the protein of noodle will change at high temperature and in the water. At the same time, the edible quality of noodle will change. The material of this paper is noodle and soup which boiled different time. We determine the content of protein of noodle and soup and edible quality of noodle.1?We determine the content of crude protein and the components of protein of noodle and soup, boiled different time, by the Kjeldahl nitrogen. The results show that, with prolonging boiling time, the content of crude protein in noodles first increased and then decreased. The content of the Qing, globulin, gliadin, soluble glutenin decreased. The content of surplus protein increased. In soup, the content of crude protein, gliadin, surplus protein content increased, the content of Qing, globulin, soluble glutenin basically remained unchanged.2?We use Fourier transform infrared analyzer to determine secondary protein structure of noodle. The results show that two stage structure in noodles mainly beta sheet and beta angle. Beta and beta angle respectively accounted for 43.31% and 31.64%. Along with prolonging boiling time, protein denaturation causes the changes of secondary protein structure. The alpha helices content decreased from 11.46% to 3.09%.. The levels of beta turn increased from 31.64% to 46.46%.. The beta sheet and random coil change without rules. We determine the polypeptide of noodle by HPLC. The results show that, with the extension of noodle cooking time, most polypeptide in noodles dissolved in the soup. And part of the protein is cleaved into peptides and dissolved in the soup under a high temperature action.3?With prolonging the noodle boiling time, starch gelatinization degree in noodles increased. It causes the noodles dry matter loss increased. Because of the gluten network structure of the noodles, it causes loss of dry matter rate tends to be invariant after a period of time. At the same time the gluten network fragments of noodles into the soup and causes protein loss rate increase. We use Texture Analyzer to determine the physical characteristics of noodle. The results show that. with the extension of the noodle boiling time, the hardness, adhesion, noodles, flexibility, adhesiveness, chewiness, resilience, tensile force, shear force and shear stress decreased. At the same time the draggle distance first increased and then decreased. The sensory evaluation show that, with the extension of noodle cooking time, the sensory evaluation scores of noodles first increased and then decreased. And sensory evaluation score is the highest in the optimum cooking time.