Physicochemical properties of flour proteins in relation to the textural and structural properties of white salted noodles.

摘要

The specific objectives of following study were: (1) to examine correlations between the physicochemical properties of wheat flour, wheat protein composition and texture properties of white salted noodles, (2) to establish a bench-scale noodle-making method and compare it with an already established pilot-scale noodle-making procedure for the evaluation of texture properties of noodles: (3) to study the effect of wheat protein content on the textural, cooking and structural properties of noodles, and (4) to study the effect of wheat flour constituents on the textural, cooking and structural properties of noodles.;Correlations data suggested that both protein content and protein composition play roles in governing the texture of noodles. The amount of total flour protein was positively related to hardness, gumminess, and chewiness of cooked noodles. Size-exclusion high performance liquid chromatography (SE-HPLC) data revealed that the amount of different protein fractions is more important than their relative proportions in total flour protein. It was found that the proportion of low molecular weight glutenins/gliadins and albumins/globulins (in total flour protein) were related positively and negatively, respectively, to the hardness, gumminess, and chewiness of cooked noodles. The proportion of beta-gliadins in total alcohol-soluble proteins was found to relate strongly with the texture parameters of noodles. Prediction equations were developed for texture parameters of noodles using SE-HPLC and rapid-visco analyzer data.;The bench-scale method developed for evaluation of cooked noodle texture using ∼10g flour samples showed similar trends in the texture parameters as observed using the pilot-scale procedure. Results also showed that the bench-scale noodle-making procedure could discriminate among wheat flours on the basis of their noodle-making properties.;Through reconstitution studies, it was observed that with increases in the protein content of the flour samples hardness, gumminess, and chewiness of cooked noodles increased, and adhesiveness and resilience of the noodles decreased. Higher Fmax and higher residual forces were observed during force relaxation of cooked noodle samples with higher protein content. The microstructure of raw noodle samples containing the highest protein level showed more developed and more continuous protein matrix when compared to samples with lower protein content.;From second set of reconstitution studies, it was found that the starch fraction of wheat flour plays a dominant role in governing the texture of noodles, followed by water-soluble fractions and then the type of protein (provided the protein content of flour is kept constant). Higher Fmax and higher residual forces were observed during force relaxation of cooked noodle samples with NuHorizon starch fraction and NuHorizon water-soluble fraction. Both Caledonia and NuHorizon gluten fractions increased the F max and residual forces of cooked noodles. NuHorizon gluten fraction also increased the continuity of protein matrix and reduced voids in the microstructure of noodles. NuHorizon glutenin-rich acid-insoluble fraction was most probably responsible for this observation.