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The aggregation characteristics of wheat globulin induced by heating and edible salts were systematically investigated using SDS-PAGE, SE-HPLC, disulfide bonds analysis, and fluorescence and Fourier-transform infrared spectroscopy. The results showed that heating induced the formation of macro-molecular globulin aggregates through disulfide bonds, similar changes occurring when heating with neutral salt. Meanwhile, the surface hydrophobicity increased and protein conformation changed from β-turns to β-sheets. Whereas heating with alkali salt induced the reduction of disulfide bonds, and non-reducible aggregation could be produced when at higher temperatures. Additionally, both the β-turns and β-sheets increased at the expense of α-helixes and random coins, and the surface hydrophobicity was overall lower than that of heat treatment alone, which further confirmed the massive aggregation of globulin. Furthermore, it was found that globulin addition could change the pasting properties as well as the quality of noodles. In particular, after heating with alkali salt, the viscosity and setback value decreased significantly, and the pasting temperature increased; moreover, the hardness and springiness of cooked noodles increased remarkably. These changes observed could attributed to the globulin aggregation analyzed above, which contributed to further strengthen the protein network structure and improve its functional characteristics during flour processing. |
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