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Soy protein isolate, soy protein hydrolysate (SPH), and texturized soy protein (TSP) were used to fortify flour nutrition, and the rheological properties of dough and qualities of noodles were determined. Soy proteins increased the peak viscosity of flour paste. Dough fortified with TSP also exhibited more solid-like behavior with the highest storage modulus, while dough fortified with SPH showed the lowest storage modulus. Soy proteins increased the cooking loss of noodles. The protein loss of SPH-W noodles was up to 32.0%, much higher than wheat noodles, 13.3%, while the protein loss of TSP-W noodles was only 14.3%. Three types of soy proteins weakened the gluten network on different levels. The larger protein molecules in TSP linked with glutenin and formed the higher molecular polymers, counterbalancing the weakening effects deriving from the interfering with the glutenin-glutenin linkages. Therefore, TSP is more suitable to utilize in noodles. Practical applicationsWheat flour noodles are widely consumed in most countries, so the protein quality in noodles is critical to consumer health. The essential amino acid, lysine, is relatively deficient in wheat proteins. Soy protein is rich in lysine and could be used to fortify the nutrition of flour products. However, some negative effects of soy protein on the qualities of flour products have been observed. Therefore, we modified Soy protein isolate (SPI), hoping to increase the interaction between soy protein and wheat protein, and reduce the negative impacts of soy protein on qualities of noodles. Results showed texturized soy protein exhibited fewer negative effects on noodle qualities than SPI and soy protein hydrolysate. The results presented in this study provided us with some useful information about how to select soy proteins to fortify noodle nutrition.

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Lysozymes play vital roles in humoural immune response against bacterial invasion by its lytic activity. In the present study, a new C‐type lysozyme was identified and characterized from Chinese soft‐shelled turtle Pelodiscus sinensis. The full‐length cDNA of PslysC was of 923 bp, encoding a polypeptide of 148 amino acid residues. The multiple alignments and phylogenetic relationship analysis revealed the highly enzyme‐related conserved residues. The real‐time PCR analysis suggested that PslysC was constitutively expressed in a wide range of tissues with highest level in blood cells and liver. The expression of PslysC could be significantly up‐regulated under Aeromonas jandaei infection and ammonia exposure, while no significant changes were found under Poly I:C infection. The rPslysC protein was expressed in E. coli and purified by Ni‐NTA. The optimal pH and temperature for rPslysC protein lytic activities were determined at pH 7 and 30℃. rPslysC can inhibit the growth of eight kinds of Gram‐negative bacteria, and three kinds of Gram‐positive bacteria. The binding activity of rPslysC to different microbial polysaccharides and microorganism was analysed. The results showed that rPslysC could bind to selected bacteria, and exhibit a strong binding activity to lipopolysaccharide and peptidoglycan, but a weak binding activity to β‐glucan. This suggests that the binding activity might be the major mechanism of action to realize the antibacterial activity. The present study will provide helpful evidence to further understand the innate immunity of P. sinensis, and the interaction mechanisms of C‐type lysozymes with bacterial membranes.