title: Release behavior of non-network proteins and its relationship to the structure of heat-induced soy protein gels.
abstract: Heat-induced soy protein gels were prepared by heating protein solutions at 12%, 15% ,or 18% for 0.5, 1.0, or 2.0 h. The release of non-network proteins from gel slices was conducted in 10 mM pH 7.0 sodium phosphate buffer. SDS-PAGE and diagonal electrophoresis demonstrated that the released proteins consisted of undenatured AB subunits and denatured proteins including monomers of A polypeptides, disulfide bond linked dimers, trimers, and polymers of A polypeptides, and an unidentified 15 kDa protein. SEC-HPLC analysis of non-network proteins revealed three major protein peaks, with molecular weights of approximately 253.9, 44.8, and 9.7 kDa. The experimental data showed that the time-dependent release of the three fractions from soy protein gels fit Fick's second law. An increasing protein concentration or heating time resulted in a decrease in diffusion coefficients of non-network proteins. A power law expression was used to describe the relationship between non-network protein diffusion coefficient and molecular weight, for which the exponent (α) shifted to higher value with an increase in protein concentration or heating time, indicating that a more compact gel structure was formed.
authors.affiliation: State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu Province 214122, People's Republic of China.
authors.forename: Chao
authors.initials: C
authors.lastname: Wu
authors.affiliation: State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu Province 214122, People's Republic of China.
authors.forename: Yufei
authors.initials: Y
authors.lastname: Hua
authors.affiliation: State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu Province 214122, People's Republic of China.
authors.forename: Yeming
authors.initials: Y
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu Province 214122, People's Republic of China.
authors.forename: Xiangzhen
authors.initials: X
authors.lastname: Kong
authors.affiliation: State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu Province 214122, People's Republic of China.
authors.forename: Caimeng
authors.initials: C
authors.lastname: Zhang
mesh_terms: D004058:Diffusion; D005782:Gels / Q000737:chemistry; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D008970:Molecular Weight; D011489:Protein Denaturation; D030262:Soybean Proteins / Q000737:chemistry*
chemical_list: D005782:Gels; D030262:Soybean Proteins
keywords: diffusion coefficients; network; non-network proteins; protein composition; release behavior; soy protein gel