This study investigates the ability of various wheat germ protein hydrolysates (WGPHs) to bind calcium and characterizes the peptide-calcium complexes. We demonstrate that the amount of Ca bound depended greatly on the type of enzyme, degree of hydrolysis (DH), amino acid composition, and molecular mass distribution of different hydrolysates. The maximum level of Ca bound (67.5 mg·g(-1)) occurred when Alcalase was used to hydrolyze wheat germ protein at a DH of 21.5%. Peptide fragments exhibiting high calcium-binding capacity had molecular mass <2000 Da. The calcium-binding peptides mainly consisted of Glu, Arg, Asp, and Gly, and the level of Ca bound was related to the hydrophobic amino acid content in WGPHs. UV-visible and Fourier transform infrared spectra demonstrate that amino nitrogen atoms and oxygen atoms on the carboxyl group were involved in complexation. Therefore, wheat germ protein is a promising protein source for the production of calcium-binding peptides and could be utilized as a bioactive ingredient for nutraceutical food production.

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Cobalt-doped graphene-coupled hypercrosslinked polymers (Co-GHCP) have been successfully prepared on a large scale, using an efficient RAFT (Reversible Addition-Fragmentation Chain Transfer Polymerization) emulsion polymerization and nucleophilic substitution reaction with Co (II) porphyrin. The Co-GHCP could be transformed into cobalt-doped porous carbon nanosheets (Co-GPC) through direct pyrolysis treatment. Such a Co-GPC possesses a typical 2D morphology with a high specific surface area of 257.8 m2 g−1. These intriguing properties of transition metal-doping, high conductivity, and porous structure endow the Co-GPC with great potential applications in energy storage and conversion. Utilized as an electrode material in a supercapacitor, the Co-GPC exhibited a high electrochemical capacitance of 455 F g−1 at a specific current of 0.5 A g−1. After 2000 charge/discharge cycles, at a current density of 1 A g−1, the specific capacitance increased by almost 6.45%, indicating the excellent capacitance and durability of Co-GPC. These results demonstrated that incorporation of metal porphyrin into the framework of a hypercrosslinked polymer is a facile strategy to prepare transition metal-doped porous carbon for energy storage applications.

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Wheat germ protein isolates were prepared from defatted wheat germ flour using alkaline solubilisation and acid precipitation. A central composite design with two independent variables (solubilisation pH and precipitation pH) and bivariate correlations was selected for the correlation analysis of the protein separation conditions and the functional properties. The results showed that the protein yield (Y) and functional properties of isolates, such as water absorption (WA) and fat absorption (FA), were sensitive to both solubilisation pH and precipitation pH, whereas the emulsification was sensitive to only solubilisation pH. Emulsifying activity (EA) and FA of isolates showed a high positive correlation with yield. Gel electrophoresis analysis of protein fractions gave evidence to the compositional changes between proteins isolated under different conditions, highly alkaline conditions result in the degradation of protein chains and formation of toxic compounds. Surface hydrophobicity suggested that proteins tend to be more denatured when solubilised at highly alkaline conditions. These conformational and compositional changes due to different protein separation conditions have contributed to the changes in functional properties of protein isolates.Effects of protein extraction conditions on functional properties F. Liu et al. Statistical analysesAll determinations were carried out in triplicate, and results were presented as mean AE standard deviation.Effects of protein extraction conditions on functional properties F. Liu et al.