No abstract

No abstract

The salt-induced gelation behavior of soy protein isolate (SPI) emulsions was markedly influenced by microbial transglutaminase (TGase) pre-crosslinking. Rheological data showed that when SPI emulsions were incubated with TGase at low concentrations (1 and 3 U/g protein) at 50°C for 30 min prior to gelation, no change in storage modulus (G'), but enhanced resistance to deformation of the gels was observed. Extensive crosslinking by TGase (5 U/g protein) resulted in severe decreases in gel firmness and fracture properties (yielding stress and strain), likely due to the impairment of hydrophobic bonds and the formation of coarse networks. The water-holding capacity of the gels was significantly enhanced by increased concentrations of TGase. Interactive force analysis indicated that non-covalent interactions and disulfide bonds are the primary forces involved in CaSO 4 -induced SPI emulsion gel, but TGase treatment may limit hydrophobic interactions within the gel network. These results are of great potential value for the application of TGase in the food industry.

Hen egg white lysozyme was lipophilized with short and middle chain saturated fatty acids (caproic, capric, or myristic acid). The yield, bactericidal properties, and structural properties of lipophilized lysozymes were investigated. The yield of lipophilization of lysozyme greatly increased with the decrease in the chain length of fatty acid. Lipophilization broadened the bactericidal action of lysozyme to Gram-negative bacteria with little loss of enzymatic activity. The bactericidal activity increased in proportion to the number of bound short chain fatty acids. The thermal stability of lipophilized lysozyme decreased in proportion to the chain length and number of bound fatty acids.

Superoxide dismutase (SOD) fusion of TAT was proved to be radioprotective in our previous work. On that basis, a bifunctional recombinant protein which was the fusion of glutathione S-transferase (GST), SOD, and TAT was constructed and named GST-TAT-SOD. Herein we report the investigation of the cytotoxicity, cell-penetrating activity, and in vitro radioprotective effect of GST-TAT-SOD compared with wild SOD, single-function recombinant protein SOD-TAT, and amifostine. We demonstrated that wild SOD had little radioprotective effect on irradiated L-02 and Hep G2 cells while amifostine was protective to both cell lines. SOD-TAT or GST-TAT-SOD pretreatment 3 h prior to radiation protects irradiated normal liver cells against radiation damage by eliminating intracellular excrescent superoxide, reducing cellular MDA level, enhancing cellular antioxidant ability and colony formation ability, and reducing apoptosis rate. Compared with SOD-TAT, GST-TAT-SOD was proved to have better protective effect on irradiated normal liver cells and minimal effect on irradiated hepatoma cells. Besides, GST-TAT-SOD was safe for normal cells and effectively transduced into different organs in mice, including the brain. The characteristics of this protein suggest that it may be a potential radioprotective agent in cancer therapy better than amifostine. Fusion of two antioxidant enzymes and cell-penetrating peptides is potentially valuable in the development of radioprotective agent.