ABSTRACT
This study aimed to investigate the effect of Gnaphalium affine extract (GAE) (0.04, 0.2 and 1 mg/g protein) on the gel properties of porcine myofibrillar proteins (MPs) in a simulated Fenton oxidation system, using tea polyphenols (TPs) at similar concentrations of 0.04, 0.2, and 1 mg/g protein, respectively, as a contrast. The findings revealed that as the TP concentration increased, the water retention of MP gels decreased significantly (p < 0.05). In contrast, MP gels containing medium and high concentrations of GAE exhibited significantly higher water retention than those with low concentrations of GAE (p < 0.05). When the concentration of GAE was increased to 1 mg/g protein, the strength of MP gels was significantly reduced (p < 0.05) by 33.32% compared with the oxidized control group, suggesting that low and medium GAE concentrations support MP gel formation. A texture profile analysis indicated that an appropriate GAE concentration improved gel structure and texture. Dynamic rheological characterization revealed that low concentrations of TP (0.04 mg/g protein) and low and medium concentrations of GAE (0.04 and 0.2 mg/g protein) strengthened the protein gel system. Conversely, high concentrations of TP and GAE (1.0 mg/g protein) damaged the protein gel system or even promoted the collapse of the gel system. Scanning electron microscopy revealed that higher TP concentrations disrupted the gel, whereas low and medium GAE concentrations maintained a more continuous and complete gel network structure compared with the oxidized control group. This indicates that an appropriate GAE concentration could effectively hinder the destruction of the gel network structure by oxidation. Therefore, based on the obtained results, 0.2 mg/g protein is recommended as the ideal concentration of GAE to be used in actual meat processing to regulate the oxidization and gel properties of meat products.
ABSTRACT
In this study,the anti-HBV effects of tea polyphenols (TP) were examined.After cells were exposed to TP for 3,6,9 days,amounts of HBsAg,HBeAg and HBV-DNA released into the supernatant of the cultured HepG2 2.2.15 cells were detected.TP,to some extent,inhibited the secre-tion of HBsAg and strongly suppressed the secretion of HBeAg in a dose-dependent (P<0.01) and time-dependent manner,with 50% maximal inhibitory concentration (IC50) value being 7.34 μg/mL on the 9th day,but the time-dependence was not significant (P=0.051).Expression of HBV-DNA in the supernatant of the cell culture also was significantly decreased in a dose-dependent fashion (P<0.01).The IC50 of TP in inhibiting HBV DNA was 2.54 μg/mL.It concluded that TP possessed potential anti-HBV effects and may be used as a treatment alternative for HBV infection.
