Edible bird's nest improves the premature ovarian failure induced by tripterygium glycosides.

Premature ovarian failure (POF) is a common disease in the field of gynecological endocrinology that seriously affects the physical and mental health of patients. Previous studies found that edible bird's nest (EBN) could improve uterine function. These suggested that EBN might also have an ameliorating effect on POF. Therefore, in this study, tripterygium glycosides (TGs) were used to induce POF in rats, and the effect of EBN on the improvement of POF was investigated. After the administration of EBN for 14 days, ovarian index and uterine index, serum hormone levels, apoptosis rate of ovarian granulosa cells, follicle-stimulating hormone receptor (FSHR) protein expression level, and the histopathological examination of the ovaries were determined. It was found that administration of medium and high EBN dose groups increased the ovarian index and granular layer thickness of rats with POF. Particularly, higher follicle-stimulating hormone levels and lower corpus luteum content were observed in the high EBN dose group. In addition, there were lower luteinizing hormone levels and fewer atretic follicles but higher progesterone levels in the medium EBN dose group. These results indicated that EBN had preventive and curative effects on POF induced by TGs. Its mechanism of action might be related to the reduction of ovarian granulosa cell apoptosis, regulation of hormones and receptors, and inhibition of follicle closure.

Preparation, structural characterization and properties of feruloyl oligosaccharide-rice protein hydrolysate conjugates.

Rice protein hydrolysate (RPH) and feruloyl oligosaccharides (FOs) were conjugated under the catalysis of laccase and free radical, and the structure and properties of the resultant conjugates were studied. Electrophoresis analysis demonstrated that conjugation with FOs increased the molecular weight of some fractions in RPH, which confirmed the formation of both conjugates. The conjugation degree of laccase-induced conjugate and radical-induced conjugate was 60.45% and 22.70%, respectively. Laccase-catalyzed conjugation decreased the tyrosine residue content of RPH but had no significant effect on the free amino group content, which suggested that tyrosine residues were the conjugation site in the laccase-induced conjugate. However, radical-catalyzed conjugation decreased both the free amino group content and the tyrosine residue content, which indicated that both free amino groups and tyrosine residues were the conjugation site in the radical-induced conjugate. The ultraviolet, fluorescence and circular dichroism spectroscopy analysis revealed that conjugation with FOs significantly altered the secondary and tertiary structure of RPH. In addition, conjugation with FOs increased the solubility and antioxidant activity of RPH but decreased the emulsifying activity and stability. Particularly, the radical-induced conjugate had greater anti-aggregation capacity and antioxidant activity but lower emulsifying activity and stability than the laccase-induced conjugate, which might be due to that their conjugation site and degree were different.

Improving the Yield of Feruloyl Oligosaccharides from Rice Bran through Enzymatic Extrusion and Its Mechanism.

Rice bran, rich in feruloyl arabinoxylan, is a good source of feruloyl oligosaccharides (FOs). To prepare FOs, bran was often hydrolyzed by amylase and protease to remove starch and protein and then hydrolyzed by xylanase, which was time-consuming and had a low yield. To solve the above problems, enzymatic extrusion was used to treat rice bran, and the effects of traditional hydrolysis, a combination of traditional extrusion and hydrolysis (extrusion-hydrolysis) and enzymatic extrusion on the yield of FOs were investigated and compared in this study. It was found that traditional extrusion and enzymatic extrusion significantly increased the yield of FOs. Particularly, the yield of FOs resulting from enzymatic extrusion was increased to 5.78%, while the yield from traditional hydrolysis was 4.23%. Microscopy analysis showed that extrusion damaged the cell wall of bran, which might increase the accessibility of xylanase to arabinoxylan and the yield of FOs. Spectroscopy analysis suggested that FOs obtained by different pretreatments had similar structures. It was obvious that enzymatic extrusion saved the time for removal of starch and protein and increased the yield of FOs. In addition, the highest yield of FOs was found at the moisture content of 30% and the screw speed of 50 rpm. This study provided an efficient method for the preparation of FOs that is suitable for industrial production.