Three protein-rich materials were pretreated with a self-designed alkaline electrolyzed water (AEW) pretreatment equipment to promote the release of angiotensin I-converting enzyme (ACE) inhibitory peptides by improving hydrolysis efficiency. According to degree of hydrolysis (DH) and ACE inhibitory activity, defatted walnut meal (DWM) was selected to study antihypertensive activity by hydrolysis in assistance of AEW pretreatment. It was found DWM pretreated with AEW at pH 11.5 followed by Alcalase hydrolysis exhibited the highest DH (21.96%), protein recovery rate (94.76%), and ACE inhibitory activity (IC 50 of 0.137 mg/mL), in which AEW pretreatment resulted in the transformation of α-helix and β-turn to random coil and the destruction of hydrogen bonds to expose more cleavage sites to enhance hydrolysis efficiency. Thereafter, ACE inhibitory peptides GIENYRVV (IC 50 of 0.102 mg/mL) and AGRISTVNSHTLPVL (IC 50 of 0.20 mg/mL) were identified from the hydrolysate. Overall, AEW pretreatment was an innovative strategy to promote the release of antihypertensive peptides during hydrolysis.
As a natural phenolic compound, carvacrol has attracted much attention due to its excellent antibacterial and antioxidant activities. However, its application is limited due to its instability, such as easy volatilization, easy oxidation, etc. Protein-polysaccharide interactions provide strategies for improving their stability issues. In this study, the plant-based carvacrol microcapsules via complex coacervation between walnut meal protein isolate (WMPI) and gum Arabic (GA) has been fabricated and characterized. The formation conditions of WMPI-GA coacervates were determined by some parameters, such as pH, zeta-potential, and turbidity. The optimum preparation conditions were achieved at pH 4.0 with a WMPI-to-GA ratio of 6:1 (w/w). The mean particle size, loading capacity (LC), and encapsulation efficiency (EE) of the microcapsules were 43.21 μm, 26.37%, and 89.87%, respectively. Fourier transform infrared spectroscopy (FT-IR) and fluorescence microscopy further confirmed the successful microencapsulation of carvacrol. The microencapsulation of carvacrol improved the thermal stability of the free carvacrol. The swelling capacity results indicated that it could resist gastric acid, and facilitate its intestinal absorption. Meanwhile, the carvacrol molecules trapped within the microcapsules could be continuously released in a concentration-dependent manner. Furthermore, the microcapsules presented good antioxidant activity and antibacterial activity against the Gram-negative (E. coli) and the Gram-positive (S. aureus) bacteria. These results indicated that the obtained carvacrol microcapsules have a potential application value as a food preservative in the food industry.Keywords:carvacrol;complex coacervation;walnut meal protein isolate;gum Arabic;bio-functional activity
Dietary fiber intake is associated with a low incidence of suffering from metabolic syndrome. To explore the potential health benefits of walnut meal dietary fiber (WMDF) as a prebiotic, the functional role of WMDF on metabolic syndrome in mice induced by high fructose diet (20%, HF) was investigated. The animal experiment results showed that administration of WMDF to HF-fed mice alleviated abnormal body weight gain, insulin resistance, oxidative stress, lipid metabolism disorders and inflammation. Histopathological observation confirmed the preventative effects of WMDF on hepatic steatosis and vascular endothelial dysfunction. Also, WMDF intake increased the production of acetic acid, propionic acid and butyric acid. Moreover, WMDF ingestion effectively improved the disorder of gut microbiota caused by HF, increased the diversity of gut microbiota and the relative abundance of short-chain fatty acids-producing bacteria. These findings demonstrate WMDF can be used as a prebiotic to prevent HF-induced metabolic syndrome.
危险品化学品经营许可证（带存储）