Analysis of antioxidant effect of two tripeptides isolated from fermented grains (Jiupei) and the antioxidative interaction with 4‐methylguaiacol, 4‐ethylguaiacol, and vanillin

Abstract

Jiupei (fermented grains) is the raw material for Baijiu distillation. The antioxidant activities of peptides Val‐Asn‐Pro (VNP) and Tyr‐Gly‐Asp (YGD) identified from Jiupei were evaluated according to in vitro chemical assays (e.g., 2,2′‐azino‐bis (3‐ethylbenzothiazoline‐6‐sulfonic acid) diammonium salt, 1,1‐diphenyl‐2‐picrylhydrazyl, and oxygen radical absorbance capacity) and 2,2′‐azobis (2‐methylpropionamide)‐dihydrochloride‐activated HepG2 cell model. The interaction on antioxidant activities between peptides (VNP and YGD) and three functional phenols (4‐methylguaiacol, 4‐ethylguaiacol, and vanillin) which were found in Baijiu was also measured. On the basis of the results, two peptides exhibited strong antioxidant ability in oxygen radical absorbance capacity (ORAC) assay. Furthermore, they suppressed the generation of reactive oxygen species. The intracellular antioxidant enzymatic system and nonenzymatic system were also regulated by VNP and YGD. In addition, it was confirmed that partial auxo‐action between peptides and phenols appeared mostly in chemical assays. The findings above might indicate that VNP and YGD are potent natural antioxidants in Jiupei even in Baijiu through distillation process and lay the foundation for illustrating the interactions among different functional substances in Baijiu.

Antioxidant effect of amaranth flour or protein isolate incorporated in high‐fat diets fed to Wistar rats. Influence of dose and administration duration

“…The SOD catalyzes the decomposition of superoxide anions into oxygen and H 2 O 2 . The CAT and the GPx can decompose excess peroxides, preventing its transformation into more active substances, such as hydroxyl radicals, which accelerate cellular decline (Jiang et al., 2019). Cells have signal transduction pathways that sense the oxidative stress (ROS) and activate the defense genes through the transcription factor Nrf2.…”

“…The SOD catalyzes the decomposition of superoxide anions into oxygen and H 2 O 2 . The CAT and the GPx can decompose excess peroxides, preventing its transformation into more active substances, such as hydroxyl radicals, which accelerate cellular decline (Jiang et al, 2019). and in their liver than the BD group, which can be associated with the fact that changes in the fatty acids profiles of diets (the higher saturated acids and cholesterol content in Chol+F, as well as its lower unsaturated acids content) could induce a change in the composition of fatty acids constituting the plasma membranes and the circulating lipoproteins, hence diminishing the lipid oxidation susceptibility.…”

Production and antioxidant capacity of bioactive peptides from plant biomass to counteract lipid oxidation

“… ( Girgih et al., 2013 ) Jiupei (fermented grains) Jiupei proteins Chemical/physical (ultrasounds) Hydrolysate and 2 fractions (UF): 2 Tripeptides: VNP in E1 and YGD in D1. Jiang et al. (2019) MW ​> ​5 ​kDa and MW ​< ​5 ​kDa.…”

“…Another way to obtain antioxidant peptides by protein hydrolysis, which is not widely reported, was the fermentation by different bacteria ( Amadou et al., 2013 ; Coda et al., 2012 ; He et al., 2012 ; Zheng et al., 2012 ). Other methods such as ultrasonic-assisted hydrolysis ( Jiang et al., 2019 ), in combination with enzymes ( Yu et al., 2012 ), or for the pretreatment of biomass proteins ( Wen et al., 2018 , 2019 ), have been tested, but with less attention. However, it has been found that the ultrasound treatment could significantly improve antioxidant activities of the hydrolysate, likely by affecting the protein structure and increasing their susceptibility to proteolysis.…”

“…In the cell model, VNP and YGD exert antioxidant effect. Jiang et al. (2019) In vitro (solution and linoleic acid model system) DPPH, HRSA, FRAP, linoleic acid oxidation (PV) Fe The MW ​< ​1 ​kDa and 5 ​< ​MW ​< ​10 ​kDa fractions exhibited significantly highest ability to scavenge DPPH, inhibition of the peroxidation of linoleic acid and the reduction of Fe 3+ to Fe 2+ .…”