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Background: 5-Hydroxymethylfurfural (HMF) is regarded as a thermal process contaminant in foods. Six flavan-3-ol fractions were isolated or semisynthesized from sorghum, cranberry and grape seed. Their unit compositions, interflavan linkages and degree of polymerization were characterized. The aim of this study was to investigate the effect of flavan-3-ols on the formation of HMF in chemical reaction models and fried potato chips., Results: Results showed that all flavan-3-ols significantly mitigated the HMF formation at concentrations of 50, 100 and 200 µg mL -1 in the chemical model system, and the inhibition was positively related to dose. Using the food model, HMF content was reduced by about 50% when potato chips were soaked in an optimal concentration of 0.1 mg mL -1 flavan-3-ol solutions before frying. Based on the same mass concentration, B-type flavan-3-ols mitigated more HMF than A-type, and oligomeric proanthocyanidins had stronger inhibitory activity than polymers. At suitable addition levels (0.01-0.1 mg mL -1 ), the browning of auto-oxidized flavan-3-ols under high temperature compensated the anti-browning effect along with the supression of the Maillard reaction; therefore, the color of fried potato chips was not affected., Conclusion: This study demonstrates that flavan-3-ols could be effective additives for reducing HMF levels in fried potato chips without changing sensory properties. © 2018 Society of Chemical Industry., (© 2018 Society of Chemical Industry.)

In order to find novel natural antioxidant peptides, the water hyacinth leaf protein was hydrolyzed by Protamex at optimum condition to prepared water hyacinth leaf protein hydrolysate (WHLPH). And antioxidant properties of WHLPH were evaluated dependent on several in vitro antioxidant systems, including superoxide anion radical-scavenging activity, ABTS cation radical-scavenging activity, reducing power, and metal chelating capacity. WHLPH showed 86.37% of superoxide anion radical-scavenging activity at 1.0 mg/mL, and 56.51% of ABTS cation radical-scavenging activity at 100 μg/mL. At 1.0 mg/mL, the reducing power of WHLPH was 0.92, and the metal chelating capacity was 68.54%. Subsequently, the WHLPH was subjected to consecutive isolation and purification by macroporous resin, gel filtration chromatography, and reverse-phase high-performance liquid chromatography, and two peptide fractions with higher radical-scavenging activity were acquired. Finally, the two peptide fractions were identified to be Phe-Phe-Glu and Leu-Phe, respectively, by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Considering the two peptides' amino acid composition, their antioxidant properties may be due to the hydrophobic and/or aromatic acid residues in their sequences. The results indicated that the isolated antioxidant peptides from WHLPH would find widespread application in food, cosmetics, and pharmaceutical industry because of their high potency, safety, low cost and abundant source. [ABSTRACT FROM AUTHOR]

In order to recover and utilize peanut protein resource, peanut meal was fermented usingBacillus subtilisto prepare antioxidant peptides in this study. The antioxidant activities of the peanut peptides were evaluated via sixin vitrotests, namely, 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) scavenging activity, inhibition of linoleic acid autoxidation, reducing power, and metal chelating capacity. The peanut peptides showed 63.28% of scavenging effect on 1,1-diphenyl-2-picrylhydrazyl radical, 70.67% of scavenging effect on 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) and 39.32% of superoxide anion radical scavenging activity at 1.0 mg/ml, and 62.69% of inhibition on linoleic acid autooxidation at 0.8 mg/ml. Besides, the peanut peptides exhibited 32.8% of reducing power and 60.44% of Fe2+-chelating capacity at 2 mg/ml. Then the peanut peptides were desalted with macroporous resin; the fraction eluted with 75% ethanol showed the highest scavenging activity on 1,1-diphenyl-2-picrylhydrazyl radical. This fraction was subject to further purification using gel filtration chromatography and reverse phase-high performance liquid chromatography. At last, a peptide was gained, and it was identified to be Tyr-Pro with matrix-assisted laser desorption/ionization time-of-flight/time-of-flight mass spectrometry. The results indicated that it is feasible to prepare natural antioxidants from peanut meal usingB. subtilisfermentation. [ABSTRACT FROM AUTHOR]

To study the influence of degree of hydrolysis (DH) on antioxidant properties of peanut peptides, the peanut meal was fermented by Bacillus subtilis. The fermentation time was 48, 72, and 96 h, respectively, to prepare peanut peptides at different degree of hydrolysis. The peanut peptides (11.18, 16.20, and 21.41% of DH, respectively) were extracted from fermentation liquid. The antioxidant properties of these peanut peptides were evaluated based on DPPH radical (1,1-Diphenyl-2-picrylhydrazyl radical) scavenging activity, superoxide anion-scavenging activity, reducing power, metal-chelating activity, and inhibition of linoleic acid autooxidation. Peanut peptides (21.41% of DH) at 1 mg/mL exhibited 80.86 and 29.35% of scavenging concentration percent on DPPH and superoxide anion radical, respectively. In addition, the reducing power of peanut peptides was 0.368 at 2 mg/mL, and they possessed 76.32% of Fe-chelation ability at 2 mg/mL and 63.75% of inhibition of linoleic acid autooxidation at 0.8 mg/mL. The antioxidant activities of the peanut peptides (21.41% of DH) were stronger compared with others (11.18 and 16.20% of DH), and this indicated the antioxidant activities of peanut peptides increased with increasing DH ( p < 0.05). To know much about the peanut peptides, they were subjected to amino acid analysis and determination of molecular weight distribution. Some acidic amino acids and essential amino acids were found, and the average molecular weight distributions were concentrated in <1,400 Da (86.96%). Combined with the results of the amino acid profiles, the peanut peptides were believed to have high nutritive value besides antioxidant activities. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine the antioxidant capacity of polyphenols extracted from black highland barley (BHLPE) in vitro and in vivo. BHLPE was found to have strong superoxide radical, hydroxyl radical and 2,2-diphenyl-1-picrylhydrazyl radical-scavenging activity, ferric reducing antioxidant power and moderate metal ion-chelating activity. Compared with a high fat diet (HFD) group, mice that were administered 600 mg BHLPE/kg body weight showed significant decreases in total cholesterol, low-density lipoprotein cholesterol and the atherosclerosis index, in addition to markedly increased high-density lipoprotein cholesterol levels. Furthermore, the antioxidant defense system and antioxidant gene expression were significantly improved in vivo in mice that were administered BHLPE compared with mice in the HFD group. These results suggest that BHLPE has significant potential as a natural antioxidant to promote health and to reduce the risk of disease. [ABSTRACT FROM AUTHOR]