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Phenolic acids existed in many agricultural products especially in vegetables and considered as important natural antioxidants. Eleven phenolic acids existed commonly in vegetables were chosen to assess the antioxidant activities using DPPH•, •ABTS + , •O 2 -, and •OH scavenging assays, as well as ferric reducing power and β-carotene bleaching assays. The results showed that caffeic and protocatechuic acid with simple dihydroxylation structures have the best antioxidant activities, while p-Hydroxybenzoic and p-Coumaric acid with mono hydroxylation structures have the lowest antioxidant activities in most assays. The antioxidant activity of caffeic acid was higher than protocatechuic acid and ferulic acid higher than isoferulic acid may be due to the substituents and the position of substituents on the benzene ring. Antioxidant activities of caftaric, chicoric and chlorogenic acid and its derivates with complex dihydroxylation structures were high relatively among phenolic acids. The different concentration ranges of phenolic acids were obtained based on the quantitative relationship between antioxidant or prooxidant activities and sample concentrations. The prooxidant effect of phenolic acids was rarely observed in the present study. The results were conducive to further research on potential biological activities of vegetables.

No abstract

Anthocyanins may be an effective way to reduce the potential risk of chronic diseases induced by glycation and inflammatory. In the present study, the anti-glycation and anti-inflammatory activities of anthocyanins...

Functional fermented fruit drinks are known worldwide for their health-promoting potential. Black wolfberry (BW) has high nutritional value, and its relative product development can be enriched through fermentation technology, so that its market might be broadened. Total acid, sugars, proteins, enzymes, anthocyanins, flavonoids, polyphenols, organic acids and DPPH free radical scavenging ability (DPPH) were tracked and determined by colorimetric method and HPLC during spontaneous fermentation of BW vinegar. The antioxidant capacity in vitro of BW vinegar was evaluated based on the dynamics of antioxidant contents and DPPH. The results showed that total acid continuously increased during fermentation, yet total sugar and reducing sugar shared a similar decreasing trend. The composition of samples differed in terms of total anthocyanins, total flavonoid, total polyphenol, total protein, superoxide dismutase (SOD), amylase, organic acids and DPPH through spontaneous fermentation. Functional compounds including total polyphenol, total flavonoid and three organic acids (γ-aminobutyric acid, lactic acid and gallic acid) played the main roles in antioxidation. Unexpectedly, SOD and ascorbic acid as antioxidants did not correlate with DPPH, but they were rich in the final products at 754.35 U/mL and 3.39 mg/mL, respectively. Generally, the quality of BW vinegar has been improved based on analyzing dynamics on functional compounds, organic acids and antioxidant capacity, which proves that BW vinegar obtained by spontaneous fermentation should be a potential source of fermented food with antioxidant effects for consumers.