Search

BACKGROUND Free fractions of different blackberry varieties' extracts are high in phenolic compounds with antioxidant activities. However, the phenolic profiles and antioxidant activities against peroxyl radicals of bound fractions of different blackberry varieties' extracts have not been previously reported. In addition, what the key antioxidant phenolic compounds are in free and bound fractions of blackberry extracts remain unknown. This study aimed to investigate the phenolic profiles and antioxidant activities of free and bound fractions of eight blackberry varieties' extracts and reveal the key antioxidant phenolic compounds by boosted regression trees. RESULTS: Fifteen phenolics (three anthocyanins, four flavonols, three phenolic acids, two proanthocyanidins, and three ellagitannins) were identified in blackberry by ultra‐performance liquid chromatography coupled with quadrupole time‐of‐flight mass spectrometry. Ferulic acid, ellagic acid, procyanidin C1, kaempferol‐O‐hexoside, ellagitannins hex, and gallic acid were major bound phenolics. Bound fractions of eight blackberry varieties' extracts were high in phenolics and showed great antioxidant activity. Boosted regression trees analysis showed that cyanidin‐3‐O‐glucoside and chlorogenic acid were the most significant compounds, contributing 48.4% and 15.9% respectively to the antioxidant activity of free fraction. Ferulic acid was the most significant antioxidant compound in bound fraction, with a contribution of 61.5%. Principal component analysis showed that Kiowa was the best among the eight varieties due to its phenolic profile and antioxidant activity. CONCLUSION: It was concluded that blackberry varieties contained high amounts of bound phenolics, which confer health benefits through reducing oxidative stress. Ferulic acid was the key compound to explain the antioxidant activities of bound fractions. © 2021 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

This study aims to evaluate phenolics, flavonoids, total and cellular antioxidant activity (CAA), antioxidant capacity in ear sections of sweet corn. Corn cob and mature corn silk showed the highest contents of total phenolics and flavonoids (p < 0.05), respectively. Gallic acid and ferulic acid were the main free and bound phenolics in each ear part of corn, respectively (p < 0.05). Corn resident (CR) had a dominant role in total antioxidant activity and cellular antioxidant activity (CAA) (p < 0.05). Considering all the antioxidant properties, CR showed the best performance. The content of ferulic acid was correlated closely with CAA (R2 = 0.898, p < 0.05) and total antioxidant capacity (R2 = 0.971, p < 0.05), and total antioxidant capacity was also connected tightly with total phenolics (R2 = 0.886, p < 0.05). The results of this investigation were significant to enhance recognition and application of ear sections in food industry. Practical applications: Sweet corn is widely cultivated in Asia, America, and other regions for fresh or industrial food because of high sugar, dietary fiber, and vitamins. However, there is no systematic assay on ear sections of sweet corn concerning antioxidant evaluation. The study investigated phytochemical profiles and antioxidant capacity in ear sections of sweet corn systematically, and made a comprehensive comparison of them combined with correlation analysis. The results indicated that ear sections of sweet corn, not only kernels, demonstrated high antioxidant capacity. Ear sections show promising potential application in food industry. [ABSTRACT FROM AUTHOR]