Distribution of Conjugated and Free Phenols in Fruits:  Antioxidant Activity and Cultivar Variations

• Published in: Journal of agricultural and food chemistry Vol. 50; no. 22; pp. 6301 - 6306
• Main Authors: Imeh, U, Khokhar, S
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Washington, DC American Chemical Society 23.10.2002
• Subjects: Agronomy. Soil science and plant productions; Antioxidants - analysis; Antioxidants - metabolism; Biological and medical sciences; Chemical constitution; Economic plant physiology; Food Analysis; Fruit - chemistry; Fundamental and applied biological sciences. Psychology; General pharmacology; Indicators and Reagents; Malus - chemistry; Medical sciences; Molybdenum; Pharmacognosy. Homeopathy. Health food; Pharmacology. Drug treatments; Phenols - analysis; Phenols - metabolism; Prunus - chemistry; Pyrus - chemistry; Tungsten Compounds; Pyrus communis; kiwi; Free form; Rosaceae; Peach; Malus domestica; Actinidiaceae; antioxidant activity; Plum; fruits; Dicotyledones; Angiospermae; Chemical composition; FRAP; Fruit tree; Intraspecific comparison; Actinidia deliciosa; Kiwi(fruit); Pear; Fruit; Prunus domestica; phenol intake; cultivars; Prunus persica; Antioxidant; Biological activity; Phenol; Apple; Spatial distribution; Health food; Phenols; Spermatophyta; Conjugated compound; Cultivar
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf020342j

Total and free phenolic contents of 16 commonly consumed fruits (comprising 9 apples, 4 pears, and one each of peach, plum, and kiwi fruit cultivars) were measured by Folin-Ciocalteu assay. Total phenol contents varied from 272 to 475 mg of CtE/100 g of fresh weight. Of the apple cultivars studied, Braeburn and Empire had the highest and lowest total phenol content, respectively. The apple cultivars ranked in the following decreasing order:  Braeburn > Red Delicious > Crisp Pink > Granny Smith > Royal Gala > Bramley > Golden Delicious > Fuji > Empire. Among pear cultivars, the order was Forelle > Taylor's > Peckham's > Conference. Peach and plum equally had high contents. The percentage of conjugated phenolics ranged between 3 (Red Delicious) and 77% (Empire) of the total phenols. Comparison of different cultivars of the same fruit and between different fruits showed broad variations in both phenolic content and in vitro antioxidant activity; a weak correlation (R 2 = 0.58) was observed between the phenolic content of the fruits and the total antioxidant activity, as estimated by the FRAP assay. The calculated dietary intake of total, free, and conjugated phenols from average per capita consumption of apples and pears in different regions of the U.K. varied between 104−126, 53−64, and 51−62 mg of CtE/day, respectively. Keywords: Phenols; fruits; apple; pear; plum; kiwi; phenol intake; antioxidant activity; FRAP; cultivars