title: Variation in major antioxidants and total antioxidant activity of Yuzu (Citrus junos Sieb ex Tanaka) during maturation and between cultivars.
abstract: Epidemiological studies suggest that a high consumption of fruits can reduce the risk of some cancers and cardiovascular disease, and this may be attributable to the antioxidant activity of vitamins and phenolic compounds. The present study investigated the variations in vitamin C, total phenolic, hesperidin, and naringin contents, and total antioxidant activity of yuzu (Citrus junos Sieb ex Tanaka)-which is a popular citrus fruit in Korea and Japan-between cultivars and during maturity. The amounts of phenolics and vitamin C and the antioxidant activity in all tested yuzu cultivars were higher in peel than in flesh. Ripening increased the total antioxidant activity and vitamin C content in both peel and flesh of yuzu. However, the amounts of all total phenolics, hesperidin, and naringin in peel increased with ripening, whereas they decreased slightly in flesh. There was a highly linear relationship between the vitamin C content and the total antioxidant activity in both peel (r(2) = 1.000) and flesh (r(2) =0.998), suggesting that vitamin C plays a key role in the antioxidant activity of yuzu. In addition, the contribution of each antioxidant to the total antioxidant activity of yuzu was determined using a 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging assay and is expressed here in terms of the vitamin C equivalent antioxidant capacity (VCEAC). The means of vitamin C, naringin, and hesperidin in yuzu were 90.4, 63.8, and 65.7 mg/100 g fresh yuzu, respectively. The relative VCEAC values of these compounds were in the following order: vitamin C (1.00) > naringin (0.195) > hesperidin (0.162). Therefore, the estimated contribution of each antioxidant to the total antioxidant capacity of 100 g of fresh yuzus is as follows (in mg of VCEAC): vitamin C (90.36 mg) > naringin (12.44 mg) > hesperidin (10.64 mg). Our results indicate that mature yuzu contains higher amounts of vitamin C and phenolics than other citrus fruits and could therefore be used as a significant dietary source of antioxidants.
authors.affiliation: Department of Food and Nutrition, Research Institute of Human Ecology, Seoul National University, Seoul 151-742, South Korea. ikhwang@snu.ac.kr
authors.forename: Kyung Mi
authors.initials: KM
authors.lastname: Yoo
authors.forename: Ki Won
authors.initials: KW
authors.lastname: Lee
authors.forename: Jae Bok
authors.initials: JB
authors.lastname: Park
authors.forename: Hyong Joo
authors.initials: HJ
authors.lastname: Lee
authors.forename: In Kyeong
authors.initials: IK
authors.lastname: Hwang
mesh_terms: D000975:Antioxidants / Q000032:analysis*; D001205:Ascorbic Acid / Q000032:analysis; D002957:Citrus / Q000737:chemistry* / Q000254:growth & development*; D044950:Flavanones / Q000032:analysis; D005638:Fruit / Q000737:chemistry* / Q000254:growth & development; D006569:Hesperidin / Q000032:analysis; D010636:Phenols / Q000032:analysis
chemical_list: D000975:Antioxidants; D044950:Flavanones; D010636:Phenols; D006569:Hesperidin; C005274:naringin; D001205:Ascorbic Acid