title: Drying effect on flavonoid composition and antioxidant activity of immature kumquat.
abstract: A seven flavonoids in hot water extract of immature kumquat (Citrus japonica var. margarita) were identified and quantified (mg/100g fresh fruit): 3',5'-di-C-β-glucopyranosylphloretin (DGPP, 285.9 ± 2.9 mg/100g), acacetin 8-C-neohesperidoside (margaritene, 136.2 ± 2.6 mg/100g), acacetin 6-C-neohesperidoside (isomargaritene, 119.1 ± 1.8 mg/100g), fortunellin (acacetin 7-O-neohesperidoside, 28.5 ± 0.7 mg/100g), apigenin 8-C-neohesperidoside (16.9 ± 0.1mg/100g), poncirin (isosakuranetin 7-O-neohesperidoside, 5.1 ± 0.1mg/100g), and rhoifolin (apigenin 7-O-neohesperidoside, 2.0 ± 0.1mg/100g). When immature kumquat was dried at 110 and 130°C for 0.5h, the antioxidant activity, total phenolic content and identified flavonoids increased. The UV absorbance of browning products of immature kumquat dried at 130°C for 1.5h increased dramatically, while the identified flavonoids decreased. Therefore, it was concluded that drying below 130°C for 1.0 h, could release phenolic compounds, which resulted in the increasing antioxidant activity. Drying at 130°C for 1.5h, it might be due to the effect of formed browning products.
authors.affiliation: Department of Food Science, National Ilan University, 260 Ilan, Taiwan. Electronic address: snlou@niu.edu.tw.
authors.forename: Shyi-Neng
authors.initials: SN
authors.lastname: Lou
authors.affiliation: Department of Food Science, National Ilan University, 260 Ilan, Taiwan.
authors.forename: Yi-Chun
authors.initials: YC
authors.lastname: Lai
authors.affiliation: Department of Food Science, National Ilan University, 260 Ilan, Taiwan.
authors.forename: Jia-De
authors.initials: JD
authors.lastname: Huang
authors.affiliation: Department of Food Science, Rutgers University, New Brunswick, NJ 08901-8520, USA.
authors.forename: Chi-Tang
authors.initials: CT
authors.lastname: Ho
authors.affiliation: Department of Food Science, National Ilan University, 260 Ilan, Taiwan.
authors.forename: Lin-Huei A
authors.initials: LH
authors.lastname: Ferng
authors.affiliation: Department of Food Science, National Ilan University, 260 Ilan, Taiwan.
authors.forename: Yung-Chung
authors.initials: YC
authors.lastname: Chang
mesh_terms: D000975:Antioxidants / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid; D002957:Citrus; D003890:Desiccation; D005419:Flavonoids / Q000032:analysis*; D005511:Food Handling / Q000379:methods; D005638:Fruit / Q000737:chemistry*; D006358:Hot Temperature; D010084:Oxidation-Reduction; D010636:Phenols / Q000032:analysis; D010936:Plant Extracts / Q000737:chemistry; D027821:Rutaceae / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D005419:Flavonoids; D010636:Phenols; D010936:Plant Extracts
keywords: Antioxidant activity; Drying treatment; Flavonoid composition; Immature kumquat