Drying effect on flavonoid composition and antioxidant activity of immature kumquat

Food Chem. 2015 Mar 15:171:356-63. doi: 10.1016/j.foodchem.2014.08.119. Epub 2014 Sep 10.

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.

Keywords: Antioxidant activity; Drying treatment; Flavonoid composition; Immature kumquat.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antioxidants / analysis*
  • Chromatography, High Pressure Liquid
  • Citrus
  • Desiccation*
  • Flavonoids / analysis*
  • Food Handling / methods
  • Fruit / chemistry*
  • Hot Temperature
  • Oxidation-Reduction
  • Phenols / analysis
  • Plant Extracts / chemistry
  • Rutaceae / chemistry*

Substances

  • Antioxidants
  • Flavonoids
  • Phenols
  • Plant Extracts