(P09-025-24) Effects of Free Sugars, Organic Acids, and Pectin on ORAC and HORAC of Apples, Pears, and Tangerines

Objectives: The effects of free sugars, organic acids, and pectin contained in apples, tangerines, and pears on the antioxidant activity of apple, pear, and tangerine juices and extracts were evaluated.

Methods: Juices and extracts were prepared using apples (Malus domestica 'Borkh'), pears (Pyrus pyrifolia (Burm f.) 'Nakai'), and tangerines (Citrus unshiu 'Marcow'), and antioxidant activity was determined through ORAC and HORAC analysis.

Results: The ORAC and HORAC of apple, pear, and tangerine juice was 48.48∼470.19 and 127.99∼700.86mg TE/100ml, respectively. Additionally, the ORAC and HORAC of apple, pear, and tangerine extracts was 34.47∼247.22mg and 21.67∼38.44mg TE/g DW, respectively. When high concentrations of free sugars, organic acids, and pectin were spiked into apple, pear, and tangerine juices and extracts, ORAC activity tended to increase in all cases, except when pear juice and extracts contained free sugars. The HORAC activity of fruit juice and all extracts tended to increase when fructose, organic acids, and pectin were spiked, and when glucose was spiked into the extract, HORAC tended to increase significantly. Free sugars, organic acids, and pectin of various concentrations were added to antioxidant standard substances to analysis changes in antioxidant activity.

Conclusions: When free sugars, organic acids, and pectin were spiked into trolox, the ORAC of trolox tended to increase, similar to the results from fruit. HORAC for trolox increased as the spike concentration of citric acid, malic acid, and gallic acid increased, showing a similar to the results of the spike experiment for fruit juice and extract. Judging from the above results, it is expected that the effect of free sugars on the antioxidant activity of fruits is small, and that the antioxidant activity of fruits is slightly increased by pectin in fruit.

Funding Sources: None