Changes in free and bound phenolic contents and antioxidant activities of melon flesh dried at different stages of fruit growth

Abstract

The phenolic contents and antioxidant activities in the methanol extract (soluble) of netted melon flesh (Cucumis melo) increased with fruit growth, and the values were higher in ‘Gurandoru’ compared with ‘Andesu’ and ‘Life’, at the commercial harvesting stage. Those in the extracts on alkali treatment (insoluble) were lower than in soluble ones. When the freeze-dried powder of flesh was exposed to air, a brown color developed and it increased with fruit growth. The phenolic contents in the extract of brown powder were lower than those before exposure to air. From these results, the freeze-dried flesh of ‘Gurandoru’ at the commercial harvesting stage is a comparatively favorable food ingredient. The possibility was suggested that browning of the dried flesh is associated with phenolic substances.