Antioxidant activity of cell-wall components in netted melon flesh against ascorbic acid oxidation during fruit development
Melon (Cucumis melo) fruit is known to contain a high level of vitamin C, as do Valencia orange and Satsuma mandarin. Previously, we reported that cell-wall components of melon flesh demonstrated a marked effect in maintaining the UV absorbance of ascorbic acid (high antioxidant activity), compared with the flesh of 18 fruit species. In this study, changes in antioxidant activity against ascorbic acid oxidation were measured in water extract of alcohol-insoluble solids (AIS) of the flesh of three cultivars of melon ('Andesu', 'Gurandoru', and 'Life') during fruit development, between 10 and 51 days after anthesis (DAA). The antioxidant activity per unit weight was increased with fruit development in all cultivars, especially after 45 DAA. The flesh firmness and dry weight of AIS decreased with fruit development. As the main component of the water-soluble fraction is pectic substances, uronic acid and neutral sugar contents in the water-soluble fraction of AIS were determined. A marked increase in the neutral sugar content was observed, while the increase of uronic acid was comparatively low. In our previous study, the antioxidant activity, measured by the ascorbic acid oxidation method, was higher in low-methylated pectins than in high-methylated pectins. Antioxidant components in AIS of melon flesh are discussed.
Motomura, Y., Sugawara, J., Aikawa, T., Nara, K. and Nishizawa, T. (2017). Antioxidant activity of cell-wall components in netted melon flesh against ascorbic acid oxidation during fruit development. Acta Hortic. 1179, 45-50
antioxidant, ascorbate, alcohol insoluble solid, ripening