A profile of physicochemical and antioxidant changes during fruit growth for the utilisation of unripe apples

The physicochemicals associated with fruit quality, antioxidant activities and changes in polyphenol composition during Fuji apple growth were investigated from the 25th to 105th day after full bloom day (DAFB). Three kinds of antioxidant assays, including oxygen radical absorbing capacity (ORAC) were executed, and polyphenol composition were examined using HPLC. The change in weight of the Fuji apples during fruit growth showed a typical sigmoidal curve. Both the rise of the soluble solid content and the drop of the titratable acidity appeared to be more significant (p < 0.05) after the 85th DAFB. Concurrently, the antioxidant activities and the polyphenol content decreased (p < 0.05) rapidly after the same date. Accordingly, a profitable thinning date can be chosen around the 85th DAFB to utilise dropped unripe apples as resources of antioxidants. Furthermore, the antioxidant activities of Fuji apples may be highly affected by the chlorogenic acid content.