The objective of this study was to investigate physicochemical and antioxidant characteristics of immature flat
persimmon during 7 heat treatment aging steps. The pH decreased, and hence, acidity increased with aging. Hunter
L value decreased with aging. The a value rapidly increased until step 3, whereas the b value decreased. Fructose
content decreased while glucose contents slightly increased during aging. Hardness, chewiness and gumminess rapidly
decreased, indicating softening in texture, but it was negligible after aging step 3. Phenolic compounds including
gallic acid and homogentisic acid were detected at step 3 and then gradually increased with aging. However, contents
of flavonoid and tannin were much higher in step 1 sample than others. The antioxidant activities observed by
DPPH, ABTS, and FRAP assay were the highest at step 1 possibly due to the higher levels of flavonoids and
tannin acid in the step 1 sample.