Abstract:

In this study, we examined changes in the contents of total phenols and condensed tannins in persimmon fruits
from 12 different varieties during growth and development by using Folin-Ciocalteu assay and vanillin-hydrochloric acid
assay, respectively. The experimental conditions for vanillin-hydrochloric acid assay were optimized by orthogonal array
design. The results indicated that the optimum conditions for condensed tannins determination by vanillin-hydrochloric
acid assay were as follows: the color was developed with 2.0 g/100 mL vanillin and 15% (by volume) concentrated HCl
in methanol for 0.5 h. The contents of total phenols and condensed tannins changed in a similar pattern during the growth
and development of persimmon fruits, reaching the maximum level at 35-50 d after the bloom stage followed by a gradual
reduction. However, the levels of both parameters in persimmon fruits were greatly different and their variation amplitudes
varied considerably among varieties. The contents of total phenols and condensed tannins were similar and changed in a
similar pattern among different varieties from each of the five groups: Japanese pollination constant nonastringent (J-PCNA),
Chinese pollination constant nonastringent (C-PCNA), pollination variant astringent (PVA), pollination variant nonastringent
(PVNA), and pollination constant astringent (PCA), and the abundance of both compounds in these five groups followed the
decreasing order: PCA, C-PCNA, PVA, PVNA, and J-PCNA.

Key words: persimmon fruit, vanillin-hydrochloric acid assay, total phenols, condensed tannins