Abstract
Recently, the various functions of kaki-tannin have been the focus of attention in many fields. The common and traditional method of preparing kaki-tannin as Kakishibu requires considerable time, usually more than 3 years, because this method includes a fermentation process in the preparation. Therefore, a novel method of quickly preparing kaki-tannin is described in this paper. Immature and mature fruits of ‘Tone-wase’ persimmon were harvested respectively and then treated with ethanol for removal of astringency, and homogenized by a juicer. These homogenates were centrifuged at 1,630 × g for 15 mins to show 3 or 4 layers in the centrifuging tubes, depending on the harvest time. Each layer was separated, removed from the tubes, and then freeze-dried. The dried powders were then solubilized to extract kaki-tannin by heating in water (121°C for 15 mins), respectively. Most of solubilized kaki-tannin was obtained from layer No. 3 in the case of immature persimmon fruit and from layer No. 2 in the case of mature fruit. The maximum recovery of kaki-tannin after astringent removal from fruit tissues was about 2% per fresh weight of the immature fruit. This method requires only 8 days to prepare kaki-tannin from immature persimmon fruits after harvest, in contrast to the traditional method. As indicated above, this method is considered very useful for preparing a large amount of kaki-tannin and it may open the door to the industrial utilization of kaki-tannin.
