Effects of activated carbon powder treatment on clarification, decolorization, deodorization and fructooligosaccharide content of yacon juice

Abstract

Fructooligosaccharides, which are mainly contained in yacon tubers, are known for their ability to keep intestines healthy. Therefore, the juice pressed from yacon tubers is expected as a sweetener containing natural fructooligosaccharides. However, the juice is usually unsuitable for beverages due to being cloudy, grassy and colored. In this study, the juice was successfully clarified, decolorized and deodorized by the treatment with activated carbon powder under the most desirable condition. Six activated carbon powders, SD, BA, TW, ZN,TA and KA, were tested (SD, BA, TW and ZN are commercial names of activated carbon powders produced by HOKUETSU TANSO KOGYO Co. Ltd. TA and KA are abbreviated names. The first is activated carbon powder from TAKEDA YAKUHIN KOGYO Co. Ltd. for decolorization and purification of SAKE. The second is activated carbon powder from KANTO KAGAKU Co. Ltd. for commercial reagents). The filtrated juice was measured for transmittance, soluble sugar and so on after stirring with each activated carbon powder for an hour at room temperature. Almost colorless, transparent and odorless juice was obtained by an addition of 2 to 3% of activated carbon powders ZN and TA. Both activated carbon powders had larger bulk volumes (>3ml/g) than others. Under the above conditions, fructooligosaccharides remained from 89% to 94% in the juice. From these results, ZN and TA among 6 activated carbon powders were suitable for practical use.