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Foods Food Ingredients J. Jpn., Vol. 213, No.8, 2008 Sugar Analysis and Utilization of Dietary Fiber from Sweetpotato as a Foodstuff -Application of Un-Utilized Polysaccharide Resources in Southern KyushuToshihiko Suganuma, Kanefumi Kitahara, and Kiyotaka Fujita Department of Biochemical Science and Technology, Faculty of Agriculture, Kagoshima University 1-21-24, Korimoto, Kagoshima 890-0065, Japan Summary Sweetpotato is one of the major crops in Southern Kyushu, utilized mainly for starch and in shochu-manufacture. Sweetpotato starch residues and shochu distillation waste are at present generally discarded without recycling. In our laboratory, we have therefore focused our research on sweetpotato cell wall material (CWM) and its conversion to dietary fiber resources. CWM was separated into pectin, hemicellulose and cellulose fractions, and comparisons were made with samples from potato and cassava. Sugar composition analysis by HPEAC-PAD indicated that sweetpotato CWM had the most abundant pectin fraction among the three CWM's. Hemicellulose fractions from the three plants showed marked differences in sugar composition. Some bacteria strain (Bacillus sp. M4) isolated from soil produces CWM solubilizing enzymes which attack protopectin moieties. Protopectinase activity is due to a complex of several related-degradation enzymes and to assess individual primary enzymes, we determined sugar alcohols derived from reducing-end residues of solubilized products. Rhamnitol and galactitol were the major products from the large and small molecule fractions, respectively, indicating that rhamnogalacturonase first attacks the protopectin moieties in sweetpotato CWM to solubilize and thereafter a galactanase removes galactan side chains. Animal testing in rats showed positive effects of solubilized products on triglycerides in blood. As an additional project, in order to reduce shochu distillation waste in Southern Kyushu, we have developed a new process of shochu making without emission. Before the distillation, fermented moromi is separated into liquid and solid fractions, which are distilled separately to give new types of shochu and residue as a foodstuff. The solid distillation residue contains rich dietary fiber and anti-oxidant substances, and thus might provide beneficial foodstuffs for metabolic syndrome patients.