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Soluble dietary fiber was prepared from corn hull produced through wet-milling process for manufacturing corn starch. Starch and protein of corn hull were removed by hydrolyzing with thermostable α-amylase and protease, respectively. Dietary fiber containing soluble hemicellulose as a main component was extracted by agitating the mixture of enzyme treated corn hull and 0.5% sodium hydroxide solution for 3 hr at 80℃. The extract was neutralized with 10% hydrochloric acid, and was hydrolyzed with cellulase, cellobiase and xylanase in order to decrease viscosity and increase transparency of the extract. The enzyme hydrolysate was refined with activated carbon and ion exchange resin, concentrated by rotary vacuum evaporator, and dried by freeze dryer. Average final yield of soluble dietary fiber prepared from initial corn hull was 23.9%, and its average dietary fiber content analyzed with Prosky-AOAC method was 85.0%. Consequently, it was found that soluble dietary fiber can be prepared easily from corn hull, a by-product of wet-milling process, and was presumed to be widely applicable to various foods including functional beverages as a nutraceutical.
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