Method for preparing soluble dietary fiber from corn hull
The present invention relates to a high yield process for producing soluble dietary fiber from corn hull. More specifically, the present invention comprises removing starch and protein with enzymes from corn hull which is by-product of wet-milling process for production of corn starch, extracting the resultant with alkaline solution to form a alkaline extract, treating the alkaline extract with enzymes, and drying the enzyme-treated solution, to produce dietary fiber with low viscosity and containing hemicellulose as a major component at high yield.
1. A method of preparing a soluble dietary fiber comprising the steps of:
(i) removing starch and protein from corn hulls;
(ii) extracting the starch- and protein-removed corn hulls with an alkaline solution, and filtering the alkaline extract through filter cloth;
(iii) treating the filtrate of step (ii) with cellulase and cellobiase;
(iv) treating the solution of step (iii) with adsorbent, and filtering it through a membrane filter; and
(v) purifying the filtrate.
2. The method of claim 1 , wherein in the step (i), the corn hulls are treated with amylase and protease simultaneously or sequentially.
3. The method of claim 2 , wherein in the step (i), after the treatment of amylase or protease, the resultant is filtered through a filter cloth.
4. The method of claim 1 , wherein in the step (ii), the alkaline solution is a 0.1 to 0.3% of NaOH solution.
5. The method of claim 1 , wherein the step (iii) further comprises a step of treating with xylanase.
6. The method of claim 1 , wherein the cellulase and cellobiase are 0.1 to 5% to the dried corn hulls, respectively.
7. The method of claim 1 , wherein before the step (iii), the alkaline extract from step (ii) is neutralized, and it is desalted and decolorized with an ion exchange resin.
8. The method of claim 7 , wherein the cellulase and cellobiase are 0.1 to 3% to the dried corn hulls, respectively.