摘要：

Cells containing starch granules are held together by a cementing substance, photopectin. The walls of parenchyma cells in sweet potato are composed almost entirely of cellulose fibrils. It was attempted to isolate starch from sweet potato and its by-product using a cell separating enzyme (CSE) preparation consisting mainly of protopectinase along with a Trichoderma cellulase preparation.1) After degradation of parenchyma into individual starch cells with CSE, the complete surface of the starch cell could be easily attacked with cellulase, resulting in complete isolation of the starch granules.2) When crushed raw sweet potato was stirred with the mixed solution of CSE and cellulase at pH 4.0,33℃ for 2 hrs, the same starch yield as obtained from the usual process was obtained.3) After a 2 hr incubation of the crushed air-dried starch waste produced enzymatically from raw sweet potato using mixed enzyme solution under the same conditions, almost all starch was recovered. Similar results were obtained after enzymic treatment of the residue produced by mechanical disintegrating raw sweet potato to isolate the starch milk.4) Application of the enzyme preparation to raw materials having high moisture content such as raw waste or pressed waste, was not desirable. Repeated treatment of such materials with mixed enzyme solution was also inadequate owing to the partial inactivation of enzyme activity.5) Prolonged incubation of air-dried purified starch waste with such a diluted enzyme solution of 0.2 percent concentration gave no appreciable result. Incubation, however, of dried starch waste produced by a continuous juicer with a diluted enzyme solution stirred for 5 hr made this possible.

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