Studies on the liquefying properties of starch for enzyme-hydrolyzed glucose production: Part V. Effects of impurities contaminated in sweet potato starch on the action of liquefying enzyme

Maezawa, Tatsuo; Hayakawa, Sachio; Okubo, Masutaro; Shinbori, F.

Nippon Nogeikagaku Kaishi Journal Agr Chem Society Jap 41(5): 231-238


Accession: 025582851

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The effects of impurities which are possibly contaminated in sweet potato starch during its manufacture on the action of liquefying enzyme were investigated. Fruit-water, a waste precipitated by acidifying fruit-water with acetic-acid, sweet potato protein and sucrose, which is the main sugar of sweet potato, have protective function against the heat-inactivation of enzyme. Alcohol extract of sweet potato was classified into 4 portions with solvents and the effect of each portion was also investigated: acetonesoluble portion decreases the degree of hydrolysis of starch in proportion to the amount added, but the fact does not necessarily stand for the inhibitory function of it; acetone-insoluble portion gives no influence; ethyl acetate-soluble and -insoluble portions have inhibitory and protective functions, respectively. Chlorine affects with extremely small quantities of less than 0.3 p.p.m. and inhibits the action of enzyme completely with the concentration of 10 p.p.m. Heavy metals such as Cu++, Hg++ and Fe+++ have inhibitory function with small quantities, but Fe+++ is the weakest among them. Synthetic detergent DBS also inhibits the action of enzyme.