An Objective Illustration of the Inadequacy of the Official EC “Ewers” Method for the Determination of Starch
作者:
John F. Kennedy,
David L. Stevenson,
Kornelia Junel,
期刊:
Starch ‐ Stärke
(WILEY Available online 1990)
卷期:
Volume 42,
issue 1
页码: 8-12
ISSN:0038-9056
年代: 1990
DOI:10.1002/star.19900420104
出版商: WILEY‐VCH Verlag GmbH
数据来源: WILEY
摘要:
AbstractTheEwersmethod for starch determination is currently the Official EEC method for measurement of starch purity. In this communication we demonstrate that the use of trifluroacetic acid for solubilisation of starch prior to polarimetric measurements is preferred over the use of mineral acids since the degree of hydrolytic degradation observed with this reagent was minimal compared to mineral acids, thereby giving improved starch purity values. Of particular concern we demonstrate that theEwersmethod is non‐specific in that the addition of an epichlorohydrin cross‐linked dextran as an adulterant enhances the value of starch purity obtained. TheEwersmethod however was able to detect agarose and carboxymethyl cellulose added to starch as adulterants.It is concluded that theEwersmethod is not an acceptably satisfactory method for starch purity measurement on which to base quality control or eligibility for rebate and refund sche
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