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MALT DIASTATIC ACTIVITY. PART I. THE EBC DETERMINATION OF DIASTATIC POWER: THE UNDERESTIMATION OF THE RELEASE OF REDUCING SUGARS BY IODOMETRIC TITRATION AND THE CHROMOGEN p‐HYDROXYBENZOIC ACID HYDRAZIDE AS ALTERNATIVE METHOD
Author(s) -
Delcour Jan A.,
Verschaeve Stefaan G.
Publication year - 1987
Publication title -
journal of the institute of brewing
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.523
H-Index - 51
eISSN - 2050-0416
pISSN - 0046-9750
DOI - 10.1002/j.2050-0416.1987.tb04488.x
Subject(s) - chemistry , iodometry , titration , hydrazide , chromatography , organic chemistry
It is shown that the reducing groups formed during the amylolysis of soluble starch in the determination of malt diastatic power are underestimated in the titration with iodine. This is due to problems associated with the overoxidation of iodine in the presence of excess alkali rather than to the binding of substantial quantities of iodine to starch. It is proposed to apply a colourimetric estimation of reducing groups with the chromogen p‐hydroxybenzoic acid hydrazide. Determination of diastatic power by this method results in lower standard deviations of individual estimations and on the average to 7·6% higher reading of diastatic power.