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Determination of Amylose in Cereal and Non‐Cereal Starches by a Colorimetric Assay: Collaborative Study
Author(s) -
Martinez Cristina,
Prodolliet Jacques
Publication year - 1996
Publication title -
starch ‐ stärke
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.62
H-Index - 82
eISSN - 1521-379X
pISSN - 0038-9056
DOI - 10.1002/star.19960480302
Subject(s) - repeatability , reproducibility , amylose , starch , iodine , relative standard deviation , absorbance , chromatography , chemistry , food science , organic chemistry , detection limit
An improved colorimetric method, based on the well‐known reaction between amylose and iodine, is described. Native starch is dissolved in ureadimethylsulfoxide and the resulting solution defatted with ethanol. An aliquot of the lipid‐free solution is then reacted with iodine and the absorbance of the blue‐coloured amylose‐iodine complex measured, thus determining the iodine‐binding capacity of starch (Blue Value). A collaborative study was conducted, according to official guidelines, to determine the method's repeatability and reproducibility: 8 participants were each sent 8 starch samples from different botanic origin for duplicate analysis. Statistical evaluation of the results gave good precision results, with an average repeatability relative standard deviation of 2.1% and an average reproducibility relative standard deviation of 5.6%. The method is, therefore, suitable to determine precisely the amylose content of native starch.