Abstract:

In this paper, the measurement uncertainty for the determination of starch content in the dried residue left afterstarch extraction from Manihot esculenta by polarimetric method was evaluated. Each uncertainty component during theprocess of measurement was modeled. The main sources of uncertainty were identified and analyzed. The impact of everyuncertainty component on the measurement uncertainty was estimated. Based on quantitative analysis of every uncertaintysource, the relative standard uncertainty of the measurement results was obtained. The starch content in the Manihotesculenta residue was still as high as 50.20 g/100 g, with a combined standard uncertainty of 0.16 g/100 g and an expandeduncertainty of 0.32 g/100 g. The evaluation indicated that repeated determinations of the total optical rotation of the Manihotesculenta residue made the most important contribution to the combined relative standard uncertainty. The influence ofrepeated determinations of the optical rotation of its alcohol-soluble fraction could not be neglected. The effect of sampleweighing was minimal. This evaluation can provide a theoretical basis for the quality control of starch content determinationin Manihot esculenta.

Key words: polarimetric method, starch, measurement uncertainty evaluation, Manihot esculenta