Publication | Open Access
Measurement of Total Starch in Cereal Products by Amyloglucosidase-α-Amylase Method: Collaborative Study
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1997
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NutritionEngineeringAmyloglucosidase-α-amylase MethodFood AnalysisWhite Wheat FlourGlycobiologyAgricultural EconomicsRelative Standard DeviationsFood BiophysicsPolysaccharideGrain QualityFood ChemistryAgricultural ChemistryBioanalysisGrain ScienceFood SciencesTotal StarchHealth SciencesFood CompositionIn Vitro FermentationFood QualityFood SafetyCereal ProductsRsdr ValueBiotechnologyFood EngineeringSeed ProcessingGrain Storage
The study evaluated the accuracy and reliability of an enzyme assay kit for measuring total starch across various cereal grains and products. The assay involved incubating flour at 95 °C with thermostable α‑amylase, adjusting pH, treating with purified amyloglucosidase to convert dextrins to glucose, and quantifying glucose via a glucose‑oxidase/peroxidase reaction; 32 collaborators analyzed 16 blinded samples of diverse cereal products, with some samples also tested using a DMSO‑cooking step. Repeatability and reproducibility relative standard deviations ranged from 2.1–3.9 % and 2.9–5.7 %, respectively, with the highest RSDr of 5.7 % observed for high‑amylose maize starch.
Abstract American Association of Cereal Chem- ists/AOAC collaborative study was conducted to evaluate the accuracy and reliability of an enzyme assay kit procedure for measurement of total starch in a range of cereal grains and products. The flour sample is incubated at 95°C with thermostable α-amylase to catalyze the hydrolysis of starch to maltodextrins, the pH of the slurry is adjusted, and the slurry is treated with a highly purified amyloglucosidase to quantitatively hydrolyze the dextrins to glucose. Glucose is measured with glucose oxidase-peroxidase reagent. Thirty-two collaborators were sent 16 homogeneous test samples as 8 blind duplicates. These samples included chicken feed pellets, white bread, green peas, high- amylose maize starch, white wheat flour, wheat starch, oat bran, and spaghetti. All samples were analyzed by the standard procedure as detailed above; 4 samples (high-amylose maize starch and wheat starch) were also analyzed by a method that requires the samples to be cooked first in dimethyl sulfoxide (DMSO). Relative standard deviations for repeatability (RSDr) ranged from 2.1 to 3.9%, and relative standard deviations for reproducibility (RSDr) ranged from 2.9 to 5.7%. The RSDr value for high amylose maize starch analyzed by the standard (non-DMSO) procedure was 5.7%; the value