Author
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Knutson Jr, Clarence |
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Submitted to: American Association of Cereal Chemists Meetings
Publication Type: Abstract Only Publication Acceptance Date: 9/19/1996 Publication Date: N/A Citation: N/A Interpretive Summary: Technical Abstract: Studies of composition and properties of jet cooked starch-oil composites require a method for quantitative determination of carbohydrate in samples containing high concentrations of oil. Experiments showed that such samples could be accurately assayed by the phenol-sulfuric acid analysis of Dubois et al (Anal. Chem. 28:350, 1956) by first suspending samples in a 1:1 solution of ethanol and water. The absorbance maximum of glucose and starch at 490 nm and absorptivity at that wavelength were unaffected by a 200-fold excess of oil. Unsaturated oils formed sulfate esters which were miscible with the reaction mixture. These esters in the presence of carbohydrates produced a chromophore with absorbance maximum at 535 nm. This chromophore, which appears to result from formation of a complex between sulfate esters and the 5-(hydroxymethyl)-furfural formed by the action of concentrated sulfuric acid on glucose, is useful for detecting small amounts of carbohydrate in oil extracted from composites. Absorbanc of the chromophore was dependent upon both lipid and carbohydrate concentrations. |
