Author
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Knutson Jr, Clarence |
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Submitted to: Cereal Chemistry
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 4/7/1997 Publication Date: N/A Citation: N/A Interpretive Summary: There is increasing demand for foods with decreased fat content for improved nutrition and health. Research at this center has resulted in development of stable composites of starch and vegetable oil which can be introduced into food products instead of pure fat, thereby substantially lowering the fat content of the food product while retaining its flavor and texture characteristics. Study of these composites in the laboratory has necessitated developing methods to measure the amounts of starch and fat in them. This paper describes an improved method for doing these measurements. This research will be used by scientists studying such composites and other mixtures containing fat and starch. Technical Abstract: Studies of composition and properties of jet cooked starch-oil composites require methods 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 results from interaction between sulfate esters and the (5 hydroxymethyl)-2-furaldehyde formed by the action of concentrated sulfuric acid on glucose, is useful for detecting small amounts of carbohydrate in oil extracted from composites. Absorbance of the chromophore was dependent upon both lipid and carbohydrate concentrations. |
