67D-2 |
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A. NAKAMURA1, M. Corredig1, T. Takahashi2, R. Yoshida2, H. Furuta3, and H. Maeda2. (1) Dept. of Food Science, Univ. of Guelph, Ontario Agricultural College, Guelph, ON N1G 2W1, Canada, (2) Food Science Research Institute, Fuji Oil Co., Ltd., 4-3 Kinunodai, Yawara-mura, Tsukuba-gun, Ibaraki, 300-2497, Japan, (3) Specialty & Functional Food Ingrediants Development Section, Fuji Oil Co., Ltd., 1 Sumiyoshi-cyo, Izumisano, Osaka, 598-0061, Japan Water-soluble soybean polysaccharide (SSPS) is an ingredient produced from the by-product of the isolation of soybean protein, with properties that have been often compared to those of pectin and gum Arabic. However, the functional properties of SSPS as emulsifier have not yet been studied. The objective of this investigation was not only to study the emulsifying properties of SSPS, but also to determine if different extracting conditions would affect the behavior of the polysaccharide when adsorbed at oil/water interfaces. Three types of SSPS, SSPL-L, SSPS-H, and SSPS-M, prepared by different extraction conditions, were used. Emulsions with SSPS was made using a laboratory scale homogenizer (EmulsiFlex C-5, Avestin, Canada) and the particle size and thickness of the SSPS adsorbed layer were evaluated using light scattering techniques (Mastersizer X and Photon Correlation Spectrometer, Malvern Inst. USA). 20% soy oil-in-water emulsions at pH 3.5 to 5.0 were stable to creaming for 30 days at concentrations of SSPS above 4%, for all types of SSPS tested. Emulsiosn were not affected by changes in pH, by addition of CaCl2 (5-25 mM) or NaCl (5-25 mM). Among the three SSPS tested, SSPS-L, which had the lowest molecular mass distribution, showed the best emulsifying properties, forming stable emulsions at concentrations of 4% and up to 50% oil. Differences in thickness of the adsorbed layer were found depending on the type of SSPS. The thickness of SSPS was determined by measuring the droplet diameter before and after treatment with hemicellulase or pectinase, and was estimated at about 17 nm (SSPS-L), 21-24 nm (SSPS-H), and 30-36 nm (SSPS-M). The enzymatic treatment of SSPS resulted in oil droplet aggregation indicating that the hydrophilic portion of the polysaccharide stabilized emulsions via steric repulsion. These results confirmed our hypothesis that the extraction conditions strongly affect the functionality of the SSPS.
Session 67D, Food Chemistry: Lipid and carbohydrate chemistry
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