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S. H. YOON, Food Function Research Division, Korea Food Research Institute, San 46-1, Baekhyundong, Boondanggu, Songnamsi, Kyunggido, 463-746, South Korea and M. Kim, Food Function Research Division, Korea Food Research Institue, San 46-1, Baekhyundong, Bundanggu, Songnamsi, Kyunggido, 463-746, South Korea. Silicate was prepared from rice hull ash (RHA) as a novel deacidification agent of fats and oils replacing conventional alkali refining process. Silicate was produced by pyrolysis of RHA at 500o C for 10 hr followed by alkalinization and neutralization. Microstructure of silicate was observed by scanning electron microscope (SEM), and x-ray diffraction (XRD) was used for characterization of silicate. Various amounts (0-5%) of silicate were added to 20 ml isooctane containing one of free fatty acids (10mM) such as capric acid, palmitic acid, stearic acid, oleic acid, linoleic acid, and linolenic acid. Same amounts of silicate were also added to 20g of deodorized soybean oil containing 10mM oleic acid, and degummed soybean oil. Mixture was agitated at 32oC and 240 rpm for 30 min, and supernatant was decanted for analyses. Efficiency of free fatty acid removal by silicate was determined by consumption of 2.5 mM NaOH for neutralization or by acid value (AV) of oil supernatant. Production yield of silicate from RHA was about 64%, and silicate was shown to contain 7,893 ppm sodium, 383ppm potassium, and 89ppm calcium besides silicone. Silicate was shown to be amorphous and porous with small openings. AV of isooctane decreased substantially with the increase of silicate amount from 4ml to 0.15 ml with 0% and 5% silicate respectively. In degummed oil, AV decreased from 1.0 to 0.76 whereas from 0.76 to 0.45 in deodorized oil under the same conditions. It was clearly shown that silicate had an effect to decrease free fatty acid contents and to have no specificity for chain length and degree of unsaturation of fatty acids.
Session 32, Food Chemistry: Component interactions and processing effects
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |