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J. N. RODRIGUES, L. A. Gioielli, R. P. Torres, and J. Mancini Filho. Faculty of Pharmaceutical Sciences, Univ. of São Paulo, Av. Prof. Lineu Prestes, 580, B16, CEP 05508-900, São Paulo, Brazil Phytosterols and their esters have been found to be effective in lowering plasma cholesterol concentrations by inhibiting its absorption from intestine. They are naturally present in vegetable oils, but their consumption is not sufficient to lower cholesterol levels. Therefore, phytosterol esters are intended for use as a food ingredient, primarily in spreads. Current literature provides much information on their effects in cholesterol lowering, but researches on their physical and chemical properties and their technological application in food products are limited. Our objective was to characterize a commercial blend of Phytosterol Esters (PE) in terms of physical and chemical properties. The fatty acid and sterol composition of PE were determined by gas-liquid chromatography. Softening point was determined by AOCS official method and a constant speed texture analyser was used to evaluate consistency and adhesivity of the samples. Solid Fat Content (SFC) and crystallization kinetics were performed by NMR. The crystal structure was observed with polarized light microscopy and scanner imaging. The results showed that ß-sitosterol is the most abundant sterol (26.2%) in the blend, followed by campesterol (18.5%) and stigmasterol (11.7%). Unsaturated fatty acids represent around 75% of total fatty acids. Softening point was 24.3°C and consistency could only be determined at 5°C. The PE blend had an SFC of 65.8% at 10°C, which progressed downward until no solid fat was present (40°C). The largest decline ocurred from 20 to 25°C. The high SFC and lack of consistency at 10°C might indicate a weak crystalline structure. Following is the PE crystal network observed at 20°C (magnification is 200X; the bar represents 100µm). The results suggest that phytosterol esters present a particular crystalline structure that is different from edible lipids composed mainly by triacylglycerols. This property can be very important when PE are added to food products and interact with other components.
Session 35, Nutraceutical & Functional Foods: General I
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |