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M. P. Pujari, A. DeMocko, and R. A. CLEMENS. School of Pharmacy, Univ. of Southern California, 1985 Zonal Ave., Los Angeles, CA 90033 Consumer demand for natural products in dietary supplements, especially herbals, has created an expanded global market that is expected to exceed $5 trillion by 2050. As the number of domestic and international suppliers rapidly increases, there is an urgent need to qualify both raw materials and finished products. Phytosterols are natural plant sterols, which have shown to reduce risk of some forms of cancer, to be an effective option in the treatment of benign prostatic hyperplasia, and to reduce atherosclerosis in mice and rabbits. Incorporated in new functional food products, phytosterols may reduce total plasma cholesterol and LDL concentration in humans. Many investigators have reported several HPLC methods to assay phytosterols in raw ingredients and finished products, most of which require tedious sample preparation and lack sensitivity. Published GC methods also require lengthy hydrolysis, saponification and derivatization prior to analysis. A simple and rapid extraction procedure with toluene and subsequent derivatization with BSTFA [N,O-bis(trimethylsilyl)trifluoroacetamide] in dry pyridine was developed and yielded a well resolved, reproducible chromatogram. This GCMS method separated campesterol, stigmasterol and b-sitosterol in 36 minutes using an Agilent® 6890N Gas Chromatograph with a 30-meter HP®-5 MS capillary GC column and a 5973N Mass Selective Detector. Quantitation was performed using Selective Ion Monitoring (SIM) mode using Electron Impact (EI) ionization. Calibration curves in the range 1-100 ppm for the phytosterols standards were linear. The Method Detection Limit (MDL) was 0.4 ppm. 5-a-Cholestane was used as an internal standard. This rugged, reproducible method yielded recoveries above 94%. Numerous phytosterols-containing foods, dietary supplements and raw ingredients were successfully analyzed using this method. The method reported here is a rapid procedure that can be readily applied to QC and QA protocols in the food and dietary supplement industries.
Session 29, Food Chemistry: Antioxidants and bioactive agents
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