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Determination of Total, Saturated, and Monounsaturated Fats In Foodstuffs by Hydrolytic Extraction and Gas Chromatographic Quantitation: Collaborative Study. J AOAC Int 2020. [DOI: 10.1093/jaoac/80.3.555] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Using gas chromatography (GC), 10 collaborating laboratories measured total, saturated, and monounsaturated fats in 8 blind duplicate pairs of foodstuffs. The method involves a hydrolysis/ether extraction of fat followed by quantitative GC analysis versus an internal standard. Calculations were designed to comply with federal regulations as specified in the Nutrition Labeling and Education Act of 1990. The range of fat contents was about 150%. Collaborators received and analyzed (in triplicate) a pre-collaborative sample of known fat content as a practice sample. After satisfactory results were obtained, participants received the 16-sample set. The repeatability standard deviations (RSDr) for total fat ranged from 2.04 to 10.6%; the reproducibility standard deviations (RSDr) for total fat ranged from 3.74 to 15.8%. The hydrolytic extrac- tion-GC method for determination of fat (total, saturated, and monounsaturated) in foodstuffs has been adopted first action by AOAC INTERNATIONAL.
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Determination of Vitamins A (Retinol) and E (alpha-Tocopherol) in Foods by Liquid Chromatography: Collaborative Study. J AOAC Int 2019. [DOI: 10.1093/jaoac/85.2.424] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
A collaborative study was conducted for the determination of vitamins A and E. Existing AOAC liquid chromatographic (LC) methods are suited for specific vitamins A and E analytical applications. This method differs from existing methods in that it can be used to assay samples in all 9 sectors of the food matrix. Standards and test samples are saponified in basic ethanol–water solution, neutralized, and diluted, converting fats to fatty acids and retinol esters and tocopherol esters to retinol and tocopherol, respectively. Retinol and alpha-tocopherol are quantitated on separate LC systems, using UV detection at 313 or 328 nm for retinol, and fluorescence detection (excitation 290 nm, emission 330 nm) for alpha-tocopherol. Vitamin concentrations are calculated by comparison of the peak heights or peak areas of vitamins in test samples with those of standards.
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