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Biomedical subjects

A F Gross

Publications and source records attributed to A F Gross.

5 recordsLinked to original sources

Food.

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Acids↗

Food.

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Food Analysis↗

Automated method for the determination of niacin and niacinamide in cereal products: collaborative study.

In a collaborative study, an automated method for the determination of niacin and niacinamide in cereal products was compared with the official final action microbiological (43.121-43.125) and chemical (43.044-43.046) methods. Ten samples of cereal products, including enriched flour, yeast-leavened baked products, fortified breakfast cereals, and baked pet food products, were submitted to 14 laboratories. Nine laboratories reported values by the automated method, 6 reported values by the microbiological method, and 7 reported values by the chemical method. The results from the microbiological method were not subjected to analysis of variance because of the unusually large between-laboratory variation. The between-laboratory coefficients of variation for the automated and chemical methods were 10.90 and 10.18%, on the basis of results from 7 and 4 laboratories, respectively. There was no significant (p greater than 0.05) difference between methods when results from the 4 laboratories who used both methods were compared. The automated chemical method has been adopted as official first action.

Autoanalysis↗

Determination of cis, cis-methylene interrupted polyunsaturated fatty acids in fats and oils by capillary gas chromatography.

A capillary gas chromatographic (CGC) method is described for the determination of cis,cis-methylene interrupted polyunsaturated fatty acids (cis-PUFA) in fats and oils. The sample is saponified and the liberated fatty acids are esterified to the corresponding methyl esters. The latter are analyzed by CGC using a 60 M. SP2340 capillary column. Area percent values for 9,12-cis,cis-C18:2 and 9,12,15-cis,cis,cis-C18:3 fatty acid methyl esters are summed to give the total cis-PUFA content. Gas chromatographic results agreed well with those obtained by an enzymatic lipoxygenase method at the 31-48% cis-PUFA levels with a correlation coefficient of 0.98. The method has a precision (relative standard deviation) of 0.33% at a 44.4% cis-PUFA level in margarine oil.

Chromatography, Gas↗