A method is described for the determination of N-nitrosoproline (NOPRO) in cured meat products. NOPRO was extracted with ethyl acetate from a slurry of cured meat and water after the addition of ammonium sulfamate and acid. This nitrosamino acid was converted to the methyl ester and after further purification, it was quantitated and confirmed by gas liquid chromatography and mass spectroscopy. Recoveries of 10 μg from spiked samples averaged about 70%. A capillary column was used to confirm the presence of low levels of MeNOPRO in the extracts. An oscilloscope, utilizing horizontal sweep magnification of the mass spectrometer output, was used to detect the elution of MeNOPRO from the column by monitoring the m/e 30 ion. The presence of 5 nanograms per injection of concentrated cured meat extract could be confirmed. NOPRO was detected in several commercial meat products. Five of six bacon samples analyzed were found to contain NOPRO at levels ranging from 13-46 ppb. A precooked ham slice and a sample of breakfast beef contained 22 and 62 ppb NOPRO, respectively. NOPRO was not detected in a sample of canned chopped ham nor a wiener sample. The detection of NOPRO, a non-volatile nitrosamine, in cured meats suggests that the formation of other non-volatile nitrosamines is possible. To date, only volatile nitrosamines have been analyzed and confirmed by mass spectrometry. The ubiquity of proline and the finding of NOPRO in several different cured meat products suggest that NOPRO could be an indicator of nitrosation in foods. Bacon cured in brines containing 800 and 1600 ppm nitrite contained about 50 and 100 ppm residual nitrite, respectively. Bacons receiving the lower nitrite level contained no NOPRO while the higher nitrite treated bacons contained over 100 ppb NOPRO. Frying of bacon was found to destroy 86 to 100% of NOPRO in the five samples analyzed. NOPRO has been reported to break down during heating to nitrosopyrrolidine (NOPYR). However, the levels of NOPRO determined in raw bacon were not sufficient to produce the amounts of NOPYR reported in fried bacon if the rate of conversion was similar to that previously reported in model studies. / Graduation date: 1974

Thirteen specified water soluble dyes are permitted for use in edible products consumed in Canada and the United States. The official chemical-physical method of analysis is not very successful when small amounts of one dye are present with larger amounts of others, or even in the analysis of a single dye if present in small quantities. The spectrophotometer has been shown to be very useful in identifying the thirteen permitted dyes individually, and by its means many previously unresolvable binary mixtures have been readily analyzed. Further investigation of the possibilities of this method of analysis is proceeding. / Science, Faculty of / Chemistry, Department of / Graduate

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Beer, nonfat dry milk, fried bacon and microwave baked fish were treated under simulated gastric and extreme nitrosation conditions to estimate their capacity for generation of endogenously formed N-nitrosamines. The level of nitrosamines in beer increased from 0.1 ppb N-nitrosodimethylamine to 0.4 ppb N-nitrosodimethylamine (p < 0.05) under simulated gastric nitrosation. The levels in the other food products were not increased under the same simulated gastric conditions (p < 0.05). Extreme nitrosation illustrated that food has a large nitrosatable amine content. Beer produced elevated levels of N-nitrosodimethylamine, N-nitrosodiethylamine, N-nitrosopyrrolidine and N-nitrosomorpholine. Nonfat dry milk produced elevated levels of N-nitrosodimethylamine, N-nitrosopiperidine, N-nitrosopyrrolidine and N-nitrosomorpholine. Fish produced elevated levels of N-nitrosodimethylamine and N-nitrosopyrrolidine. Overall, certain food products provide exposure to ample amounts of nitrosatable amines, but it appears that these food products do not produce a significantly increased risk from endogenous N-nitrosamine exposure. / Graduation date: 1987

A high performance liquid chromatography (HPLC) procedure using a LiChrosorb-NH₂ column and a eluant buffer of 75:25 (v/v) of acetonitrile:0.05 M KH₂P0₄, pH 5.95, was developed for the successful separation and determination of ascorbic and erythorbic acids in selected food samples. Application of the method, which is sensitive, rapid and simple, for the analysis of ascorbic and erythorbic acids in frozen apples, potato products, fruit and vegetable concentrated juices, frozen juices, natural and artificial flavor drink mixes, and Hi-C drinks gave satisfactory results. Dehydroascorbic and dehydroerythorbic acids in these samples could also be determined after reduction with dithiothreitol. It was verified by HPLC that the presence of erythorbic acid affected the determination of ascorbic acid levels by the spectrophotometric method by causing elevated absorbance readings and hence, abnormally high values. Erythorbic acid seriously affects the true determination of ascorbic acid contents in food samples by the spectrophotometric method. The use of HPLC is recommended for the routine analysis of ascorbic acid of those samples containing both ascorbic and erythorbic acids. / Graduation date: 1986

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published_or_final_version / Chemistry / Master / Master of Philosophy