[Effect of various blockers of nitrite and nitrogen oxide on the formation of nitrosamines]. / Influence de quelques bloquants du nitrite et de l'oxyde azotique sur la production de nitrosamines.

The effects of galacturonic, gallic, acetylneuraminic acid, ascorbate, cysteine, glutathion and imidazole on the formation of dimethylnitrosamine and diethylnitrosamine was studied in a simple aqueous medium with four different nitrite contents (50, 100, 500 and 1 000 ppm) and the two amines, compared with control samples. The nitrosamines were determined by the TELLING method (confirmed by photolysis). The results observed were compared with the laws of fixing nitrite in the form of nitrogen oxide, studied previously. For sarcosin and imidazole, the fixing takes into account the phenomena observed. The other substances lead to a conclusion that there are two stages in the process: 1) fixing of the nitrite to a greater or lesser degree in the form of a nitrogen oxide complex, 2) direct effect on the nitrosation reaction which is catalysed or slowed down. The discussion based on the literature, concludes that the final nitrosation reaction give rise to free radicals, even in an aqueous medium.

[Determination of nitrates and nitrites in animal products]. / Dosage des nitrates et des nitrites dans les produits animaux.

Meat is a complex medium in which nitrates and nitrites react by processes which are not well known. We do not know how to determine the quantities added, and estimating the residual doses depends on the analytic techniques studied. The analysis begins with extractions and purifications by various techniques described. A brief description is then given of 13 techniques for determining nitrites, 5 of which were applied successfully to meat products, and 18 techniques for determining nitrates, 12 of them suitable for meats. The references are given. The authors conclude by stressing the need for better knowledge of the effect of extraction and preparation techniques in order to give meaning to the results obtained.

[Preservation of vitamin B1 and B2 during the preparation of pork meat]. / Devenir des vitamines B1 et B2 dans la fabrication des charcuteries.

Thiamin and riboflavin seem to resist fairly well to the proceedings of meat products studied here (cooked hams, patties, dry sausages). This result is normal enough to riboflavin, it is less for thiamin which sensitive to nitrite and to heating is well established by the literature. The origin of these observed phenomenons of protection is probably due to the complexation of these vitamins by the meat proteins. A similar phenomenon has been seen before by several authors on milk proteins, eggs and specially sulfhydril groups. This complexation is confirmed by the important release of both vitamins we noted during processing. They are determined much more easily on processed meat products than on raw materials. The nutritional repercussion of the observed phenomenon is difficult to estimate accurately. The vitamins release we find out, make them more available for the organism but it would be compared to the enzymatic decomplexation which occurs in vivo, during digestion, that we did not studied. Nevertheless such an approach would be necessary for the estimation of the practical value of the analytical determinations generally used.

[Structure of nitroso pigments in meats]. / Structures des pigments nitroso des viandes.

The study is concerned with the nitrosopigments formed during curing time. It concludes that a reductant nitrosohaem is formed, with a breakdown of the bond between haem and histidine, and it gives the accurate sequence of the reactions. This study has been conducted by measurement of the iron-dried material ratio, electrophoresis on acetonic extracts of pigments formed with ascorbate or cystein, measurement, during the photodecomposition of this extract, of photometric spectra, of ionised iron, and characterization of pyrroles functions.

[State of nitrite in meat products]. / Etudes sur l'état du nitrite dans les produits de viandes.

The authors search the form under which nitrite is in cured products. Nitrate formation found by official methods is not confirmed by qualitative characterization. The calculations, according to the chemical equations, show the total breakdown of nitrite in nitroge oxide: NO, bound by many substances which are in meats. The distillation experiments confirm the calculations, the characteristic photometric spectra get in sulfitic medium and the modified Zambelli's reaction. These results lead to estimate that both technologic and toxicologic actions impute to nitrite is dominated by the idea of NO more or less bound, according to the medium composition.