Reaction Of Sorbic Acid Research Articles

Solvent effects in the decomposition reaction of some products formed by the reaction of sorbic acid with sodium nitrite: 1,4‐dinitro‐2‐methylpyrrole and ethylnitrolic acid

AbstractA kinetic study of the decomposition reaction of 1,4‐dinitro‐2‐methylpyrrole (NMP) and ethylnitrolic acid (ENA), both formed in the reaction between sorbic acid and sodium nitrite was performed in the 3.5–4.2 pH range in water/dioxane mixtures. Conclusions were drawn as follows: (i) The decomposition of NMP occurs through nucleophilic attack by OH− ions, the rate equation being: r = kdecNMP [OH− ][NMP]. (ii) The rate law for the decomposition of ENA is: r = $k_{dec}^{ENA}$ [ENA]Ka/(Ka + [H+]), Ka being the ENA dissociation constant. (iii) The value of Ka decreases when the water/dioxane ratio decreases, log Ka being proportional to the Onsager parameter (ϵ − 1)/(2ϵ + 1). This permits the equilibrium between non‐dissociated and the dissociated forms of ENA to be rationalized. (iv) No appreciable variation in the ΔH# and ΔS# values with composition of the medium was observed, either in the NMP decomposition reaction, or in the ENA decomposition reaction. Copyright © 2008 John Wiley & Sons, Ltd.

Reactivity of Some Products Formed by the Reaction of Sorbic Acid with Sodium Nitrite: Decomposition of 1,4-Dinitro-2-methylpyrrole and Ethylnitrolic Acid

Sorbic acid reacts with nitrite to yield mutagenic products such as 1,4-dinitro-2-methylpyrrole (NMP) and ethylnitrolic acid (ENA). In order to know the stability of these compounds, a kinetic study of their decomposition reactions was performed in the 6.0-9.5 pH range. The conclusions drawn are as follows: (i) The decomposition of NMP occurs through a nucleophilic attack by OH- ions, with the rate equation as follows: r = k(dec)NMP[OH-][NMP] with k(dec)NMP (37.5 degrees C) = 42 +/- 1 M(-1) s(-1). (ii) The rate law for the decomposition of ENA is as follows: r = k(dec)ENA[ENA]K(a)/(K(a) + [H+]), with K(a) being the ENA dissociation constant and k(dec)ENA (37.5 degrees C) = (7.11 +/- 0.04) x 10(-5) s(-1). (iii) The activation energies for NMP and ENA decomposition reactions are, respectively, E(a) = 94 +/- 3 and 94 +/- 1 kJ mol(-1). (iv) The observed values for the decomposition rate constants of NMP and ENA in the pH range of the stomach lining cells, into which these species can diffuse, are so slow that they could be the slow determining step of the alkylation mechanisms by some of the products resulting from NMP and ENA decomposition. Thus, the current kinetic results are consistent with the low mutagenicity of these species.

Catalysis of the sorbic acid-thiol reaction by bovine serum albumin

Summary The effect of bovine serum albumin (BSA, 0–4%, w/v) in increasing the rate of reaction of sorbic acid with mercaptoethanol, mercaptoacetic acid, cysteine and glutathione (pH 5.0, 40°C) is comparable to that of the nonionic surfactant, Tween 80. For cysteine and glutathione, BSA has a similar effect to that of the cationic surfactant dodecyltrimethylammonium bromide, but is less effective for mercaptoethanol and mercaptoacetic acid. These preliminary observations are interpreted in terms of interactions between the reactants and nonionic environments on the BSA molecule.

Reaction of sorbic acid in wheat flour doughs: reaction with thiols.

The general characteristics of the reaction between sorbic acid and thiols are reviewed. Cysteine adds to the conjugated diene in position 5 to form the substituted 3-hexenoic acid. This is labile in acid solution, yielding a quantitative amount of sorbic acid. When wheat flour doughs are treated with sorbic acid and heated, a significant amount of the sorbic acid is not recovered on extraction with methanol. The use of acidified methanol leads to a quantitative recovery of the preservation and evidence is presented to suggest that sorbic acid-thiol adducts are formed. This is the first report of 'reversibly bound' sorbic acid in a food.

Reaction of sorbic acid with nucleophiles: Preliminary studies

Mercaptoethanol and cysteine were found to react slowly with sorbic acid when heated over several days at 80°C, pH 3·7–7·8. At pH 3·7, both reactions were of overall second order (k 2 = 0·48 and 0·65 m −1h −1, respectively) and it is suggested that cysteine behaves as a sulphur-nucleophile. The reaction of cysteine with sorbic acid is shown to proceed with 1:1 stoichiometry. A product isolated from the reaction involving mercaptoethanol gives rise to mass spectroscopic data consistent with nucleophilic attack at position 5 of sorbic acid to give also, the 1:1 adduct. The effect of pH on rate of reaction is small. Amines ( n-butylamine, t-butylamine and glycine) were found to be unreactive under the same conditions.

Desmutagenic action of food components on mutagens formed by the sorbic acid/nitrite reaction.

The desmutagenic activity of various food components on C-nitro mutagens formed by the nitrite/sorbic acid reaction was assayed and several vegetable juices were found to be effective for eliminating the mutagenicity of the nitrite/sorbic acid system. Especially, the desmutagenic activity of pumpkin juice was investigated, and ascorbic acid, cysteine and other reducing compounds were found to be responsible for desmutagenic actions on 1, 4-dinitro-2-methyl pyrrole, the main mutagen formed by the reaction of sorbic acid with sodium nitrite, by reduction of the conjugated C-nitro group to a C-amino group.

A new furoxan derivative and its precursors formed by the reaction of sorbic acid with sodium nitrite

A new furoxan derivative ( 3 ) and its precursors ( 4a and 4b ) were isolated from the reaction mixture of sorbic acid with sodium nitrite, and their structures were determined by spectroscopic and X-ray crystallographic analysis.

A new n-nitropyrrole : 1,4-Dinitro-2-methylpyrrole, formed by the reaction of sorbic acid with sodium nitrite

A new N-nitropyrrole, 1,4-dinitro-2-methylpyrrole, has been isolated and identified as one of the active products of the acidic reaction mixture of sorbic acid and sodium nitrite in the rec-assay and growth inhibition tests on bacteria. The various spectral data that led to the proposed structure, and some of its chemical properties are described.

Formation of ethylnitrolic acid by the reaction of sorbic acid with sodium nitrite.

Formation of ethylnitrolic acid by the reaction of sorbic acid with sodium nitrite.