The toxicology of antioxidants has become one of the more controversial areas in the continuing debate on the safety of food additives. In recent years, problems have arisen with the antioxidants butylated hydroxyanisole (BHA) & butylated hydroxytoluene (BHT) when new long-term studies showed that these compounds could produce tumours in animals. Chemicals which have been shown to cause cancer in long-term animal studies are normally not permitted as food additives, & regulatory authorities would have little hesitation in making such a decision in the case of any new chemical submitted to them for approval which appeared to be a genotoxic carcinogen. However, with BHA & BHT, not only did the new findings conflict with the results of earlier, negative, long-term studies, but also their significance for hazard assessment in man was surrounded by even more uncertainties than those which toxicologists are used to considering when extrapolating from animal experiments to man.

Toxicological Aspects of Antioxidants Used as Food Additives

Antioxidants are components which prevent auto-oxidation of oils and fats by giving their hydrogen to free radicals formed in the initiation and propagation stages of autoxidation. During the past two decades, a lot of researches using natural plants extract in edible oils have been carried out due to the trend to minimize or avoid the use of synthetic food additives. According to the most studies, there are various natural antioxidants which can be extracted from low cost resources, such as most parts of olive plant, green tea, sesame, medicinal plants, etc. One of the most important requirements for a suitable antioxidant in oils and fats is the thermal stability during heat processing. It has been shown that most of natural additives have more antioxidants activity and thermal stability than synthetic ones in different edible oils. In this review, recent advances in the application of natural antioxidants in the food industry will be covered.

Application and stability of natural antioxidants in edible oils in order to substitute synthetic additives

1,4-Dioxane is classified as a probable human carcinogen. It is used as a stabilizer for chlorinated solvents, particularly, 1,1,1-trichloroethane (TCA), and it is formed as a by-product during the manufacture of polyester and various polyethoxylated compounds. Improper disposal of industrial waste and accidental solvent spills have resulted in the contamination of groundwater with 1,4-dioxane. Volatilization and sorption are not significant attenuation mechanisms due to 1,4-dioxane's complete miscibility with water. At present, advanced oxidation processes (AOPs) are the only proven technology for 1,4-dioxane treatment. 1,4-Dioxane was believed to be very resistant to both abiotic and biologically mediated degradation due to its heterocyclic structure with two ether linkages. However, recent studies have shown that 1,4-dioxane can be biodegraded as a sole carbon and energy source, and that cost-effective biological treatment processes can be developed. Future work should be oriented towards the developme...

Occurrence and Treatment of 1,4-Dioxane in Aqueous Environments

Antioxidative activities of Olea europaea leaves and related phenolic compounds

Sulphites in various forms have been added to foods for centuries. Their use became an issue of concern when certain sensitive individuals exhibited adverse reactions to sulphite residues in foods. Analytical methods were developed to monitor these compounds at the regulatory limit of 10 ppm. In this report, analytical methods for determining sulphites in foods are reviewed, along with a critique of their chemistry and procedural schemes. An assessment of the key features of each method category is presented together with some comparative data. The classification scheme used is based upon the fact that determination of the sulphite content of a food is influenced more by the treatment and cleanup of the test solution than by the final determinative step. Based on a 60-year database, the Monier-Williams procedure still remains the method of choice.

A review of sulphites in foods: Analytical methodology and reported findings

Recently, semicarbazide has been found in food in jars sealed with cap liners that were manufactured using azodicarbonamide as a blowing agent. These reports raised the concern that the use of azodicarbonamide-an approved dough conditioner-may result in semicarbazide residues in bread. To answer this question, a method based upon the previously reported liquid chromatography/tandem mass spectrometry determination of the semicarbazone of o-nitrobenzaldehyde was utilized. The method adopted for this work includes an extensive cleanup and reaction with o-nitrobenzaldehyde at pH 3.5, rather than with the widely used 0.1 M HCl, to form the semicarbazone derivative. A stable isotope dilution assay was used to determine the free semicarbazide present in the bread products. Levels of semicarbazide ranged from 10 to 1200 ppb in commercial bread products with azodicarbonamide listed among their ingredients.

The determination of semicarbazide (N-aminourea) in commercial bread products by liquid chromatography-mass spectrometry.

Fate of antioxidants and antioxidant-derived products in deep-fat frying and cookie baking.

Reactions of antioxidants in foods

Quantitative Determination of Isosorbide Dinitrate and Two Metabolites in Plasma

The objective of this work was to develop a reliable, rugged high-performance liquid chromatographic (HPLC) method for determination of trace levels of bromate (< 10 micrograms/l) in bottled water. HPLC separation was achieved by ion interaction chromatography using a C-18 reversed-phase column and a mobile phase consisting of methanol/water (20:80, v/v) with tetrabutylammonium acetate as the ion interaction reagent. A post-column reaction based on oxidation of o-dianisidine in acidic solution to a product detected at 500 nm provided selective measurement of the oxidants. The limit of detection and the limit of quantitation were 1 and 3 micrograms/l, respectively. Iodate, chlorite, and nitrite were chromatographically separated from bromate and measured by monitoring the post-column reaction. Chloride and chlorate at levels that might be found in bottled water did not interfere with the determination of bromate. Bromate was detected in bottled waters at concentrations up to 40 micrograms/l.

Charles R Warner

Papers

The determination of semicarbazide (N-aminourea) in commercial bread products by liquid chromatography-mass spectrometry.

Fate of antioxidants and antioxidant-derived products in deep-fat frying and cookie baking.

Reactions of antioxidants in foods

Quantitative Determination of Isosorbide Dinitrate and Two Metabolites in Plasma

Measurement of bromate in bottled water by high‐performance liquid chromatography with post‐column flow reactor detection