Mutagenic activity of heated potato/oil systems

In vitro genotoxicity assessment of French fries from mass catering companies: a preliminary study

It is generally assumed that French fries are likely to have weak in vitro mutagenic activity, but most studies thereof have only assessed gene mutations. In this article, the genotoxicity of 10 extracts of French fries was assessed using the in vitro micronucleus test (following the principles of the OECD 487 guidelines). Each sample was obtained from a different mass catering company in Navarra (Spain). This assay, together with the Ames test, is recommended in the basic in vitro phase included in the European Food Safety Authority Opinion on Genotoxicity Testing Strategies Applicable to Food and Feed Safety Assessment. Eight of 10 samples from mass catering companies induced chromosomal aberrations in the in vitro micronucleus test. Moreover, French fries deep-fried in the laboratory for different periods of time (0, 3, 5, 10, 20, 30 min) were assessed using the in vitro micronucleus test. Genotoxicity was observed in all time periods from 3 min on. The biological relevance of these results must be further explored.

Differences in the frequency of micronucleated erythrocytes in humans in relation to consumption of fried carbohydrate-rich food

The aim of this study was to investigate if consumption of ordinary carbohydrate-rich food prepared in different ways has an impact on chromosome stability, i.e., on the formation of micronucleated young erythrocytes in humans. Twenty-four persons, divided into two groups, participated during 4 days in a semi-controlled food-consumption study. One group (low-heated-food-group, LowHF-group) consumed only food boiled in water (max 100 degrees C) and the other group (high-heated-food-group, HighHF-group) consumed preferentially strongly heated (fried) food. From each of the subjects, blood samples were drawn, before and after 4 days. The frequency (f) of micronucleated (MN) very young erythrocytes (transferrin-positive reticulocytes, Trf-Ret), fMNTrf-Ret, was determined, and the difference in the frequency, before and after the eating period, was calculated. The obtained mean differences for the two groups were compared. As an indicator of highly heated food the acrylamide (AA) content in part of the consumed foodstuffs was analysed by use of LC/MS-MS and the AA intake estimated. In the blood samples the hemoglobin-adduct levels from AA were analysed as a measure of the internal AA dose. The differences between the mean fMNTrf-Ret, before and after the eating period, were -0.15 per thousand for the LowHF-group and +0.17 per thousand for the HighHF-group, p<0.005 (t-test, one-tailed). The mean total AA intake in the HighHF-group during 4 days was estimated to about 3000+/-450microg per person. For the LowHF-group, the mean AA intake was low, 20+/-10microg per person. The lowest dose of AA that caused a significant increase of micronucleated erythrocytes in mice is more than a hundred times higher than the AA level in this study. Thus, it is unlikely that the exposure to AA is the major cause behind the observed difference. The answer is probably to be found in other compounds produced at the same time during heating of the food.

Food processing and lipid oxidation

Food lipids are principally triacylglycerides, phospholipids and sterols found naturally in most biological materials consumed as food and added as functional ingredients in many processed foods. As nutrients, lipids, especially triglycerides, are a concentrated caloric source, provide essential fatty acids and are a solvent and absorption vehicle for fat-soluble vitamins and other nutrients. The presence of fat significantly enhances the organoleptic perception of foods, which partly explains the strong preference and market advantage of fat-rich foods. As a class, lipids contribute many desirable qualities to foods, including attributes of texture, structure, mouthfeel, flavor and color. However, lipids are also one of the most chemically unstable food components and will readily undergo free-radical chain reactions that not only deteriorate the lipids but also: (a) produce oxidative fragments, some of which are volatile and are perceived as the off-flavors of rancidity, (b) degrade proteins, vitamins and pigments and (c) cross-link lipids and other macromolecules into non-nutritive polymers. Free-radical chain reactions are thermodynamically favorable, and as a result, evolutionary selection has strongly influenced the chemistry, metabolism and structure of biological cells to prevent these reactions kinetically. However, the loss of native structure and the death of cells can dramatically accelerate the deteriorative reactions of lipid oxidation. The effects of all processing steps, including raw product selection, harvesting, storage, refining, manufacturing and distribution, on the quality of lipids in the final commodity are considerable. Certain key variables now known to influence oxidative processes can be targeted to increase food lipid stability during and after processing. Retention of or addition of exogenous antioxidants is a well-known consideration, but the presence and activity of catalysts, the integrity of tissues and cells, the quantity of polyunsaturated lipids and the structural properties of the final food product, including total surface area of lipids, and the nature of surfactant materials all play important roles in final product stability.

The formation and occurrence of amino acid pyrolysates and related mutagens in cooked foods

The classes of cooked foods that contain detectable levels of mutagenic activity are discussed together with the effects of different cooking procedures on the extent of mutagen formation. Analytical procedures that have so far been devised to quantify the concentrations of specific mutagenic compounds are described and the levels of these species that have been detected in cooked foods are detailed.