4-Hydroxy-2-Trans-Nonenal (HNE), a toxic degradation product of lipid oxidation, in fried chicken and donut

Abstract

Alpha, beta-unsaturated-4-hydroxyaldehydes, a group of secondary lipid oxidation products, are highly interesting due to their high reactivity to various biological compounds including amino acids and DNA. 4-Hydroxy-2-trans-Nonenal (HNE), one of the most abundant and toxic compound in this group, was measured in commercial fried chicken breasts, chicken thighs, chicken nuggets and raised glazed donuts from different fast food stores and supermarkets. Samples were analyzed for fat content, fatty acids distribution and HNE concentration. Fried chickens and donuts were selected because they are very common fast food and they are deep-frying at high temperatures (160-190 °C). Preliminary experiments were conducted using the thiobarbituric acid (TBARS) assay to obtain the secondary lipid oxidation products such as aldehydes, ketones and related carbonyl compounds. HNE concentration was measured as 2,4-dinitrophenylhydrazone derivatives using an HPLC method. HNE concentrations in fried chickens from 3 different sources are between 10.02 and 11.89 µg HNE/100 g breast and between 19.80 and 24.41 µg HNE/100 g thigh. For chicken nuggets and popcorn chicken, HNE concentrations are between 9.00 and 47.93 µg HNE/100 g samples. For donut samples from 3 different brands, HNE concentrations were between 18.55 and 21.71 µg HNE/100 g donut. Measured HNE amount in chicken thighs samples is greater than chicken breasts samples, suggesting the heme iron content existed in dark meat possibly act as a catalyst to accelerate the lipid oxidation in the meat. These results indicated that HNE is incorporated into the fried chickens and glazed donuts samples from frying oils and might pose a public health concern for long-term consumption given the toxicity of HNE.