4-Hydroxynonenal (HNE), a Toxic Aldehyde in Fried Chicken from Fast Food Restaurants and a Grocery Store

Abstract

The lipid oxidation product, the toxic 4-hydroxynonenal, was measured for fried chicken in commercial samples from two fast food restaurants and one commercial establishment. The fried chicken samples were breasts, thighs, chicken nuggets and popcorn chicken. Fried chicken samples were separated to breast skin and meat, and thigh skin and meat. Chicken nuggets and popcorn chicken were not separated from the coating materials and the meat was analyzed together. Samples were analyzed for total fat, fatty acid distribution, reactivity with thiobarbituric acid (TBAR), measuring the secondary lipid peroxidation products such as aldehydes, ketones and related carbonyl compounds. Samples were analyzed for HNE, a toxic aldehyde using high performance liquid chromatography (HPLC). Fatty acid distribution showed in breast and thigh meats, a higher level of palmitic acid, compared to the breast and thigh skins. TBAR values were significantly higher in all breast meats compared to skins. TBAR values were significantly higher in thigh meat than in skin samples. HNE concentrations (µg HNE/g fat) were significantly very low in breast skins compared to breast meat. HNE concentration was generally higher in thigh meat than skin but not in every sample. In chicken nuggets, both the TBAR value and HNE concentration were much higher from one establishment than from the two others. Chicken nuggets TBAR and HNE concentrations resembled one of the chicken nugget samples. The average toxic HNE concentration for 100 g fried chicken breast (skins + meat) was 12.55 µg and for thighs (skin + meat) was 26.76 µg. The average total HNE concentration was 2.1 times higher in the fried chicken thighs than in the breasts. It is clear that HNE is produced during the heating process of oils and incorporated into the fried meat and skin samples during the frying process. If HNE, a toxic aldehyde, is consumed with the food, over long periods of time it could be related to a number of pathological conditions.