Modifying Cooking Practices to Reduce the Formation of Heterocyclic Amines

Abstract: Commonly cooked meat dishes contain heterocyclic amines (HAs) at ng/g levels. HAs are animal carcinogens, form DNA adducts in human tissues, and have been associated with increased risk of cancer in epidemiological studies, and it is thus recommended that human intake be decreased. The aim of this investigation was to find ways of modifying cooking practices to reduce the formation of HAs. Various factors that influence the formation of HAs during cooking of chicken breasts and beefburgers were investigated. The factors studied included cooking method, time, temperature, heat transfer, weight loss during cooking, the chemical composition of beefburgers and antioxidants. The conditions for the cooking experiments were similar to those employed in normal domestic, restaurant and industrial cooking. The analysis of HAs was focused on MeIQx, 4,8-DiMeIQx, PhIP, Harman and Norharman, as these compounds are considered to be the most abundant HAs in cooked meat. The concentrations ranged from undetectable amounts to 30 ng/g. Cooking temperature was shown to be an important factor, especially during frying, since large concentrations of HAs can be formed at high temperatures. Avoiding over-cooking of meat seems to be another important way to decrease the content of HAs. Reducing the weight loss during cooking may be a means of decreasing the formation of HAs, and this correlation is probably due to the transport of water-soluble precursors to the meat surface. This transport can be lowered by the addition of water-holding ingredients, such as common salt or potato starch. Addition of carbohydrates may also affect the formation of HAs chemically. Frying in oil containing antioxidants may also provide a way of reducing the amount of HAs formed, although the amounts of antioxidants and the effect of storage must be taken into consideration. A kinetic model was used to describe the formation of HAs and this can be further developed to predict the formation of HAs. The results from this research can be used to design cooking equipment and processes and to form a basis for guidelines to consumers, restaurants and industry, on how to obtain a product with good sensoric properties and minimised contents of HAs. Such recommendations may decrease the human intake of HAs. The data on HAs in ordinary cooked meat can be compiled into a database for intake estimates, epidemiological studies and for future risk assessment.