17D-9 |
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J. AHN1, I. U. Gruen2, and L. N. Fernando2. (1) Department of Food Science, University of Missouri, 256 Eckles Hall-Stringer Wing, Columbia, MO 65211, (2) Dept. of Food Science, Univ. of Missouri- Columbia, 256 Eckles Hall - Stringer Wing, Columbia, MO 65211 Heterocyclic amines (HAs) are categorized as typical carcinogens/mutagens found in cooked foods. Understanding the mechanism of HA formation is essential for preventing their formation and reducing the health risks from the consumption of cooked meats. The objective of this study was to elucidate the effects of time, temperature, and precursors on the formation of HAs in cooked ground beef. Freshly ground beef was heated at four different temperatures (153, 175, 194, 210°C) for four different time intervals (5, 10, 15, 20 min). HAs were extracted and purified using solid-phase extraction and quantified using reverse-phase HPLC equipped with UV/visible and scanning fluorescence detectors. Selected HAs standards, namely IQ, MeIQ, MeIQx, 4,8-DiMeIQx, norharman, harman, PhIP, and AaC, were used to establish standard curves. Creatine and glucose were measured using the a-naphthol-diacetyl method and the phenol-sulfuric acid method, respectively. The temperature dependency of HAs formation was predicted using the Arrhenius and Eyring equations. The highest amount of MeIQx formation of 23.93 ng/g was found after heating for 20 min at 210°C. No formation of 4,8-DiMeIQx was observed at 153, 175, 194, and 210°C for 5min. Formation of norharman and 4,8-DiMeIQx was more sensitive to temperature change, while formation of MeIQx and AaC was less so. In general, formation of HAs increased with increasing time and temperature. Glucose and creatine decreased in the same pattern that HAs increased. Temperature-sensitive HAs were formed to a greater extent at higher temperatures and longer heating times. MeIQx, a less temperature-sensitive HA, had the lowest activation energy (8.80 kJ/mol) and was extensively formed at all temperatures. The formation of HAs followed a bimolecular mechanism with one reactant concentration in large excess. The results provide practical information to predict the relationship between the formation of heterocyclic amines and the reduction of creatine and glucose as time and temperature change.
Session 17D, Food Chemistry: Chemical effects of food processing and preservation
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