Effects of skin and grilling method on formation of heterocyclic amines in chicken pectoralis superficialis muscle

Mutagenic heterocyclic amines (HAs) originate in processed proteinaceous foods. The effects of the presence of skin (with vs. without) and of grilling method (two plate vs. infrared) on the content of HAs in grilled chicken pectoralis superficialis muscle (temperature, 220 °C) were investigated. HA precursors (creatine, creatinine, free amino acids and carbohydrates) and HAs of these raw and grilled breast muscles were determined. The muscles originated from 24 birds of either sex (provenance Ross; aged 40–45 days). The HA content was determined in homogenates of the upper and lower surface slices of the grilled muscles (Ti = 82 °C). A higher content of total free amino acids was seen for the muscle (27.1 mmol kg−1 raw meat) than for the skin (21.7 mmol kg−1 raw meat). The creatine, creatinine and carbohydrate levels in the skin were below the limits of detection. The contents of creatine (31.8–38.7 mmol kg−1) and creatinine (0.24–0.33 mmol kg−1) in the breast muscle were determined. Relatively high levels were seen for glucose (23 mmol kg−1 raw meat) and fructose (10 mmol kg−1 raw meat) in the muscle, with other sugars present at low levels (<2 mmol kg−1 raw meat). For the chicken muscle grilled on a two-plate grill, the contents of total HAs (PhIP, MeIQx, DiMeIQx, Harman and Norharman) were lower with the skin in place than in the muscle grilled without the skin (3.5 μg kg−1vs. 4.8 μg kg−1). Also, during infrared grilling with the skin, lower amounts of HAs were formed than with grilling on the two-plate grill (2.4 μg kg−1vs. 3.5 μg kg−1). On average, the infrared-grilled samples with skin contained 3-fold more total HAs than similar samples without the skin (2.4 μg kg−1vs. 0.8 μg kg−1), with the highest levels seen for PhIP and MeIQx.