Reduction of the polycyclic aromatic hydrocarbon (PAH) content of charcoal smoke during grilling by charcoal preparation using high carbonisation and a preheating step

摘要

Charcoal-grilling may lead to contamination of food with carcinogenic polycyctic aromatic hydrocarbons (PAHs) during the grilling process. The objective of this work was to determine the effect of charcoal preparation on 16 USEPA priority PAHs in the smoke produced during the grilling process. Firstly, mangrove charcoal was prepared at carbonisation temperatures of 500, 750 and 1000℃. The charcoal were then preheated by burning at 650℃. This preheating step is usually used to prepare hot charcoal for the grilling process in the food industry. In this study, charcoal was preheated at different burning times at 5,20 min and 5 h, at which time partial and whole charcoal glowed, and charcoal was completely burnt, respectively. Finally, PAHs in the smoke were collected and determined by GC/MS. The result showed that charcoal prepared at a carbonisation temperature of 500℃ had higher levels of PAHs released into the smoke. In contrast, charcoal produced at 750 and 1000℃ had lower PAHs released for all burning times. In addition, PAHs released for 5, 20 min and 5 h of burning time were about 19.9, 1.2 and 0.7 μg g~(-1) dry charcoal for charcoal produced at 500℃, and about 0.9-1.4, 0.8-1.2 and 0.15-0.3 μg g~(-1) dry charcoal for charcoal produced at 750 and 1000℃, respectively. Therefore, this research suggests that food grilled using charcoal carbonised at a high temperature of about 750° C presents a lower risk of PAH contamination. In addition, in the preheating step, whole charcoal should fully glow in order to reduce the PAH content in charcoal before grilling.