Abstract
Experimental studies were performed on the formation of carcinogenic 3, 4-Benzpyrene in meat treated under pyrolytic conditions.
(1) As the temperature to which meat is subjected in usual cooking is 300°C to 500°C, the experimental pyrolysis of meat was made at 300°C and 500°C in both aerobic and a nitrogen atmosphere and at 700°C in a nitrogen atmosphere.
(2) Chemical analysis was performed in the following manner on the tarry material obtained from the scorches of meat and the smoke generated, respectively. One kilogram of minced meat was first dried at 110°C for 3 hours, and pyrolysed at the specific temperature. The smoke generated was absorbed in a series of bottles containing aceton or benzene. The solvent was evaporated off under reduced pressure in a nitrogen atmosphere to get a tarry material. The scorches were seperated and extracted with aceton in a Soxhlet apparatus for several hours. The aceton extract was then evaporated off to obtain a tarry material.
(3) The tarry material obtained from smoke was washed with 10% NaOH, 10% H2SO4 and water. The neutral fraction of tarry material thus obtained was chromatographed repeatedly on activated alumina until it decreased to about 0.5g. Benzene, cyclohexane, and petroleum ether containing 5% acetone were used as eluents.
(4) The final column chromatogram was carried out using alumina containing 3% H2O as adsorbent and cyclohexane followed by cyclohexane containing 10 to 30% benzene as eluent. The purification of 3, 4-benzpyrene and other polycyclic aromatic hydrocarbons was made by paper chromatography using acetylated paper. The polycyclic aromatic hydrocarbons contained in each eluate fraction were identified and determined by the absorption spectrophotometry reported by Cooper.
(5) The amounts of 3, 4-Benzpyrene detected in the smoke and scorches obtained by pyrolysis of meat (1kg. wet material) were as follows:
4580μg and 132μg at 700°C under N2, 31μg and 16μg at 500°C under N2, and 2μg in smoke at 500°C under the ordinary atmosphere. No 3, 4-Benzpyrene was detected in the tarry material obtained under other experimental conditions.
