Abstract: High-temperature roasting and high-temperature deodorization during the processing of peanut oil readily lead to the generation of toxic substances. In this paper, the changes in the contents of 3,4-benzo(a)pyrene (BaP) and 3-monochloropropane-1,2-diol esters (3-MCPDE) during the high-temperature steps of peanut oil processing were examined, and the removal of BaP and 3-MCPDE was further explored. Results indicated that there were significant effects of roasting temperature and time as well as deodorization temperature and time on BaP and 3-MCPDE contents in peanut oil. The two parameters increased significantly when the discharging temperature and time exceeded 210 ℃ and 60 min during the roasting step, respectively. BaP content decreased significantly in peanut oil deodorized under high steam flux as compared with low steam flux. When the deodorization temperature was raised from 240 to 250 ℃, BaP and 3-MCPDE contents increased significantly (P < 0.05). Deodorization time had a continuous effect on BaP content while its influence on 3-MCPDE content was limited from 120 min onward. The content of chlorine in peanut oil before deodorization had a significant effect on the content of 3-MCPDE after deodorization. The amount of activated carbon, adsorption time and adsorption temperature had significant effects on the removal of BaP and 3-MCPDE. The best removal efficiency was obtained for both compounds under the conditions of 0.5% YS-900 activated carbon, 30 min and 110 ℃, and the residual amount and removal rate of BaP were 0.52 μg/kg and 77.5%, respectively. Three adsorbents were ranked in order of decreasing adsorption capacity toward 3-MCPDE as follows: YS-900 activated carbon > activated clay > ordinary activated carbon, and the highest removal rate was 23.5%. The adsorbents could not only significantly reduce the contents of BaP and 3-MCPDE in the peanut oil decolonization system, but also have a certain catalytic effect on the formation of both compounds.

Key words: peanut oil, roasting, deodorization, benzo(a)pyrene, 3-monochloropropane-1,2-diol esters, adsorption