| Peanut oil is one of the main vegetable oils consumed by people in China, which is easily contaminated by aflatoxin B1(AFB1). AFB1 has strong toxicity with the capacity of carcinogenity. It is a secondary metabolite mainly produced by Aspergillus flavus and Aspergillus parasiticus. AFB1 can be found in soil, agricultural products contaminated by Aspergillus, especially peanut and peanut oil, which seriously threat the health of people. So, it is important question in food safety for oil industy to solve presently. In this paper, the detoxification process of AFB1 in peanut oil with alkali refining was studied; the factors influencing detoxification efficiency of AFB1 and its effects on the quality of peanut oil were investigated. In addition, the safety of peanut oil contaminated by AFB1 after being alkali refined was evaluated. The main results were as follows:1)Alkali liquor could degrade AFB1 rapidly in model system.Pure solution of AFB1 of which concentration was 100 μ g/kg could be degraded entirely by alkali liquor of which concentration was 1.0 % in 300 min.2) The main factors affecting the detoxification of alkali refining were alkali concentration > amount of excess alkali > end temperature of alkali refining > initial temperature of alkali refining. The response surface methodology was used to optimal the the detoxification process, which was as followed: alkali concentration of 23.42 %, excess alkali of 0.3 %, initial temperature of 43.51 ℃ and final temperature of 77.07 ℃, mixing method for the initial temperature of 180 r/min(25 min)to final temperature of 120 r/min(20 min). Under these conditions, the concentration of AFB1 was degrade from 34.78 μg / kg to 0.37 μg/kg, with a degradation rate of 98.94%. The established prediction model could predict the effect of alkali refining detoxification in peanut oil accurately. The aflatoxin concentration of peanut oil after alkali refining was far below national standards of 20 μg /kg(GB 1534-2003).3) Alkali refining detoxification has little effects on the quality of peanut oil. After detoxification with alkali refining, the L value(lightness) of peanut oil increased significantly(P <0.05), and more clear and transparent than that of the control. The acid values of peanut oil refined with alkali insignificant improved, which dropped from the initial 1.81±0.01 mg / g to 0.076±0.00 mg / g, and reduced by 95.8%,(P<0.05). The peroxide values of peanut oil refined with alkali increased from 1.20±0.02 mmol/kg to 2.29±0.04 mmol/kg(P<0.01). The acid value and peroxide value of peanut oil with alkali refing did not exceed the limit requirements of A class superfine fragrant pressing peanut oil of GB 1534-2003(acid value≤ 1.0 mg/g, the peroxide value ≤6 mmol/kg). The unsaturated fatty acids in peanut oil after being alkali refined were not significant changed.4) During the storage of 90 days, the acid value and peroxide value of peanut oil refined with alkali were all increased significantly, i.e. the acid value of peanut oil increased from 0.076±0.00 mg/g to 0.275±0.00 mg/g, and the peroxide values increased from 2.288±0.01 mmol/kg to 2.693±0.02 mmol/kg. However, they were all far less than those of the limit requirements in GB1534-2003.5) The safety of peanut oil contaminated AFB1 after being refined with alkali was significantly improved.The extract from peanut oil contaminated AFB1 after being refined significant reduced the numbers of revertants in TA97, TA98, TA100 and TA 102 strains(P<0.05), and it had lost the mutagenesi for AFB1 in peanut oil refined with alkali at the optimal detoxification process. In addition, the activity of Hep G2 cells reached to 95.45 %, which was insignificant differences compared with that of negative control(P> 0.05). |
PDF Full Text Request