Chemical Removation Of Aflatoxins And Effects On Quality Of Peanuts

Aflatoxins are toxic secondary metabolites produced by fungal strains. As the mainfoodstuff product, peanuts are easily polluted by aflatoxins owing to unsuitable growing orstoring conditions. Polluted peanuts are harmful to human and animal health due to theirtoxicity. So, developing methods or technologies to degrade or remove aflatoxins in peanutshave gradually became the research focus. In this paper, ozone, chlorine dioxide andmicrowave-assisted sodium hydroxide were used to degraded aflatoxins in peanuts, and Amestests were used to evaluate the safety of peanuts after detoxication. The results are asfollowed:1. Aflatoxins in peanuts could be degraded effectively by ozone, and exposure time andrelative humidity of ozone could influence their degradation efficiency obviously (P＜0.05).The better conditions for degrading aflatoxins in peanuts were that the relative humidity ofozone was50%, the exposure time was30minutes at the ozone concentration89mg/L, flowrate of ozone1L/min, and stirring speed70r/min-1. Under the conditions, the contents ofaflatoxin B1, B2, G1and G2in peanuts were decomposed from87.53μg/kg、21.99μg/kg、9.71μg/kg and4.38μg/kg to15.23μg/kg、8.31μg/kg、2.81μg/kg and2.11μg/kg，respectively, and their degradation rates were82.6%,62.2%,71.1%and51.8%, respectively.2. Both chlorine dioxide and microwave-assisted alkali had the capability of detoxificationin peanuts after steeping treatment. The detoxification capability was improved with theincrease of concentration of chlorine dioxide, the ratio of liquid to solid, and the treatmenttime. The degradation rate of aflatoxin B1was up to99.53%when the detoxificationconditions were as followed: chlorine dioxide concentration was20g/L, ratio of solution tosubstrate (mL/g) was7:1, treatment time was90min. Under these conditions, peroxide valueof the peanuts was3.45mmol/kg, and acid value was0.24mg/g, which were much lower thanthose setted in the GB16326-2005. The degradation rate of aflatoxin B1in peanuts was up to95.34%when used microwave-assisted alkali: microwave heating120s before added thepH11alkali, then added lye with the ratio of7:1(lye:peanuts), and then microwave heated120s. Compared with the control, peroxide value and acid value of peanuts went beyondobviously the limits in GB16326-2005after being treated by microwave-assisted alkalimethod. So it is, not a suitable method to degrading aflatoxins in peanuts. 3. Ames tests indicated that the mutagenicity of aflatoxin-contaminated peanuts had beengreatly reduced after being treated by the three methods, and then the safety of peanuts wasimproved.4. Compared to the three methods, ozone was chosed as the best method to degradeaflatoxins in peanuts due to its easily operation, low cost, friendly-environment, safety andhighly detoxification efficiency. The results provide technical references for peanuts storageand processing enterprises to reduce aflatoxins in peanuts, and ensure the safety of peanuts toeat.