Research On Detection,Degradation And Source Of Citrinin In Food

Citrinin is the secondary metabolite of fungus with neurovirulence, a kind of strong toxic substances, which has a teratogenic, carcinogenic, lethal effect on human and animal. Howere, citrinin widely exists in our daily life, it has become a hot problem in the study now. In this thesis, the method of purification and detection of citrinin in food samples, the degradation effect of malt enzyme, microbe, organic acids, illumination on citrinin, and the application of PCR to monitoring of citrininsources in food were researched.1、The separation, purification and recycling of citrinin in monascus powder was compared among silkworm protein affinity column, yolk protein affinity column, bullfrogs protein affinity column, acidic alumina column and immune affinity column. It turned out that immune affinity column showed the best purification ability, the average recovery rate was84.72%; Bullfrog protein column had a worse purification ability than acidic alumina column, but had a better recycling ability which was77.88%, and the average recovery rate of acidic alumina column was71.33%; Both silkworm protein affinity column and yolk protein affinity column had a unsatisfied purification effect, the average recovery rate was respective11.99%and49.55%.2、Establishing a method to test citinin in food samples about meat product, salted vegetables, dairy product, juice, soy sauce, fermented bean curd, rice wine, rice vinegar and so on by immunoaffinity column clean-up and HPLC-FLD detection, the result showed that the citrinin content of fermented bean curd was8.46mg/kg, soy sauce was up to2.52mg/kg and its of millet wine was1.91mg/kg, dried meat products was a bit low of0.68mg/kg. And fruit juice, cereal, vegetables, dairy products and candied or preserved fruit had a low citrinin content; The citrinin content in fruit juice was a bit higher of0.07-0.17mg/kg.3、The degradation effect of mixed malt enzyme on citrinin was not obvious, besides in the experiment of red kojic rice powder, mixed malt enzyme was beneficial to promote the synthesis of citrinin; Yeast and lactic acid bacteria had degradation ability to citrinin, and Yeast was relative stonger. Caprylic Acid could degrade citrinin, degradation rate reached more than50%. Acetic acid and lactic acid had certain degradation effect, but tartaric acid and citric acid had little degradation ability. Citrinin was degraded under UV irradiation.4、Applied PCR to yellow rice wine, soy sauce, fermented bean curd and rice vinegar, the DNA fragments related to produce citrinin was found in fermented bean curd. During the rice wine processing, the related DNA fragments was also found in yellow rice wine fermentation and sterilization, but not in preservation. When the rice wine was treated with70℃or80℃for less than20min, the related DNA was not degraded. The same result appeared when the rice wine was treated with90℃for10min. Howere, the related DNA fragments disappeared quickly at100℃.