发酵剂对全脂酸奶中9种有机磷农药的降解作用

Degradation of nine organophosphorus pesticides in full-fat yogurt by two starters

目的：研究2种直投式发酵剂对全脂酸奶发酵时9种有机磷农药降解的影响。方法42℃下发酵不同时间的全脂酸奶样品,经萃取和净化处理后,气相色谱法定量分析9种有机磷农药残留,并计算有机磷农药降解动力学常数。结果在发酵过程中9种有机磷农药残留量呈现逐步降低趋势。全脂酸奶发酵时9种有机磷农药的降解速率常数为0.0200~0.0364 h-1,而其在全脂乳中的降解速率常数仅为0.0126~0.0191 h-1。9种有机磷农药中,敌敌畏的降解速率常数较大而马拉硫磷的降解速率常数较小。结论全脂酸奶发酵时2种发酵剂对9种有机磷农药的降解有不同程度的促进作用,敌敌畏较易降解而马拉硫磷较稳定。

Objective The impacts of two directed vat-set (DVS) starters on the degradation of nine organophosphorus pesticides (OPPs) in full-fat yogurt during lactic fermentation were studied. Methods The nine residual OPPs in the full-fat yogurt fermented at 42 ℃ for different times were detected by a gas chromatography (GC) method after OPPs extraction and purification process. Degradation kinetic parameters of the nine OPPs were calculated thereof. Results Nine OPPs had decreased trends in their residual levels during a fermentation time of 5 h. The degradation rate constants of the nine OPPs in the yogurt were found to be 0.0200~0.0364 h-1, while those in control whole milk were 0.0126~0.0191 h-1. Among the OPPs investigated, dichlorvos had the higher rate constant while malathion behaved the lower one. Conclusion Two DVS starters had different acceleration on OPPs degradation in the whole milk during yogurt fermentation, and dichlorvos was easier to be degraded but malathion was more stable.