不同植物精油对大米青霉和黑曲霉的抑菌效果

为探明部分植物精油对大米的防霉效果,选取提自蓝桉叶、薄荷、山苍子、孜然、丁香、肉桂、花椒、香茅以及迷迭香的9种精油为研究对象,以大米青霉和黑曲霉为目标菌,通过测定抑菌圈直径、最小抑菌浓度、最低生长下降浓度和联合抑菌效果,以确定单一精油的抑菌效果、复配精油的协同抑菌效果及其最佳配比。结果表明,在所选9种精油中,肉桂和丁香精油对大米青霉和黑曲霉的抑菌效果最好,山苍子和蓝桉叶精油次之。在两两复配精油中,当肉桂精油与山苍子精油的比例为3:1(v/v)时,对大米青霉和黑曲霉的抑制效果最佳,其最小抑菌浓度为0.1 μL/mL,比单一精油的浓度下降了20~180倍。研究表明按适当比例复配的肉桂与山苍子复合精油是具良好应用前景的大米防霉保鲜剂。

Antimicrobial Effects of Different Essential Oil against the Rice Penicillium and Aspergillus niger

This paper aimed to investigate the antimicrobial effects of several plants essential oils against rice mildewing. Nine essential oils derived from Eucalyptus globulus,peppermint,Litsea cubeba,cumin,cloves,cinnamon,pepper,citronella,and rosemary were taken as materials,and Penicillium and Aspergillus niger from rice were taken as targets. The antimicrobial effects of single,and every mixture of two or three essential oils and the optimal ratio of the optimum mixture were determined by testing of diameter of bacteriostatic circle,minimum inhibitory concentration(MIC),minimum growth decrease concentration(MGDC)and joint inhibitory effect. The results showed that essential oils derived from cinnamon and cloves possessed the best antimicrobial effect,followed by essential oils derived from Litsea cubeba and eucalyptus globulus,among nine essential oils. Among every mixture of two essential oils,the best one against the rice Penicillium and Aspergillus niger was mixture of essential oils derived from cloves and Litsea cubeba. The MIC reached 0.1 μL/mL,which was lower by 20~180 times than that of single counterpart,when the ratio of cinnamon essential oil to Litsea cubeba essential oil was 3:1 (v/v). This study showed that mixture of essential oils from cloves and Litsea cubeba in a proper proportion should be a promising anti-mildewing agent for rice.