肉桂-山苍子复合植物精油对发霉花生黑曲霉BQM菌的抑菌效果

The Antifungal Effect of Cinnamon-Litsea Cubeba Compound Essential Oil on Aspergillus niger BQM of Moldy Peanuts

花生果在不良的贮藏条件下极易发生霉变,从而降低其食用品质。为了寻找安全有效的花生防霉方法,研究了提自肉桂、山苍子、丁香、香茅及百里香的5种植物精油对分离自发霉花生的优势霉菌的抑菌效果。首先,从发霉的花生中分离纯化得到1株优势霉菌BQM,通过形态学特征,并结合18S rRNA基因序列分析,对其进行鉴定。然后,通过抑菌圈试验评价5种植物精油对菌株BQM的单一及复合抑菌效果,筛选出抑菌效果最佳的精油组合和复合精油的最佳比例。最后,通过扫描电镜观察复合精油对霉菌BQM菌丝结构的影响。试验结果表明:经鉴定,从发霉的花生上分离到的优势霉菌菌株BQM属于黑曲霉。肉桂-山苍子复合精油对黑曲霉BQM的抑菌效果最好,最小抑菌浓度(MIC)为0.125μL/mL,复合精油最佳体积配比为V_(肉桂精油)∶V_(山苍子精油)=3∶5。扫描电镜结果表明,经肉桂-山苍子复合精油处理的黑曲霉BQM菌丝体损伤严重,发生皱缩、干瘪、凹陷等变形现象,说明该精油可用于花生防霉处理。

Peanuts easily go moldy under unsafe storage conditions,reducing their edible quality.In order to seek for safe and effective anti-mildewing methods for peanuts'storage,the antifungal activity of plant essential oils from cinnamon,litsea cubeba,clove,citronella and thyme against advantage molds of moldy peanuts was investigated in this study.At first,a mold strain,BQM,was isolated from moldy peanuts.The strain BQM was identified by morphological characters combined with 18S rRNA sequence analysis.Then the antifungal effects of five kinds of single plant essential oil and their mixtures on BQM were evaluated by the inhibition zone test.The composition of the mixed oils with best antifungal effect was also determined.Finally,the effect of mixed oils on the mycelia of BQM was observed under scanning electron microscope.The results indicated that:the mold strain BQM was identified as Aspergillus niger;the cinnamon-litsea cubeba mixed essential oil displayed the best antifungal effect on Aspergillus niger BQM and the minimum inhibitory concentration(MIC)was 0.125μL/mL,and the best ratio of essential oil was determined as cinnamon∶Litsea cubeba=3∶5;the pictures of scanning electron microscope showed that the morphology of mycelia treated by cinnamon-litsea cubeba mixed essential oil was seriously damaged and the deformation phenomena such as shrinking,shrivelling and sinking occurred.Therefore,cinnamon-litsea cubeba mixed oil may have great potential for peanut anti-mildewing due to its effective antifungal activity against Aspergillus niger BQM.