Influence of oil phase composition on antifungal and mycotoxin inhibitory activity of clove oil nanoemulsions

JING WAN, Shaobin Zhong, PAUL Schwarz, Bingcan Chen, Jiajia Rao

Index: 10.1039/C7FO02073B

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Abstract

The influence of oil compositions on the physical properties, antifungal and mycotoxin inhibitory activity of clove oil-in-water nanoemulsion were investigated. The physically stable clove oil-in-water nanoemulsions could be fabricated by incorporating either ≥ 75 wt% of corn oil, or ≥ 50 wt% of medium-chain triacylglycerol (MCT) into clove oil before homogenization to prevent Ostwald ripening. The clove oil-in-water nanoemulsions with mean diameters <150 nm showed high physical stability over 30 days of storage time. The antifungal activity of physically stable clove oil nanoemulsions were further evaluated using effective concentration (EC) and inhibitory activity towards mycotoxin production in two chemotypes of Fusarium graminearum isolates. The composition of oil phase, i.e., ripening inhibitor type and concentration, in clove oil-in-water nanoemulsions had a remarkable impact on antifungal activity as well as inhibition of mycotoxin production. In general, under the same clove oil concentration in oil phase, the addition of MCT decreased the antifungal and mycotoxin inhibitory activity of clove oil more than corn oil. Compared with bulk clove oil, this study also indicated that mycotoxin inhibitory activity of clove was significantly enhanced when encapsulated in nanoemulsions. These results have important implications for the design of essential oil based nanoemulsions as effective antifungal and detoxification delivery system in food or other industries.