Antifungal activity of 10-oxo-trans-8-decenoic acid and 1-octen-3-ol against Penicillium expansum in potato dextrose agar medium

In mushrooms, 10-oxo-trans-8-decenoic acid (ODA) and 1-octen-3-ol are secondary metabolites produced naturally by the enzymatic breakdown of linoleic acid. Both compounds were determined to inhibit the mycelial growth of Penicillium expansum PP497A, a common food spoilage organism, when added to potato dextrose agar medium. ODA and 1-octen-3-ol were inhibitory at concentrations of >1.25 mM (230 μg/g for ODA and 160 μg/g for 1-octen-3-ol). At pH 5.6, 1-octen-3-ol was more inhibitory than ODA. However, at pH 3.5, both compounds (especially ODA) were more inhibitory than they were at pH 5.6. This finding indicates that the undissociated carboxyl of ODA was important for inhibition. At a concentration of 2.5 mM and a pH of 3.5, ODA and 1-octen-3-ol inhibited growth by 43.1 and 41.9%, respectively. An additive effect was observed when both compounds were added at a combined concentration of ≥1.25 mM; when both were added at a combined concentration of 2.5 mM, mycelial growth was inhibited by 48.8 and 72.8% at pHs of 5.6 and 3.5, respectively. Although the antifungal activity levels for these two compounds were lower than those observed for equal molar concentrations of sorbate, a common antifungal compound, these findings indicate that further investigation of the potential of ODA and 1-octen-3-ol for use as natural food preservatives is warranted.