Selective solubilization of tomato fruit epicuticular wax constituents by Triton X-100 surfactant

The effect of the surfactant Triton X-100, alpha-[4-(1,1,3,3-tetramethylbutyl)phenyl]-omega -hydroxypolyoxy-1,2-ethanediyl, on solubilization of epicuticular wax of mature tomato (Lycopersicon esculentum Mill.) fruit was investigated. The surfactant solubilized the unsaturated hydrocarbons, hexacosene and tritriacontadiene, and the triterpenols, alpha- and beta -amyrins; solubilization was concentration dependent above the critical micelle concentration. Only traces or nondetectable quantities of saturated hydrocarbons were solubilized. Our data provide a definitive evidence that the surfactant solubilized selective constituents of epicuticular wax. Based on calculation of the logarithm of octanol/water partition coefficients for wax constituents, it appears that the mechanism of surfactant solubilization of the constituents was not solely related to the hydrophobicity of the constituents, but may involve pi-pi interaction, van der Waals interaction or molecular conformation of the solubilized constituents. This solubilization of epicuticular wax may decrease the diffusive resistance of the cuticular membrane and, hence, facilitate penetration of surfactant-formulated foliar applied agrochemicals.