Composition of the surface wax from tomatoes

Abstract

From the skins of tomatoes (Lycopersicon esculentum), the surface wax was rinsed with a tert-butylmethyl ether (TBME)/methanol (9+1) mixture. The wax components were separated into three fractions by elution from a small silica gel column. Toluene/hexane (2+1) eluted n-alkanes (C21–C35), iso- and anteiso-alkanes, n-alkadienes and -trienes (C33, C34 and C35) as well as some aldehydes. Elution with hexane/TBME (3+1) yielded n-alkanols (C18–C34), n-alkadienols and alkatrienols (C22, C24 and C26), small amounts of alkanoic acids (C18–C34) as well as sterols and triterpenols. Among the latter were identified: stigmasterol, β-sitosterol, α-, β- and δ-amyrin, taraxerol, taraxasterol, ψ-taraxasterol, lupeol, multiflorenol, cycloartenol, germanicol and bauerenol. Final elution with TBME/methanol (9+1) resulted only in naringenin-chalcone, accompanied by small amounts of naringenin as an artifact formed during sample preparation. All components in those three fractions were identified by mass spectrometric analysis of the initial gas-chromatographic peaks or of peaks obtained from suitable derivatives.