Thermally produced ω-(o-alkylphenyl)alkanoic acids provide evidence for the processing of marine products in archaeological pottery vessels

ω-(o-Alkylphenyl)alkanoic acids with 16, 18 and 20 carbon atoms were identified in archaeological pottery vessels from coastal sites in Southern Brazil. Such compounds are presumed to form during heating of triunsaturated fatty acids (C_16:3, C_18:3 and C_20:3), which are commonly found in the tissues of marine animals. The detection of these unusual cyclic compounds together with the isoprenoid fatty acids, 4,8,12-trimethyltetradecanoic acid and phytanic acid and substantial quantities of archaeological bones of fish and mollusca, provides evidence for the processing of marine animal products in archaeological pottery.