Analysis of annatto (Bixa orellana) food coloring formulations. 2. Determination of aromatic hydrocarbon thermal degradation products by gas chromatography

Twenty samples of commercial annatto formulations have been analyzed for,m- xylene and toluene using ambient alkaline hydrolysis, followed by solvent e xtraction and capillary gas chromatography. Fifteen of the samples containe d <5 mg/kg toluene, four samples contained between 5 and 10 mg/kg toluene, and one sample contained 12 mg/kg toluene. The amounts found of m-xylene we re 200 mg/kg (one sample), 160 mg/kg (one sample), between 30 and 88 mg/kg (four samples), between 7 and 25 mg/kg (seven samples), and <5 mg/kg (seven samples). Bixin-in-oil formulations contained the highest m-xylene concent rations and also gave the largest increase in headspace m-xylene concentrat ion when heated in closed systems. The results are evidence for the thermal degradation of annatto during source extraction and processing, resulting in contamination by internal generation of both bixin and norbixin types wi th aromatic hydrocarbons. Two samples of norbixin of known production histo ry (i.e., thermal versus nonthermal processes) were analyzed specifically t o identify possible differences in their degradation component profiles. Th ey were found to differ significantly in m-xylene content, which is consist ent with their respective production histories.