Authenticity investigation of bovine tallow for biodiesel production via mass spectrometry: a comparison with traditional methodology

摘要

Biodiesel has emerged as a promising alternative to fossil fuels due to advantages related to sustainability and reduction of polluting gases emission and, in Brazil, the main raw materials used by biodiesel industry are soybean oil and bovine tallow, however, bovine tallow stands out due to its low cost, supply without competition with food market, high calorific value, high number of cetanes, and most importantly, because of its 100% conversion rate. It is produced by transesterification or esterification process of triglycerides with low content of free fatty acids or raw material rich in free fatty acids in the presence of a catalyst. The extensive usage of bovine tallow in biodiesel production values it, and similar to important commodities, it has also been frequently adulterated with the addition of specific products (frying residual oils and other animal fats from industrial by-products) decreasing the raw material quality. Consequently, there is a need for fast and reliable analytical methods for quality control. Therefore, this work evaluated the lipid quality of bovine tallow provided by biodiesel industry to confirm its authenticity; fatty acid composition was obtained by gas chromatography coupled with flame ionization detector. The lipid profile was obtained by fingerprint applying direct electrospray ionization mass spectrometry. Additionally, the lipid profile obtained for bovine tallow samples were compared with the lipid profiles obtained for soybean oil, poultry oil and a standard bovine tallow. Conclusively, fraud in bovine tallow by poultry oil was observed in one sample.