Download Fatty Acids and Alcohols Composition of Brazilian Sugarcane Waxes

Fatty Acids and Alcohols Composition of Brazilian Sugarcane Waxes
Thais M. F. S. Vieira1; Daniel Barera-Arellano2; Pierre Villeneuve3 & Bruno Barea3.
2
Fats & Oils Lab. DTA- FEA. State University of Campinas- UNICAMP, Campinas, SP;
1
University of São Paulo – ESALQ/USP, Piracicaba, SP, Brazil; 3CIRAD-AMIS,
Montpellier, France
Improved knowledge of the properties, composition, and analysis of sugarcane wax
would assist in efforts for its industrial application. Waxes can be applied in food and
cosmetic industries. Sugarcane wax also can be applied in pharmaceutics, due to the
presence of long chain aliphatic alcohol (policosanol) that appears to have
hypocholesterolemic effect. Waxes extracted from sugarcane filter mud, from
sugarcane harvested in 2001 in Sao Paulo, Brazil were analyzed. Commercial bee and
carnauba wax were also subjected to analysis as a reference. Sugarcane wax samples
were prepared by extraction with n-hexane from filter cake. Purified sugarcane samples
were prepared following precipitation in n-hexane and acetone. Derivation was carried
out at room temperature with Grignard reagent (ethyl magnesium bromide 3.0 M). Wax
esters were converted to primary and tertiary fatty alcohols separated by preparative
thin layer chromatography (TLC) and analyzed by HRGC equipped with flame ionization
detector. TLC of wax samples showed distinctive dark bands of hydrocarbons, wax
esters, triglycerides, free fatty acids and fatty alcohols. The reaction with Grignard
during 40 min at ambient temperature promoted the derivation of wax ester into tertiary
fatty alcohols (from fatty acids) and primary fatty alcohols (from fatty alcohols) in
samples analyzed, confirmed by analytical TLC analysis of the resulting products.
Derived wax samples showed dark bands relatives to primary and tertiary fatty alcohols,
hydrocarbons (that were not changed by the Grignard reaction) and sterols. In
sugarcane waxes the major fatty alcohol was octacosanol (C28), followed by
triacontanol (C30). Commercial waxes (bee, carnauba and candelilla) presented longer
fatty alcohols (C30 and C32) as major component. Octacosanol content in sugarcane
wax samples ranged from 118,57 to 224,89 mg.g-1. Fatty acids of sugarcane waxes
were mainly saturated compounds, predominantly C16:0 (palmitic) and C28:0
(octacosanoic).