Determination of Phenolic Acids in Raw Propolis Using Near Infrared Spectroscopy

The objective of this studyis the assessment of the viability of using Near-Infrared Spectroscopy (NIR) technology todetermine the phenolic composition in propolis samples The chemicalcomposition and the floral origin of propolis are closely related, samples from differentgeographic and climatic areas varies greatly depending on the local flora andsite of collection1. The identification and quantification of thephenolic compounds is therefore of great interest as they may affect itsbiological activities and consequently its clinical properties. HPLC is the mostfrequently used technique for the characterisation of phenolic compounds2.(NIR) is known for being a multiparametric,rapid, and non destructive technique. It has been used to determine thephenolic composition in different extracts3. The most determinant aspect of this methodology isthat it could be developed and applied to any type of raw propolis of varyingorigins, grinding up the samples without destroying the propolis. The HPLC method wasapplied to the analysis of phenolic acids in 50 propolis extracts. It waspossible to identify and quantify 6 phenolic acids: caffeic acid, p-coumaricacid, cinnamic acid, ferulic acid, Isoferulic acid and 3,4 dimethyl-caffeicacid (DMCA). The results show thatwe can use the NIR methodology to determine caffeic acid, cinnamic acid,ferulic acid, isoferulic acid and 3,4 dimethyl-caffeic acid (DMCA) with values comparable to those obtained by HPLC.