Desenvolvimento de métodos analíticos para a análise de própolis utilizando técnicas espectrométricas e análise multivariada

Abstract

In this work, chemometric methods of exploratory analysis such as Principal Component Analysis and Partial Least Squares Discriminant Analysis were used to classify commercial extracts of propolis from southern and southeastern Brazil, in order to ensure their origin. A multivariate calibration model using the Partial Least Squares was developed and validated for determination of dry extract content incommercial extracts of propolis. A chemometric methodology proposed for determination of dry extract content in commercial extracts of propolis was a suitable alternative compared to traditional gravimetric method, once it is faster, less laborious and decreased solvent consumption. Folin-Ciocalteu methodology optimization for total phenols determination in propolis extracts was performed. The quantities of reagents Folin-Ciocalteu and sodium carbonate buffer, reaction time, scattering ofthe radiation, the formation of solid in suspension and hypsochromic shift of the wavelength of maximum absorption were evaluated. The optimization of the methodology spectrophotometric Folin-Ciocalteu added advantages to the proposed methodology, such as reducing costs and time of analysis, and obtaining an exact method. The determination of total phenols content of propolis extracts studied was performed using the Folin-Ciocalteu method, obtaining appropriate values comparedwith that required by Brazilian law. Chromatographic analyses of extracts from southern and southeastern Brazil, of common and green propolis, were performed. In these analyzes were observed a similarity in the chemical composition of common and green propolis extracts of the region southeast, indicating that they, regardless of their labeling, will present the same chemical composition. In these extracts, phenoliccompounds majority were artepillin C and pinocembrin. In the southern region it was observed a great variation in the chemical composition.