Caracterização de Óleos Vegetais e Análise de Fraude por Técnicas de Separação, Espectroscópicas, Termoanalíticas e Metodos Quimiométricos.

Abstract

Adulteration occurs in several areas, and can be divided into two types, alteration and intentional, in which the first occurs through the environment and the second is generally carried out with the addition of products of inferior quality to the authentic product, thus generating a product low quality. Oils obtained by cold pressing are susceptible to intentional adulteration due to the low production volume and their high added value, this occurs using vegetable oils from solvent extractions. For this reason, the objective of this work was to develop and apply an analytical method to detect adulterants in Extra Virgin Olive Oil (EVOO), Evening Primrose Oil (EPO) and Extra Virgin Avocado Oil (EVAO), using DSC as techniques together with chemometric and univariate methods. Separation, spectroscopic and thermoanalytical techniques were used to characterize the oils. Binary mixtures were prepared EVOO with sunflower, corn and soybean oils, EPO with soybean oil and EVAO with cottonseed, corn and soybean oils simulating as adulterants. For this purpose, the materials were weighed and prepared in proportions that varied from 5 to 95% (m/m). The samples were subjected to DSC analysis. The chemometric models were built based on DSC data, the curves were normalized by the respective initial masses of the samples, in order to eliminate the influence on the mass variation. Sample data were pre-processed, normalized by their respective standard deviations and centered on the mean. The results of the multivariate analysis were also compared with the univariate calibration using Tonset data. PLS models were constructed conducive to quantifying the level of adulteration for each material. The univariate models demonstrated linearity and are also a strategy capable of quick and easy analysis to detect adulterants in materials. Furthermore, a DSC-based strategy was pertinent for detection of seed oils as adulterants in EVOO, EPO and EVAO.