Avaliação de índices de identidade e qualidade de amostras de azeite de oliva extravirgem, em comparação com óleo de soja: problematização e proposta de potenciais métodos eletroanalíticos

Abstract

The olive oil production industry is an important segment in Brazil and the world, with significant impacts on the economy of the food sector and has been the main target of fraud and food adulteration in the last decade due to its high nutritional and economic value, which represents a threat to food security. The most common adulteration in extra virgin olive oil (EVOO) is the addition of cheaper, low-quality edible oils, especially soybean oil and refined olive oil. Therefore, this work aims to compare identity and quality indicators in commercial samples of EVOO and soybean oil, using traditional methods, discussing and problematizing possible limitations of these methods in detecting adulterations. Additionally, Electrical Impedance Spectroscopy (EIS) studies were performed on EVOO and soybean oil to evaluate the potential use of this technique as a complementary method to authenticate and control EVOO adulteration. The results indicated that the official methods (specific extinction coefficient and saponification index) are capable of identifying the addition of soybean oil in a proportion of 25% (v/v) and electroanalytical techniques appear as a good alternative as they present differences significant in their spectra contributing, in the future, to the characterization and quality control of vegetable oils, in addition to being techniques for easy data acquisition and, therefore, fast, practical and low cost. EIS has been used to detect adulteration in other foods (e.g. milk and honey).