Autoria: BRILHANTE, N. S.; BIZZO, H. R.; FARIA-MACHADO, A. F. de; SANTOS, M. C. da S.; GAMA, P. E.

Resumo: Olive oil consists mainly of triglycerides, in about 97 to 99% by weight. The minor compounds are a complex mixture of polar, apolar and amphiphilic substances, such as tocopherols, phenolic compounds, sterols, chlorophyll, carotenoids, terpene acids, monoglycerides and diglycerides, free fatty acids and volatile compounds. These volatiles are the compounds directly responsible for the aroma of the oil. Extra virgin olive oil has a complex aroma with more than 100 volatile compounds identified, among aldehydes, alcohols, esters, hydrocarbons, ketones and furans. The objective of this study was to develop an analytical method for volatile compounds in olive oils using solid-phase microextraction (SPME), gas chromatography coupled to mass spectrometry (GC-MS) and gas chromatography with flame ionization detection (GC-FID). For the SPME, different parameters like flask size (4, 10 and 20 mL), sampling temperatures (40 and 60 °C), headspace conditioning (10 and 60 min) and fiber exposure times (15 and 40 min) were tested. For GC analyses two different internal standards, methyl octanoate and tetradecane, were tested, as well as sub-ambient oven temperatures with liquid nitrogen. A 1 g of sample and a divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PMDS) fiber were used in all the tests. Analytical curves from the FID data were constructed for linearity evaluation, whereas internal standard was used for quantification ofcompounds such as 3-hexenol, 2-hexanal and limonene. Identification was performed based on mass spectra, co-injection of standards and retention indices data. The best conditions for SPME analysis were sample temperature of 40 °C, 10 min of headspace conditioning and fiber exposure for 40 min, in a 4 mL flask. For the chromatographic analyzes, tetradecane was chosen as the internal standard. Oven temperature program with cryofocusing led to a much better separation and, therefore, better quantitation and identification of the morevolatile compounds.

Ano de publicação: 2019

Tipo de publicação: Resumo em anais e proceedings

Unidade: Embrapa Agroindústria de Alimentos

Palavras-chave: GC-FID, GC-MS, Olive oil, SPME, Volatile compounds