Effect of Biophenols on Olive Oil Stability Evaluated by Thermogravimetric Analysis

Abstract

Virgin olive oil stability to autoxidation is mainly due to phenolic compounds naturally occurring in it, but contrasting data have been published on the effectiveness of the same antioxidant compounds. With thermogravimetric analysis (TGA) it is possible to have an estimation of oil resistance to oxidation, having a measure of weight gain percent due to reaction of sample with oxygen during the oxidation, and of initial and final oxidation temperatures. The following samples were examined: virgin olive oil, olive oil, and olive oil spiked with different amounts of some antioxidants. Tested phenols were p-HPEA, 3,4-DHPEA, 3,4-DHPEA-EA, caffeic acid, oleuropein, and, moreover, BHT and BHA. Data showed that natural antioxidant addition (especially oleuropein, 3,4-DHPEA, and 3,4-DHPEA-EA) could extend the olive oil shelf life and could protect oil from decomposition naturally occurring during thermal treatments (such as cooking process). Keywords: Biophenols; olive oil stability; lipid autoxidation; thermogravimetric analysis

Physico-Chemical Properties, Fatty Acids Content, Oxidative Stability and Antioxidant Activity of some Virgin Olive Oil Cultivars

“…Gennaro et al (1998) and Ali (2008), who reported that the stability of olive oil samples correlated mainly with the total polyphenols content.…”

Thermoanalysis of soybean oil extracted by two methods

“…Gennero et al 12 . stated that lipid autoxidation contributes significantly to the deterioration and reduction of the shelf life of many products due to a free-radical chain reaction, and that some of the effects of lipid oxidation are changes in color, texture, odor, and flavor.…”

Quality Assessment of Olive Oil by 1H-NMR Fingerprinting

“…polyphenols and tocopherols. The oxidative stability of VOO has been evaluated by several methods: Rancimat test (Di Lecce et al, 2009;Esquivel et al, 2009;Kamvissis et al, 2008;Mateos et al, 2006;Platero-López & García-Mesa, 2007), oxygen stability index (OSI) (Carrasco-Pancorbo et al, 2007;Ceci & Carelli, 2010;Cercaci et al, 2007;Gómez-Caravaca et al, 2007;Márquez-Ruiz et al, 2008), peroxide value (Carrasco-Pancorbo et al, 2007;Di Lecce et al, 2009;Márquez-Ruiz et al, 2008), AOCS method (Diraman, 2008), conjugated dienes (Deiana et al, 2002) and conjugated trienes (Hrncirik & Fritsche, 2005) analyses, K 232 and K 270 UV indexes (Antolin & Meneses, 2000;Cañizares-Macías et al, 2004a;Márquez-Ruiz et al, 2008;Platero-López & García-Mesa, 2007), thermogravimetry analyses (Coni et al, 2004;García Mesa et al, 1993;Gennaro et al, 1998;Santos et al, 2002;Vecchio et al, 2009), differential scanning calorimetry analyses (Vecchio et al, 2009), 13 C NMR on chromatographically enriched oil fractions (Hidalgo et al, 2002), high-resolution chromatographic techniques coupled with UV spectrometry or mass spectrometry (B. Baccouri et al, 2008;Gallina-Toschi et al, 2005;Tena et al, 2009), capillary electrophoresis (Carrasco-Pancorbo et al, 2007;Gallina-Toschi et al, 2005), ultrasound-assisted method (Cañizares-Macías et al, 2004b;Platero-López & García-Mesa, 2007), microwave-assisted method …”