Monitoring the oxidation of vegetable oil by ultrasound-assisted-ATR-FTIR spectroscopy

CANALS, ANTONIO; GRANÉ, NURIA; MARTIN, M. LUISA; ROMÁN, IVÁN; STAYKOVA, MILENA ; DOMINI, CLAUDIA

Hamburgo (ALEMANIA)

Congreso; 10th meeting of European Society of Sonochemistry, ESS 10; 2006

10th meeting of European Society of Sonochemistry, ESS 10

Oil degradation is a very complex process, whose main phases are essentially known, although the rate of degradation may differ from oil to oil. Fourier Transform Infrared Spectrometry (FTIR) is a verysuitable technique due to the great amount of information collected thereby in a few minutes. Generation of oxidation products, as well as removal of transformed components can be followedsimultaneously and very easily. Moreover, Attenuated Total Reflectance avoids the use of organic solvent, reducing lab-waste production. Aging oils by ultrasound energy has been proved moreeffective reducing the experiment time.Samples: 5 Monovarietal olive oils from cultivars: Arbequina, Cornicabra, Hojiblanca, Manzanilla and Picual, 2 sunflower oil, 2 soybean oil and 2 corn oil available from Spanish market.8 mL of oil from each cultivar were placed in a flow cell and degraded by ultrasound energy (Ultrasonic processor, UIP 500, Dr. Hielscher GmbH, Teltow, Germany) with 500 W effectivepower/amplitude output and working frequency of 20 kHz equipped with an all-glass sonotrode (BS 22, Dr. Hielscher, GmbH, Teltow, Germany).Optimal degradation conditions: Ultrasound amplitude 80%, room temperature and oxygen flow of 150 mL/min.A FTIR Spectrometer, Vector 22 (Bruker), and an Attenuated Total Reflection technique were used. Triplicate spectra and sample triplicate of 0.5 mL of sample were recorded, everyday, co-adding 128scans at a 4 cm-1 resolution and a gain of 2.0. Spectral parameters were provided by Opus 3.1 software.