Samples from each oil were analysed in triplicate. The samples
were heated from 30 C until 170 C, increasing by steps of 10 C,
the first spectrum being taken at the room temperature (25 C).
UV–Vis spectra were acquired in the range 300 to 540 nm (steps
of 2 nm) in a 1 mm quartz cuvette. Data were analysed using MATLAB
version R2007b (The Mathworks Inc., MA, USA) where chemometric
curve resolution was performed by Multivariate Curve
Resolution with Alternating Least Squares (MCR-ALS). The MCRALS
algorithm code and Guidelines User Interface for MATLAB
are freely available from the home page of MCR at