Classification of edible oils using synchronous scanning fluorescence spectroscopy

Fluorescence spectroscopy and chemometrics in the food classification - a review

“…Spectral data are then treated to highlight the relation between these data and the class considered. Various methods can be used, like linear discriminant analysis (LDA) (Sikorska et al 2005), factorial discriminate analysis (FDA) , or K-nearest neighbours (kNN) (Sikorska et al 2005). In any case, the purpose is to form weighted linear combinations of the data to minimise within class variance and to maximise between class variance.…”

“…No special smoothing algorithms are needed when the multivariate data approach is used (Norgaard Karoui & Dufour (2006) front-face (56°) CCSWA Karoui et al (2006a) Soft cheese front-face (52°) PCA, CCSWA Karoui et al (2007a) front-face (56°) PCA, FDA, CCA Eggs front-face (22.5°) PCA, FDA Karoui et al (2006d) Fish front-face (56°) PCA, FDA Karoui et al (2006e) Meat front-face (180°), EEM PCA, PLS, PARAFAC Møller et al (2003) Olive oils right-angle, EEM PCA, PARAFAC Guimet et al (2004) right-angle, EEM PCA, PARAFAC, LDA, PLSR Guimet et al (2005) right-angle, EEM NMF, PARAFAC, LDA, PLSR Guimet et al (2006) right-angle, EEM, SFS PCA, HCA Poulli et al (2005) Vegetable oils right-angle, EEM, SFS kNN, LDA Sikorska et al (2005) Honey front-face (56°) PCA, FDA Karoui et al (2007b) Front-face fluorescence 1995). Obviously raw spectra are used as acquired in right-angle geometry without any pretreatment.…”

“…The kNN method was applied using the entire spectra as input, while the linear discrimination method used six excitation and emission wavelength pairs as input. Both methods provided a very good discrimination between the oil classes with a low classification error (Sikorska et al 2005).…”

Evaluation of α-tocopherol in virgin olive oil by a luminescent method

“…The ability of virgin olive oil to emit fluorescent radiation is partially due to the presence of chlorophylls, pheophytins and tocopherols (Galano Diaz et al, 2003;Sikorska et al, 2004). Thus, spectrofluorimetric methods have been used to distinguish diverse edible oils (Sikorska et al, 2005) to characterize olive oil designations (Nicoletti, 1990) and to detect the presence of hazelnut oil in olive oil (Sayago et al, 2004). Studies based on virgin olive oil fluorescence have associated several regions of the spectrum with different parameters or variables of virgin olive oil: (i) the region of 380-400 nm seems to concern tocopherols; (ii) the region of 420-490 nm shows good correlations with conjugated dienes (K 232 ) and trienes (K 270 ); (iii) vitamin E is also associated with the region of 490-600 nm; and (iv) the bands of the region 650-700 nm are associated with chlorophylls and pheophytins.…”

“…Studies based on virgin olive oil fluorescence have associated several regions of the spectrum with different parameters or variables of virgin olive oil: (i) the region of 380-400 nm seems to concern tocopherols; (ii) the region of 420-490 nm shows good correlations with conjugated dienes (K 232 ) and trienes (K 270 ); (iii) vitamin E is also associated with the region of 490-600 nm; and (iv) the bands of the region 650-700 nm are associated with chlorophylls and pheophytins. An emission band in the range of 300-350 nm has also been associated with the tocopherols dissolved in n-hexane (Sikorska et al, 2005) although other authors (Zandomeneghi et al, 2005) have associated the tocopherols dissolved in methanol with a unique band that goes from 300 nm to 400 nm.…”