IMAGE ANALYSIS OF OXIDATION INDUCED FOOD COLOUR CHANGES
 
L. Pezo, Z.Marković, M.Pavlović, M.Kićanović, S.Ostojić, S. Zlatanović, J.Gvozdenović UDC: (663.051.022.392)
Abstract:
Colour evaluation, by means of multivariate image analysis was applied on colour lightness changes corresponding to oxidative browning of minimally-processed basil-based food emulsions. We have analysed the influence of metal-chelating protein lactoferrin on browning of emulsions (atributed to enzymaic and non-enzymatic oxidation). The colourgram of digitalized images, taken during oxidation of the samples, was evaluated, both by colour analysis and by PCA analysis. The basic colour information was derived from frequency colour distribution for RGB and HSV colour system, while the PCA analysis was carried out by evaluating covariance matrix, for raw, mean centered and autoscaled matrix of the basic R, G, B colour information, and the evaluation of eigenvalues and eigenvectors for all three numeric models. The resulting colourgram information is one-dimensional signal, which consists of 4900 elements, and describes colour properties of the image. The changes in material due to oxidation was observed by the changes in lightness frequency distribution (L).