Effects of tuna pâté thickness and background on CIEL∗a∗b∗ color parameters and reflectance spectra

Measuring color is important for classifying raw materials and for knowing how technological processes affect the same. Objective color can be studied by means of CIEL∗a∗b∗ coordinates and reflectance spectra, both physical methods being simple and non-destructive. For fish and fish products no standard or specific recommendations exit as regards sample thickness and background when evaluating color. In this work the reflectance spectra (360-740 nm) and CIEL∗a∗b∗ coordinates of tuna pâté are described against different background colors and for different sample thickness. Background color was seen to be important not only for the measurement of thinner samples. When white paper, yellow plastic, black plastic or aluminum foil are used as background, the pâté sample thickness had no effect on the color measurement. In the case of tuna pâté, sample thickness must be taken into consideration only when white ceramic or white plastic are used as background.