COMPARISON OF D65/10° AND TL84/10° ILLUMINANT/OBSERVER SYSTEMS IN MEASUREMENTS OF COLOUR IN RAW PORCINE LONGISSIMUS MUSCLE

This study involved 240 samples of longissimus lumborum muscle taken from 240 carcasses (with an average weight of 90.3 ±7.6 kg) of pigs slaughtered on an industrial production line. The moisture content, crude protein, intramuscular fat content, water holding capacity (WHC), and pH48 were determined. Colour measurements were taken using the CIELAB and CIELCh colour scales, using the D65/10° and TL84/10° illuminant/observer systems. Reflectance measurements were taken in the 400–700 nm range (at intervals of 10 nm). The chromatic absorbance at a wavelength of 525 nm (A525p) and the relative quantities of MbO2, MetMb, and Mb were calculated, before and after illuminated, and differences (Δ) were calculated. Hue difference (∆H) and total colour difference (∆E) were also calculated. The use of the TL84/10° illuminant/observer system for measuring the colour of raw pork longissimus muscle, as compared to the D65/10° system, changed the observed effect of the amount of pigments and relative quantities of myoglobin chemical forms on colour parameters, mainly a* and h° as well as C* and in the effect result in higher correlation coefficients between WHC and pH48 and changes in redness (∆a*) and hue angle (∆h°) as well as chroma (∆C*) of colour. The TL84/10° system, as compared to the D65/10° system, may be more useful for measuring changes in the colour of raw pork, especially for determining ∆a* and ∆h° as well as ∆H and ∆E.