Research Article

Comparison of D55/10° and TL84/10° illuminant/observer systems in measurements of colour in raw porcine longissimus muscle

Tadeusz Karamucki  

Department of Microbiology and Biotechnology, West Pomeranian University of Technology in Szczecin, al. Piastów 45, 70-311 Szczecin, Poland

1. Acta Sci. Pol. Zootechnica, 22(3), 2023

Abstract. 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 (A_525p) and the relative quantities of MbO₂, MetMb, and Mb were calculated, before and after illuminated, and differences (Δ) were calculated. Hue difference (ΔH) and total colour difference (ΔE) 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 (Δa*) and hue angle (Δh°) as well as chroma (ΔC*) 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 Δa and Δh° as well as ΔH and ΔE.

Keywords: colour of meat, illuminant, pork quality, CIELAB, CIELCh