Research note: Colorimetric phenotyping of bruises in broiler carcasses under commercial slaughterhouse conditions

Bruising in broiler carcasses is an important quality defect and a potential indicator of pre-slaughter handling conditions. This study evaluated the color properties of broiler carcass bruises using CIE L*a*b* and ΔE* parameters under commercial slaughterhouse conditions. A total of 79 carcass bruises with a diameter ≥1 cm were included in the analysis. These included 48 breast, 16 leg, and 15 wing bruises. Color was measured in the central area of each bruise using a portable colorimeter. Color parameters were compared among anatomical regions, and the optimal number of clusters was assessed using the gap statistic before k-means clustering of Z-score standardized CIE L*a*b* coordinates and ΔE* values. Significant anatomical differences were observed for a* and b*, but not for L* or ΔE*. Leg bruises showed a stronger red-yellow profile, whereas wing bruises shifted toward blue-purple discoloration. The gap statistic supported a three cluster solution, which identified three colorimetric profiles that were partly associated with anatomical location. These findings indicate that broiler carcass bruises are colorimetrically heterogeneous and that quantitative color assessment may support standardized bruise characterization at slaughterhouse.