Submitted to: Poultry Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/10/2003
Publication Date: 1/1/2004
Citation: Liu, Y., Lyon, B.G., Windham, W.R., Lyon, C.E., Savage, E.M. 2004. Principal component analysis of physical, color, and sensory characteristics of chicken breasts deboned at 2, 4, 6, and 24 hours post-mortem. Poultry Science. 83:101-108. Interpretive Summary: It is important to poultry processors to understand how processing techniques affect the numerous quality factors of their products. However, the techniques to obtain either instrumental or sensory properties are destructive, time consuming and unsuitable for use directly on-line in processing plants. Hence, it is desirable to develop fast, non-destructive procedures, such as on-line/at-line near-infrared (NIR) spectroscopy techniques, to determine poultry meat eating qualities. In this study, we investigated different deboning times (2, 4, 6, and 24 hr) to provide a range of tenderness quality in poultry. Measurements of 24 different sensory and instrumental attributes were statistically analyzed by Principal Component Analysis (PCA) for subsequent study with NIR spectral data. Results indicated that both the objective (pH, color change, cooking yield and WB shear force) and the sensory attributes were affected by post-mortem deboning times. WB shear force had strong and positive correlations with five sensory texture attributes (cohesiveness, hardness, particle size, bolus size, and chewiness), and had insignificant correlations with sensory flavor and afterfeel/aftertaste attributes. Variables of pH, delta-L*, delta-a*, delta-b*, and cook yield were not correlated significantly with WB shear force or any of the 18 sensory characteristics. Although PCA results illustrated the possibility to differentiate muscles by debone time, more research is needed to determine methods to distinctly classify muscles by post-mortem debone time.
Technical Abstract: The effects of various post-chill deboning times on functional, color, yield and sensory attributes were determined. Broiler breast muscles were deboned at 2, 4, 6, and 24 hr after immersion chilling and pH, color change, cooking yield, shear force values, and sensory traits were recorded. Data were examined by multivariate data analysis, namely principal component analysis (PCA). Averages of 13 variables (pH, delta-a*, shear force, and sensory attributes of cardboardy, wet feathers, springiness, cohesiveness, hardness, moisture release, particle size, bolus size, chewiness and metallic) decreased gradually as deboning time increased from 2 to 24 hr, especially for shear values after 4 hr post-mortem aging. Univariate correlation coefficients between 24 variables indicated several significant correlations. Warner-Bratzler shear force had strong and positive correlations with five sensory texture attributes (cohesiveness, hardness, particle size, bolus size, and chewiness), and insignificant correlations with sensory flavor and afterfeel/aftertaste parameters. The parameters of pH, delta-L*, delta-a*, delta-b*, and cooking yield were not obviously correlated with shear force values or any of the 18 sensory characteristics. PCA score plot showed no clear separation of the breast muscles deboned at different post-mortem times, but it was still possible to differentiate them. The loading bi-plot suggested that 18 variables were effective in sample differentiation, delta-L*, shear force, cooking yield, six sensory flavor attributes (brothy, cardboardy, wet feathers, blood / serumy, salty, and sour), all sensory texture attributes except springiness, and all afterfeel/aftertaste properties.