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Title: Variation and pearson correlation coefficients of warner-bratzler shear force measurements within broiler breast fillets

item Zhuang, Hong
item Savage, Elizabeth

Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/20/2008
Publication Date: 1/1/2009
Citation: Zhuang, H., Savage, E.M. 2009. Variation and pearson correlation coefficients of warner-bratzler shear force measurements within broiler breast fillets. Poultry Science. 88:214-220.

Interpretive Summary: Tenderness or texture is a major quality concern with boneless skinless broiler breast fillets. The tenderness of chicken breast is commonly measured by shearing a strip of fillet with an instrument, such as a Warner-Bratzler (WB) shear device or Allo-Kramer shear press. However, there is lack of information about how the sampling location within chicken breast fillets affects tenderness measurements and the ability to use a measurement from one location to easily predict the measurement at another location. Our current research showed that sampling locations within early deboned fillets significantly affected the tenderness measurement results, expressed by Warner-Bratzler shear force values. The toughest location was in the middle of the fillets. When comparing one sampling location to another, our results also showed that the strength of the relationship (linear) of the tenderness measurements varied within the fillets. In addition, these location differences in the tenderness measurements and the linear correlations between them changed with deboning time (post-mortem aging) and cold storage. Our study demonstrates that sampling location could have the significant impact on the results of tenderness measurements and the ability to correctly predicting the tenderness among the locations. Additionally, the effect of sampling locations on the tenderness measurements and relationships between locations can change with post-mortem aging time and storage. These published results can be used by poultry researchers and quality assurance personnel as a reference to better understand published texture analysis results, plan experimental designs and determine sampling methods for chicken fillet texture measurements.

Technical Abstract: Measurements of texture properties related to tenderness at different locations within deboned broiler breast fillets have been used to validate techniques for texture analysis and establish correlations between different texture evaluation methods. However, it has been demonstrated that meat texture can vary from location to location within individual muscles. The objective of our study was to investigate the intramuscular variation and Pearson correlations of Warner-Bratzler (WB) shears within early deboned broiler breast fillets and the effect of deboning time and cold storage on the variation and correlations. Broiler breast fillets were removed from carcasses early post-mortem (2h) and later post-mortem (24h). Storage treatments of the 2h samples included: 0d; 7d at 3oC; 7d at -20oC; and 6d at -20oC plus 1d at 3oC. WB shears were measured using a TA-XTPlus Texture Analyzer and a TA-7 WB shear type blade. Our results showed that the average WB shear values differed significantly within the 0d, 2h fillets with the highest WB shear value in the center location. The Pearson correlation coefficients were significant between the locations; however, strength of the correlation depended on the paired locations. Location differences in the WB shear values and the strength of the correlations between them changed with deboning time and cold storage. These results demonstrate that the variation of WB shear force measurements is substantial within early-deboned broiler breast fillets and the Pearson correlation strength varies among the locations. Both the variation and the Pearson correlations can be affected by post-mortem aging time and storage.