The use of elastography to measure quality characteristics of pork semimembranosus muscle

The objectives of this study were to determine if ultrasonic strain image a nalysis could estimate pork eating quality parameters (such as fresh color, drip loss, and Warner/Bratzler shear). Intact semimembranosus (SM) muscles (cap off) were analyzed for ultimate pH (pH(ult)). Forty-five SM muscles w ere selected from the larger allotment of fresh hams over a 3-week period. The SM muscles were selected based on high and low pH,I, in an attempt to r epresent a wide range of pork quality. Ultrasonic strain images were obtain ed perpendicular to the SM muscle fibers of an 8-cm cube. Radio-frequency d ata from each SM were obtained from a field-of-view (FOV) of 40x30 mm(2) an d digitized for each compression step. Tissue displacements were computed f or each compression step. Tissue strains were computed from displacement da ta located in the FOV representing areas of harder and softer muscle tissue and converted to gray scale images at 256 levels. Tissue irregularity of h ardness and softness was measured using Fractal dimension and Haralicks par ameters. Twenty-one Fractal dimension (FR) parameters, at two neighborhood distances (N), from each strain image and nine Haralick's (HAR) textural pa rameters (inter-pixel distance = 1) were analyzed for each image. The varia ble FR4N4 had a -0.279 correlation with SM ultimate pH (p < 0.10); FR6N8 co rrelated to WE sheer force at 0.325 (p < 0.05); and FR21N8 had a correlatio n coefficient of 0.364 with intramuscular fat (p < 0.01). Linear regression equations generated from FRN and HAR parameters for intramuscular fat (R-2 = 0.468), Warner/Bratzler shear (R-2 = 0.360), and 30 h drip loss (R-2 = 0 .208). Although elastographic measurement was significantly correlated to s hear (p < 0.05), a better understanding of physical meat texture is necessa ry before elastography can be used to identify superior quality pork. (C) 1 999 Elsevier Science Ltd. All rights reserved.