The Impacts of Intramuscular Fat Content and Other Biochemical Attributes of Fresh Pork Loins on Sensory Characteristics

113 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2007.The effect that marbling, or intramuscular fat, has on sensory properties (tenderness, juiciness, flavor) and mechanical tenderness has been of interest with many food service and retail programs marketing high quality pork. Two trials were conducted to determine if marbling improves sensory properties within a single genotype. Loins were collected from pigs to range from 1% to 8% marbling while holding as many other factors as possible constant. Regression analysis was used to determine the effects of increasing fat level and R 2 values did not exceed 0.13 for any parameter (trained sensory panel tenderness, juiciness, pork flavor, Warner-Bratzler shear force) at any degree of doneness (60°C, 70°C, and 80°C). Because marbling did not appear to improve palatability of fresh pork loins, further research was conducted to determine what does contribute to sensory properties. A commercial line of pigs with known variation in tenderness was identified and used for this research. Typical pork quality measurements were collected including pH (45 m, 3 h, 6 h, 24 h post mortem), visual color, firmness, and marbling, objective color, and proximate composition. Simple correlation coefficients were generated to evaluate the relationships between typical measures of quality and sensory panel evaluations. The various pH time points correlated fairly well with color, water holding capacity, and sensory panel tenderness, but correlations of ultimate pH with shear force did not exceed R-values of -0.22. Extractable lipid, drip loss, and objective color all correlated with shear force with absolute values in the 0.2--0.3 range. Biochemical factors shown to affect tenderness through previous research were also evaluated on a subset of these loins. The selected loins fit into 3 unique groups based on characteristics of post mortem tenderization. Some did not become more tender while others did. Glycolytic potential, collagen content, sarcomere length, desmin degradation, and muscle fiber type were all evaluated. Very few differences were present in the loins identified. It was noted though proteolysis was still occurring in loins that did not become more tender with post mortem storage. This research demonstrates the need for continued investigation of what drives tenderness of pork.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD