28-5 |
Thermal and viscoelastic properties of purified porcine myofibrillar gels when mixed with commercially available pork collagen |
D. R. DOERSCHER, Meat Applications, Proliant Inc., 2325 N. Loop Dr., Ames, IA 50010, S. M. Lonergan, Iowa State Univ., 2372 Kildee Hall, Ames, IA 50011, and J. L. Briggs, Thermo Electron Corp., 5225 Verona Rd., Madison, WI 53711-4495. Myofibrillar proteins are the primary components responsible for the heat-set gel matrix formed in thermally processed meats. Functional ingredients may also contribute to the gel structure, but are typically included in formulations for improving water-binding, processing yield, and blend cost. The objective of this study was to examine the thermal and viscoelastic properties of mixed protein systems containing purified myofibrils from porcine semimembranosus (MP) and commercially available pork collagen (PC) using differential scanning calorimetry and oscillatory rheology. MP:PC (100:0, 90:10, 80:20, 70:30, 60:40, 50:50) samples were standardized in a 0.6M NaCl, 50mM Na phosphate buffer, pH 6.0 at a total protein concentration of 4% (w/v). One primary endothermic transition peak with a denaturation temperature of 66oC was observed for all treatments. There were no significant differences (P>0.05) observed for temperature of onset, temperature of denaturation, and enthalpy of transition. Storage modulus (G’) increased upon heating for all treatments, but rate of gel formation and 85oC G’ value were significantly lower (P<0.05) as the PC fraction increased. Upon cooling, gels revealed a significantly lower (P<0.05) rate of gel formation and significantly lower (P<0.05) 5oC G’ value at a 20% inclusion of PC and higher. 10% inclusion of PC increased the rate of gel formation (P<0.05) and yielded a gel with similar (P>0.05) rigidity to the control at 5oC. Furthermore, addition of PC yielded a significant linear (R2=0.65; P<0.01) effect on water holding capacity of the gels indicating that the matrix formed in MP:PC gels had a greater ability to entrap water than that of the control gels. These results give insight to how PC may react in meat applications. PC can be used to manipulate texture, control purge, or improve cook yields. All of which are beneficial attributes in the development and continuing improvement of processed meat products.
Session 28, Muscle Foods: General I
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