Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada.
Poult Sci. 2011 May;90(5):1112-23. doi: 10.3382/ps.2010-01185.
Functional and rheological properties of proteins from frozen turkey breast meat with different ultimate pH at 24 h postmortem (pH(24)) have been studied. Sixteen breast fillets from Hybrid Tom turkeys were initially selected based on lightness (L*) values for each color group (pale, normal, and dark), with a total of 48 breast fillets. Further selection of 8 breast samples was made within each class of meat according to the pH(24). The average L* and pH values of the samples were within the following range: pale (L* >52; pH ≤5.7), normal (46 < L* < 52; 5.9 < pH <6.1), and dark (L* <46; pH ≥6.3), referred to as low, normal, and high pH meat, respectively. Ultimate pH did not cause major changes in the emulsifying and foaming properties of the extracted sarcoplasmic and myofibrillar proteins. An SDS-PAGE profile of proteins from low and normal pH meat was similar, which revealed that the extent of protein denaturation was the same. Low pH meat had the lowest water-holding capacity compared with normal and high pH meat as shown by the increase in cooking loss, which can be explained by factors other than protein denaturation. Gel strength analysis and folding test revealed that gel-forming ability was better for high pH meat compared with low and normal pH meat.Dynamic viscoelastic behavior showed that myosin denaturation temperature was independent of pH(24). Normal and high pH meat had similar hardness, springiness, and chewiness values as revealed by texture profile analysis. The results from this study indicate that high pH meat had similar or better functional properties than normal pH meat. Therefore, high pH meat is suitable for further processed products, whereas low pH meat may need additional treatment or ingredient formulations to improve its functionality.
已经研究了在死后 24 小时（pH24）具有不同最终 pH 值的冷冻火鸡胸肉中的蛋白质的功能和流变性质。最初根据每个颜色组（浅色、正常色和深色）的 L值（亮度）选择了来自 Hybrid Tom 火鸡的 16 个鸡胸肉片，总共 48 个鸡胸肉片。然后根据 pH24 在每个肉类类别中进一步选择 8 个鸡胸肉样本。样本的平均 L和 pH 值在以下范围内：浅色（L* >52；pH ≤5.7）、正常色（46 < L* < 52；5.9 < pH <6.1）和深色（L* <46；pH ≥6.3），分别称为低 pH、正常 pH 和高 pH 肉。最终 pH 并未对提取的肌浆和肌原纤维蛋白质的乳化和起泡特性造成重大变化。低 pH 和正常 pH 肉的蛋白质 SDS-PAGE 图谱相似，这表明蛋白质变性程度相同。与正常和高 pH 肉相比，低 pH 肉的持水力最低，这可以通过烹饪损失的增加来解释，这可能与蛋白质变性以外的因素有关。凝胶强度分析和折叠试验表明，与低 pH 和正常 pH 肉相比，高 pH 肉的凝胶形成能力更好。动态粘弹性行为表明，肌球蛋白变性温度与 pH24 无关。正常和高 pH 肉的硬度、弹性和咀嚼性值相似，这可以通过质地分析来揭示。这项研究的结果表明，高 pH 肉具有与正常 pH 肉相似或更好的功能特性。因此，高 pH 肉适合进一步加工的产品，而低 pH 肉可能需要额外的处理或成分配方来改善其功能。
