Institute of Qinghai-Tibetan Plateau, Southwest Minzu University, Chengdu 610041, China.
College of Life Sciences, South-Central University for Nationalities, Wuhan 430074, China.
Meat Sci. 2022 Mar;185:108723. doi: 10.1016/j.meatsci.2021.108723. Epub 2021 Dec 16.
The aim of the study was to investigate the denaturation manner of sarcoplasmic proteins (SP) under PSE condition to explain their positive impacts on water-holding compacity. We found that the SP precipitation under PSE-like condition (pH 5.5, 40 °C) and heating conditions (pH 5.5, 7.0, 8.0, 55 °C) were similar, but the myofibrillar water-holding capacity was improved only under PSE-like condition (pH 5.5, 40 °C). To understand the denaturation mechanism of SP, their physicochemical properties were examined. Results demonstrated that PSE-denaturation and heat-denaturation of SP were two different processes. At pH 7.0 and 8.0, the unfolding of SP due to temperature elevation did not alter the overall net surface negative charges but only increased hydrophobicity, whereas at pH 5.5, the net surface positive charges and hydrophobicity increased dramatically. We hypothesized that in PSE meat, denatured SP became highly positively charged and hydrophobic and easier to bind to the negatively charged MF, which is related to the improvement on water-holding capacity.
本研究旨在探究应激条件下肌浆蛋白（SP）的变性方式，以解释其对保水性的积极影响。我们发现，在类似 PSE 条件（pH 5.5，40°C）和加热条件（pH 5.5，7.0、8.0、55°C）下，SP 沉淀的方式相似，但仅在类似 PSE 条件（pH 5.5，40°C）下可提高肌原纤维的保水性。为了了解 SP 的变性机制，我们检测了其理化性质。结果表明，PSE 变性和 SP 热变性是两个不同的过程。在 pH 7.0 和 8.0 时，由于温度升高导致的 SP 展开并未改变整体净表面负电荷，只是增加了疏水性，而在 pH 5.5 时，净表面正电荷和疏水性显著增加。我们假设，在 PSE 肉中，变性的 SP 带正电荷和疏水性增加，更容易与带负电荷的 MF 结合，这与保水性的提高有关。
