The Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria 3010, Australia; The ARC Dairy Innovation Hub, The Department of Chemical and Biomolecular Engineering, The University of Melbourne, Parkville, Victoria 3010, Australia.
Infrared Microspectroscopy (IRM) Beamline, ANSTO - Australian Synchrotron, 800 Blackburn Road, Clayton, Victoria 3168, Australia.
Food Chem. 2020 Dec 1;332:127327. doi: 10.1016/j.foodchem.2020.127327. Epub 2020 Jun 15.
The effect of variation in acid gel pH during cream cheese production was investigated. The gel microstructure was denser and cheese texture firmer, as the pH decreased from pH 5.0 to pH 4.3, despite the viscoelasticity of these gels remaining similar during heating. Protein hydration and secondary structure appeared to be key factors affecting both cheese microstructure and properties. Proteins within the matrix appeared to swell at pH 5.0, leading to a larger corpuscular structure; greater β-turn structure was also observed by synchrotron-Fourier transform infrared (S-FTIR) microspectroscopy and the cheese was softer. A decrease in pH led to a denser microstructure with increased aggregated β-sheet structure and a firmer cheese. The higher whey protein loss at low pH likely contributed to increased cheese hardness. In summary, controlling the pH of acid gel is important, as this parameter affects proteins in the cheese, their secondary structure and the resulting cream cheese.
研究了干酪制作过程中凝乳 pH 值变化对其的影响。尽管这些凝胶在加热过程中的弹性相似，但随着 pH 值从 5.0 降至 4.3，凝胶微观结构更加致密，奶酪质地更加坚实。蛋白质水合作用和二级结构似乎是影响奶酪微观结构和特性的关键因素。在 pH 值为 5.0 时，基质中的蛋白质似乎会膨胀，导致更大的颗粒结构；同步辐射傅里叶变换红外（S-FTIR）微光谱也观察到更多的β-转角结构，奶酪也更柔软。pH 值降低会导致更致密的微观结构，增加聚集的β-折叠结构，使奶酪更硬。在低 pH 值下，乳清蛋白损失较高，可能导致奶酪硬度增加。总之，控制酸性凝胶的 pH 值很重要，因为该参数会影响奶酪中的蛋白质、它们的二级结构以及由此产生的奶油干酪。
