Salting is an essential step in the production of Cheddar and other cheese varieties and is a well-studied process but the effect of salt addition on the microstructure of the milk ingredients and resulting cheese is not well known. This study provides insights into how the primary components in milk and the cheese matrix respond to salting. High concentrations of salt (15–25% (w/w) NaCl) disrupted fat globules due to the increased osmotic pressure. This led to fat coalescence, resulting in large fat globules >10 μm in diameter, together with submicron sized fat globules ~ 120–500 nm in diameter. Salt addition also prevented the visualization of the milk fat globule membrane when added at high concentrations (25% (w/w) NaCl) and induced asymmetry in liquid ordered domains at lower concentrations (10% (w/w) NaCl). The microstructure of the surface of the milled curd was compacted by salt, appearing coarse with 5% (w/w) NaCl or more hydrated with a denser protein structure with 2.5% (w/w) NaCl. After pressing, the curd junctions were fine and thin within the unsalted sample but coarse and thick where 5% (w/w) NaCl was added. Such coarse junctions appear to reduce binding between curd particles leading to a less cohesive cheese. Our results show that NaCl can significantly impact on the structure of fat and protein matrix of the curd surface if salt is not evenly distributed during dry salting. High concentrations of salt can also change the microstructure and texture of the cheese, resulting in a more heterogeneous product.

中文翻译：

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盐对单个脂肪小球结构和干咸切达干酪微结构的影响

腌制是切达干酪和其他奶酪品种生产中必不可少的步骤，并且是经过充分研究的过程，但是加盐对牛奶成分和所得奶酪的微观结构的影响尚不为人所知。这项研究提供了有关牛奶和奶酪基质中的主要成分如何响应盐分的见解。由于渗透压升高，高浓度的盐（15-25％（w / w）NaCl）破坏了脂肪球。这导致脂肪聚结，导致直径大于10μm的大脂肪球以及直径约120-500 nm的亚微米大小的脂肪球。加高浓度（25％（w/ w）NaCl）和在较低浓度（10％（w / w）NaCl）的液体有序域中引起的不对称性。腐乳表面的微观结构被盐压实，在5％（w / w）NaCl或更高水合的条件下显得粗糙，而在2.5％（w/ w）氯化钠。压制后，未加盐的样品中的凝乳结细而细，但加入了5％（w / w）NaCl的地方却粗而厚。这种粗糙的连接似乎减少了凝乳颗粒之间的结合，从而导致干酪的粘合性降低。我们的结果表明，如果盐在干盐过程中分布不均匀，则NaCl会显着影响凝乳表面脂肪和蛋白质基质的结构。高浓度的盐也会改变奶酪的微观结构和质地，从而导致产品的异质性更高。