Comparison of milk protein composition and rennet coagulation properties in native Swedish dairy cow breeds and high-yielding Swedish Red cows.
Comparison of milk protein composition and rennet coagulation properties in native Swedish dairy cow breeds and high-yielding Swedish Red cows.
复制标题
瑞典本土奶牛品种和高产瑞典红牛的乳蛋白组成和凝乳酶凝固特性的比较。
DOI：
10.3168/jds.2017-12920
复制
发表时间：
2017
影响因子：
3.5
通讯作者：
L. B. Larsen
中科院分区：
文献类型：
--
作者：
N. Poulsen;M. Glantz;A. K. Rosengaard;M. Paulsson;L. B. Larsen
最近的研究报告说，瑞典红奶牛的非脱脂奶频率很高。根本因素尚未完全了解。在这项研究中，我们探讨了凝乳酶诱导的凝血特性和相对蛋白质谱的牛奶从本地瑞典山区和瑞典红色无角奶牛，并将它们与一个子集的nonloops（NC）和良好的loops（WC）牛奶样品从现代瑞典红牛。与瑞典红牛相比，本地品种的NC牛奶和上级牛奶凝固特性的患病率非常低。两个地方品种的主要变体是αS1-酪蛋白（αS1-CN）B、β-CN A2和β-乳球蛋白（β-LG）B。对于κ-CN，瑞典山地牛中以B变体为主，而瑞典无角红牛中以A变体最常见。地方品种的αS1-CN蛋白质组成相似，但含有9个磷酸化丝氨酸（9 P）的αS1-CN含量不同。在瑞典山地奶牛中，我们观察到κ-CN的相对浓度与胶束大小之间存在很强的负相关性，钙离子与凝胶硬度之间存在正相关性。为了进行比较，我们调查了一个子集的29 NC和28 WC牛奶样本，代表的极端方面的凝固特性的基础上初步筛选的395瑞典红牛。在瑞典红中，发现NC乳性质与较高频率的β-CN A2、κ-CN E和A变体以及β-LG B相关，并且NC组中β-和κ-CN的主要复合基因型为A2 A2/AA。一般而言，A2 A2/AA复合基因型与κ-CN亚型的相对浓度较低和αS1-、αS2-和β-CN的相对浓度较高相关。与WC组相比，NC组αS2-CN和α-乳清蛋白（α-LA）含量较高，αS1-CN 9 P含量较低。总之，来自瑞典本土品种的牛奶具有良好的奶酪牛奶特性，可以在利基乳制品中开发。在瑞典山地奶牛的牛奶中，钙离子的水平似乎是更重要的凝乳酶诱导的凝胶硬度比相对蛋白质谱的变化。在瑞典红乳中，蛋白质含量较低，αS2-CN含量较高，αS1-CN 9 P含量较低。此外，通过选择性育种降低复合β-κ-CN基因型A2 A2/AA的频率可能对牛奶凝固特性产生积极影响。
Recent studies have reported a very high frequency of noncoagulating milk in Swedish Red cows. The underlying factors are not fully understood. In this study, we explored rennet-induced coagulation properties and relative protein profiles in milk from native Swedish Mountain and Swedish Red Polled cows and compared them with a subset of noncoagulating (NC) and well-coagulating (WC) milk samples from modern Swedish Red cows. The native breeds displayed a very low prevalence of NC milk and superior milk coagulation properties compared with Swedish Red cows. The predominant variants in both native breeds were αS1-casein (αS1-CN) B, β-CN A2 and β-lactoglobulin (β-LG) B. For κ-CN, the B variant was predominant in the Swedish Mountain cows, whereas the A variant was the most frequent in the Swedish Red Polled. The native breeds displayed similar protein composition, but varied in content of αS1-CN with 9 phosphorylated serines (9P) form. Within the Swedish Mountain cows, we observed a strong inverse correlation between the relative concentration of κ-CN and micelle size and a positive correlation between ionic calcium and gel firmness. For comparison, we investigated a subset of 29 NC and 28 WC milk samples, representing the extremes with regard to coagulation properties based on an initial screening of 395 Swedish Red cows. In Swedish Red, NC milk properties were found to be related to higher frequencies of β-CN A2, κ-CN E and A variants, as well as β-LG B, and the predominant composite genotype of β- and κ-CN in the NC group was A2A2/AA. Generally, the A2A2/AA composite genotype was related to lower relative concentrations of κ-CN isoforms and higher relative concentrations of αS1-, αS2-, and β-CN. Compared with the group of WC milk samples, NC milk contained a higher fraction of αS2-CN and α-lactalbumin (α-LA) but a lower fraction of αS1-CN 9P. In conclusion, milk from native Swedish breeds has good characteristics for cheese milk, which could be exploited in niche dairy products. In milk from Swedish Mountain cows, levels of ionic calcium seemed to be more important for rennet-induced gel firmness than variation in the relative protein profile. In Swedish Red, lower protein content as well as higher fraction of αS2-CN and lower fraction of αS1-CN 9P were related to NC milk. Further, a decrease in the frequency of the composite β-κ-CN genotype A2A2/AA through selective breeding could have a positive effect on milk coagulation properties.