Stocco Giorgia, Summer Andrea, Cipolat-Gotet Claudio, Malacarne Massimo, Cecchinato Alessio, Amalfitano Nicolò, Bittante Giovanni
Department of Veterinary Science, University of Parma, 43126 Parma, Italy.
Department of Veterinary Science, University of Parma, 43126 Parma, Italy.
J Dairy Sci. 2021 Aug;104(8):8439-8453. doi: 10.3168/jds.2021-20233. Epub 2021 May 28.
Natural variations in milk minerals, their relationships, and their associations with the coagulation process and cheese-making traits present an opportunity for the differentiation of milk destined for high-quality natural products, such as traditional specialties or Protected Designation of Origin (PDO) cheeses. The aim of this study was to quantify the effects of the native contents of Ca, P, Na, K, and Mg on 18 traits describing traditional milk coagulation properties (MCP), curd firming over time (CF) equation parameters, cheese yield (CY) measures, and nutrient recoveries in the curd (REC) using models that either included or omitted the simultaneous effects of milk fat and casein contents. The results showed that, by including milk fat and casein and the minerals in the statistical model, we were able to determine the specific effects of each mineral on coagulation and cheese-making efficiency. In general, about two-thirds of the apparent effects of the minerals on MCP and the CF equation parameters are actually mediated by their association with milk composition, especially casein content, whereas only one-third of the effects are direct and independent of milk composition. In the case of cheese-making traits, the effects of the minerals were mediated only negligibly by their association with milk composition. High Ca content had a positive effect on the coagulation pattern and cheese-making traits, favoring water retention in the curd in particular. Phosphorus positively affected the cheese-making traits in that it was associated with an increase in CY in terms of curd solids, and in all the nutrient recovery traits. However, a very high P content in milk was associated with lower fat recovery in the curd. The variation in the Na content in milk only mildly affected coagulation, whereas with regard to cheese-making, protein recovery was negatively associated with high concentrations of this mineral. Potassium seemed not to be actively involved in coagulation and the cheese-making process. Magnesium content tended to slow coagulation and reduce CY measures. Further studies on the relationships of minerals with casein and protein fractions could deepen our knowledge of the role of all minerals in coagulation and the cheese-making process.
乳中矿物质的自然变化、它们之间的关系以及它们与凝固过程和奶酪制作特性的关联,为区分用于高品质天然产品(如传统特色产品或原产地保护(PDO)奶酪)的牛奶提供了契机。本研究的目的是使用包含或省略乳脂肪和酪蛋白含量同时影响的模型,量化钙、磷、钠、钾和镁的天然含量对描述传统乳凝固特性(MCP)、凝乳随时间变硬(CF)方程参数、奶酪产量(CY)指标以及凝乳中营养成分回收率(REC)的18个特性的影响。结果表明,通过在统计模型中纳入乳脂肪、酪蛋白和矿物质,我们能够确定每种矿物质对凝固和奶酪制作效率的具体影响。总体而言,矿物质对MCP和CF方程参数的明显影响中,约三分之二实际上是由它们与乳成分(尤其是酪蛋白含量)的关联介导的,而只有三分之一的影响是直接的且与乳成分无关。在奶酪制作特性方面,矿物质的影响仅在很小程度上由它们与乳成分的关联介导。高钙含量对凝固模式和奶酪制作特性有积极影响,尤其有利于凝乳中的水分保留。磷对奶酪制作特性有积极影响,因为就凝乳固体而言,它与CY的增加以及所有营养成分回收率特性相关。然而,乳中非常高的磷含量与凝乳中较低的脂肪回收率相关。乳中钠含量的变化仅对凝固有轻微影响,而在奶酪制作方面,蛋白质回收率与该矿物质的高浓度呈负相关。钾似乎未积极参与凝固和奶酪制作过程。镁含量倾向于减缓凝固并降低CY指标。对矿物质与酪蛋白和蛋白质组分关系的进一步研究可能会加深我们对所有矿物质在凝固和奶酪制作过程中作用的认识。