Department of Animal Sciences and Industry and Food Science Institute, Kansas State University, Manhattan 66506.
Department of Animal Sciences and Industry and Food Science Institute, Kansas State University, Manhattan 66506.
J Dairy Sci. 2018 Nov;101(11):9714-9724. doi: 10.3168/jds.2018-14781. Epub 2018 Aug 30.
Because of their high protein and low lactose content, milk protein concentrates (MPC) are typically used in the formulation of ready-to-drink beverages. Calcium-mediated aggregation of proteins during storage is one of the main reasons for loss of storage stability of these beverages. Control and calcium-reduced MPC [20% calcium-reduced (MPC-20) and 30% calcium-reduced (MPC-30)] were used to evaluate the physicochemical properties in this study. This study was conducted in 2 phases. In phase I, 8% protein solutions were prepared by reconstituting the 3 MPC and adjusting the pH to 7. These solutions were divided into 3 equal parts, 0, 0.15, or 0.25% sodium hexametaphosphate (SHMP) was added, and the solutions were homogenized. In phase II, enteral dairy beverage formulations containing MPC and a mixture of gums, maltodextrin, and sugar were evaluated following the same procedure used in phase I. In both phases, heat stability, apparent viscosity, and particle size were compared before and after heat treatment at 140°C for 15 s. In the absence of SHMP, MPC-20 and MPC-30 exhibited the highest heat coagulation time at 30.9 and 32.8 min, respectively, compared with the control (20.9 min). In phase II, without any addition of SHMP, MPC-20 exhibited the highest heat coagulation time of 9.3 min compared with 7.1 min for control and 6.2 min for MPC-30. An increase in apparent viscosity and a decrease in particle size of reconstituted MPC solutions in phases I and II with an increase in SHMP concentration was attributed to casein micelle dissociation caused by calcium chelation. This study highlights the potential for application of calcium-reduced MPC in dairy-based ready-to-drink and enteral nutrition beverage formulations to improve their heat stability.
由于其高蛋白和低乳糖含量，浓缩乳蛋白（MPC）通常用于配制即饮饮料。在储存过程中，蛋白质受钙离子介导发生聚集是导致这些饮料储存稳定性下降的主要原因之一。本研究使用控制型 MPC 和低钙型 MPC（20%低钙型 MPC 和 30%低钙型 MPC）来评估其理化性质。该研究分两个阶段进行。在第一阶段，通过复溶 3 种 MPC 并将 pH 值调节至 7.0 来制备 8%蛋白质溶液。将这些溶液分为 3 等份，分别向其中添加 0、0.15 或 0.25%的六偏磷酸钠（SHMP），并进行均质处理。在第二阶段，采用与第一阶段相同的方法，评估含有 MPC 和混合胶、麦芽糊精和糖的肠内营养乳剂配方。在两个阶段中，在 140℃下加热 15s 前后，比较热稳定性、表观黏度和粒径。在没有 SHMP 的情况下，与对照（20.9min）相比，MPC-20 和 MPC-30 的热凝固时间分别高达 30.9 和 32.8min，最高。在第二阶段，在不添加 SHMP 的情况下，与对照（7.1min）和 MPC-30（6.2min）相比，MPC-20 的热凝固时间最长，为 9.3min。第一阶段和第二阶段中，随着 SHMP 浓度的增加，复溶 MPC 溶液的表观黏度增加，粒径减小，这归因于钙离子螯合导致的酪蛋白胶束解离。本研究强调了在基于乳制品的即饮和肠内营养饮料配方中应用低钙型 MPC 以提高其热稳定性的潜力。
