Abstract In this work the fat mimicking mechanism of microparticulated whey proteins (MWP) in milk-based systems was studied using rheological and tribological techniques. Flow curves and friction measurements in a soft contact of skim milk-MPW dispersions (SM-MPW) and skim milk-dairy fat emulsions (SM-DF) at different concentrations (3, 6, 9, 12, 15, 18 and 20% w/w) and temperatures (25 °C and 37 °C) were carried out and compared. Friction coefficient curves of SM-MPW dispersions as a function of the product of entrainment speed and viscosity collapsed into a single master curve in the mixed and elastohydrodynamic (EHL) regimes when the high shear viscosity values as obtained through Carreau-Yasuda model were used. This suggests that the dispersions as a whole entrained in the contact. However, in the case of SM-DF emulsions, a very good collapse is obtained if only SM is assumed to pass through the contact. Simulations of friction coefficient within the EHL region showed a reasonably good continuity of the experimental data for SM-MPW dispersions and SM-DF emulsions. Finally, it was observed that friction levels attained with MPW proteins and DF at typical speeds involved in oral processing were comparable, hence demonstrating the capability of SM-MPW proteins dispersions to imitate DF in milk-based systems from a lubrication point of view.

中文翻译：

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乳制品系统中用作脂肪替代品的微粒乳清蛋白的软润滑特性

摘要 在这项工作中，使用流变学和摩擦学技术研究了乳基系统中微粒乳清蛋白 (MWP) 的脂肪模拟机制。不同浓度（3、6、9、12、15、18 和 20%）的脱脂牛奶-MPW 分散体 (SM-MPW) 和脱脂牛奶-乳制品脂肪乳剂 (SM-DF) 在软接触中的流动曲线和摩擦测量w/w) 和温度（25 °C 和 37 °C）进行比较。当使用通过 Carreau-Yasuda 模型获得的高剪切粘度值时，作为夹带速度和粘度乘积的函数的 SM-MPW 分散体的摩擦系数曲线在混合和弹性流体动力学 (EHL) 方案中折叠成一条主曲线。这表明分散体作为一个整体被夹带在接触中。然而，在 SM-DF 乳液的情况下，如果仅假设 SM 通过接触，则获得非常好的坍塌。EHL 区域内摩擦系数的模拟表明 SM-MPW 分散体和 SM-DF 乳液的实验数据具有相当好的连续性。最后，观察到 MPW 蛋白质和 DF 在口腔处理中的典型速度下达到的摩擦水平是可比的，因此从润滑的角度证明了 SM-MPW 蛋白质分散体在基于牛奶的系统中模仿 DF 的能力。