1 Instituto de Tecnología de los Alimentos, Universidad Nacional del Litoral, Argentina.
2 Facultad de Ingeniería Química, Universidad Nacional del Litoral, Argentina.
Food Sci Technol Int. 2017 Jun;23(4):371-381. doi: 10.1177/1082013217695170. Epub 2017 Jan 1.
Edible films with whey protein concentrate (WPC) with a lipid component, sunflower oil (O) or beeswax (W), to enhance barrier to water vapor were obtained. Brea gum was used as emulsifier and also as matrix component. In order to achieve emulsion with small and homogeneous droplet size, an ultrasonicator equipment was used after obtaining a pre-emulsion using a blender. The films were made by casting. Effects of lipid fraction on droplet size, zeta potential, mechanical properties, water vapor permeability (WVP), solubility, and optical properties were determined. The droplet size of emulsions with BG decreased when decreasing the lipid content in the formulation. The zeta potential was negative for all the formulations, since the pH was close to 6 for all of them and pI of BG is close to 2.5, and pI of ß-lactoglobulin and α-lactalbumin (main proteins in WPC) are 5.2 and 4.1, respectively. Increasing W or SO content in blended films reduced the tensile strength and puncture resistance significantly. BG and WPC films without lipid presented better mechanical properties. The presence of lipids decreased the WVP, as expected, and those films having BG improved this property. BG films were slightly amber as a result of the natural color of the gum. BG has shown to be a good polysaccharide for emulsifying the lipid fraction and improving the homogeneity and mechanical properties of the films with WPC and beeswax or oil.
获得了含有乳清蛋白浓缩物 (WPC) 和脂质成分（向日葵油 (O) 或蜂蜡 (W)）的可食用薄膜，以增强对水蒸气的阻隔性。角叉菜胶被用作乳化剂和基质成分。为了获得粒径小且均匀的乳液，在使用搅拌机获得预乳液后，使用超声仪设备进行处理。通过浇铸法制备薄膜。测定了脂质分数对乳液粒径、Zeta 电位、力学性能、水蒸气透过率 (WVP)、溶解度和光学性能的影响。随着配方中脂质含量的减少，含有 BG 的乳液的粒径减小。所有配方的 Zeta 电位均为负值，因为所有配方的 pH 值都接近 6，而 BG 的等电点接近 2.5，WPC 中的主要蛋白质 β-乳球蛋白和α-乳白蛋白的等电点分别为 5.2 和 4.1。在共混薄膜中增加 W 或 SO 的含量会显著降低拉伸强度和穿刺阻力。不含脂质的 BG 和 WPC 薄膜具有更好的机械性能。如预期的那样，脂质的存在降低了 WVP，而含有 BG 的那些薄膜则改善了这一性能。由于角叉菜胶的天然颜色，BG 薄膜略带琥珀色。BG 已被证明是一种很好的多糖，可用于乳化脂质成分，并改善含有 WPC 和蜂蜡或油的薄膜的均匀性和机械性能。
