Department of Food Engineering and Process Management, Faculty of Food Sciences, Warsaw University of Life Sciences-SGGW, 159c Nowoursynowska Street, Warsaw, Poland.
J Sci Food Agric. 2010 Aug 15;90(10):1673-80. doi: 10.1002/jsfa.4001.
Edible films and coatings based on protein/lipid combinations are among the new products being developed in order to reduce the use of plastic packaging polymers for food applications. This study was conducted to determine the effect of rapeseed oil on selected physicochemical properties of cast whey protein films.
Films were cast from heated (80 degrees C for 30 min) aqueous solutions of whey protein isolate (WPI, 100 g kg(-1) of water) containing glycerol (50 g kg(-1) of WPI) as a plasticiser and different levels of added rapeseed oil (0, 1, 2, 3 and 4% w/w of WPI). Measurements of film microstructure, laser light-scattering granulometry, differential scanning calorimetry, wetting properties and water vapour permeability (WVP) were made. The emulsion structure in the film suspension changed significantly during drying, with oil creaming and coalescence occurring. Increasing oil concentration led to a 2.5-fold increase in surface hydrophobicity and decreases in WVP and denaturation temperature (T(max)).
Film structure and surface properties explain the moisture absorption and film swelling as a function of moisture level and time and consequently the WVP behaviour. Small amounts of rapeseed oil favourably affect the WVP of WPI films, particularly at higher humidities.
为了减少食品应用中塑料包装聚合物的使用，正在开发基于蛋白质/脂质组合的可食用薄膜和涂层等新产品。本研究旨在确定菜籽油对铸型乳清蛋白膜某些物理化学性质的影响。
将乳清蛋白分离物（WPI，水的 100 g kg(-1)）的加热（80°C 30 分钟）水溶液（含甘油（WPI 的 50 g kg(-1)）作为增塑剂和不同水平的添加菜籽油（0、1、2、3 和 4% w/w WPI）浇铸制成薄膜。对膜微观结构、激光光散射粒度、差示扫描量热法、润湿性能和水蒸气透过性（WVP）进行了测量。在干燥过程中，乳液结构在膜悬浮液中发生显著变化，出现油的增稠和聚结。随着油浓度的增加，表面疏水性增加了 2.5 倍，WVP 和变性温度（T(max)）降低。
膜结构和表面性质解释了水分吸收和膜膨胀作为水分水平和时间的函数，以及 WVP 行为。少量的菜籽油有利于改善 WPI 膜的 WVP，特别是在较高的湿度下。
