Optimization of edible whey protein films containing preservatives for water vapor permeability, water solubility and sensory characteristics

The effect of protein, sorbitol, beeswax and potassium sorbate concentrations in whey protein films on their water vapor permeability, water solubility and organoleptic properties was investigated using mixture response surface methods. All factors including protein, sorbitol, beeswax and potassium sorbate influenced water vapor permeability and water solubility of the films. Beeswax was the most important factor influencing the stickiness and appearance of the films. Amount of protein (50–65%, w/w) had no effect on stickiness and appearance, while the amount of sorbitol (35–50%, w/w) in the films had no influence on appearance. Mixture proportions of protein = 0.53, sorbitol = 0.38, beeswax = 0.08 and potassium sorbate = 0.01 would yield an edible film with minimum stickiness, water vapor permeability ⩽ 9 g mm m−2 h−1 kPa−1, water solubility ⩾ 39% and appearance score ⩾ 80.