EFFECT OF OLIVE OIL AND GLYCEROL ON PHYSICAL PROPERTIES OF WHEY PROTEIN CONCENTRATE FILMS
Olive oil was incorporated into whey protein through emulsification to produce films. Whey protein films were prepared by dispersing 10% protein in distilled water; and plasticized with different levels of glycerol (glycerol : protein [Gly : pro ] = 0.5 and 0.6). Olive oil was added at different levels (oil : pro = 0.0, 0.2, 0.3 and 0.4). The emulsion films were evaluated for mechanical properties, water vapor permeability (WVP) and opacity. Increasing the levels of Gly or olive oil in the films led to decreases in modulus and tensile strength. Increasing Gly content of films at oil/pro ratios of 0.2, 0.4 led to slight increases in elongation (EL). Increasing the oil : pro ratio further resulted in a decrease in EL for all films. No significant difference in WVP and opacity was observed between films made from mixtures of various proportions of whey protein concentrate–Gly with increasing olive oil (addition) at all levels of the plasticizer. PRACTICAL APPLICATIONS
The main advantages of using edible films are extending food shelf life, improving food quality, adding value to the edible film-forming polymer and reducing synthetic packaging materials. Whey, obtained as a by-product in cheese, is produced in large quantities and has excellent functional properties and could potentially be used for edible films.
Document Type: Research Article
Affiliations: Department of Food Science, Ayatollah Amoli BranchAzad Islamic UniversityPO Box 678, Amol, Iran
Publication date: October 1, 2008