Assessment of physical properties of whey protein-monoglyceride edible film and its coating effect on the moisture loss and sensory properties of fresh mutton

Plastics have been used in the food industry as packaging materials for over 50 years. However, their use causes environmental and economic problems. To solve these problems, edible films and coatings based on polysaccharide, proteins, lipids and/or their blends have found use in the food packaging industry. Edible films and coatings offer a variety of advantages in the meat-processing industry, such as reducing moisture loss; preserving color, odor and nutrients; and reducing microbial loads. The objectives of this study were to determine the physical properties of a whey protein-monoglyceride edible film and its effect on the moisture loss and sensory properties of fresh mutton. Two types of edible films–a whey protein-monoglyceride one and a whey protein one–were prepared and their physical properties (permeability to water-vapor and oxygen) were determined. Samples of thigh muscles of mutton were then coated with a solution of the whey protein-monoglyceride edible film and refrigerated. At days 0, 1, 3, and 5 days the moisture content, moisture loss, and sensory properties (juiciness, color and odor) of the coated samples were determined and compared with those of uncoated samples. The permeability to water vapor and to oxygen of the whey protein-monoglyceride edible film was significantly lower than of the whey protein edible film (P<0.05). The moisture content, percentage of moisture loss, juiciness, and color were significantly different between the coated and uncoated meat samples (P<0.05), but their odor was not different (P>0.05). Permeability to water vapor and to oxygen of a whey protein edible film could be reduced by adding monoglyceride. Thus, using a whey protein-monoglyceride as a coating on the fresh mutton can lead to a good-quality product with regard to moisture loss, juiciness and color.