As the accompanying Scientific Status Summary suggests, we are steadily enriching our basic understanding of edible films. This understanding allows them to be used in target applications. And, several commercially available films and coatings give product developers an opportunity to solve very specific design problems. One of the most useful functions of edible films is their ability to act as barriers, either to gas, oil, or, more often water. Moisture levels in foods are critical for maintaining freshness, controlling microbial growth, and providing mouthfeel and texture.
Edible films can control water activity preventing either moisture loss or uptake.
Here the zein coating prevents moisture migration from the raisins to the dry cereal helping to maintain their quality. The ingredients vary depending on the application such as no fat, no preservatives, or other considerations. It can be used to coat nut meats and confectionery products such as gummy bears, chocolate covered peanuts and licorice candy. The zein-based coating functions as a moisture and oxygen barrier and can fix antioxidants to the product surface. Besides being moisture and gas barriers, edible coatings can act as barriers to oil uptake.