Surface Treatments and Edible Coatings in Food Preservation
Consumer interest in health, nutrition, and food safety combined with environmental concerns has renewed efforts in edible coating research. Renewable and abundant resources are available for use as film-forming agents that could potentially reduce the need for synthetic packaging filius that add to waste-disposal problems. Alternatives to petroleum-based packaging include naturally occurring lipid, resin, protein, and carbohydrate film formers and their derivatives. In fact, coating techniques had been in use for decades, and even centuries, before the development of plastic polymers. For example, beeswax was used to coat citrus fruit to retard water loss in China during the twelfth and thirteenth centuries, and "larding" (coating food with fat) to prevent desiccation was practiced in sixteenth-century England. The use of synthetic and natural waxes and resins to coat fresh fruits and vegetables has been researched and practiced in the United States, the United Kingdom, and Australia since the 1930s. Development of edible coatings for use on meat products was first reported in the late 1950s.
Currently, edible coatings and films are commonly used on many commodities such as candies, fresh fruits and vegetables, and processed meats. New research seeks to expand and improve coating technologies and materials to further enhance food stability and quality. Other surface treatments for foods include application of antioxidants, acidulants (or other pH-control agents), fungicides, preservatives, and mineral salts, some of which are more extensively covered in other chapters of this volume.