Edible Coatings for fruits and vegetables
September 11, 2013

Edible Coatings For Fruits And Veggies Get More Popular And Sophisticated

redOrbit Staff & Wire Reports - Your Universe Online

Advances in food technology responsible for bringing ready-to-eat fresh-cup apple slices into school cafeterias, grocery stores and fast-food restaurants could soon expand to include other types of fruits and vegetables.

Speaking at the 246th National Meeting & Exposition of the American Chemical Society (ACS), Dr. Attila E. Pavlath of the USDA’s Western Regional Research Center in California discussed how edible coatings make it possible to help keep other foods fresh, flavorful and safe for longer periods of time.

Pavlath explained that the use of these invisible, colorless, odorless and tasteless films has grown drastically over the past several decades. In the 1980s, only 10 companies produced these edible coatings. These days, however, that has grown to over 1,000 companies combining to earn over $100 million in annual sales.

“Ready-to-eat fruits and vegetables now account for about 10 percent of all produce sales, with sales exceeding $10 billion annually,” the ACS said in a statement. “The use of edible films likely will expand dramatically in the future - especially for fruits and vegetables – as health-conscious consumers look for more foods that require minimal preparation like cut fruit and premixed salads, he noted.”

“Fruits and vegetables have skins that provide natural protection against drying out, discoloration and other forms of spoilage,” added Pavlath. “Cutting and peeling remove that natural protection, allowing deterioration and spoilage to begin. It's visible within minutes for foods like apples and bananas, but occurs without any outward sign for other fruits and vegetables. Nature is a very good chemist and we are learning from that and sometimes improving on it with new edible coatings that protect the quality and nutritional value of food.”

These coatings are comprised of a thin layer of edible material that is applied to the surface of a food product. This protective layer helps preserve freshness. For example, apple slices lose some of their natural wax coating when they are washed following a harvest, the ACS said. The replacement is a thin layer of wax obtained from palm tree leaves, known as carnauba wax, which also gives sugar-coated chocolate candy a glossy sheen.

Pavlath headed up the team that invented this technology, making it possible for health-conscious men and women of all ages to enjoy refrigerated, pre-packaged apple slices capable of staying crisp and fresh for far longer than normal. Once cut or peeled, apples typically begin turning brown in just 30 minutes or less. However, Pavlath’s technology can increase their lifespan to as much as three weeks by treating them with a form of vitamin C.

“Pavlath pointed out that edible films are by no means a 21st century innovation,” the ACS said. “Edible films were used at least as early as the 1100s, when merchants in citrus-growing regions of southern China used wax to preserve oranges shipped by caravan to the Emperor's table in the North. People in Europe for centuries preserved fresh fruit with ‘larding,’ a coating of the melted fat from hogs. Those coatings sealed off the fruit, preventing the exchange of gases with the air, essential for sustaining good quality.”

“Today's edible films, however, allow that exchange of gases and have other features that maintain freshness, flavor, aroma, texture and nutritional value,” the organization added. “They generally provide the same protection against bacteria as the natural skin if the foods are handled under sterile conditions when they are cut in the factory."

"Workers either spray on the films or immerse the foods in the liquid coating after cutting. The finished fruits and vegetables then go to consumers in sealed containers.”

Going forward, Pavlath said that there are two major challenges facing research and development in the field of edible coating. One involves developing a coating for bananas, which are consumed in quantities greater than apples and oranges combined, and the other pertains to keeping avocados fresh, as the increasingly popular fruit is known for discoloring rapidly once they are peeled.