Investigate edible coatings from fruit purees.

Edible films and coatings, by regulating the transfer of moisture, oxygen, carbon dioxide, lipid, aroma and flavor compounds in food systems, can increase a product's shelf life and improve its quality. These materials can also decrease the amounts of conventional synthetic packaging materials needed to preserve and protect foods, as well as improve package recyclability by decreasing the need for coating, laminating or coextrusion techniques. As part of a larger project investigating new ways to increase the utilization of fruits and vegetables, scientists with the USDA/ARS (Western Regional Research Center, 800 Buchanan Street, Albany, CA 94710) have turned to fruit purees to form edible coatings and barrier films.

ARS scientists have found that all purees are capable of producing commercial edible films. Films have been made from peach, apricot, apple, pear, strawberry and grape purees. Vegetable films have been produced from red pepper, carrot, broccoli and corn purees.

USDA researchers were the first to form edible barrier films and coatings from fruit purees. Water vapor and oxygen permeabilities (WVP and O2P) of peach puree films were evaluated at different relative humidities and temperatures. Peach puree was not a good water barrier. Peach and apricot films exhibited lower WVPs than pear and apple films. Adding calcium, increases in relative humidity and decreases in temperature resulted in increased WVP values for peach puree edible films.

Peach puree films are very good oxygen barriers, and fruit barrier films are good for low to intermediate moisture food systems, such as nuts, confections and baked goods, especially products susceptible to oxidation and that exhibit low to intermediate water activities. Fruit puree edible films and coatings could be used to improve the organoleptic appeal, enhance the quality and extend the shelf life of food products, as well as control mass transfer. The materials also act as flavor enhancers. Using fruit puree coatings on whole fruits and vegetables may slow respiration rates and extend product shelf life.

Fruit puree edible barriers may be used in food systems to control mass transfer, improve product quality and extend shelf life. At the same time, these fruit barriers can act as flavor enhancers for the overall food product. Good oxygen barriers typically exhibit good flavor, aroma and lipid barrier properties. Therefore, fruit puree-based barriers may be desirable on food products where flavor and aroma loss is problematic.

Further information. Tara McHugh; phone: [phone]; fax: [phone]; email: [e-mail].