Cellulose coating extends shelf life of nutmeats at room temperature.

Edible coatings that offer a variety of gas and moisture permeability characteristics have extended the realm of potential uses for the materials. Oxygen barrier films are needed to prevent vitamin degradation, lipid oxidation and other oxidative reactions. Flavor-exchange barriers are needed to retain the sensory individuality of different components. Light barrier films could be used to protect pigments, flavors and nutrients from photodegradation.

Cellulose-based coatings are among the possibilities. For instance, nuts stored for a long time-up to about a year-can rapidly become stale unless they're kept frozen. USDA/ARS research horticulturists (Citrus and Subtropical Products Research Laboratory, PO Box 1909, Winter Haven, FL 33880 and Southeastern Fruit and Tree Nut Research Laboratory, 21 Dunbar Rd., Byron, GA 31008) have teamed up to extend the shelf life of pecans. They have developed an edible coating that keeps pecans stored for 10 months at room temperature from becoming rancid. The technology might also be applied to other nuts.

They used three different coatings made from cellulose that kept the nuts tasting good. Cellulose is a natural product. It is commercially available and relatively inexpensive. It would be easy for a processor to spray these coatings on the nutmeats. The experimental coatings are made from methyl, hydroxy propyl and carboxy methyl cellulose (CMC). CMC turned out to be the best preserver of flavor. It also gave the pecans a high gloss, improving their appearance.

The CMC coating imparted a shine, the nuts didn't look or feel oily, and their color was not as dark as the control, or untreated, nuts. Color is a potentially important factor because consumers associate dark-colored pecans with rancidity. The coatings, which are GRAS, would need to be listed on the label as ingredients. We're told that the pecan industry is interested in further developing the coatings, which could promote year-round consumption of their product. Now the investigators would like to scale their process up to commercial levels.

Further information. Elizabeth Baldwin; phone: [phone]; fax: [phone]; or Bruce Wood; phone: [phone]; fax: [phone].