FRUIT COATINGS CONTAINING AMMONIA INSTEAD OF MORPHOLINE

Authors: Hagenmaier, Robert - Bob

Submitted to: Proceedings of Florida State Horticultural Society
Publication Type: Proceedings
Publication Acceptance Date: 12/27/2004
Publication Date: 12/31/2004
Citation: Hagenmaier, R.D. 2004. Fruit coatings containing ammonia instead of morpholine. Proceedings of Florida State Horticultural Society. 117:396-402.

Interpretive Summary: As preparation for sale of the fresh fruit, apples and citrus fruit are coated in packinghouses to enhance appearance and preserve them against weight loss. The packinghouses in the United States are expected to follow FDA guidelines on selection of ingredients to use in the coatings. Morpholine is approved by FDA but is not permitted in European packinghouses. Therefore, it would seem prudent to know how to make coatings that do not contain morpholine, which is an ingredient of coatings used in the United States. This paper shows how to make morpholine-free coatings from carnauba wax, a popular coating ingredient for both citrus and apples.

Technical Abstract: Virtually all citrus and apple coatings now in use in the United States contain morpholine. This chemical is not permitted as an ingredient of coatings used in Europe, presumably because it is known to be a precursor of N-nitrosomorpholine, a carcinogen. Morpholine-containing coatings are relatively easy and cheap to make, stable and have relatively low odor. Ammonia may be substituted for morpholine, but ammonia based-coatings are difficult to make, less stable, and of course have an ammonia odor. However, these properties are advantages only to the middlemen, not the consumer. Although ammonia-based microemulsions of carnauba wax are normally made in pressure cells, a method was developed for making these with very simple laboratory equipment. Many ammonia-based, carnauba-wax coatings were made and tested in our laboratory. The successful formulation of these coatings required use of a combination of oleic acid and a saturated fatty acid, preferably lauric or myristic. They were tested on citrus fruit with good results.