Cereal Chem 69:66-69   |  VIEW ARTICLE

Preservation of High-Moisture Maize by Various Propionate Treatments.

M. O. Raeker, C. J. Bern, L. A. Johnson, and B. A. Glatz. Copyright 1992 by the American Association of Cereal Chemists, Inc. 

We investigated the feasibility of using propionates produced from fermentation of maize starch to preserve high-moisture maize. The preservative effects of regular (pH 9.60), semiacidified (pH 4.86), and acidified (pH 1.70) salt solutions of a mixture of sodium propionate and sodium acetate (4.86:1.00) and of pure propionic acid were determined at propionate levels of 0.5 and 1.0% on maize harvested during 1987 at 17.6, 23.0, and 26.8% moisture. In a second test, the propionate treatments were applied to maize harvested during 1988 at 26.8 and 29.6% moisture, except the regular salt solution was replaced with either simulated fermentation broth or actual fermentation broth enriched with pure propionic acid. All propionate treatments except the regular (unadjusted pH) salt solution acted as fungicides and maintained maize in a mold-free condition for more than a year. All treatments prevented growth of Aspergillus flavus inoculated into the maize. Propionic acid fermentation broths were as effective as pure propionic acid. Pure propionic acid maintained the color of high-moisture maize better than did the other treatments. However, all propionate-treated samples were rated as "U.S. Sample Grade" at the end of one year of storage because of objectionable odor and high total damage.