F. G. Dollear

Elimination of aflatoxins from peanut meal

Peanut meal containing aflatoxins was heat treated in the presence of moisture and chemicals to reduce the aflatoxin content. Treatments with ammonia, methylamine, sodium hydroxide and ozone were effective in either destroying aflatoxins or greatly reducing aflatoxin levels as indicated both by TLC analysis and feeding experiments with ducklings and rats. Weight gains for animals receiving the treated meals were essentially comparable to those for animals receiving aflatoxin-free meal. The treated meals, however, had somewhat reduced protein efficiency ratios, as indicated by rat feeding tests. Complete elimination of aflatoxins from contaminated peanut meal was achieved by extraction with a 90% acetone-10% water (w/w) solvent system. The extracted aflatoxin-free peanut meal gave good growth in the duckling and rat feeding tests, and had a relatively high protein efficiency ratio.

Inactivation of aflatoxins in peanut and cottonseed meals by ammoniation

Aflatoxins in peanut and cottonseed meal can be inactivated by treatment with gaseous ammonia. In pilot plant runs, contaminated peanut meal was ammoniated at two levels each of moisture content, reaction time, temperature and ammonia pressure. Thin layer chromatography indicated that ammoniation inactivated the aflatoxins (121 ppb) in the meal to a nondetectable level. With a similar treatment, total aflatoxins (350 ppb) in cottonseed meal were reduced to 4 ppb. A series of runs was made with large scale equipment using cottonseed meal containing an average of 519 ppb total aflatoxins. Under optimum processing conditions, aflatoxin content of this meal was reduced to below 5 ppb and non-detectable levels.

Reduction of aflatoxin levels in cottonseed and peanut meals by ozonization

Cottonseed and peanut meals were treated with ozone to destroy or eliminate aflatoxins. High meal moistures (cottonseed 22%, peanut 30%), high temperature (100C), and longer treatment times favored inactivation as measured by thin-layer chromatography. Aflatoxins B1 and G1 were readily destroyed by the ozone processes whereas aflatoxin B2 appeared relatively resistant. In cottonseed meal, 91% of the total aflatoxins was destroyed in 2 hr, a decrease from 214 to 20 ppb; in peanut meal, 78% was destroyed in 1 hr, a decrease from 82 to 18 ppb. In both meals, aflatoxin B1 was totally inactivated within the times specified.

CHEMICAL INACTIVATION OF AFLATOXINS IN PEANUT AND COTTONSEED MEALS

Organic and inorganic reagents have been tested for destruction or inactivation of the aflatoxins present in peanut and cottonseed meals. The treatments were made in a special laboratory-scale reactor, and were evaluated by determination of the aflatoxins in the products by thin layer chromatography. In some instances, a larger pilot-plant scale reactor was used. Ammonia, methylamine, sodium hydroxide and formaldehyde reduced aflatoxin levels and appear practical for large scale treatments. Effects of various reaction parameters including time, temperature and moisture content on the efficiency of these reagents are presented.

Removal of aflatoxins from oilseed meals by extraction with aqueous isopropanol

Aqueous isopropanol was found to be an effective solvent for removal of aflatoxins from contaminated cottonseed and peanut meals. Extraction with 6 passes of 80% aqueous isopropanol at 60C resulted in complete removal of aflatoxins in both meals, as measured by thin-layer chromatography. Under similar extraction conditions, the isopropanol-water azeotrope, 88% isopropanol by weight, removed 88% of the total aflatoxins in peanut meal, a reduction from 82 to 10 ppb, and 79% of the total aflatoxins in cottonseed meal, a reduction from 214 to 46 ppb. Lower temperatures were less effective with both solvent systems.

Aflatoxin Inactivation: Treatment of Peanut meal with formaldehyde and Calcium Hydroxide

A peanut meal contaminated with ca. 600 ppb aflatoxins was treated with formaldehyde alone and in combination with calcium hydroxide in a benchscale reactor, operated both sealed and at atmospheric pressure. In general, thin layer chromatographic assays revealed that addition of calcium hydroxide to formaldehyde caused greater inactivation of the toxins than did formaldehyde alone. With the reactor sealed and 25% moisture in the meal, treatments for 1 hr with 0.5% and 1.0% formaldehyde plus 2.0% calcium hydroxide yielded products having 3 and 1 ppb aflatoxins, respectively, whereas under reflus at atmospheric pressure with 20% meal moisture, 1 hr treatment with 1.0% calcium hydroxide yielded a product with 5 ppb aflatoxins.

Solvent extraction of aflatoxins from contaminated agricultural products

Abstract and SummarySolvent extraction of agricultural products has been suggested as an effective means of removing aflatoxins from mold-damaged commodities. The use of various polar solvents such as the azeotrope of acetone-hexane-water and of 2-propanol-water, aqueous acetone, and aqueous ethanol has been reported in the literature. This paper examines the overall aspects of solvent extraction, in particular the use of the azeotrope of 2-propanol-water, to remove aflatoxins from prepress solvent extracted cottonseed meal.

Physical properties and aflatoxin content of individual cateye fluorescent cottonseeds

The density and aflatoxin content of individual cateye fluorescent cottonseeds have been investigated. In general, higher average levels of aflatoxin contamination were found among the lower density seeds. However, significant amounts of aflatoxins were detected in a few of the higher density seeds. Subjective evaluation of color and texture of disected kernels indicated a predominance of poor quality seeds at the lower densities. Visually determined physical characteristics, however, were not indicative of the presence or absence of aflatoxins.