EFFECT OF OCHRATOXIN PRODUCING FUNGI ON THE CHEMICAL-COMPOSITION OF WHEAT AND BARLEY

Autoclaved barley and wheat samples were separately inoculated with Aspergillus alutaceus (formerly called A. ochraceus Wilhelm NRRL-3174) and Penicillium verrucosum Dierckx and incubated at 28C for 7, 15 and 30 days. Ochratoxin A (OA), fungal growth (glucosamine concentration), changes in the content of starch, lipids and protein, and the amino acid profile were estimated. OA production of P. verrucosum on both barley and wheat increased significantly over time (P < 0.05 and P < 0.01) with the values being 56 mug/g and 109 mug/g, respectively (after 30 days of incubation). OA production was significantly higher (P < 0.01) for A. alutaceus on wheat (79 mug/g) compared with that on barley (38 mug/g). Furthermore, wheat supported growth of both fungi better than barley (P < 0.01). The principal changes in cereal constituents induced by the ochratoxigenic fungi were a marked decrease in the lipids (a minor component) in wheat and barley (P < 0.05), a modest decrease in their content of starch (P < 0. 05), an enhanced concentration of protein in wheat (P < 0.06 and 0.01 with the two fungal species), and a change in the relative concentrations of some of the amino acids in wheat (P < 0.05). These results demonstrate that under certain conditions relatively large amounts of OA can be produced in grains with correspondingly small effects on the content of the starch and protein.