Effects of processing whole oats on the analysis and fate of mycotoxins and ergosterol

Abstract

Grinding and dividing equipment were evaluated for their ability to comminute and divide ground oats in preparation for mycotoxin analysis. Four different grinders, using various settings, were evaluated for their ability to comminute oats and produce small particle sizes. Rotor beater type grinders produced the more desirable finer ground samples as compared to burr type mills. Four different division methods (manual scooping, rotary sample division, and two designs of gravity-fed dividers) were assessed for their ability to produce sub-samples with consistent particle size fraction distributions. No practical differences were observed on the particle size fraction distribution of test portions of finely ground oats produced using the four different division methods; therefore, no effects on mycotoxin analysis were anticipated. The effects of processing naturally contaminated whole oats on mycotoxin concentrations was also assessed. Laboratory scale dehulling, steaming, and kilning were examined. Dehulling showed the greatest impact and removed 60-100% of various Fusarium- and Alternaria-produced mycotoxins, as well as ergosterol, present on the naturally contaminated whole oats. Different from the other analytes studied, only 48% of the mycotoxin plant transformation product deoxynivalenol-3-glucoside was present in hulls and removed during dehulling. Steaming and kilning appeared to increase ergosterol in groats, as well as decrease deoxynivalenol and deoxynivalenol-3- glucoside. The observed inconsistent changes in concentrations of tentoxin after heat treatment of groats appeared to be due to sample heterogeneity.