Date of Award
Doctor of Philosophy
This study consisted of three parts: (1) the development of analytical techniques for the collection, separation, identification, and quantitation of volatile organic components commonly reported to be associated with moldy feeds and feed components; (2) to develop a controlled laboratory model for growing molds on grain and collecting any volatiles produced; and (3) to test the correlation, if any, between volatiles found and molds or mold toxins present;Several analytical gas chromatographic techniques were investigated for the analysis of headspace volatiles, including organic compound adsorption onto Tenax('RM) resin with subsequent thermal desorption onto packed column GLC, capillary GLC, mega-bore capillary with cryogenic focusing, and precolumn secondary resin trapping onto fused-silica capillary with cryogenic focusing. Each method presented advantages and disadvantages. The packed column method was used in most of the present work for reasons of ruggedness and resistance to loss of resolution from the effects of sample moisture. Volatiles were collected in two ways, dynamic headspace at room temperature; and volatiles thermally stripped from a 0.2 gm subsample using inductively coupled heating. The volatile collection from inductive heating yielded better recovery of C(,5) and heavier alcohols. The headspace enabled higher recoveries of the lighter components;Three models of culturing moldy feed were tested: open cell growth, closed cell growth with no stirring, and closed cell growth with stirring. The third model, closed cell with stirring was chosen as the most representative of fungi growing wild, yet allowed sampling of a more homogeneous grain mass than the other two models;Volatile profiles were collected from a number of Aspergillus parasiticus-inoculated and Fusarium roseum-inoculated ground corn cultures over a period of time. The Aspergillus profile was characterized by three peaks, one of which was identified as 1-octene-3-ol using retention time and GC/MS. The Fusarium cultures did not show any of these three peaks consistently but occasionally did give up 1-octene-3-ol. Also, the appearance of the volatiles did not correlate completely with toxin production, but rather with initial toxin metabolism or perhaps some other process, such as sporulation, which is related to toxin metabolism.
Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/
Walter Gaylord Hyde
Hyde, Walter Gaylord, "The analysis of volatiles in moldy corn and their correlation to mold presence and mycotoxin production " (1985). Retrospective Theses and Dissertations. 8708.