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Title: Detection of matrix-bound fumonisins in nixtamalized corn

Author
item BURNS, TANTIANA - TOX PROG/UGEORGIA, ATHENS
item Snook, Maurice
item Mitchell, Trevor
item Voss, Kenneth

Submitted to: Meeting, Center for Food Safety, University of Georgia
Publication Type: Abstract Only
Publication Acceptance Date: 2/27/2008
Publication Date: 3/4/2008
Citation: Burns, T.D., Snook, M.E., Mitchell, T.R., Voss, K.A. 2008. Detection of matrix-bound fumonisins in nixtamalized corn. University of Georgia Center for Food Safety. March 4-5, 2008. Atlanta, GA.

Interpretive Summary: Abstract - no summary required.

Technical Abstract: Fumonisins are mycotoxins found in corn and corn-based foods worldwide. They are produced by Fusarium, most notably F. verticillioides. Nixtamalization involves cooking and steeping corn in an alkaline solution and has been shown to reduce the amount of detectable fumonisins in the cooked products. However, there is emerging evidence that fumonisins might bind to food matrix components and, if so, standard extraction and quantification methods may underestimate the total fumonisin concentrations of some foods. The extent to which fumonisins bind to the matrix of whole kernel corn during nixtamalization has not been extensively investigated. Therefore, whole kernel corn was nixtamalized and the concentrations of free (unbound) FB1 and its hydrolysis product HFB1 before and after cooking were determined using a standard quantification method. In addition, protein-bound and residual (nonprotein)-bound fumonisins (FB1 plus HFB1; detected as HFB1) concentrations in the uncooked and nixtamalized kernels were compared using a modification of the method of Park et al. (Food Addit. Contam. 21: 1168-1178, 2004). The uncooked kernels contained free FB1 (23 + 11.5 ppm = 32.3 + 15.9 nmol/g FB1) and a lesser amount of free HFB1 (0.33 + 0.10 ppm = 0.81 + 0.25 nmol/g HFB1). The concentration of protein-bound fumonisins found in the nixtamalized kernels (0.40 + 0.20 ppm = 0.98 + 0.49 nmol/g HFB1) was 5 to 6-fold greater than in the uncooked kernels (0.17 + 0.12 nmol/g HFB1). Residual (non-protein) bound fumonisin was also found to be present at higher concentrations (about 15 fold) in the nixtamalized (0.32 + 0.17 ppm = 0.79 + 0.42 nmol/g HFB1) than in the uncooked kernels (0.05 + 0.02 nmol/g HFB1). These observations indicate that (a) fumonisin-matrix binding does occur but that (b) the bound fumonisins account for only a small percentage of the total fumonisins found in the nixtamalized kernels.