|De marco, Cristian|
Submitted to: Journal of Food Analytical Methods
Publication Type: Peer reviewed journal
Publication Acceptance Date: 7/11/2013
Publication Date: 4/1/2014
Citation: Valenzano, S., Lippolis, V., Pascale, M., De Marco, C., Maragos, C.M., Suman, M., Visconti, A. 2014. Determination of deoxynivalenol in wheat bran and whole-wheat flour by fluorescence polarization immunoassay. Journal of Food Analytical Methods. 7(4):806-813. Interpretive Summary: Many countries have problems with naturally occurring toxins in grains. One such toxin is deoxynivalenol (DON), which is commonly found in wheat, barley, and corn. When grains are processed, DON does not distribute equally among the fractions. The increasing inclusion of bran into food formulations, as a source of dietary fiber, necessitates increased monitoring for DON in such fractions. As part of efforts to improve monitoring of the toxin, a method for detecting DON in wheat bran and whole-wheat flour using fluorescence polarization immunoassay was developed at the Institute of Sciences of Food Production (ISPA) in Bari, Italy, with help from ARS scientists in Peoria, IL. The technique was successfully used to measure DON in samples of naturally contaminated bran and whole-wheat flours, with results that agreed well with a reference method. The result is a rapid method that can be used to monitor DON in wheat bran and whole-wheat flour.
Technical Abstract: A rapid and accurate fluorescence polarization (FP) immunoassay has been optimized for the determination of deoxynivalenol (DON) in bran and whole-wheat flour. A preliminary treatment with activated charcoal was used to eliminate the strong matrix effect due to highly colored interfering compounds present in raw bran extracts. In particular, matrix effect was removed by adding activated charcoal to the bran extract (3.5 mg/mL) and mixing for 3 minutes of incubation time prior to the FP immunoassay analysis. No preliminary treatment was necessary for whole-wheat flour. Average recoveries from samples spiked with DON at levels of 500, 1000 and 1500 µg/kg were 95% for bran and 94% for whole-wheat flour, with relative standard deviation generally lower than 13%. Limits of quantification (LOQ) of the optimized FP immunoassay were 120 µg/kg for both matrices. The overall times of analysis were lower than 15 minutes for bran and 10 minutes for whole-wheat flour. Good correlations (r > 0.971) were observed between DON contents obtained by both FP immunoassay and high-performance liquid chromatography with immunoaffinity clean-up for 37 and 23 naturally contaminated bran and whole-wheat flour samples, respectively. These results show that the FP immunoassay is suitable for high throughput screening as well as for quantitative determination of DON in bran and whole-wheat flour.