The influence of milling and sifting processes on deoxynivalenol distribution in whole-wheat flour and its products

Milling and sifting of grain are important processes that affect mycotoxin distribution in the chain of grain products. The level of deoxynivalenol (DON) in white flour cannot be reduced by sifting because it is concentrated within a specific white flour fraction. The objective of this study was to investigate the influence of milling and sifting processes on the reduction of DON contamination in whole-wheat flour and in the chain of spring wheat products (grain bran - white flour - white flour fractions) from artificially and naturally (2016) and naturally (2017) infected grain samples. The current study showed that the distribution of DON in the grain products (whole-wheat flour - bran - white flour) depends on the weather conditions of the season and grain contamination level. This was particularly evident in the naturally contaminated grain in 2017. The highest DON concentrations were determined in bran. Higher DON concentrations in the bran from the naturally infected grain indicate the protective function of the grain hull, which provides partial protection for grain embryo against higher contamination. With a delay in harvesting, which resulted in increased DON concentrations, bran remained the most contaminated product; however, this was not true for the products from artificially infected grain. The DON level in bran was not significantly different at P<0.05 from that in whole-wheat flour from artificially infected grain, it indicates that after inoculation, bran had biochemical compounds capable of significantly diminishing trichothecene production. It was investigated that DON levels were concentrated in white flour fractions 160 and 112 mu m from naturally infected grains and in white flour fraction (residues) from artificially and naturally infected grains harvested later. The results obtained in this study could be further used for developing novel strategies aimed at limiting mycotoxin contamination in food and feed.