engleski

Distribution of zearalenone in malted barley fractions dependent on Fusarium graminearum growing conditions

The aim of this work was to determine zearalenone (ZON) distribution in main fractions of malted barley dependent on incubation time (17, 26, 34 days), water activity (0.95 and 0.98) and temperature (20°C and 30°C). Malted samples were sterilized and inoculated with Fusarium graminearum. After incubation, malted barley was dried, germ and rootlets were detached and grain was milled and sieved to obtain flour and bran. ZON was determined by LC-MS/MS following immunoaffinity clean-up. Zearalenone levels were higher (p < 0.01) in bran and germ compared to flour at almost all growing conditions except 34-day incubation length. Incubation at 30°C resulted in generally lower (p < 0.01) ZON levels in germ and bran, regardless of aw and incubation time. After 34 days, ZON levels in flour from samples that were incubated at the higher temperature, rose significantly. At 20°C ZON concentration showed a bell-shaped concentration profile over the increasing incubation time (especially at aw 0.95) in bran and germ, while ZON levels in flour increased at aw 0.98 and dropped at the lower aw. The results indicate the importance of storage conditions for ZON levels in commercially relevant grain fractions of malted barley and help predict existing mycotoxin levels or manipulate storage conditions to reduce ZON content.

malted barley; zearalenone; Fusarium graminearum; water activity; temperature; incubation time

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