Abstract:

The effects of extrusion parameters on the degradation rate of aflatoxin B1 (AFB1) in cereals were explored
to provide references for processing extruded cereal products with reduced AFB1 levels. A double-screw extruder was
used to extrude AFB1-contaminated brown rice, and the degradation rate of AFB1 was investigated as a function of barrel
temperature, raw material moisture content, feeding speed and screwing speed. T he four operating parameters were
optimized by orthogonal array design. T he results of single-factor designs showed that the maximum degradation rate of
AFB1 was 37.1% at a barrel temperature of 170 ℃, 37.2% at a raw material moisture content of 24%, 37.8% at a feeding
speed of 30 g/min, and 39.2% at a screwing speed of 200 r/min. T he optimal conditions for these parameters that provided
maximum degradation rate of AFB1 (48.6%) were determined as 180 ℃, 24%, 30 g/min and 160 r/min, respectively. It was
demonstrated that barrel temperature had a highly significant effect on AFB1 degradation, raw material moisture content
exerted a significant effect, while the effects of feeding speed and screwing speed were not significant. T herefore, extrusion
offers an effective way of reducing AFB1 in cereals.

Key words: aflatoxin B1, brown rice, extrusion cooking, reduction