Reduction of Deoxynivalenol in Wheat with Superheated Steam and Its Effects on Wheat Quality

Abstract

Deoxynivalenol (DON) is the most commonly found mycotoxin in scabbed wheat. In order to reduce the DON concentration in scabbed wheat with superheated steam (SS) and explore the feasibility to use the processed wheat as crisp biscuit materials, wheat kernels were treated with SS to study the effects of SS processing on DON concentration and the quality of wheat. Furthermore, the wheat treated with SS were used to make crisp biscuits and the texture qualities of biscuits were measured. The results showed that DON in wheat kernels could be reduced by SS effectively. Besides, the reduction rate raised significantly with the increase of steam temperature and processing time and it was also affected significantly by steam velocity. The reduction rate in wheat kernels and wheat flour could reach 77.4% and 60.5% respectively. In addition, SS processing might lead to partial denaturation of protein and partial gelatinization of starch, thus affecting the rheological properties of dough and pasting properties of wheat flour. Furthermore, the qualities of crisp biscuits were improved at certain conditions of SS processing.

Keywords: crisp biscuit; deoxynivalenol; superheated steam; wheat; wheat quality.

Figure 1

Effect of steam temperature on the contents of DON in wheat kernels (a) and wheat flour (b) * Sample H: Scabbed wheat sample with relatively higher content of DON; Sample L: Scabbed wheat sample with relatively lower content of DON; FH: Wheat flour milled from Sample H; FL: Wheat flour milled from Sample L. Same designations were used in Figure 2. and Figure 3. Processing time and steam velocity are fixed at 6 min and 3 m/s respectively. Data are given as means of triplicate assays ± SD (standard deviation). Values with different letters on the same kind of bars are significantly different (p < 0.05). The bars are labeled by the letters a to f from the highest to the lowest. The same expressing methods are used in Figure 2 and Figure 3.

Figure 2

Effect of processing time on the contents of DON in wheat kernels (a) and wheat flour (b). * Steam temperature and steam velocity are fixed at 225 °C and 3 m/s respectively.

Figure 3

Effect of steam velocity on the contents of DON in wheat kernels (a) and wheat flour (b). * Steam temperature and processing time are fixed at 225 °C and 6 min respectively.

Figure 4

Schematic diagram of superheated steam device (1, Steam generator; 2, Heater; 3, Thermostat; 4, Processing chamber; 5, Centrifugal fan; 6, Pressure gauge; 7, 8, 9, Thermometer; 10, Flowmeter.).