Study to analyze the influence of sprouting of the wheat grain on the grinding process

Several studies have been carried out on the grinding characteristic of three species of common wheat (Triticum aestivum, ssp. vulgare). The three-day germinated kernels were pulverized in a micro hammer mill equipped with a changeable screen. The moisture of samples was 12% (w.b.). The results showed that the sprouting of wheat had a significant influence on the grinding process. The average particle size of the pulverized material obtained from the sprouted kernels was almost always significantly lower than those from the sound kernels. The highest changes were observed in the increase of the fraction of particles below a size of 200 pm, caused by sprouting. The sprouting caused a decrease in the value of specific grinding energy in all cultivars. Based on the parameters of screen openings and cultivar, the values of specific grinding energy ranged from 35.5 to 141.6 kJ kg(-1) and from 41.4 to 164.3 kJ kg(-1) for the sprouted and sound kernels, respectively. In addition, the other values of grinding energy indices confirmed that sprouting significantly reduced the grinding energy requirements. The average value of the grinding ability index was 3.9 and 4.8 kJ m(-2) for the sprouted and sound wheat, respectively. Whereas, sprouting caused a decrease in the average value of the grinding index from 71.2 to 58.0 kJ kg(-1) mm(0.5). (C) 2009 Elsevier Ltd. All rights reserved.