A survey has been conducted to explore industrial milling process in 31 Moroccan barley mills that produce semolina and flour for human consumption. The results of the survey have revealed that:
- On third of barley mills surveyed are equipped with pre-cleaning machine used to reduce the charge of dockage before storing barley grains in silo or warehouses ;
- Barley grains are thoroughly cleaned by running through two essential cleaning machines: cleaner-separator and destoner ;
- Dehullers are installed right after the destoner to take out the hulls and parts of grain pericarp by abrasion with an average of two successive runs. The rate of dehulling obtained varies from 25 to 30 % ;
- Dehulled grains are processed without tempering, by millstones, metallic roller mills or a combination of both.
- The sieving of milling products is performed by plansifters or by vibro-sifters. A high proportion of sieved material goes to the purifiers where different types of semolina are extracted for bagging;
- Barley plants have lower milling capacities (12 to 80 metric tons per 24 hours) compared to durum and common wheat mills ;
- The production equipment is very outdated and comes from the modernization of durum or bread wheat mills ;
- Barley millers stock up mainly of the market of the import.
The results obtained have allowed us to raise the main parameters indicative of the value of barley semolina and develop model diagrams for cleaning, dehulling and milling barley.
