Reduction of wheat middlings using a conventional and eight-roller milling systems

Abstract

Possibilities for the rationalization of the wheat flour milling process using the eightroller mill on the 1M and 2M passages of the reduction system have been investigated. At the same roll gaps and under the same sieving conditions, the lower flour yield has been obtained using an eight-roller mill compared to the conventional milling system (5-8 %) followed by a higher energy requirements for grinding. By decreasing the roll gap setting and increasing the upper size limit of flour in the process with the eight-roller mill it is possible to increase flour yield and therefore decrease milling energy consumption per unit mass of flour produced without deterioration of flour quality as determined by ash content. With appropriate adjustments of the processing parameters in the eight-roller milling system it is possible to achieve similar milling results to those in the conventional system, while the overall investment, energy and maintenance costs are significantly lower.Ispitivana je mogucnost racionalizacije tehnoloskog postupka mlevenja psenice ukljucivanjem osmovaljne stolice na prolazistima mlevenja griza 1M i 2M. Pri istom vodjenju valjaka i pri upotrebi istog sloga sita za prosejavanje mliva, u postupku sa osmovaljnom stolicom ostvaruje se manji prinos brasna nego u klasicnom postupku (5-8%), dok je specificni utrosak energije po jedinici mase brasna veci. Nizim vodjenjem valjaka u postupku sa osmovaljnom stolicom razlika u ostvarenom prinosu brasna u pomenutim postupcima se smanjuje bez promene sadrzaja pepela u brasnu. Korekcijom sloga sita u postupku sa osmovaljnom stolicom (povecanjem velicine otvora sejnog tkiva za odsejavanje brasna) znacajno se povecava prinos brasna u pomenutom postupku, sto doprinosi smanjenju specificnog utroska energije za usitnjavanje. Takodje, pri tome nije konstatovana promena sadrzaja pepela u brasnu. Odgovarajucim prilagodjavanjem procesnih parametara mogu se u postupku sa osmovaljnom stolicom ostvariti efekti usitnjavanja bliski efektima u klasicnom postupku, a istovremeno se ostvaruju znacajne investicione i energetske ustede, sto doprinosi racionalizaciji tehnoloskog postupka mlevenja psenice.