Submitted to: Milling Journal
Publication Type: Other
Publication Acceptance Date: 4/1/1997
Publication Date: N/A
Technical Abstract: Interactions among five major milling variables (flute angle, number of corrugations, flute orientation, speed differential of the grinding rolls and wheat moisture) were investigated from the "First Break" products of a pilot-scale durum mill. A complete factorial design was arranged for statistical analysis. Within the boundaries of the variables, two-way analysis of variance showed that the true interactions of angle*orientation, corrugation*orientation, and speed differential*orientation had significant (P <0.01) effects on the first break release sifted through a 14W sieve and on the semolina and flour yields. Dull-to-dull orientation resulted in the highest break release and the highest semolina and flour yields when the flute angle profiles were 45/60 degrees and the corrugations were 8 flutes/inch of roll surface. In comparison, sharp-to-sharp orientation resulted in the highest break release and highest semolina and flour yields when the flute angle profiles were 25/65 degrees. Sharp-to-dull orientation resulted in the highest semolina and lowest flour yields when the speed differential of the rolls was 1.5:1. Wheat moisture content was independent of any true interactions, but its influence was significant (P <0.01) on first break yields. Tempered wheat moisture content was positively correlated to the yield of the top coarse milled fraction and negatively correlated to the yields of the finer milled fractions. A comparison between dull-to-sharp and sharp-to-dull grinding orientations showed that product yield with these mill settings were similar.