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United States Department of Agriculture

Agricultural Research Service

Title: Interaction Effects of Five Milling Variables on Durum Wheat in the First Break System

Authors
item Hareland, Gary
item Shi, Yuxin - BUHLER, INC. MPLS, MN

Submitted to: Technica Molitoria
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 21, 2001
Publication Date: December 1, 2001
Citation: Hareland, G.A., Shi, Y. 2001. Interaction effects of five milling variables on durum wheat in the first break system. Technica Molitoria. 52(12):1220-1228.

Interpretive Summary: Five major milling variables (flute angle, number of corrugations, flute orientation, speed differential of the grinding rolls, and wheat moisture were investigated to determine the yield of products from the initial first break rolls of the pilot-scale durum mill. Two-way analysis of variance showed that the 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 roll orientation resulted in the highest break release and 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 the 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 significant (P <0.01) on product yields in the first break. Tempered wheat moisture content was positively correlated to the yield of the 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.

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 brake 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 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.

Last Modified: 7/24/2014
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