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United States Department of Agriculture

Agricultural Research Service

Title: Break Roll Speed Differential on Product Yeild and Semolina Granulation in a Durum Pilot Mill System.

Author
item Hareland, Gary

Submitted to: Cereal Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 29, 1998
Publication Date: N/A

Interpretive Summary: Studies were conducted to determine the effects of roll speed differential on semolina yield and granulation. Changes in roll speed differential in a durum pilot mill system (300 lb/hr feed rate capacity) affected the total yield of semolina, flour, and bran; semolina yield from the different purifiers; and semolina granulation (particle size range 150 um to 841 um). When the speed differential was adjusted in the break and chunk roll pairs from 1.5:1 to 2.5:1 to 3.5:1, semolina yield increased significantly from 55% to 67% to 72%, respectively, and bran yield decreased significantly from 24% to 15%, to 11, respectively. Shorts yield was not affected by speed differential. At the 1.5:1 differential, semolina contained 9% flour compared with 5% flour at the 2.5:1 and 3.5:1 differentials.

Technical Abstract: Changes in roll speed differential in a 25-q (55-cwt) durum pilot mill system (136 kg/hr feed rate capacity) affected total yield of semolina, flour, and bran; semolina yield from the different purifiers; and semolina granulation (particle size range 150 um to 841 um By adjusting the speed differential of the break and chunk roll pairs from 1.5:1 to 2.5:1 to 3.5: 1, semolina yield increased significantly from 55% to 67% to 72%, respectively, and bran yield decreased significantly from 24% to 15%, to I 1%, respectively. Shorts yield was not affected by speed differential. At the 1.5:1 differential, semolina contained 9% flour compared with 5% flour at the 2.5:1 and 3.5:1 differentials.

Last Modified: 9/2/2014
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