Studies on the properties of dough and bread using polished-graded wheat flour

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A soft-type wheat cultivar, 'Norin 61' was polished using a modified rice-polisher by the polished-grading method from the outer layer by 10% of the total weight. As the control, Norin 61 was conventionally milled and called it as N61. General properties of the soft-type graded flours was as follows : the appearance of all the graded flours was distinctly more brownish ; and larger amounts of dietary fiber, ash and minerals (K, Ca and Fe), diastatic activity and damaged starch were contained as compared with that of conventionally milled flours. These properties were almost similar to that of a hard-type graded flour prepared from wheat cultivar '1CW'. Any kind of graded flours alone could not make a good gluten structure and the dough was clearly hard and not extensible. The substitution of the graded flours for conventionally milled N61 improved the dough and baking properties. Moreover, the addition of hemicellulase (HEM), pentosanase (PEN) or cellulase (CEL) to the N61 flour increased the loaf volume and retarded the staleness of bread.All the soft-type graded flours contained larger amounts of water soluble (WSP) and insoluble pentosan (WISP) than those of Hermes and N61. The WSP and WISP of NA-8 (30-0% layer) included the larger amount of ferulic acid, and also the WSP made protein foam more stable against heating than those of Hermes and N61.The WSP formed from enzyme hydrolysis of WISP had favorable effects on the breadmaking. Therefore, the substitution of graded flours and PEN for N61 improved breadmaking by the presence of WSP rather than WISP.