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Title: PHYSICAL AND CHEMICAL CHARACTERIZATION OF WHEAT FLOUR MILING CO-PRODUCTS

Author
item KIM, Y - KANSAS STATE UNIVERSITY
item Flores, Rolando
item Chung, Okkyung
item Bechtel, Donald

Submitted to: Journal of Food Process Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/18/2003
Publication Date: 6/18/2003
Citation: KIM, Y.S., FLORES, R.A., CHUNG, O.K., BECHTEL, D.B. PHYSICAL AND CHEMICAL CHARACTERIZATION OF WHEAT FLOUR MILING CO-PRODUCTS. JOURNAL OF FOOD PROCESS ENGINEERING. 2003. Vol. 26. pg. 469-488.

Interpretive Summary: The first step in food product formulation and development is the characterization of the raw materials. This basic understanding of the properties of the raw materials permits improvement of the products and the development of new products. This study compared the properties of hard red winter and hard red spring wheat milling co-products such as bran, germ, shorts, and red dog. The properties studied included true and bulk density size, proximate analysis (protein, ash, lipid and fiber), and thermal properties (thermal conductivity and specific heat). All properties were determined for samples originating in different commercial and pilot plant mills. The results of this study update previous characterization studies and fill in the information gaps for wheat milling co-products not previously available.

Technical Abstract: Hard red winter (HRW) and hard red spring (HRS) wheat milling co-products (bran, germ, shorts, and red dog) from three commercial flour mills and the Kansas State University pilot mill were evaluated for differences in physical, chemical, and thermal properties. The true and bulk densities of co-products were significantly (p less than 0.05) related to the wheat's moisture content (R(2)of 0.913 to 0.999 and 0.817 to 0.999 for true and bulk densities, respectively). The red dog had the smallest geometrical mean diameter with the highest variation (coefficient of variation of 23.8%). The average thickness of bran and germ particles measured with image analysis was significantly different (p less than 0.05) among separation sizes, different wheats, and milling flows. Chemical compositions (protein, ash, fiber, and lipid) of co-products in this study were within the range of published data. Thermal conductivity measured with hthe line source technique was significantly related to moisture content of the sample, with R(2) ranging from 0.740 to 0.998. Specific heat of co- products, measured with a differential scanning calorimeter exhibited a wider range (1.08 - 1.94 kJ/kgK) than that observed in whole wheat kernels and wheat flour. The variability observed among the samples was due to different sources of wheat and characteristic milling flows for the flour mills.