Submitted to: Annual Meeting of the Institute of Food Technologists
Publication Type: Abstract Only
Publication Acceptance Date: 4/1/2007
Publication Date: 7/28/2007
Citation: Liu, K., Barrows, F., Woolman, M.J. 2007. Comparison of dry fractionation methods to produce barley fractions enriched in proteins. 2007 Annual Meeting of the Institute of Food Technologists. (Abstract) # 011-40.p. 47.
Technical Abstract: At USDA-ARS, we initiated a trout-grains project to develop plant-based diets. Dry fractionation has been a primary means to enrich protein in cereal grains. Previous reports have not compared different methods, nor included analysis of mass balance for enriched fractions of cereal grains, which is critical for commercialization. The objective was to determine which method or combinations were best for separating barley into high protein fractions with a maximum yield. Two genotypes were used, low protein hulled and high protein hulless. Dehulled or hulless seeds were pearled for 6 cycles, with each cycle removing 8% surface layers. The 6 bran fractions and 6 portions of corresponding kernels were retained. Each type of kernels was then ground by abrasive milling or impact milling. The resulting flours were then screened with series of sieves. The weight and protein content in all pearled or sized fractions after milling were measured. Results show that milling followed by sieving separated fractions with varying protein contents. Yet, the method of milling significantly affected the efficiency of protein enrichment and the protein content in individual sized fractions. The abrasive milling produced sized fractions with much higher variation in protein content than the impact milling. The best approach to produce high protein fractions was to de-bran barley into different surface layers. Milling the high protein genotype generated fractions with much higher protein content than milling the low protein genotype, but the percentage of protein increase was less in the high protein line. With a combination of methods, a 172% increase in protein content was achievable, generating fractions that had a combined mass of 35.2% of original sample weight and represented 61.6% of total protein recovery. In conclusion, abrasive milling and/or its combination with sieving were effective in separating barley into high protein fractions having maximum yields.