44-6 |
Isolation and characterization of aleurone from wheat bran |
J. J. LAUX, W. von Reding, and R. C. Buri. Corporate Development, Buhler AG, Uzwil, CH-9240, Switzerland A new, patented industrial process has been developed to isolate aleurone in good yield and high purity from wheat bran. Most of the nutritionally important substances of whole grain, such as dietary fiber, vitamins, minerals, antioxidants and phytonutrients, are concentrated in the aleurone. Technically considered a part of the endosperm, aleurone is removed along with the bran layer in the flour milling process and used predominately for animal feed. This process breakthrough enables recovery of the valuable aleurone from wheat bran to yield a light colored, free-flowing powder ingredient that can be used to enrich a host of food applications without sacrificing taste and texture. To characterize this new ingredient, chemical composition, in vitro digestibility and in vitro fermentability were investigated and microscopy was used to visualize morphological changes. Arabinoxylans with an A:X ratio of 0.43 constituted the main part of the dietary fiber fraction. Digestibility was 28%, and a 56% increase in protein digestibility versus wheat bran was measured. The rate of in vitro fermentability was 30% higher than wheat bran. Ratios short chain fatty acids were similar, with ratios of propionate and butyrate slightly above average compared to other dietary fiber sources. Arabinoxylans from aleurone were completely degraded within 8h, whereas with wheat bran, substantial amounts were still present after 24h. Microscopic investigations confirmed the better fermentability of aleurone compared to wheat bran. Determination of lignans and plant sterols revealed a significant enrichment of these important phytonutrients in aleurone. Free radical scavenging capacity of aleurone was 36% higher than wheat bran, and an impressive 60% higher than whole grain. The use of aleurone in food applications such as bread & bakery, RTE-cereals and pasta will be discussed, and the results of clinical studies in human volunteers to determine the Glycemic Index of aleurone-enriched bread will be disclosed.
Session 44, NEW PRODUCTS & TECHNOLOGIES
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