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Submitted to: Journal of Cereal Science
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 6/5/2014 Publication Date: 8/16/2014 Citation: Liu, K. 2014. Fractionation of oats into products enriched with protein, beta-glucan, starch, or other carbohydrates. Journal of Cereal Science. 60:317-322 DOI:10.1016/j.jcs.2014.06.002. Interpretive Summary: Oat ranks sixth in world cereal production behind wheat, corn, rice, barley and sorghum. It has relatively higher contents of oil and protein with better quality than other cereal grains. Furthermore, oat is among very few grains that contain mixed linkage (1-4, 1-3) beta-D-glucan (BG), which is a soluble dietary fiber and has been shown to lower cholesterol. Many processing methods have been described to produce fractions enriched in protein, BG, and/or starch from oats. One common problem with wet extraction methods is that the alkaline slurry of ground oat groats becomes viscous and difficult to filter. Also, among the reported studies on oat fractionation almost all dealt with enrichment of one or two components, and many focused on nutrient concentrations in resulting fractions but neglected recovery. Furthermore, although both regular and defatted oat groats were used for BG or protein enrichment, there is no single study for a direct comparison of the two materials for fractionation. The present study dealt with developing a modified wet method to fractionate oats into value-added ingredients, each enriched with protein, beta-glucan, starch, or other carbohydrate Technical Abstract: A modified wet method was developed to fractionate ground oat groats into 4 fractions enriched with beta-glucan (BG), protein, starch, and other carbohydrates (CHO), respectively. Effects of defatting oats and centrifuge force for separation were also investigated. Results show that, depending on the two factors, nutrient concentrations in the corresponding fractions ranged 28.53-44.84% (dry matter) for BG, 72.41 to 92.62% for protein, 79.13-81.69% for starch, and 37.47-42.16% for other CHO. Nutrient recoveries from each fraction were 39.82-51.20% for BG, 60.36-72.08% for protein, 77.04-87.25% for starch, and 24.87-29.68% for other CHO. For the protein fraction, defatting improved the protein content but did not on its recovery. For the starch fraction, the effect of defatting was just opposite, improving the starch recovery but not the starch content. Centrifuge force increased the BG content in the BG fraction when the defatted sample was used. The cumulative recovery of each component in the combined fractions was not affected by oil removal or centrifuge force. Overall, the wet method described was relatively effective in recovering the major nutrients from oats into their respective fractions, while alleviated the problems of viscous slurry upon mixing ground oat groats with an alkaline solvent and difficulty of slurry separation. |
