Freeze-Thaw Treatment in 2 w/w NaOH-6 M Urea Enhanced Extraction of β-(1,3;1,4)-Glucan from Corn Pericarp

摘要

Enhancement of the extraction rate of b-glucan from corn pericarp (CP) by repeated freeze-thaw treatment of 2% w/w NaOH-6 M urea solution was investigated with emphasis on the association of b-glucan with cellulose in CP. Three freeze-thaw cycles were found to be adequate for extraction of b-glucan at a rate of 97.8%. The increase in extraction rate induced by the freeze-thaw treatment was estimated to be approximately 20%. The natural cellulose I structure of the cellulose in CP was disrupted by the freeze-thaw treatment, suggesting that the increase was due to greater b-glucan solubilization owing to the disruption of its association with cellulose by hydrogen bonds. The applicability of the present technique to other cereals was also demonstrated; extraction rates of 82.8% for oat meal and 92.5% for barley flour were achieved.