Extraction and partial characterization of feruloylated glucuronoarabinoxylans from wheat bran
1998
Schooneveld-Bergmans, M.E.F. | Hopman, A.M.C.P. | Beldman, G. | Voragen, A.G.J.
Feruloylated glucuronoarabinoxylans were extracted from wheat bran by means of cold water, steam and dilute alkali, yielding approximately 1, 20 and 3%, respectively, of the glucuronoarabinoxylans originally present in the bran. The extracts had ferulic acid contents ranging from 0.1 to 0.6% (w/w). Both the cold water and steam extract had a low total sugar content and a relatively low content of high molecular weight material. Moreover, the ferulic acid content of the water extract was low (0.1%) and the amount of degradation products in the steam extract was relatively large. Both extracts appeared to give no increase in viscosity upon addition of oxidative reagents, such as hydrogen peroxide plus peroxidase or ammonium persulphate. The alkaline extracts obtained with saturated calcium hydroxide or 0.05 M barium hydroxide had high total sugar contents, the majority of which was accounted for by glucuronoarabinoxylan (>90%). These extracts had moderate ferulic acid contents of 0.3% and consisted predominantly of high molecular weight material. Addition of oxidative reagents resulted in an increase of viscosity. The extent of this increase in viscosity was shown to be influenced by the oxidative reagent used, the purity of the extract, its molecular weight distribution and the degree of substitution of the glucuronoarabinoxylan.
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