ALKALINE EXTRACTION AND CHARACTERIZATION OF HETEROXYLANS FROM MAIZE BRAN

Response surface methodology was used to study the alkaline extraction of heteroxylans from maize bran. The ratio volume of alkali/weight of bran and the particle size had no effect on extraction yield, whereas the yield increased significantly with the temperature and time of extraction and the concentration of the alkali. The variation in the yield depended on the nature of the alkali, and empirical second-order models were built to fit the results obtained by extraction with KOH and Ca(OH)(2). Comparison of the compositional and structural features of the heteroxylans obtained by extraction with 0.8 M KOH at 85 degrees C, saturated Ca(OH)(2) at 95 degrees C and 0.5 M KOH at 65 degrees C with one obtained by industrial lime-cooking of maize kernels showed that all four samples were very similar and that a very high extraction yield (87%) was achieved.