Preparation of L-arabinose from sugar beet

A method of preparing L-arabinose from sugar beet pulp comprises the steps of (a) treating sugar beet pulp with aqueous alkali to provide a crude araban extract; (b) treating the extract with a precipitating agent, such as carbon dioxide, to precipitate an insoluble salt from the extract; (c) removing the insoluble salt; (d) ultra-filtration to remove impurities and concentrate the extract; (e) acid hydrolysis of the purified extract to provide a crude L-arabinose solution; (f) ultra-filtration and neutralisation (in any order) of the solution to provide a purified L-arabinose solution, and (g) concentration and crystallisation of pure L-arabinose. Preferably, the method does not comprise a chromatographic purification step. The L-arabinose solution may also undergo treatment with an anionic exchange resin to remove anionic impurities and may be contacted with a polymeric adsorption resin to decolourise the solution. The crystalline product typically comprises 97-99% L-arabinose.