FRUCTOSE SYRUPS AND ETHANOL-PRODUCTION BY SELECTIVE FERMENTATION OF INULIN

Jerusalem artichoke is a favorable substrate for inulin or fructose sy rup production. The sugar content and the fructose ratio of inulin dep end on various factors, particularly on the date of harvest. Incomplet e fermentation of extracts by selected yeasts allows the production of inulin with increased fructose content. The yeast strains (Saccharomy ces cerevisiae, S. diastaticus ...) are chosen for their ability to fe rment sucrose and inulin small polymers, but not easily inulin large p olymers. A good increase in the fructose ratio and a good yield in res idual sugars can be obtained with the better strains. After fermentati on and acid or enzymatic hydrolysis, extracts from ''early'' and ''lat e'' harvested tubers lead to syrups of good quality containing up to 9 5% and 90% of fructose respectively. This fermentative enrichment proc ess is competitive with others (for example, chromatographic enrichmen t), is appropriate to raw extracts, simplifies the purification steps, and also permits the simultaneous benefit of production of by-product s in the form of ethanol and yeast (in addition to the pulps). Unhydro lyzed inulin polymers with high fructose content can be recovered by t his selective fermentation.