Production of High-Fructose-Containing Syrups from Jerusalem Artichoke Extracts with Fructose Enrichment Through Fermentation

Abstract

Jerusalem artichoke is a suitable raw material for fructose syrup production. The sugar content and the inulin/fructose ratio depend on various factors, in particular on the date of harvest. Incomplete fermentation of extracts by selected yeasts allows the production of syrups with increased fructose content. The yeast strains used ( Saccharomyces cerevisiae, S. diastaticus, Schizosaccharomyces pombe and others) readily ferment sucrose and inulin oligomers, but not easily larger inulin polymers. The better strains bring about a distinct increase in the fructose/inulin ratio with a good yield in residual sugars. After fermentation of low-molecular-weight saccharides, followed by acid or enzymatic hydrolysis extracts of early and late harvested tubers led to syrups of good quality containing up to 95% and 90% fructose, respectively. This fermentative enrichment process is competitive with other ones ( e.g. chromatographic enrichment) employed in the technical production of fructose syrups: it can be applied in case of raw extracts, it simplifies purification and it permits a simultaneous valorization of by-products such as ethanol and yeast (in addition to the pulps).