Inulin Potential for Enzymatic Obtaining of Prebiotic Oligosaccharides

Abstract

Oligosaccharides have been marketed since the 80s as low-calorie agents and recently have gained interest in the pharmaceutical and food industry as functional sweeteners and prebiotic enriching population of Bifidobacteria. Currently, they have an approximated value of $200 per kg and recently, inulin has been proposed as a feedstock for production of oligosaccharides through selective hydrolysis by action of endoinulinase. High optimum temperature (60°C) and thermostability are two important criteria that determine suitability of this enzyme for industrial applications as well as enzyme cost, a major limiting factor. Significant reduction in cost can be achieved by employing low-value and abundant inulin-rich plants as Jerusalem artichoke, dahlia, yacon, garlic, and onion, among others. In general, the early harvested tubers of these plants contain a greater amount of highly polymerized sugar fractions, which offer more industrial value than late-harvested tubers or those after storage. Also, development of recombinant microorganisms could be useful to reduce the cost of enzyme technology for large-scale production of oligosaccharides. In the case of fungal inulinases, several studies of cloning and modification have been made to achieve greater efficiency. The present paper reviews inulin from vegetable sources as feedstock for oligosaccharides production through the action of inulinases, the impact of polymerization degree of inulin and its availability, and some strategies to increase oligosaccharide production.

Keywords: Endoinulinases; inulin; polymerization degree; prebiotics; thermostability.