Strategies for Fructo-oligosaccharides production with high-content and purity

Abstract

[Excerpt] The consumers’ interest in healthy and high nutritional food has significantly increased in the recent years. This trend towards the adoption of healthier lifestyles has been the main driver for the great demand of functional ingredients, such as the prebiotics fructo-oligosaccharides (FOS). Industrially, FOS are produced from sucrose through purified enzymes, in two-step bioprocesses, with low theoretical yields (0.50-0.55 gFOS.gSucrose-1) and purities (50-55%). Downstream steps are therefore needed to remove the non-prebiotic sugars and enable the incorporation of these FOS mixtures in diabetic, dietetic and healthy foods. In the last ten years, we have been investigating new strategies to produce FOS with higher contents, purities and differentiated functionalities. We have been exploring Aureobasidium pullulans and Aspergillus ibericus as FOS producers, in one-step fermentation processes, using the whole cells of the microorganisms instead of the isolated enzymes. This strategy proved to be efficient, fast and economic, yielding 0.64 gFOS.gSucrose-1. The FOS mixtures produced were able to stimulate the growth of probiotic strains and were simultaneously resistant to hydrolysis along the gastrointestinal system confirming their health claims as prebiotics. The probiotic strains preferentially metabolized the FOS mixture synthesized by A. ibericus, followed by the one from A. pullulans and lastly the commercial FOS. [...]