Extraction and characterization of bioactive oligosaccharides from pulse processing byproducts using subcritical...

This study aimed to convert insoluble fiber byproducts of black bean and lentil protein extraction into bioactive oligosaccharides using subcritical water extraction (SWE). A screening of temperatures (120, 160, 200 °C) and extraction times (up to 1 h) demonstrated that SWE at 200 °C generated a diverse oligosaccharide profile rich in pentose-oligosaccharides. SWEs using 20 g dry mass of material at 200 °C achieved estimated oligosaccharide recovery yields of 10.9% and 9.6% (g/g) from de-starched bean and lentil insoluble fibers, respectively. While the oligosaccharides in the pre-equilibrium fraction (i.e., temperature/pressure ramping period) were primarily comprised of glucose (β-glucan and/or starch-derived), fractions collected after reaching target subcritical conditions generated oligosaccharides containing xylose, galactose, and arabinose (hemicellulose-derived). Select strains of Lactobacillus and Bifidobacterium grew with some subcritical extracts as the sole carbon source. This proof-of-concept study demonstrated the efficacy of SWE in valorizing pulse byproducts into oligosaccharide-rich extracts with nutraceutical potential.