Valorization of Peach Palm (Bactris gasipaes Kunth) Waste: Production of Antioxidant Xylooligosaccharides

In Brazil, the production and consumption of palm heart, especially from the Bactris gasipaes Kunth, generates a large number of lignocellulosic by-products. This study reports the obtainment of xylooligosaccharides (XOS) from xylans extracted from these residues. Xylans from peach palm waste (inner sheath and peel) were extracted using a mild alkali treatment with recovery yields of 82% and 80%, respectively. XOS were obtained through enzymatic hydrolysis employing a commercial xylanase with yields from xylan inner sheath and xylan peel of 50.1% and 48.8%, respectively. The antioxidant potential of XOS was measured employing five of the most commonly used procedures. In overall terms, the XOS from the xylans of peach palm wastes showed higher antioxidant capacity than the XOS obtained from the commercial xylans. The chemical structures of the XOS were determined by mass spectrometry (ESI–MS). The ESI–MS spectra suggest that XOS with grouped xylose or arabinose units ranging from 2 to 5 (differing by 132 Da) and as sodium adduct ions [M + Na]+ in the range of 100–1000 m/z. These results indicate that peach palm wastes can be explored to XOS production, which could be applied as natural antioxidants in functional food and pharmaceutical preparations.