One-Step Fractionation of Xylo-oligosaccharides Using Nanofiltration Membranes to Obtain Hydrolysates with Distinct Biological Activities

Xylo-oligosaccharides (XOS) are oligomers obtained through the hydrolysis of xylan that exhibit distinct biological activities. This study aimed to apply nanofiltration in an XOS suspension obtained by enzyme-assisted hydrolysis of xylan and evaluate the antioxidant and antidiabetic activities of the fractions obtained. The NP030 nanofiltration membrane demonstrated superior XOS fractionation performance, boasting a high selectivity (1.29 ± 0.10) in separating XOS with high-polymerization degree (xylotetraose and xylopentose) from xylose. The crude xylan hydrolysate exhibited antioxidant capacities of 160.70 ± 1.32 μmol Trolox.g⁻¹ and 268.45 ± 16.57 μmol FeII.g⁻¹ according to the 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and ferric reducing antioxidant power (FRAP) methods, respectively. However, the retentate fraction in the nanofiltration membranes showed greater antioxidant capacity than did the crude hydrolysate or the permeate fraction, reaching 309.01 ± 0.81 μmol Trolox.g⁻¹ and 464.20 ± 28.10 μmol FeII.g⁻¹ for the ABTS and FRAP methods, respectively. In addition, the hydrolysate inhibited the enzyme α-amylase by 30.14 ± 3.94%, and this activity improved after the fractionation process, reaching an inhibition of 77.09 ± 24.76% for the permeate fraction. Thus, one-step fractionation improved the beechwood xylan hydrolysate’s antioxidant and antidiabetic activities. This duality of functional benefits provides a promising outlook for future industrial applications highlighting the versatility and unexplored biological potential of fractionated XOS.