Effects of L.plantarum dy-1 fermentation time on the characteristic structure and antioxidant activity of barley β-glucan in vitro

This article explored the effect of Lactobacillus plantarum dy-1 (L. plantarum dy-1) fermentation on the basic physicochemical properties and associated in vitro antioxidant activity of barley β-glucan, including its molecular weight, monosaccharide composition, characteristic structure and rheology. Its DPPH, ABTS, hydroxyl radical scavenging capacity, and ferric reducing antioxidant potential (FRAP) were measured at different fermentation times. The results showed that the molecular weight of barley β-glucan was decreased from 1.052 × 105 Da to 4.965 × 104 Da within 0–24 h by L. plantarum dy-1 fermentation, but there was no effect on its characteristic structure. The water- and oil-holding properties of barley β-glucan were significantly enhanced with increased fermentation time, and the fluid viscous behavior of barley β-glucan was enhanced at 6% concentration, while elastic characteristics were weakened. The fermentation had no significant effect on the scavenging effect of DPPH and ABTS radicals of barley β-glucan, but the hydroxyl radical scavenging activity and total antioxidant capacity of FRAP were enhanced with increased fermentation time. Fermentation time may change the physicochemical properties and enhance antioxidant activity of barley β-glucan by reducing its molecular weight.