Soybean whey is a high-yield but low-utilization agricultural by-product in China. In this study, soybean whey was used as a substrate of fermentation by Lacticaseibacillus plantarum 70810 strains. An exopolysaccharide (LPEPS-1) was isolated from soybean whey fermentation by L. plantarum 70810 and purified by ion-exchange chromatography. Its preliminary structural characteristics and antioxidant activity were investigated. Results show that LPEPS-1 was composed of mannose, glucose, and galactose with molar ratios of 1.49:1.67:1.00. The chemical structure of LPEPS-1 consisted of →4)-α-D-Glcp-(1→, →3)-α-D-Galp-(1→ and →2)-α-D-Manp-(1→. Scanning electron microscopy (SEM) revealed that LPEPS-1 had a relatively rough surface. In addition, LPPES-1 exhibited strong scavenging activity against DPPH and superoxide radicals and chelating ability on ferrous ion. This study demonstrated that soybean whey was a feasible fermentation substrate for the production of polysaccharide from L. plantarum 70810 and that the polysaccharide could be used as a promising ingredient for health-beneficial functional foods.

polysaccharide, fermentation, structure characterization, Antioxidant activity, Lacticaseibacillus plantarum 70810, soybean whey

13C NMR data:
Linkage	Residue	C1	C2	C3	C4	C5	C6
	aDGlcp	102.19	73.88	75.13	79.52	73.88	63.11


1H NMR data:
Linkage	Residue	H1	H2	H3	H4	H5	H6
	aDGlcp	5.37	3.58	3.93	3.67	3.78	3.82


1H/13C HSQC data:
Linkage	Residue	C1/H1	C2/H2	C3/H3	C4/H4	C5/H5	C6/H6
	aDGlcp	102.19/5.37	73.88/3.58	75.13/3.93	79.52/3.67	73.88/3.78	63.11/3.82

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

*O[C@H]1[C@H](O)[C@@H](O)[C@@H](*)O[C@@H]1CO

162.141 g/mol (C₆H₁₀R₂O₅, R = next and previous repeats, not counted in mol weight)