Influence of fermentation with lactic bacteria on the structure, functional properties and antioxidant activity of flaxseed gum.

ABSTRACT

Flaxseed meal is a by-product of flaxseed oil extraction. In this research, lactic acid bacteria suitable for modification of flaxseed gum were screened based on cellulase activity and the extraction rate of flaxseed gum. The enzyme-weight method was employed to extract flaxseed gum (SDF). The influences of fermentation modification on the extraction yield, structure, function, and antioxidant activity of flaxseed gum was investigated. Based on the enzyme-producing activity and extraction rate, Lactobacillus plantarum (LP-3), Bacillus paracaetocasei (KLDS-82), and Lactobacillus acidophilus (LAC-11) were identified as the most suitable strains for modifying flaxseed gum. The results indicated that the extraction yield of flaxseed gum was 18.45 % ± 0.2 % after fermentation with KLDS-82, which was significantly higher than that of the unmodified group. After fermentation, the microstructure of flaxseed gum became looser and more porous. The characteristic absorption peak of polysaccharide was observed through scanning electron microscopy (SEM), Fourier transform infrared (FT-IR), and X-ray diffraction (XRD), and the crystallization area was reduced. Simultaneously, its swelling capacity, water-holding capacity, oil-holding capacity, and other physicochemical properties have also been enhanced. The glucose adsorption capacity, cholesterol adsorption capacity, sodium cholic acid adsorption capacity, cation exchange capacity, α-glucosidase inhibitory activity, and antioxidant properties of SDF modified by Bacillus paracaetocasei (F-SDF) were significantly higher than those of Lactobacillus acidophilus modified SDF (S-SDF), Lactobacillus plantarum modified SDF (Z-SDF), and unmodified SDF (U-SDF). In conclusion, the modification effect of KLDS-82 is the most remarkable. Therefore, it can be utilized as a functional raw material in food.