Effects of enzymes combined with Lactobacillus plantarum and Bifidobacterium on the properties and in vitro hypoglycemic activity of sea buckthorn insoluble dietary fiber

Abstract

Sea buckthorn seed meal is rich in insoluble dietary fiber (IDF), which is a by-product of sea buckthorn oil extraction. The effects of an environmentally friendly combination of microbial fermentation (Lactobacillus plantarum and Bifidobacterium) and enzymatic hydrolysis (cellulase and xylanase) on the structure, physicochemical and in vitro hypoglycemic activity of IDF in sea buckthorn seed meal were studied. Compared with the untreated IDF sample, the surface structure of the modified IDF was loose and porous, with reduced crystallinity and thermal stability. The water/oil holding capacity, swelling capacity, cationic exchange capacity (0.20 ± 0.01 mmol/g), the adsorption capacity of glucose (85.83 ± 1.04 mg/g), nitrite ion adsorption capacity (1351 ± 0.47 μg/g), cholesterol adsorption capacity (15 ± 0.53 mg/g), inhibition the activity of α-amylase and α-glucosidase of IDF were also effectively increased. Correlation analysis indicated that the adsorption capacity of IDF exhibited a negative correlation with both particle size and relative crystallinity while demonstrating a positive correlation with the specific surface area of IDF. The findings suggest that this modification method effectively improves the structural, physicochemical, and functional properties of sea buckthorn seed meal IDF, thereby increasing its economic value.