Fermentation of grapefruit peel by an efficient cellulose-degrading strain, (Penicillium YZ-1): Modification, structure and functional properties of soluble dietary fiber

In the study, a highly efficient cellulose-degrading strain was screened, which was identified as a fungus in the genus Penicillium sp., named YZ-1. The content of soluble dietary fiber was greatly increased by the treatment of this strain. In addition, the effects of soluble dietary fiber from high-pressure cooking group (HG-SDF), strain fermentation group (FG-SDF) and control group (CK-SDF) on the physicochemical structure, and in vitro hypolipidemic activity were investigated. The results showed that the physicochemical structure of the raw materials was improved after fermentation, and FG-SDF exhibited the loosest structure, the highest viscosity and thermal stability. Furthermore, compared to CK-SDF and HG-SDF, FG-SDF showed the most significant improvement in functional properties, including cholesterol adsorption capacity (CAC), inhibition of pancreatic lipase activity (LI) and mixed bile acid adsorption capacity (BBC). Overall, these findings will provide new insights into dietary fiber modification and improve the comprehensive use value of grapefruit by-products.