Abstract:Insoluble dietary fiber （IDF） was extracted from pomace，a by-product of Morella rubra fruit processing，through five different methods：acid-alkali method，ultrasound-assisted alkali method，microwaveassisted method，dual-enzyme method，and ultrasound-assisted enzyme method. A comparative study was conducted on the physicochemical properties，antioxidant activity，and in vitro blood glucose-lowering activity of the IDF obtained from these five methods. The results showed significant differences in the extraction yields of IDF. The dual-enzyme，microwave-assisted，and ultrasound-assisted enzyme methods had higher yields of IDF，whereas the acid-alkali method resulted in the lowest yield. The IDF extracted by the ultrasound-assisted alkali method exhibited a higher swelling capacity. Compared with that obtained via other methods，the IDF obtained via the dual-enzyme method demonstrated superior water-holding and oil-holding capacities. The biological activities of the IDF varied obviously depending on the extraction method. Regarding antioxidant activity，the systematic multi-index evaluation （involving DPPH free radical scavenging activity，hydroxyl free radical scavenging activity，and ferric reducing antioxidant power） revealed that the IDF extracted by the ultrasound-assisted alkali method exhibited stronger antioxidant capacity. In terms of blood glucose-lowering effects，the product obtained via the acid-alkali method showed a better inhibitory effect on α-glucosidase activity and demonstrated excellent glucose adsorption capacity.