Structural, rheological properties and antioxidant activities of polysaccharides from mulberry fruits (Murus alba L.) based on different extraction techniques with superfine grinding pretreatment.

The structural characteristics and biological activity of polysaccharides were influenced by different extraction methods. In this study, polysaccharides from mulberry fruits (Murus alba L., which were pre-treated with superfine grinding process) (MFP) were exacted using hot-water extraction (HWE), enzyme-assisted hot water extraction (EAHE), ultrasonic-assisted hot water extraction (UAHE), and high-speed shear homogenization-assisted hot water extraction (HSEHE). The extraction yield, structure, rheological properties and antioxidant activities of MFPs were investigated. MFP extracted using the HSEHE method have the highest extraction yields than other extraction methods. The smaller particle size of mulberry powder was found to improve the extraction yields. The MFPs were obtained by the combination between different extraction methods and superfine grinding pretreatment (through 100 mesh sieve) (MFP-HWE100, MFP-EAHE100, MFP-UAHE100, MFP-HSEHE100) showed the same levels of monosaccharide compositions and glycosyl linkages, However, these methods can produce MFP with different monosaccharide proportions, branching degree, different molecular weight, particle size and microstructure. MFP-HSEHE100 achieved the lowest molecular weight and particle size, which exhibited better thixotropy and antioxidant activities than other MFPs. This study identified that HSEHE was the most suitable extraction method for MFP.