Molecular properties and antioxidant activities of polysaccharide-protein complexes from selected mushrooms by ultrasound-assisted extraction

Ultrasound-assisted extraction (UAE) was evaluated for isolation of polysaccharide-protein (PSP) complexes from three important medicinal mushrooms (Grifola frondosa, Coriolus versicolor and Lentinus edodes). Compared with those of conventional hot-water extraction (HWE), the PSP yield of UAE was similar with G. frondosa, notably higher with L. edodes but lower with C. versicolor, and the extraction rate of UAE was notably higher with G. frondosa and L. edodes but much lower with C. versicolor. The PSPs from all three mushrooms by UAE had higher protein but lower carbohydrate contents than those by HWE, and their molecular weight (MW) profiles exhibited an overall shift to lower MW and a major low-MW peak near 1.0 kDa. All PSPs from UAE but none from HWE exhibited 3-4 distinct protein bands between 10 and 130 kDa. The antioxidant activities of PSPs extracted by UAE were generally higher than those by HWE.