Abstract:To elucidate the mechanism of the growth-promoting effect of seed melon polysaccharides on intestinal probiotics，seed melon polysaccharides were extracted by ultrasound-assisted water extraction method.Subsequently，three fractions（SMP-1，SMP-2 and SMP-3）were obtained by DEAE cellulose DE-52 isolation.They were used as a substitute for carbon sources to compare their growth-promoting effect on intestinal probiotics.Further structural characterization of SMP-1 was carried out for molecular weight，monosaccharide，and functional group composition.The results showed that SMP-1，SMP-2 and SMP-3 significantly promoted the growth of Bifidobacterium adolescentis，Bifidobacterium longum，Bifidobacterium infantis，lactobacillus acidophilus and the growth-promoting effects of different fractions were significantly different.Among them，the growth-promoting effect of SMP-1 was better than that of SMP-2 and SMP-3.The molecular weight of SMP-1 was 97 403 kDa.Moreover，SMP-1 was primarily comprised of arabinose and galactose，and the molar ratio between them was 0.271∶0.729.The main chain of SMP-1 was connected by→6）-β-D-Galp-（1→3）-β-D-Galp-（1→ glycosidic bond，while the end group α-L-Araf-（1→ was attached to the main chain by an O-3 bond.