The Investigation Of The Prebiotic Properties Of Neoagaro-oligosaccharides

Prebiotics are defined as non-digestible food ingredients that beneficially affect the host by selectively stimulating the growth and/or activity of one or a limited number of bacteria in the colon, which can improve the host health. Because of the beneficial effects, such as preventing intestinal infection,advancing immune function, modulating blood lipids, cancer prevention and therapy et al, prebiotics have caught more and more attentions recently. And a considerable amount of researches have been performed on developing new prebiotics. The non-digestible oligosaccharides (NDOs), just like inulin and fructo-oligosaccharides (FOS), are regarded as nice prebiotics and used most widely. By now, more than 20 kinds of NDOs have been used commercially. But none of them is extracted from marine organism. The neoagaro-oligosaccharides (NAOS) is a kind of neuteroligosaccharides and prepared by enzymatic hydrolysis from agar or agarose withβ-agarases. Bioactivity studies demonstrated that NAOS showed almost no physiological functions. The aim of this study is to determine, through in vitro and in vivo examination about influences on intestinal microbial flora, the potential application of NAOS as prebiotics, and the relationship between the prebiotic effectiveness and degrees of polymerization.In previous studies, we cloned twoβ-agarase genes, agaA and agaB, from marine Pseudoalteromonas sp. CY24. The recombinant AgaA and AgaB show high activity and specificity. When agarose is used as the substrate, the final products of AgaA , referred to as NAOS-A, are mainly neoagarotetraose (51.1%) and neoagarohexaose (48.9%), whereas the hydrolytic products of AgaB, referred to as NAOS-B, are mainly comprised of neoagarooctaose (42.5%), neoagarodecaose (37.8%) and neoagarododecaose (19.7%).Firstly,in vitro digestion experiments demonstrated that NAOS was highly...