Seperation, Structure Analysis Of Banana Oligosaccharides From Different Cultivars

This study was designed to extract the banana oligosaccharides from different bananacultivars, including Xiangyajiao,Dajiao,Fenjiao,Huangdijiao, and further isolation andpurifiation, identification analysis on the banana oligosaccharide structure, monosaccharidecomposition, glycosidic linkages, were carried out.The ultrasonic assistant extraction, ultrahigh pressure assistant extraction,microwaveassistant extraction and solvent extraction methods werecompared in extraction efficiency ofbanana oligosaccharides and were then optimized by orthogonal experiments. Resultsshowed that the optimized parameters for solvent extraction method as follows: ethanolconcentration was25%, water bath temperature was50℃, extraction time was40min, theratio of material to solvent was1︰2, by which the yield of oligosaccharides from banana was14.73±0.52%. The optimum conditions for ultrasonic assistant extraction were as follows:total ultrasonic treating time was40min, ultrasonic power was500W, the ratio of material tosolvent (w/v) was1︰2.5, by which the yield of oligosaccharides was17.89±0.57%. Theoptimum conditions for microwave assistant extractionwere as follows: total microwavetreating time was2.5min, microwave power was462W, the ratio of material to solvent (w/v)was1︰15, by which the yield of oligosaccharides was17.72±0.49%. The optimumconditions for ultrahigh pressure assistant extraction were as follows: total ultrahigh pressuretreating time was15min, ultrahigh pressure was300MPa, the ratio of material to solvent (w/v)was1︰2, by which the yield of oligosaccharides was8.05±0.03%. Among the abovemethods, ultrasonic assistant extraction methodwas the best method for the extraction ofbanana oligosaccharides considering the yield of oligosaccharides and cost.Sephadex G-25and DEAE sepharose fast flow column chromatography were used forfurther separation and purification of oligosaccharides fromXiangyajiao,Fenjiao,Huangdijiaocultivars. The results showed that Sephadex G-25was betterthan DEAE sepharose fast flow in efficiency. Sephadex G-25analysis results showed that theelution curve had four peaks. oligosaccharides-Ⅰ prepared from the all three cultivars(Xiangyajiao,Fenjiao,Huangdijiao) showed similar in physical characters,such as state, flaor,water-solubility, ethanol-solubility.The structural analysis on the oligosaccharides-Ⅰprepared fromXiangyajiao,Fenjiao,Huangdijiaocultivars were performed. Mass spectrometry (MS) was usedto determine the molecular weight; Thin layer chromatography (TLC) and high performance liquid chromatography (HPLC) were used to analyze the monosaccharide composition; Theindicant bond and structure of oligosaccharides were employed to analyze by using Fouriertransform infrared spectroscopy and nuclear magnetic resonance. Results showed thatoligosaccharides-Ⅰfrom Xiangyajiao cultivar was composed of one β-D-pyran glucose unitlinked with C3-C5and seven β-D-pyran mannose units linked with C1-C5;oligosaccharides-Ⅰ from Fenjiao cultivar was composed of one β-D-pyran glucose unitlinked with C1-C6, seven β-D-pyran mannose units linked with C4-C6, one β-D-pyranfructose unit linked with C1-C6; oligosaccharides-Ⅰ from Huangdijiao cultivar wascomposed of four β-D-pyran glucose units linked with C1-C6and six β-D-pyran mannoseunits linked with C2-C6.