Study On The Preparation Of Phosphoryl Oligosaccharides From Potato Starch By Enzymatic Technology

Phosphoryl Oligosaccharides,newly produced malto oligosaccharides(DP3～7) having C-O-P groups in their molecules,are isolated from potato starch hydrolysate.It is a new type of functional oligosaccharides with many functional properties.For example,it could inhibit the formation of calcium phosphate,prevent caries and suppress the retrogradation of starch.Researches on POs started from 90's of the last century.At present, products can be found in the markets of Japan,mainly to Phosphoryl Oligosaccharides of calcium(Pos-Ca).Until recently,there have been little researches on POs in China.In order to develop this new kind of oligosaccharide and to make full use of raw material of potato starch,the experiments on POs have been initiated and the objective of this dissertation is to prepare Pos from potato starch by enzymatic hydrolysis.In this thesis,maltooligosaccharides with a low dextrose equivalent(DE)were prepared from potato starch,and then Pos were separated from it by column layer analysis. The qualitative analysis of Pos was also presented.This Study established theoretical and practical basis for the further research in preparation technology,and also benefited the early realization of its application and industrial production.A jet liquefaction process was adopted to prepare maltose oligosaccharides with a low dextrose equivalent.The following conditions of the process are obtained:Potato starch with the concentration of 7°Bé,thermostableα-amylase with the amount of 167,2000U,jet liquefaction temperature 105℃,liquefaction with the temperature and time of 95℃and 30min respectively.And then glucoamytase with the amount of 1075,7900U was added to the syrup and maintained for 60min at 60℃.In final,amylase was deactivated for 10min at 100℃.The composition of maltooligosaccharides was analyzed by HPLC.The result showed that glucose and maltose oligosaccharides(mainly to DP2, DP3,DP4,DP5)were included in the sample we prepared.Weakly basic anion-exchange resin HJ-30 and HJ-31 were Surveyed according to the yield for Pos.The results demonstrated that:the Pos yields of HJ-30 and HJ-31 were 87.3%and 74.1%respectively,so the former was obviously better than the latter.Using HJ-30 as the column packing,influence of the solvent concentration and the ratio of elution on the separation of Pos was investigated.The result indicated that the optimum conditions to prepare Pos were as follows:after eluting neutral oligosaccharides with de-ionized waters,Pos was obtained with 0.5mol/L NaCl and the eluting rate was 1.2ml/min.Structural analysis of POs was done by infrared chromatography.The results showed that thereare phosphate ester bonds in the sample.TLC and HPAEC were also empolyed in the qualitative analysis of POs.For TLC,the optimum solvent(butyl alcohol:acetic acid: water=3:1:1)and Visualization reagent(aniline-Diphenylamine-phosphorous acid)were presented by optimizing the condition of solvent and Visualization reagent.The results demonstrated that there were four carbohydrate components(DP3～7)in the sample of Pos at least.For HPAEC,the results demonstrated that at least one or more kinds of oligosaccharides(included G1～G7)in sample of Pos.