| Chinese jujube (Ziziphus jujuba Mill.), a native plant of China, belongs to thegenus Ziziphus (Rhamnaceae) and is a medicinal plant of China which has a long historyof over7000years and is widely distributed in China with a total growing area of over2,000,000hectares. Chinese jujube has activities of nourishing blood, sedation, antitumoreffect, immune-modulability, etc, known as "natural health food". Chinese jujube fruit isfamous for its high content sugar. Generally, total sugar content in the dry jujube is ashigh as60-80%, in the fresh jujube is25-30%. Our previous researches revealed thatjujube fruit is not only rich in the glucose, fructose and sucrose, pectic polysaccharidecontent is rich, but also contain functional oligosaccharides. Until recently, there is somelack of knowledge about extraction, purification and there is little information availablein literature about preparation oligosaccharides by degrading water-solublepolysaccharide. In order to utilize the jujube reasonably and develop functional food, thisstudy analyzed the changes of carbohydrate content in fruits of different cultivars,developing stage and different organs. Moreover, the biological activities ofoligosaccharides from Chinese jujube fruis and degrading polysaccharide, and werestudied.The results were as follows:1. The changes of carbohydrate including monosaccharide, oligosaccharide,polysaccharides, reducing sugars and total sugars in fruits of ‘Jinsixiaozao’,‘Dongzao’and ‘Zanhuangdazao’, different developing stages and different organs were determinedby HPLC and spectrophotometer method. The result showed that the contents in fruits ofdifferent developing stage were increasing firstly, then falling and contents ofoligosaccharide was gradually reducing, but contents of total soluble sugar increasing continuously. The comparition of composition of sugar in ripe fruit was sucrose＞fructose＞glucose＞polysaccharide＞oligosaccharide. The content of polysaccharide inflower was higher than in fruit but the content of sucrose in flower was lower.2. The full red fruit powder of ‘Jinsixiaozao’ were extracted with distilled water. After removed polysaccharide by precipitation with alcohol from the aqueous extract, wegot crude oligosaccharide solution. After DEAE Sepharose chromatography and Bio gelp-2chromatography, one oligosaccharide was purified, and it was a disaccharide outsidethe sucrose, lactose and maltose. The500Da nanofiltration membranes were used to getnatural oligosaccharide from crude oligosaccharides solution.3. Degradation of polysaccharide from Chinese jujube ‘Jinsixiaozao’ were studied inthis paper. Through the response surface model, the degradation conditions ofpolysaccharide by using acid hydrolysis and enzymatic hydrolysis were optimized underthe laboratory condition. The results showed that the best acidolysis condition for jujubepolysaccharide fragment into oligosaccharides with HCl0.6mol/L, substrateconcentration3%, reaction time1h. The total rate of degradation was66.87%under thebest condition. And the best enzymolysis condition for jujube polysaccharide fragmentinto oligosaccharides with cellulose solution (4.0mL) and substrate solution (0.5mL) inthe5ml reaction system, reaction time7.3h. The total rate of degradation was41.38%under the best condition.4. Based on the stimulation effect on animal intestinal probiotics proliferation, thebiological activities of oligosaccharides were determined. The results showed when theconcentration of adding natural oligosaccharides was1.0%the promotable effect onchicken-original J-4was the best. The concentration of adding natural oligosaccharideswas0.5%, the promotable effect on chicken-original JM-11, rabbit-original Tu-569andswine-original Z-27is the best and higher concentration of natural oligosaccharides wasbad for their growth. Compared to natural oligosaccharides, the oligosaccharides bypolysaccharides degradation revealed lower activitied. And compared to theoligosaccharides by hydrochloric acid hydrolysis, the activity of oligosaccharides byenzymolysis was higher. |
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