Research On The Production Of Inulin From Jerusalem Artichoke And Its Degradation To Fructooligosaccharide

Jerusalem artichoke(Topinambur), is widely cultivated in china and it is one of the most promsing non-food energy plants in our country. Jerusalem artichoke was wasted greatly because of being pickled vegetables. Chicory root is rich in inulin. Inulin is a natural fructans,formed with fructose connected by the bond β(2â†'1) which terminal is unit of glucose. The degree of polymerization is from 2 to 60, and the average degree is about 10. It has a variety of excellent functional properties which can be widely used as functional components in food and health products industry. This paper firstly studied on the extraction and purification of inulin, and then discussed the enzymatic hydrolysis of inulin, finally discussed the purification of fructooligosaccharide. The main contents are as follows:(1) The composition of artichoke was analysizd. The level of total sugar, reducing sugar,fat, ash and moisture were 16.89%, 1.43%, 2.66%, 0.22%, 2.42% and 75.80%. And the extraction of inulin was studied, to optimize the extraction. Time, temperature, solid-liquid ratio, pH and times were studied. The optimal conditions were as follows: the time was 60 min, temperature was 85℃, solid-liquid ratio was 1:16, pH was 6.5 and the time of extraction was 2. The extraction rate was 94.67%.(2) The purification of inulin was studied. It was Purified by ultrafiltration and ion exchange resin. The process of ultrafiltration was studied. And the optimal conditions were as follows: operation pressure of 0.65 MPa, circulating flow rate of 2 L/min, feed concentration of 40 mg/mL, pH 6.5, 45℃and twice; In this conditions, the transmission rate of inulin was92.24%, and the removal rate of protein is 93.59%. The purification process of ion exchange resin was studied. And the optimal conditions were as follows: pH was 6.0, temperature was50℃, 80 min, treatment capacity was 3 times of anion exchange resin, anion exchange resin and cation exchange resin was 1:1.5(v:v); In this conditions, the decolorization rate was96.16% and the desalination rate was 98.30%. Further purification of ultrafiltration with molecular weight of 1000 to separate fructose, sucrose and inulin. The purity of inulin was98.3% analysed by HPLC.(3) Based on the purification of inulin, the enzymatic hydrolysis of inulin by endoinulinase was studied. The content of monosaccharide,sucrose and fructooligosaccharide were analysed by HPLC. The optimal conditions of enzymatic hydrolysis were shown as follows:15%(w/w) inulin, pH 5.5, temperature was 55℃, 26 h and the enzyme concent raion of 12 U/g substrate; the content of fructooligosaccharide was up to 77.65% from 25%.(4) The purification technology of fructooligosaccharide was studied. CSR-1Na was selected. And the optimal conditions were: 60℃, pH 6.0~6.5, feed concentration was 55%and the volume flow rate was 1.5 mL/min; In this conditions, the recovery rate of the fructooligosaccharide with a purity of more than 95% was 83.26%, and it is in line with thenational standards.In the product, kestose accoutde for 35.6%, nystose accoutde for 28.27%,1F-Fructofuranosyl nystose accoutde for 23.31%, fructooligosaccharide accoutde for 97.85%,and its purity meets the requirements of the product.