| Jerusalem artichoke is a kind of perennial herbaceous plants that it with food and it is rich in inulin.lnulin is formed with fructose connected by the β-(1→2)which terminal is the unit of glucose.At present,inulin is a very popular functional food in the international market,and has broad application prospects in the fields of food,beverage,health care products,medicine and so on.This paper firstly studied the extraction technique and structure of inulin from Jerusalem artichoke,studied antioxidant activity of inulin and the analyzed its effects of on the growth of lactobacillus in vitro and the effect of HT-29 cells and Caco-2 cells studied.The main research contents are as follows:(1)Study on extraction process of inulin.Jerusalem artichoke powder as raw material,the best extraction conditions were determined through experiments.The optimal conditions were as fllows:solid:solvent ratio 1:30 m/v,ultrasonic power for 600W,ultrasonic time for 58 minutes,the extraction rate was 95.81%.(2)Study on the purification of inulin from Jerusalem artichoke.To crude extract of inulin impurities adopted the lime milk-phosphoric acid method,the best process condition was determined by the single factor experiment for pH 10,temperature 69 ℃,time of 10 min,from Jerusalem artichoke extract of impurity removal rate was 52.21%,Jerusalem artichoke inulin retained rate was 93.39%.After comparison,the S-8 macroporous resin was used to get better decolorization effect,after drying of alcohol precipitation and vacuum freezing and drying,separated and purified by Sephadex G-50 column chromatography from Jerusalem artichoke.The purity of the purified product was 96.97%.(3)The structures of the inulin had been characterized by several analytical methods:gas chromatography,FT-IR spectrum and NMR analysis.The average molecular weight of inulin 2784 Da and is degree of polymerization value was 17.The results showed that the Jerusalem artichoke inulin were composed of fructose residues linked by β-1-2)glucoside bond and one glucose residue linked byα-(1→2)glucoside bond at the end of linear straight sugar chain.(4)Study the antioxidation of Jerusalem artichoke inulin and the growth-promoting action of inulin on lactic acid bacteria in vitro.The results showed that the 0.10mg/ml concentration of inulin to DPPH free radical scavenging capacity of 91.30%,anti superoxide anion free radical ability of 205.59U/L,inhibition of hydroxyl radical rate was 96.00%;(5)The antibacterial activity of inulin and its effect on the proliferation of lactic acid bacteria were detected.The results showed that:low concentration of inulin can promote the growth of lactic acid bacteria,high concentration of inulin can inhibit the growth of lactic acid bacteria.In the concentration range,0.5%inulin of lactic acid bacteria growth promoting effect is most pronounced and of lactic acid bacteria against Escherichia coli,Staphylococcus aureus,Salmonella antimicrobial effect is synergistic effect.(6)By using MTT cell proliferation assay and fluorescence staining method of inulin on colon cancer cell HT-29 and Caco-2 cell growth inhibition,MTT test results show that in a certain range of concentration,inulin can significantly inhibited the growth of HT-29 and Caco-2 cells and presents certain dose and time effect relationship,the inhibitory effect on the growth of HT-29 cells and the inhibitory effect of ratio of Caco-2 is more obvious.Inulin concentration was 250μg/ml,HT-29 cells were cultured for 24h,48h,72h after,cell inhibition rate was 59.53%,63.41%and 66.46%respectively.Fluorescence staining method was used to detect the cell morphology,and different concentrations of chrysanthemum sugar can cause HT-29 cell morphological changes,cell nuclear condensation,and increased with the concentration of apoptotic bodies increased gradually. |
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