| Wheat bran is one of the by-product of wheat processing, its output accounts for about 20% of the volume of wheat, wheat bran is rich in cellulose and semi cellulose, the main component of hemicellulose is xylan, xylooligosaccharide is prepared from xylan by enzymatic. In this study, enzymatic method was used to prepare xylooligosaccharide from xylan which was extracted from wheat bran. Its antioxidant activity and physicochemical property were studied in this paper. These subject main aspects and the results were represented as follows:(1)Response Surface Methodology (RSM) was used on the experiment of xylan by ultrasonic assisted alkali method from wheat bran. On the basis of, select the level of experimental factors. According to the result of single factor tests and the experimental design principles of the Centrl Composite Design(CCD), Investigate the influence of four factors of xylan content:ultrasonic power, ultrasonic time. NaOH concentration, temperature of preparation, The xylan content in response to the value of establishing mathematical model, The optimum conditions were as follow:the ultrasonic power was 348w. ultrasonic time was 32min. NaOH concentration was 3.18%, temperature was 68℃, Under this condition,19.92% was produced.(2)Response Surface Methodology (RSM) was used to optimize the processing of enzymatic preparation of xylooligosaccharide from wheat bran. On the basis of, select the level of experimental factors. According to the result of single factor tests and the experimental design principles of the Box-Benhnken central composite design (BBD), using four factors and three levels of response surface methodology to analyse each factor. The reducing sugar content in response to the value of establishing mathematical model, The optimum conditions were as follow:the pH was 6.3, zymohydrolysis time was 76min, the accession of the xylan was 790U/g, zymohydrolysis temperature was 63.3℃, Under this condition,5.22mg/mL reducing sugar was produced.(3)The HPLC method was used for detecting the xylooligosaccharide. Its component and physicochemical property were studied. The results showed that: Column for HP-Amino(150mm×4.6mm,5μm), mobile phase of acetonitrile:water (V:V)= 85:15, flow rate:1.0ml/min, column temperature:30℃, Differential refractive index detector. Concentration of xylose xylobiose xylotriose and xylotetraose were 0.417mg/mL,0.604mg/mL,0.347mg/mL,0.288mg/mL. The percentage were 8.34%,12.08%,6.94%,5.74%. The sweetness of xylooligosac-charide is 25%; The degree of polymerization was 3.243; it had good stability in pH2-8; the viscosity decreased with increasing temperature and increased as the concentrations increased.(4)The antioxidant activity of xylooligosaccharide was studied by determining clearance rates of free radicals and the experiment the mice. The experiments of antioxidant activity of xylooligosaccharide had shown that clearance rates of I mg/mLxylooligosaccharide to DPPH free radicals and hydroxyl free radicals reached to 76.55% and 80.30% respectively.However,it showed a weak inhibiting effect on uperoxide anion free radicals, the maximum clearance rate was only 41.12%.In conclusion, xylooligosaccharide showed effectively free radicals and a well antioxidant activity. The content of MDA in mouse liver has a significant difference between the high group(4.68 nmol/mL) and normal group(6.08 nmol/mL),and in mouse serum the high the middle and the low group (7.47、7.68、7.72 nmol/mL) were significant different with the normal group (8.67 nmol/mL).But in mouse brain there was no significant difference between them; GSH-Px activity in the mouse liver the high the middle and the low group (320.30、297.62、284.83 U/mL) were significant different with the normal group(227.42 U/mL). in mouse serum the high(308.98 U/mL) and the middle(314.48 U/mL) were significant different with the normal group(228.11 U/mL). in mouse brain the high the middle and the low group (184.47、 144.72、139.78 U/mL) were significant different with the normal group (124.15 U/mL); CAT activity in the mouse liver the high group(18.92 U/mL) was significant different with normal control group(15.22 U/mL),in mouse serum the high group(31.53 U/mL) was significant different with normal control group(23.09 U/mL),in the brain there was no significant different... |
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