| Premna microphylla Turcz(PMT),is a perennial deciduous shrub belonging to the Verbenaceae family.It has a certain history in the folks to make edible "Fairy Tofu".It has been paid more and more attention by scholars because it contains rich pectin.In order to further study the characteristics of Premna microphylla Turcz pectin(PMTP),this article takes the PMT in Henan Shangcheng County as raw material,the pectin content of the PMT was determined by the existing six determination methods;then the yield of PMTP was compared by using four common pectin extraction methods,to determine the feasibility of extracting pectin pectin;the separation and purification of the PMTP extracted by ultrasonic assisted ammonium oxalate and its properties were studied;and the monosaccharide composition of the PMTP was also analyzed,which provided a theoretical reference for better development and utilization of the PMTP resources.The main findings are as follows:1.The order of the pectin content of the PMT leaves was as follows:acidification enzyme solution>3,5-xylenol colorimetric method>carbazole colorimetry>Spectrophotometry(Acid extraction)>Gravimetric method>Spectrophotometry(alkaline extraction).The acidification enzyme method determined that the pectin content of PMT was the highest,but it was necessary to measure the activity of the enzyme,which was troublesome to operate.Therefore,the establishment of the method for determining the pectin content of PMT needs further exploration.2.The extraction rate of PMTP was as follows:sodium hexametaphosphate extraction>ammonium oxalate solution extraction>HCl extraction>hot water extraction.The extraction rate of sodium hexametaphosphate is as high as 85%or more.However,due to its low purity,high ash content,the progress of subsequent experiments is affected,and the extraction rate of hydrochloric acid extraction method and hot water extraction method is too low.Ammonium oxalate was used as an extractant to assist ultrasonic extraction of PMTP with a yield of 39.29±0.52%.3.By compared the two purification methods,X-5 macroporous adsorption resin column chromatography was better than DEAE-52 cellulose column chromatography,and the optimal adsorption conditions are optimized as follows:the loading concentration was 10 mg/mL,the loading volume was 15 mL,and the loading speed was 1.0 mL/min;the optimal analytical conditions were:ethanol eluent concentration of 30%,elution volume of 20 BV,and elution rate of 1.0 mL/min.4.The purified PMTP was scanned by near-infrared spectroscopy to obtain the characteristic absorption peak of carbohydrates,which was basically consistent with the commercial citrus pectin.The measured indexes all met the requirements of GB 25533-2010 commercial pectin standards;Static rheological analysis of temperature,heat treatment time,sucrose content,NaCl concentration and pH value showed that PMTP solution is a typical pseudoplastic fluid behavior,and the concentration dynamic rheological analysis found that PMTP increased with concentration.It showed better gelation;and the texture properties of the gel samples with PMTP added to the base gel samples were significantly higher than those of the gel samples with the commercial citrus pectin.5.The monosaccharide composition of PMTP pectin was analyzed by PMP pre-column derivatization HPLC.The results showed that PMTP consisted of mannose,rhamnose,galacturonic acid,glucose,galactose and arabinose.And the molar ratio of monosaccharides was,1.46:2.62:58.94:19.37:5.88:11.73. |
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