| Tartary buckwheat was one of the false grains of the buckwheat genus in the Liao family,and it was also one of the main planting varieties of buckwheat.Extraction of polysaccharides from plants as functional components was one of the current research hotspots.At present,there were few research literatures on tartary buckwheat polysaccharides,and there was no report on the structure analysis of tartary buckwheat polysaccharides extracted by multi-frequency ultrasound.Therefore,this paper takes the tartary buckwheat produced in Youyang,Chongqing as the research object,and uses a new multi-frequency ultrasonic extraction method to extract tartary buckwheat polysaccharides.The tartary buckwheat polysaccharide was extracted by dualfrequency ultrasonic,and its separation,purification and structural characterization were carried out.It was hoped that this study will provide theoretical reference for the in-depth development and utilization of tartary buckwheat polysaccharides.The research contents and results of this paper were as followed:(1)The single-factor method was used to determine the time,temperature,liquid-tomaterial ratio,times,and ultrasonic power for ultrasonic extraction of tartary buckwheat polysaccharide.Taking the yield of tartary buckwheat polysaccharide as an index,the optimal conditions for ultrasonic extraction of tartary buckwheat polysaccharide were obtained as follows: 30 min,60 ℃,25:1,360 W,extracted twice.(2)Tartary buckwheat polysaccharides were extracted with five frequencies(20 k Hz,40 k Hz,20/28 k Hz,20/40 k Hz,20/28/40 k Hz).The results showed that the five tartary buckwheat polysaccharides were different in chemical composition,the monosaccharide composition was the same,the monosaccharide molar ratio was different,and there was no significant difference in ultraviolet,infrared,rheological,and thermogravimetric analysis.All five kinds of tartary buckwheat polysaccharides have antioxidant capacity in vitro,and the antioxidant capacity of tartary buckwheat polysaccharides extracted at 20/28 k Hz was more prominent.(3)Tartary buckwheat polysaccharides were extracted by dual-frequency ultrasound at 20/28 k Hz,and separated and purified by DEAE-52 anion exchange column chromatography and Sephadex G-100 gel column chromatography.Five tartary buckwheat polysaccharide fractions were isolated,and the TBPs-1A tartary buckwheat polysaccharide fractions were selected for structural characterization.The results show that the TBPs-1A component was a α-configuration of neutral tartary buckwheat polysaccharide with typical polysaccharide characteristic absorption peaks.It can form stable crystals under various conditions,in rod-like and flake-like shapes,with a molecular weight of 39664 Da,monosaccharide composed of galactose,glucose,mannose,arabinose,rhamnose,glucosamine hydrochloride,galactosamine hydrochloride,fucose,xylose,glucuronic acid,galacturonic acid;based on peak area The corresponding molar ratio can be obtained as:0.36:0.18:0.12:0.13:0.09:0.06:0.02:0.01:0.02:0.01:0.01。(4)The tartary buckwheat polysaccharide extracted by 20/28 k Hz ultrasonic was used as the carbon source to cultivate Lactobacillus acidophilus and Lactobacillus plantarum.The fermented strain of tartary buckwheat polysaccharide was added to fermented yoghurt,and the optimum conditions for fermentation of tartary buckwheat polysaccharide yogurt were obtained through orthogonal experiments,and the quality of tartary buckwheat polysaccharide yogurt was determined.The results obtained the optimal fermentation conditions of tartary buckwheat polysaccharide yoghurt.The fermentation time was 7 h,the addition amount of tartary buckwheat polysaccharide was 0.05%,and the inoculum of lactic acid bacteria was 1%.greater than the blank control group. |
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