Optimization And Design Of The Wet Dehulling Process Of Sesame And Characterization Of Polysaccharide From The Waste Liquor

In this article,parameters of the soaking process and the sesame polysaccharides from decortication process were studied.The structure and characterization of the extracted sesame polysaccharide were analysed,and the production process and equipment of wet sesame dehulling were preliminary designed preliminarily.The paper was aim to pave the way for subsequent experiments study on the recovery of sesame dehulling wastewater and extraction of sesame seed polysaccharide and other useful substances.In order to increase the volume of the substance dissolved in the dehulling process without compromising on products quality and function,studies was carried out to investigate the effect of alkali concentration,temperature,time and solid-liquid ratio to dissolved matter in the liquid and the sesame after soaking.Influence of temperature and alkali concentratiodetected to the corrosion of sesame epidermis was detected by scanning electron microscope electron microscopy.The results showed that the dissolution and the quality of dehulled sesame were optimal when soaked in 6 times of Na OH of 5 g/L at temperature of 60°C for 10 min.The moisture,protein,total sugar,crude fat,crude fiber and oxalic acid content of the dehulled sesame in different treatments and the basic index of the extracted oil were detected.With the increment of operation temperature,the contents of ash and crude oil are higher,whereas crude protein,fiber,polysaccharide and water were lower.SEM result shows that the destruction of the sesame coat is easier to be influenced by the concentration of alkali rather than temperature.In order to characterize the polysaccharide in the waste water,lye mixture after soaking was isolated and identified in this paper.The solutions were concentrated before it was precipitated by ethanol,the precipitate was then decolorized and deproteinized by the Sevag method,and lastly lyophilized to obtain the refined crude polysaccharide.After that the crude polysaccharide was applied to a DEAE cellulose-52 column eluted by 0,0.1,0.2,0.3 and 0.5 M Na Cl solution to get four clean fractions.Study of the four isolated polysaccharides included determination of the molecular weight of the polysaccharides,monosaccharide composition and IR analysis.Results showed that the polysaccharide eluting with distilled water contains no uronic acid,and polysaccharides eluted by Na Cl was acidic polysaccharide,further proved by the infrared analysis results.Absorption peaks near 1046 cm-1 showed that the polysaccharide components were all sorts of pyranose ring.The thermal stability of the obtained polysaccharides was analyzed by thermogravimetric analysis.crystallinity index(Cr I)of sesame coats without alkali treatment and with alkali treatment(1 M,2.5 M,5 M)were respectively 35.18%,29.55%,29.24% and 26.35%,calculated according to X ray diffraction patterns.It indicated that the increased of concentration of lye accelerated the destruction of crystalline skin sesame.According to the analysis results and the parameters of sesame decotication process,equipments and the whole production line of the simple wet sesame dehulling process was designed,and the recycling of alkali liquor was realized.Large scale production line based on this will be designed with recyclable lye and instrument that can collect and purify bioactive substances soaked in the water.