The Preparation And Properties Of Dietary Fiber From Auricularia Auricular Residues With Cellulase

Dietary fiber (DF) is composed of cellulose, hemicellulose, lignin, pectin,soluble polysaccharide and other components. Due to DF’s nutritional properties,physiological functions,widely applications,it has been concerned by nutritionsts and the public who from all over the world.Auricularia auricular residues-which are by-products obtained after auricularia aurilular polysaccharide extraction were always abandoned. In this study, soluble dietary fiber(SDF) and insoluble dietary fiber (IDF) were extracted from auricularia auricula polysaccharide extraction residues with cellulase,characteristics and properties of both SDF and IDF were evaluated.Cellulase dosage, material-liquid ratio, extraction temperature, extraction time and pH has been discussed on influence of the rate of SDF,IDF and IF/SF.The Optimal condition for extracting dietary fiber was obtained, that was cellulase dosage100U/g, material-liquid ratio1:30, extraction temperature55℃, extraction time90min, pH5.0. Under the optimum extraction conditions, the ratio of soluble dietary fiber was9.28%, the ratio of insoluble dietary fiber was40.32%, and IF/SF ratio of4.34.FTIR,SEM and series of chemical methods were used to evaluate characteristics and properties of SDF and IDF.The results show that SDF which extracted from the residues belongs to typical polysaccharide,SDF contents was91.11%,water-holding capacity(WHC) was7.92g/g,oil-holding capacity(OHC) was2.98g/g,swelling capacity was8.91g/g. The SEM images revealed that SDF particles were porosity and irregular.The cholesterol absorption capacity was24.653mg/g under pH2.0,31.160mg/g under pr7.0;NO2-absorption capacity was22.560mg/g under pH2.0,2.819mg/g under pH7.0;cholate adsorption capacity was5.116%.With increase of glucose concentration,glucose adsorption capacity (GAC) increased and glucose retardation index(GRI) was decreased with increase of time.Analysis of apparent viscosity showed that viscosity of SDF increased with SDF concentration increase,decreased with temperature increase,while the pH,sucrose concentration and salt concentration has also influenced the viscosity.The influence of temperature and pH for SDF solubility were that:with temperature increase solubility increased,with pH increase solubility increased under acidic and with pH increase solubility decreased under alkalinity.IDF particles were tight and regular,belongs to typical polysaccharide too.lDF contents was 90.32%,water-holding capacity (WHC) was27.46g/g, oil-holding capacity(OHC) was4.43g/g,swelling capacity was17.74g/g. The positive iron exchange capacity of IDF was significant,and the cholesterol absorption capacity was7.320mg/g under pH2.0,21.920mg/g under pH7.0;NO2-absorption capacity was34.032mg/g under pH2.0,18.631mg/g under pH7.0; cholate adsorption capacity was3.011%.