| Agaric, shii-take and tremella are the three important homologous mushrooms, in China the crop farmers of such three kinds of edible fungi are distributed around the country, thus the output of such three kinds of edible fungi in China ranks at the top position all over the world, and this also provide the abundant foundation of raw material. There are plenty of edible fiber inside these three kinds of edible fungi, therefore, in this experiment the agaric, shii-take and tremella are taken as the raw material, to study the optimal process for abstracting the soluble edible fiber with enzyme hydrolysis method and the optimal process of one-extrusion modification method, and then studies the changes of soluble edible fiber physical and chemical properties before and after the modification and performe the analysis on the scanning results by infrared spectrum and electron microscope. The research findings of this paper are given as below:1. The optimal process for abstracting the soluble edible fiber with enzyme hydrolysis method is:(1)while the agaric powder with particle size in 80 mesh, ratio of material to solvent is 1:40, enzyme hydrolysis temperature 50℃, added enzyme quantity 0.9%, enzyme hydrolysis time 3.5h, pH value is 5.0, the output of agaric SDF is 9.05g/100g;(2)the optimal extracting conditions for Shii-take show that: particle size 80 mesh, ratio of material to solvent is 1:30, enzyme hydrolysis temperature 50℃, added enzyme quantity 0.8%, enzyme hydrolysis time 4.0h, pH value is 5.0, and at this time the output of shii-take SDF is 12.35g/100g;(3)the optimal extracting condition for tremella shall be: particle size 80 mesh, ratio of material to solvent is 1:40, enzyme hydrolysis temperature 50℃, added enzyme quantity 0.8%, enzyme hydrolysis time 3.0h, pH value is 5.0, and under this condition the output of shii-take SDF is 6.85g/100 g.2. The research findings for one-extrusion modification method:(1) the optimal condition for one-extrusion modification method used for agaric is: the ratio of material to solvent is 1:1.1g/g, extrusion temperature 140℃, feeding rate 30kg/h, particle size of the material is 120 mesh;(2)the optimal condition for one-extrusion modification method used for shii-take is: the ratio of material to solvent is 1:0.9g/g, extrusion temperature 150℃, feeding rate 25kg/h, particle size of the material is 100 mesh;( 3)the optimal condition for one-extrusion modification method used for tremella is: the ratio of material to solvent is 1:1.0g/g, extrusion temperature 140℃, feeding rate 30kg/h, particle size of the material is 100 mesh.3. Through single factor and orthogonal experiments the optimum formula obtaine as follows: when ultrasonic power is 160W(processing amount is 5g), material-to-liquid ratio is 1:30g/mL, sodium carbonate concentration is 2.00 mol/L, extraction duration is 70 min.4. The research findings on the physical property of three kinds of edible fungi before and after the one-extrusion modification show that:(1) Before modification the relative properties of edible fungi shall be:(1) the agaric SDF-water holding capacity 8.42g/g, water-binding capacity 6.76g/g, expansibility 9.05 m L/g, oil-holding capacity 2.63g/g, adsorption capacity to cholesterol 24.66(pH2.0), 30.72(pH7.0) mg/g,adsorption capacity to nitrite ion 22.47(pH2.0), 2.79(pH7.0) mg/g;(2)the shii-take SDFwater holding capacity 6.32g/g, water-binding capacity 3.74g/g, expansibility 5.26 m L/g, oil-holding capacity 2.13g/g, adsorption capacity to cholesterol 20.35(pH2.0),23.83(pH7.0) mg/g,adsorption capacity to nitrite ion 22.65(pH2.0),1.02(pH7.0) mg/g;(3) the tremella SDF-water holding capacity 7.26g/g,water-binding capacity 4.38g/g, expansibility 6.15mL/g, oil-holding capacity 2.25g/g, adsorption capacity to cholesterol 21.85(pH2.0), 27.23(pH7.0)mg/g,adsorption capacity to nitrite ion 20.59(pH2.0), 1.26(pH7.0) mg/g.(2) After modification the relative properties of edible fungi shall be:(1) the agaric SDF-water holding capacity 8.67g/g, water-binding capacity 6.93g/g, expansibility 9.61 m L/g, oil-holding capacity 4.76g/g, adsorption capacity to cholesterol 28.76(pH2.0), 38.72(pH7.0) mg/g,adsorption capacity to nitrite ion 25.83(pH2.0), 4.79(pH7.0) mg/g;(2)the shii-take SDF-water holding capacity 6.61g/g, water-binding capacity 4.35g/g, expansibility 5.47 m L/g, oil-holding capacity 3.65g/g, adsorption capacity to cholesterol 24.65(pH2.0),22.56(pH7.0) mg/g,adsorption capacity to nitrite ion 23.71(pH2.0),1.21(pH7.0) mg/g;(3) the tremella SDF-water holding capacity 7.67g/g, water-binding capacity 4.93g/g, expansibility 6.31 m L/g, oil-holding capacity 2.46g/g, adsorption capacity to cholesterol 23.76(pH2.0), 29.72(pH7.0) mg/g,adsorption capacity to nitrite ion 23.83(pH2.0), 2.15(pH7.0) mg/g.5. After the one-extrusion modification process and auricularia auricula melanin by alkaline extraction on edible fungi, the surface of edible fungi SDF becomes scraggy with clear level and layer and honeycomb hols in uneven sizes. Such porous and ravines structure implies that the surface area of the fiber increases greatly and results in the increase adsorption capacity to a large extent.6. Through observing the infrared spectrum of SDF, it can find that, the infrared spectrum of SDF before and after the modification are basically the same, all with the characteristic adsorption peak of saccharides as the aldehyde group and hydroxy group etc. This shows that the modification process does not damage the functional groups inside the molecule, and protect the majority of hydrophilic group and other active groups inside the SDF quite well, those groups should play the important role on improving the expansibility, water-absorbing capacity and water-holding capacity of edible fungi. |
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