Research On Extraction Methods Of Soluble Nitrogen-containing Compounds In Lentinus Edodes

Eight common edible fungi riched in flavor amino acids, sush as glutamic acid, aspartic acid, glycine and alanine, especially in the lentinus edodes, golden mushroom and agaricus bisporus, which accounted for more than40%of the total amino acid contents, glutamate levels in the highest, followed aspartic, and they tasted delicious and refreshing extremely. Delicate flavors of the lentinus edodes displayed strongest, mainly because of contained more flavor nucleotides and glutamic acid, especially its flavor nucleotides of5’-GMP content was extremely higher. In order to improve the utilization percent of edible fungi resources and processing value of edible mushroom, deep processing and comprehensive utilization of edible fungus for further research, selected lentinus edodes as subject of this paper. Fresh lentinus edodes was enzymic hydrolysis by pectinase ot treated with high pressure homogenizing respectively even combined them; Dry edible fungi enzymolysis by proteinase after the screw extrusion pretreatment; The ultimate purpose was dissolved more umami substances of soluble nitrogen compounds from lentinus edodes cells. Major consequences as followed:1.The result founded out that pectinase exhibited the best cell disruption activity from four cell disruption enzymes (Pectinase, cellulase, xylanase,(3-glucanase) better than cellulose enzyme which common used. Then set pectinase as the study object, through single factors and orthogonal experiments determined the influence on soluble nitrogen release ratio of lentinus edodes by each pectinase hydrolysis factor, soluble nitrogen release ratio reached up to87.83%in the single factor experiments, while orthogonal experiment reached to57.53%. And the optimum processing conditions of pectinase enzymolysis:liquid ratio1:5, enzymatic hydrolysis temperature45℃, initial pH6.0, treated for lh and0.12%pectinase.2.Compared with three kinds of physical treatment methods:Organization mashed, Colloid mill and high pressure homogenizing, founded that the best deal methods was high pressure homogenization which reached up to52.86%, higher than colloid mill broken7.27%, higher than organization mashed broken10%. And then choose high pressure homogenization processing as the research object, single factors experiment combined with orthogonal experiment studied on high pressure homogenization influence factors on soluble nitrogen release rate of Lentinus edodes. Took soluble nitrogen release rate as assessment indicators, the influence sequence as:liquid ratio of homogeneous> number of homogeneous> homogeneous pressure> initial temperature of homogeneous, The influence of liquid ratio reached a best significant level among them. Optimal level combination was A3B1C3D2, which were liquid ratio of1:7, homogeneous number of twice, homogeneous pressure40MPa and homogeneous temperature of50℃.On this basis, high pressure homogenization first and then Pectinase hydrolysis that made soluble nitrogen release rate up to66.79%, which was higher than enzymatic or high-pressure homogeneous treatment alone, the increase range from4.92%to11.37%.3.Dry Lentinus edodes powder was treated by the screw extrusion technology for providing further advantage of protease hydrolysis conditions. Combined with physical properties parameters as amino nitrogen, puffed degrees, water binding capacity and water content, we set NSI, soluble protein content as the main index to investigated the material moisture, screw speed, feed speed and the cylinder temperature of screw extrusion influence on the wall-breaking activity. Orthogonal test design on the basis of single factor of various factors, indicated that best technical parameters of double screw extrusion machine treated at dry lentinus edodes powder was material moisture10%, the cylinder temperature at160℃, screw speed at25rpm and feeding speed9rpm, the NSI reached73.93%. The influence sequence of the NSI content as:screw speed>material moisture>barrel temperature> feeding speed.4.In order to validate the effect of double screw extrusion technology pretreated lentinus edodes, extrusion products as substrate and trypsin as enzymolysis.Set soluble nitrogen release rate as assessment indicator, and refered to amino nitrogen content changing in single factor and orthogonal experiments, optimized the trypsin enzymatic parameters. The optimum conditions as material to liquid was1:11, enzyme treated for1.5h at50℃and0.5%of trypsinase made73.33%of soluble nitrogen release, which was5.25%higher than the best result of orthogonal test and amino nitrogen increased by11.43%. The solution soluble nitrogen release rate and amino nitrogen content of combined the best enzyme hydrolysis conditions with the screw extrusion pretreatment were increased94.94%,82.94%respectively from the crew extrusion or enzyme hydrolysis treatment alone.