| Burdock is a kind of medicinal and food homologous plant,which is widely cultivated in China.In the process of deep processing of burdock root,a large nubmer of scrap will be produced,and the use of solid-state fermentation technology for the comprehensive utilization of burdock root scraps has recently attracted attention in order to improve its economic value.Studies have shown that solid-state fermentation technology has the advantages of promoting the precipitation of active ingredients,generating new active substances,improving flavor and increasing efficacy.In this experiment,the chemical composition of burdock root scraps from different regions was compared for the first time,and then Anqiu burdock root scraps was selected as the fermentation substrate,and Ganoderma lucidum was used as the fermentation strain to carry out solid-state fermentation,optimize the fermentation conditions and fermentation substrate formulation,and carry out preliminary research on the changes of chemical composition of the fermentation substrate before and after fermentation.The aim is to explore a suitable fermentation system for the solid-state fermentation of burdock root scraps,to improve the content of effective chemical components in the fermented bacteria,and to provide some reference and theoretical basis for the development of new livestock and poultry feed additives.(1)Determination of chemical composition of burdock root from different origins.According to the main source regions of burdock root scraps,burdock root scraps from Anqiu,Xuzhou,Haozhou,Cangshan,Longnan and Chengyang were selected to determine their chemical composition contents in order to screen the most suitable substrate for fermentation.In terms of nutrient composition,the highest content of inulin,total sugar,amino acid,total nucleoside and protein were found in Anqiu sample,with 10.40 g/100 g,11.79 g/100 g,0.72g/g,0.66 g/g and 185.04 μg/g,respectively;the highest content of reducing sugar was found in Chengyang sample,with 0.09 g/g,which had a highly significant difference with that of Haozhou.(P<0.01).In terms of potent components,the highest flavonoid content was found in the Anqiu sample,with 6.72 mg/g,which was significantly different from Longnan(P<0.01);the highest total triterpene acid content was found in the Chengyang sample,with 0.15 mg/g,which was significantly different from Xuzhou(P<0.01).In terms of volatile substances,the total volatile substances in Anqiu samples were the most abundant,with 108 species,among which aldehydes,alcohols,ketones,alkenes and nitrogen heterocycles were relatively more abundant,with 23,11,11,9 and 19 species,respectively;the total volatile substances in Chengyang samples were the least abundant,with 67 species,among which aldehydes and nitrogen heterocycles were relatively more abundant,with 15 and 10 species,respectively.The relative content of total volatile substances in Anqiu sample was the highest,with 78.47%,among which the relative content of aldehydes,alcohols,organic acids and nitrogen heterocyclic volatile substances were the highest,26.35%,7.31%,10.28% and 12.76%respectively;the relative content of total volatile substances in Chengyang sample was the lowest,with 14.23%,among which the relative content of aldehydes,alcohols and other volatile substances were the relative contents of aldehydes and alcohols were low.The growth and propagation of mycelium of require abundant carbon and nitrogen sources and other nutrients,therefore,burdock root scraps in Anqiu area,which is relatively rich in carbon and nitrogen sources,was selected as the solid fermentation substrate.(2)Optimization of process parameters for solid-state fermentation of burdock root scraps by Ganoderma lucidum.With fermentation solution incubation time,p H and mycelium dry weight as indicators,the seed solution incubation time and p H were optimized by single factor,seed solution optimization results: optimized to get the best fermentation time for 70 h,p H 4.5or so,at this time the surface burr of mycelium ball is uniform,light color,vigorous growth;microscopic examination of mycelium wall without obvious buds and lock joint,and a small amount of mycelium autolysis.No miscellaneous bacteria;smell fresh,mycelium balls,slightly viscous,at this time the seed liquid as the seeding age of mycelium suitable.The results of solid-state fermentation conditions optimization: the best sterilization time for burdock root scraps(wet material)was determined as 2 h(121 ℃),and the best solid state fermentation conditions were determined as follows: water content 65%,inoculum amount 10 m L/100 m L,and mycelium growth.The best solid-state fermentation conditions were determined as follows:65% water content,10 m L/100 g inoculum,300 g/bag,26 ℃,and 16 day.Under these conditions,the mycelium of erysipelas grew fast and densely white,and the bag was full for the shortest time.The solid state fermentation formulations with different carbon sources(glucose,sucrose,soluble starch,maltose,fructose,and lactose),nitrogen sources(ammonium sulfate and diammonium hydrogen phosphate(inorganic nitrogen sources),and peptone,yeast extract and fish meal peptone(organic nitrogen sources))were optimized by single factor,and the preliminary results of solid state substrate formulations were: the best carbon source was soluble starch,and soluble starch was the fastest.The best carbon source was soluble starch,the soluble starch group had the fastest mycelium growth,the shortest bag filling time,and the highest amino acid,protein and total triterpene acid contents in the fermenting mycelium;the best nitrogen source was peptone,the peptone group had the fastest mycelium growth,the shortest bag filling time,and the highest amino acid,protein and total triterpene acid contents in the fermenting mycelium.(3)A study on the content of chemical components and their change pattern of burdock root scraps from solid-state fermentation of Ganoderma lucidum.The nutrients(proteins,amino acids,total sugars,reducing sugars and inulin and nucleotides(cytidine,uridine,guanosine,inosine and adenosine)),potent components(flavonoids and total triterpene acids),volatile substances(alkenes,amines,alkanes,aldehydes,ethers,alcohols,esters,ketones,phenols,organic acids,sulfur-containing compound,nitrogen heterocyclic compound,oxyheterocyclic and aromatic hydrocarbons compound)were determined and analyzed at each time point.In terms of nutrients,the amino acid content decreased significantly(P<0.01)after fermentation,and the lowest content was 5.63 g/100 g at the 19 th day of fermentation;the protein content increased significantly(P<0.01)after fermentation,and the highest content was at the 16 th day of fermentation,which was about 1.16 times of the unfermented sample;after the fermentation of burdock root scraps with mycelium of Ganoderma lucidum,the total sugar and inulin content decreased significantly(P<0.01)compared with the unfermented sample.After the fermentation of burdock root scraps,the content of total sugar and inulin decreased significantly(P<0.01)compared with unfermented samples,and gradually decreased during the fermentation process;the content of reducing sugar increased significantly(P<0.01)after the fermentation,and the highest content was found at the 13 th day of fermentation,which was about 3 times of the unfermented samples.This may indicate that total sugars and inulin were used and transformed by the mycelium of Ganoderma lucidum during the fermentation process,which proves that solid-state fermentation is “bi-directional”.The total amount of nucleosides increased significantly after fermentation(P<0.01)and reached the highest level at the 16 th day of fermentation,about 14.25 times that of the unfermented sample,and new nucleosides(guanosine,inosine and adenosine)were produced after fermentation.In terms of efficacy components,flavonoid compounds were 6.72 mg/g before fermentation and were not detected in the fermentation bacteria;total triterpenoid acid content increased highly significantly(P<0.01)after fermentation and was about 3.29 times higher than that of the unfermented sample,indicating that the fermentation of Ganoderma lucidum-Burdock root scraps was able to produce triterpenoids.In terms of volatile substances,the types of total volatile components in the bacteria on the 16 th day of fermentation were less than those in unfermented samples.Among them,the types of alkenes,alkanes,aldehydes,ethers,alcohols,organic acids and nitrogen heterocyclic compounds were significantly reduced after fermentation.In particular,alcohols,organic acids and nitrogen heterocyclic compounds have changed the most,reducing from 11,8,19 to 3,2,and 9 respectively.The relative content of total volatile substances has increased by 83.74%.Aldehydes,ketones,and oxygen,the relative content of heterocyclic compounds has increased significantly,from 26.35%,3.05%,4.34% to 91.42%,22.38%,and20.21%,respectively.After Ganoderma lucidum-fermentation,the relatively unpleasant highcontent aroma components are removed and reduced.In the 16 th day fungal substance,15 kinds of aroma components have a high content,isovaleraldehyde,hexanal,furfural,benzaldehyde,5-methylfuran aldehyde,phenylacetaldehyde,coca aldehyde,methyl nonyl ketone and 2-Acetylpyrrole has good aroma quality,which directly promotes the formation of the aroma quality of fermented bacteria.In unfermented samples,β-elemene,2-methylbutanal,and trans-2-nonene Aldehydes,2-butyl-2-octenal,2-ethylhexanol,5-methyl-2-hexanone,hexanoic acid and heptanoic acid with high content of compounds disappeared after fermentation,indicating that the leftovers of burdock root.After fermentation,the bad smell of the burdock root itself is reduced or removed,and the aroma quality is greatly improved.To sum up,the results of burdock root scraps-Ganoderma lucidum fermentation showed that the two-way solid-state fermentation technology was beneficial to the substantial increase of protein,reducing sugar,total nucleoside and total triterpene acid content of Ganoderma lucidum-burdock root scraps.After the fermentation of Ganoderma lucidum,the bad smell of burdock root residue was removed,and the pleasant smell was better presented,which provided some ideas for the development and technological innovation of new feed additives for related enterprises. |
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