Analysis Of Nutritional Quality Formation Factors,identification Of Functional Components And Application Of Liquid Fermentation In Morchella Spp.

Morchella(Morchella spp.)is the collective term for the species of genus Morchella in the Morchella family of the Ascomycota.It is a rare edible fungus,rich in polysaccharides,proteins,minerals,trace elements,dietary fiber,vitamins and other active substances.It has many functions such as lowering blood lipids,anti-fatigue,antivirus and anti-tumor.With the rapid increase in the demand for the domestication and application of Morchella,the variety selection and identification of Morchella have also increased accordingly.However,the current breeding and production of Morchella are still based on primary sensory indicators and fruit body yield,lacking clear,systematic and feasible objective criteria for variety differentiation,evaluation and identification.At the same time,the current research on Morchella is focused on variety breeding,cultivation technology,growth mechanism,activity of polysaccharide,etc.There is a lack of research on the effective evaluation system of key quality indexes such as nutritional value evaluation and flavor substance identification of Morchella fruiting body.There are also few reports on the separation and purification of non-volatile small molecule natural products from fruiting bodies and the evaluation of biological activity.In order to solve the key problems of quality appraisal,composition analysis and liquid fermentation of Morchella,the nutritional components,non-volatile and volatile flavor substances of Morchella were firstly compared and analyzed in different base species,different habitat conditions and different development stage.Secondly,the small molecular substances of fruiting bodies were isolated,purified and functionally identified.Finally,the application conditions of Morchella liquid fermentation were optimized.Through this study,we provided the evaluation criteria,components and feasible application strategies for the basic and applied research of Morchella.The main results were as follows:1.Quality evaluation studies on the base strains of the three main production varieti es of Morchella: Morchella importuna,Morchella Sextelata and Morchella Septimelata.The results showed that: 1)There were complete types of amino acids in Morchella ma terial from different base strains,and the proportion of flavoring amino acids was bitter amino acids > umami amino acids > sweet amino acids.The difference of content propo rtion among different base strains was small,and the difference of flavor was not obviou s;2)The threonine,valine,phenylalanine + tyrosine of different base source strains wer e relatively excessive,and the tryptophan was relatively insufficient.The score of ratio c oefficient(SRC)was about 60%,and there was no significant difference in nutritional v alue;3)The 5'-nucleotides of Morchella were complete,including 6 mononucleotides:5'-CMP,5'-AMP,5'-IMP,5'-GMP,5'-UMP and 5'-XMP;4)The ECU of different base strains were significantly different,reaching the second and third levels respectively,and the difference in umami taste was significant.Further analysis showed that the aldehyde s were aboundant in 9 different strains,and 2-methylpropanal and 2-methylbutanal were the main aroma substances.Mim-01,Mim-02,Mim-03,Mim-04,Msx-02 and Mim-05 contained unique sulfur compounds,which contributed the most to the aroma of Mim-01,Mim-02,Mim-03 and Msx-02.Principal component analysis(PCA)was conducted o n the relative contents of volatile substances in different base source species to obtain th e comprehensive evaluation model: F=24.830%F1+22.374%F2+14.553%F3+13.955% F4+9.697%F5+6.159%F6.According to the comprehensive scores of different principal c omponents,the comprehensive ranking of aroma quality from high to low was: Mim-04,Mim-02,Mim-01,Msx-02,Mim-03,Mim-05,Msp-01,Msx-03,and Msx-01.Through t hose results,we found that Morchella importuna was the dominant strain,which layed t he germplasm foundation for further related studies.2.Nutritional quality analysis and evaluation of different Morchella importuna strains.The results showed that: 1)The amino acid content,total amino acid content and medicinal amino acid content of the 20 different tested strains were significantly different,while the amino acid content,total amino acid content and medicinal amino acid content of Mim-S04 strain were higher than those of other strains;2)The leucine and lysine of different tested strains were relatively insufficient.The essential amino acid index(EAAI)and biovalent(BV)values showed that the Mim-S20,Mim-S04,Mim-S07 and Mim-S18 strains had higher nutritional value and higher digestion absorption efficiency in human body;3)The PCA model for the evaluation of volatile substancearomas of the tested strains was: F=33.983%F1+18.567%F2+14.136%F3+11.697%F4+6.299F5+5.398%F6.By calculating principal component scores and comprehensive scores,mim-S04,MimS20,Mim-S08,Mim-S14,and Mim-S12 ranked in the top 5 principal component scores,which was consistent with the cluster analysis(CA)results.Based on these results,we confirmed that Mim-S04 was the dominant strain and which provided a reliable material for applied basic research.3.To explore the effects of different habitat conditions on the quality of Morchella,the fruiting body quality of Morchella importuna cultivated in western Sichuan Plateau,eastern Sichuan region,Chengdu plain and hilly areas were analyzed and evaluated.The results showed that there was no significant correlation between the contents of umami amino acids,soluble sugars,sugar alcohols,organic acids,single nucleotide and total nucleotide with the habitat conditions.And the habitat conditions had no obvious effect on umami flavor either.The isothermal concentration values belong to the second level.The main volatile aroma components of samples from different habitats were similar,including 2-methylpropanal,ethyl acetate,2-methylbutanal,hexanal,2-methylbutanal,and ethyl caproate.On the other hand,there were certain specific components in the fruiting body of Morchella under different habitat conditions.The Chengdu Plain samples,Mim-Py01,Mim-Py02 and Mim-Py03 contained 1-octene-3-ol,while the hilly area samples,Mim-QL01,Mim-QL02 and Mim-QL03 contained dimethyl disulfide.Both PCA and CA analysis showed that the non-volatile and volatile flavoring substance compositions were similar in the domesticated samples under similar habitat conditions.This study provided a theoretical basis for sample collection and guided the postproduction and processing.4.The material basis of quality formation at the three developmental stages of Morchella,young stage(Mim-YS),mature stage(Mim-MS)and post-ripening stage(Mim-LS).The results showed that with the development of Morchella,the content of flavor substances accumulated,the EUC increased,and the umami taste increased.Systematic cluster analysis of total volatile compounds showed that Mim-MS and MimLS had more similar volatile components than Mim-YS,which provided a reference standard for timely harvesting of Morchella.Metabolites of the three stages of the fruiting body were further analyzed using metabolomics techniques.The results showed that the growth and development processes of Morchella were closely related to more than 53 differentially expressed metabolites including the pyrimidine metabolism,vitamin B6 metabolism,arginine biosynthesis,lysine biosynthesis and lysine degradation metabolic pathways.The contents of amino acids,fatty acids,organic acids and sugars were abundant at different growth and development stages,and different changes were presented in related metabolic pathways,which provided a basis for the study of the differential performance of metabolome in the growth and development process of Morchella fruiting body.5.Based on the partial extraction of fruiting body extracts from Morchella morchella,the functional activities of non-volatile compounds were investigated,isolated,purified and identified.Measurements of mouse body weight,intestinal length changers,colon tissue myeloaxinase(MPO),superoxide dismutase(T-SOD)activity,malondialdehyde(MDA)content and serum diamine oxidase(DAO)activity showed that high concentration of Morchella extracts had therapeutic and relieving effects on colitis in mice.Further isolation and purification of the extract to obtain 16 monomer compounds,and 3,5-dihydroxy 4-methoxy benzyl alcohol(YDJ-E-3-1-1),3,5-dihydroxy benzoic acid(YDJ-E-5-1-1),3,4-dihydroxy benzoic acid(YDJ-E-5-1-2),5,7-dihydroxy phthalein(YDJ-E-4-1-1),protocatechuic acid(YDJ-B-1-S-1)and uracil(YDJ-B-2-6-2-7-4-1)were successfully identified.these results provided the research foundation for precise development and in-depth application of Morchella products in the future.6.improving the liquid fermentation process of Morchrels and simplify the cultivation process.Based on the optimization of single factor fermentation conditions,biomass and total phenol content were taken as response values,the response surface analysis was further used to establish an optimization model and fit the regression equation to obtain the optimal combination: Glucose 3.2%,yeast powder 2.1%,p H 5.6,24?,120 r/min,pod extract 20.1%.The results provided a feasible basis for returning soybean pod to field as nutrient for Morchella growth,and also provided an effective reference for the development and application of liquid fermentation of Morchella.The active ingredient of the nitrogen source additive soybean pod was further identified,and10 compounds were identified,of which 5 were new compounds.Based on the above research results,this dissertation systematically studied the influencing factors in quality characteristics and formation rules of Morchella,comprehensively and deeply understood the composition,content and substance formation mechanism of Morchella.Further studies on the activity,isolation,purification and identification of small molecular substances of Morchella,and optimization of liquid fermentation process of Morchella,provided theoretical basis and material basis for further basic and application research of Morchella.