Identification Of Key Aroma Compounds Of Straw Mushroom And Its Taste Peptides Preparation

In this paper,the key aroma compounds of straw mushroom were characterized and its umami peptides were identified after a series separation and purition techniques guided by sensory evaluation.These findings provided an important scientific basic to better develop the food value of edible fungi.The main research contents and results are as follows:(1)Identification of the key aroma compounds in straw mushrooms by two different extraction methods: headspace-solid phase microextraction and solvent-assisted flavor evaporation,combined with gas chromatography-mass spectrometry and gas chromatography olfactometry.The results showed that dihydro-beta-ionone,1-octen-3-one,1-octen-3-ol,?-unsecalactone,3-octanol,3-octanone,2-octanone,hexanal,2-methylbutanal,camphene,carvone,2-nonanone,and phenylacetaldehyde were the key aroma compounds.(2)The flavor substance in straw mushroom was prepared by the cooking method and the enzymatic hydrolysis method.The conditions for three extract methods were optimized and were as follows: the best extraction conditions for high pressure cooking were: ratio of material to liquid 1:1.5,time 1.5 h,pressure 40 kPa;The best extraction conditions for atmospheric cooking were: ratio of material to liquid 1:1.5,time 2h,temperature 100 °C;The best extraction conditions for enzymatic hydrolysis were: cellulase and flavor protease step by step,the ratio of material to liquid is 1:40,the hydrolysis time is 1.5h,and the temperature of cellulase was 45 °C,pH 3.5,the added amount was 0.5% of the substrate mass;the temperature of the flavor protease was 50°C,pH 6.0,and the added amount was 0.4% of the mass of the substrate.(3)The effects of three pretreatment methods(atmospheric cooking,high pressure cooking and enzymatic hydrolysis)on the release of flavor substances of straw mushroom were studied.The results showed that after atmospheric cooking,autoclaving and enzymatic hydrolysis,the content of less than 500 Da components increased,and the increase of high-pressure cooking was the most significant.The content of components less than 3000 Da is the highest after high pressure cooking,indicating that high-pressure cooking is one of the effective treatment methods for preparing taste peptides.(4)The peptides were separated and purified from the straw mushroom by ultrafiltration,gel filtration chromatography and reversed-phase high performance liquid chromatography.The amino acid sequence of the taste peptide was determined by ultra performance liquid chromatography with quadrupole time-of-flight mass spectrometry.The amino acid sequences were ASNMSDL,YYGSNSA and LQPLNAH.These identified peptides were subjected to solid phase synthesization and further sensory analysis to analyze their taste characteristics,umami enhancement effects,and dose-response relationships.