Reaction products of 2,4,6-tris(4-phenyl-phenoxy)-1,3,5-triazine derived from 4-phenylphenol cyanate ester and phenyl glycidyl ether were analyzed. In addition to an isocyanurate compound and an oxazolidone compound w...Reaction products of 2,4,6-tris(4-phenyl-phenoxy)-1,3,5-triazine derived from 4-phenylphenol cyanate ester and phenyl glycidyl ether were analyzed. In addition to an isocyanurate compound and an oxazolidone compound which were well known as reaction products of cyanate esters and epoxy resins, compounds with hybrid ring structure of cyanurate/isocyanurate were determined. Gibbs free energies of the compound having hybrid ring structure of cyanurate/isocyanurate with two isocyanurate moiety were found to be lower than that of the compound with cyanurate ring structure through calculations. Calculation data supported the existence of hybrid ring structure of cy-anurate/isocyanurate. It was revealed that isomerization from cyanurate to isocyanurate occurs via hybrid ring structure of cyanurate/isocyanurate in the reaction of aryl cyanurate and epoxy.展开更多
Lactic acid bacteria(LAB)fermentation is one of the important ways to improve the flavor profile of soymilks.In this study,the biotransformation of 4 important soymilk off-flavor components(ISOCs),including hexanal,(E...Lactic acid bacteria(LAB)fermentation is one of the important ways to improve the flavor profile of soymilks.In this study,the biotransformation of 4 important soymilk off-flavor components(ISOCs),including hexanal,(E)-2-heptenal,(E)-2-hexenal and 1-octen-3-ol during LAB fermentation was studied.A LAB fermentable simulated soymilk with low and stable levels of soymilk borne volatile compounds was prepared and used as fermentation bases.After the LAB fermentation of simulated soymilks with different levels of added ISOCs and the subsequent HS-SPME-GC-TOF-MS analysis,ISOCs derived biotransformation products were screened from the total volatile compounds using chemometric approaches,and the possible metabolic pathways were proposed.Subsequently,quantitative analysis of conversion rates and mass balances was conducted to study effects of ISOCs loads,variations in starter cultures and fermentation conditions on the LAB fermentationinduced biotransformation.Finally,the flavor intensity of different odor descriptors as affected by the biotransformation of ISOCs were evaluated based on the odor activity value calculation.This study provided technical methods for screening and quantitative analysis as well as experimental facts of the LAB fermentationinduced biotransformation of ISOCs.展开更多
文摘Reaction products of 2,4,6-tris(4-phenyl-phenoxy)-1,3,5-triazine derived from 4-phenylphenol cyanate ester and phenyl glycidyl ether were analyzed. In addition to an isocyanurate compound and an oxazolidone compound which were well known as reaction products of cyanate esters and epoxy resins, compounds with hybrid ring structure of cyanurate/isocyanurate were determined. Gibbs free energies of the compound having hybrid ring structure of cyanurate/isocyanurate with two isocyanurate moiety were found to be lower than that of the compound with cyanurate ring structure through calculations. Calculation data supported the existence of hybrid ring structure of cy-anurate/isocyanurate. It was revealed that isomerization from cyanurate to isocyanurate occurs via hybrid ring structure of cyanurate/isocyanurate in the reaction of aryl cyanurate and epoxy.
基金supported by the National Natural Science Foundation of China(32272243 and 32072164)the Key Research and Development Program of Shandong Province(2022CXGC010603)the China Postdoctoral Science Foundation(2020M671342).
文摘Lactic acid bacteria(LAB)fermentation is one of the important ways to improve the flavor profile of soymilks.In this study,the biotransformation of 4 important soymilk off-flavor components(ISOCs),including hexanal,(E)-2-heptenal,(E)-2-hexenal and 1-octen-3-ol during LAB fermentation was studied.A LAB fermentable simulated soymilk with low and stable levels of soymilk borne volatile compounds was prepared and used as fermentation bases.After the LAB fermentation of simulated soymilks with different levels of added ISOCs and the subsequent HS-SPME-GC-TOF-MS analysis,ISOCs derived biotransformation products were screened from the total volatile compounds using chemometric approaches,and the possible metabolic pathways were proposed.Subsequently,quantitative analysis of conversion rates and mass balances was conducted to study effects of ISOCs loads,variations in starter cultures and fermentation conditions on the LAB fermentationinduced biotransformation.Finally,the flavor intensity of different odor descriptors as affected by the biotransformation of ISOCs were evaluated based on the odor activity value calculation.This study provided technical methods for screening and quantitative analysis as well as experimental facts of the LAB fermentationinduced biotransformation of ISOCs.
