Riboflavin is an essential micronutrient for humans and must be obtained exogenously from foods or sup-plements.Numerous studies have suggested a major role of riboflavin in the prevention and treatment of various dis...Riboflavin is an essential micronutrient for humans and must be obtained exogenously from foods or sup-plements.Numerous studies have suggested a major role of riboflavin in the prevention and treatment of various diseases.There are mainly three strategies for riboflavin synthesis,including total chemical syn-thesis,chemical semi-synthesis,and microbial fermentation,the latter being currently the most promis-ing strategy.In recent years,flavinogenic microbes have attracted increasing attention.Fungi,including Eremothecium ashbyii and Ashbya gossypii,and bacteria,including Bacillus subtilis,Escherichia coli,and lac-tic acid bacteria,are ideal cell factories for riboflavin overproduction.Thus they are good candidates for enhancing the level of riboflavin in fermented foods or designing novel riboflavin bio-enriched foods with improved nutritional value and/or beneficial properties for human health.This review briefly describes the role of riboflavin in human health and the historical process of its industrial production,and then highlights riboflavin biosynthesis in bacteria and fungi,and finally summarizes the strategies for ribofla-vin overproduction based on both the optimization of fermentation conditions and the development of riboflavin-overproducing strains via chemical mutagenesis and metabolic engineering.Overall,this review provides an updated understanding of riboflavin biosynthesis and can promote the research and development of fermented food products rich in riboflavin.展开更多
Glutaraldehyde(GTA) crosslinking is commonly used to improve the thermal stability and mechanical strength of collagen casings. The aim of this research was to determine the optimal pH of the crosslinking between GTA ...Glutaraldehyde(GTA) crosslinking is commonly used to improve the thermal stability and mechanical strength of collagen casings. The aim of this research was to determine the optimal pH of the crosslinking between GTA and collagen as well as the crosslinking mechanisms. The weakly alkaline environment could facilitate the generation of GTA polymerization through the rapid generation of -C=C-C=O and -N=C-C=C- conjugated structures, and enhance the crosslinking reaction of GTA polymers with collagen amino groups. In the pH range of 8–10, the fibril diameter and d-space value declined significantly in the self-assembled collagen fibril-GTA system. Meanwhile, collagen casing films crosslinked with GTA in weakly alkaline conditions exhibited higher mechanical strength and thermal stability. These results suggest that the crosslinking of collagen casings and GTA can be improved by adjusting the pH. Possible crosslinking mechanisms related to the formation of conjugated long chains have also been proposed. This study could provide guidance on the appropriate use of GTA in the production process of collagen casings.展开更多
基金supported by China Central Public-Interest Scientific Institution Basal Research Fund, Chinese Academy of Agricultural Sciences, China (Y2020XK05)the Shanghai Pujiang Talent Plan, Shanghai, China (18PJ1404600)
文摘Riboflavin is an essential micronutrient for humans and must be obtained exogenously from foods or sup-plements.Numerous studies have suggested a major role of riboflavin in the prevention and treatment of various diseases.There are mainly three strategies for riboflavin synthesis,including total chemical syn-thesis,chemical semi-synthesis,and microbial fermentation,the latter being currently the most promis-ing strategy.In recent years,flavinogenic microbes have attracted increasing attention.Fungi,including Eremothecium ashbyii and Ashbya gossypii,and bacteria,including Bacillus subtilis,Escherichia coli,and lac-tic acid bacteria,are ideal cell factories for riboflavin overproduction.Thus they are good candidates for enhancing the level of riboflavin in fermented foods or designing novel riboflavin bio-enriched foods with improved nutritional value and/or beneficial properties for human health.This review briefly describes the role of riboflavin in human health and the historical process of its industrial production,and then highlights riboflavin biosynthesis in bacteria and fungi,and finally summarizes the strategies for ribofla-vin overproduction based on both the optimization of fermentation conditions and the development of riboflavin-overproducing strains via chemical mutagenesis and metabolic engineering.Overall,this review provides an updated understanding of riboflavin biosynthesis and can promote the research and development of fermented food products rich in riboflavin.
基金supported by National Key R&D Program of China(2023YFF1104302)the Soft Science Research Project of Wuxi Science and Technology Association(KX-23-C042)the program of“Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province”,China
文摘Glutaraldehyde(GTA) crosslinking is commonly used to improve the thermal stability and mechanical strength of collagen casings. The aim of this research was to determine the optimal pH of the crosslinking between GTA and collagen as well as the crosslinking mechanisms. The weakly alkaline environment could facilitate the generation of GTA polymerization through the rapid generation of -C=C-C=O and -N=C-C=C- conjugated structures, and enhance the crosslinking reaction of GTA polymers with collagen amino groups. In the pH range of 8–10, the fibril diameter and d-space value declined significantly in the self-assembled collagen fibril-GTA system. Meanwhile, collagen casing films crosslinked with GTA in weakly alkaline conditions exhibited higher mechanical strength and thermal stability. These results suggest that the crosslinking of collagen casings and GTA can be improved by adjusting the pH. Possible crosslinking mechanisms related to the formation of conjugated long chains have also been proposed. This study could provide guidance on the appropriate use of GTA in the production process of collagen casings.
