In this study,the structural characters,antioxidant activities and bile acid-binding ability of sea buckthorn polysaccharides(HRPs)obtained by the commonly used hot water(HRP-W),pressurized hot water(HRP-H),ultrasonic...In this study,the structural characters,antioxidant activities and bile acid-binding ability of sea buckthorn polysaccharides(HRPs)obtained by the commonly used hot water(HRP-W),pressurized hot water(HRP-H),ultrasonic(HRP-U),acid(HRP-C)and alkali(HRP-A)assisted extraction methods were investigated.The results demonstrated that extraction methods had significant effects on extraction yield,monosaccharide composition,molecular weight,particle size,triple-helical structure,and surface morphology of HRPs except for the major linkage bands.Thermogravimetric analysis showed that HRP-U with filamentous reticular microstructure exhibited better thermal stability.The HRP-A with the lowest molecular weight and highest arabinose content possessed the best antioxidant activities.Moreover,the rheological analysis indicated that HRPs with higher galacturonic acid content and molecular weight showed higher viscosity and stronger crosslinking network(HRP-C,HRP-W and HRP-U),which exhibited stronger bile acid binding capacity.The present findings provide scientific evidence in the preparation technology of sea buckthorn polysaccharides with good antioxidant and bile acid binding capacity which are related to the structure affected by the extraction methods.展开更多
Carbon dioxide fixation technique was developed as an alternative dechlorination method of chlorobenzenes. Electrolysis of chlorobenzene was carried out in a one-compartment cell fitted with an aluminium anode and a p...Carbon dioxide fixation technique was developed as an alternative dechlorination method of chlorobenzenes. Electrolysis of chlorobenzene was carried out in a one-compartment cell fitted with an aluminium anode and a platinum cathode. Electrolysis in N, N-dimethylformamide （DMF） solution containing 0.1 M of tetrapropylammonium bromide （TPAB） at 0 ℃, 100 ml/min of CO2 flow rate and 120 mA/cm^2 of current density was found to be the optimum conditions of this electrocarboxylation, which gave 72% yield of benzoic acid from chlorobenzene. These conditions were then applied to 1,2-dichlorobenzene and 1,3-dichlorobenzene in order to convert them to their corrcsponding benzoic acids.展开更多
Liquid-phase acrylic acid hydration over solid-phase catalysts is a key reaction for the industrial productionof 3-hydroxypropionic acid. However, the relevant literature primarily focuses on the experimental aspects ...Liquid-phase acrylic acid hydration over solid-phase catalysts is a key reaction for the industrial productionof 3-hydroxypropionic acid. However, the relevant literature primarily focuses on the experimental aspects of catalystscreening and exploring reaction conditions, with few accurate descriptions of the reaction kinetics and determination ofthe reaction mechanism. Here, we combined kinetics experiments and theoretical calculations to elucidate the kinetics andmechanism of acrylic acid hydration on a resin catalyst. The pseudo-homogeneous model, and Langmuir-Hinshelwood-Haugen-Watson and Elie-Riedel (ER) heterogeneous models were used to explain the experimental kinetics data. TheER model can explain the experimental data very well, suggesting strong adsorption of acrylic acid on the surface of theresin catalyst. Furthermore, density functional theory calculations show that the hydration follows a stepwise, rather than aconcerted, reaction pathway. The present study provides theoretical insights into the reaction mechanism and kinetics, fillingthe gap in our understanding of the reaction on a fundamental level.展开更多
为促进花生粕的综合利用,以13株乳酸菌发酵花生粕乳,采用逼近理想解排序(TOPSIS)法分别从酸度、黏度、氨基酸态氮浓度、持水力、活菌数和感官属性等方面进行综合评价,探究乳酸菌在花生粕乳中的发酵性能。结果表明,植物乳杆菌植物亚种(L6...为促进花生粕的综合利用,以13株乳酸菌发酵花生粕乳,采用逼近理想解排序(TOPSIS)法分别从酸度、黏度、氨基酸态氮浓度、持水力、活菌数和感官属性等方面进行综合评价,探究乳酸菌在花生粕乳中的发酵性能。结果表明,植物乳杆菌植物亚种(L6)的产酸速率最高,达到9.57°T/h,其次是植物乳杆菌(X2),为9.26°T/h。植物乳杆菌(X2)和副干酪乳杆菌(X5)的后酸化能力较弱,贮藏期间酸度变化量分别为10.84°T和9.58°T,且这两株菌产氨基酸态氮浓度较高,分别为589.87μg/mL和562.28μg/mL。嗜热链球菌(S2)的产黏能力和持水力最强,分别为1227.33 mPa·s和42.62%,且其综合感官评分最高,为89.75分。发酵乳杆菌(FYa1)和植物乳杆菌(MDb2)的活菌数最高,分别为8.89 lg CFU/mL和8.80 lg CFU/mL。采用TOPSIS法综合评价,得出嗜热链球菌(S2)为综合发酵性能较优良的菌株,以其为核心菌株辅以乳酸杆菌作为发酵剂应用于花生粕乳的发酵,可为花生粕乳发酵产品的开发提供有效路径。展开更多
基金The Guangdong Basic and Applied Basic Research Foundation(2022A1515010730)National Natural Science Foundation of China(32001647)+2 种基金National Natural Science Foundation of China(31972022)Financial and moral assistance supported by the Guangdong Basic and Applied Basic Research Foundation(2019A1515011996)111 Project(B17018)。
文摘In this study,the structural characters,antioxidant activities and bile acid-binding ability of sea buckthorn polysaccharides(HRPs)obtained by the commonly used hot water(HRP-W),pressurized hot water(HRP-H),ultrasonic(HRP-U),acid(HRP-C)and alkali(HRP-A)assisted extraction methods were investigated.The results demonstrated that extraction methods had significant effects on extraction yield,monosaccharide composition,molecular weight,particle size,triple-helical structure,and surface morphology of HRPs except for the major linkage bands.Thermogravimetric analysis showed that HRP-U with filamentous reticular microstructure exhibited better thermal stability.The HRP-A with the lowest molecular weight and highest arabinose content possessed the best antioxidant activities.Moreover,the rheological analysis indicated that HRPs with higher galacturonic acid content and molecular weight showed higher viscosity and stronger crosslinking network(HRP-C,HRP-W and HRP-U),which exhibited stronger bile acid binding capacity.The present findings provide scientific evidence in the preparation technology of sea buckthorn polysaccharides with good antioxidant and bile acid binding capacity which are related to the structure affected by the extraction methods.
文摘Carbon dioxide fixation technique was developed as an alternative dechlorination method of chlorobenzenes. Electrolysis of chlorobenzene was carried out in a one-compartment cell fitted with an aluminium anode and a platinum cathode. Electrolysis in N, N-dimethylformamide （DMF） solution containing 0.1 M of tetrapropylammonium bromide （TPAB） at 0 ℃, 100 ml/min of CO2 flow rate and 120 mA/cm^2 of current density was found to be the optimum conditions of this electrocarboxylation, which gave 72% yield of benzoic acid from chlorobenzene. These conditions were then applied to 1,2-dichlorobenzene and 1,3-dichlorobenzene in order to convert them to their corrcsponding benzoic acids.
文摘Liquid-phase acrylic acid hydration over solid-phase catalysts is a key reaction for the industrial productionof 3-hydroxypropionic acid. However, the relevant literature primarily focuses on the experimental aspects of catalystscreening and exploring reaction conditions, with few accurate descriptions of the reaction kinetics and determination ofthe reaction mechanism. Here, we combined kinetics experiments and theoretical calculations to elucidate the kinetics andmechanism of acrylic acid hydration on a resin catalyst. The pseudo-homogeneous model, and Langmuir-Hinshelwood-Haugen-Watson and Elie-Riedel (ER) heterogeneous models were used to explain the experimental kinetics data. TheER model can explain the experimental data very well, suggesting strong adsorption of acrylic acid on the surface of theresin catalyst. Furthermore, density functional theory calculations show that the hydration follows a stepwise, rather than aconcerted, reaction pathway. The present study provides theoretical insights into the reaction mechanism and kinetics, fillingthe gap in our understanding of the reaction on a fundamental level.
文摘为促进花生粕的综合利用,以13株乳酸菌发酵花生粕乳,采用逼近理想解排序(TOPSIS)法分别从酸度、黏度、氨基酸态氮浓度、持水力、活菌数和感官属性等方面进行综合评价,探究乳酸菌在花生粕乳中的发酵性能。结果表明,植物乳杆菌植物亚种(L6)的产酸速率最高,达到9.57°T/h,其次是植物乳杆菌(X2),为9.26°T/h。植物乳杆菌(X2)和副干酪乳杆菌(X5)的后酸化能力较弱,贮藏期间酸度变化量分别为10.84°T和9.58°T,且这两株菌产氨基酸态氮浓度较高,分别为589.87μg/mL和562.28μg/mL。嗜热链球菌(S2)的产黏能力和持水力最强,分别为1227.33 mPa·s和42.62%,且其综合感官评分最高,为89.75分。发酵乳杆菌(FYa1)和植物乳杆菌(MDb2)的活菌数最高,分别为8.89 lg CFU/mL和8.80 lg CFU/mL。采用TOPSIS法综合评价,得出嗜热链球菌(S2)为综合发酵性能较优良的菌株,以其为核心菌株辅以乳酸杆菌作为发酵剂应用于花生粕乳的发酵,可为花生粕乳发酵产品的开发提供有效路径。
