Numerical models of trajectories of small aerosol spheres relative to oblate spheroids were used to determine ice crystal scavenging efficiencies. The models included the effects of aerodynamic flow about the ice part...Numerical models of trajectories of small aerosol spheres relative to oblate spheroids were used to determine ice crystal scavenging efficiencies. The models included the effects of aerodynamic flow about the ice particle, gravity, aerosol particle inertia and drag and electrostatic effects. Two electric configurations of the ice particle were investigated in detail. The first applied a net charge to the ice particle, of magnitude equal to the mean thunderstorm charge distribution, while the second applied a charge distribution, with no net charge, to the ice particle to model the electric multipole charge distribution. The results show that growing ice crystals with electric multipoles are better scavengers than single ice crystals with net thunderstorm charges, especially in the Greenfield gap (0.1 to 1.0 um), and that larger single crystals are better scavengers than smaller single crystals. The results also show that the low density ice crystals are more effective scavengers with net charges than they are with charge distribution.展开更多
The DPPH scavenging ability of soymilk fermented with lactic acid bacteria under different fermentation conditions were investigated in this paper. According to the result, the optimal combination of starter species w...The DPPH scavenging ability of soymilk fermented with lactic acid bacteria under different fermentation conditions were investigated in this paper. According to the result, the optimal combination of starter species was S. thermophilus, L. plantarum and L. helveticus at a ratio of 2∶1.5∶1.5. The optimal fermentation parameters were temperature of 37 ℃, solids content of 12% and fermentation time of 6 h.Under above conditions, the fermented soymilk showed the highest ability to scavenge DPPH free radicals（84.3%）. Besides, the radical scavenging ability of fermented soymilk was compared with that of Baiyu lactone soymilk and bean curd which were coagulated by chemical method. The result indicated that the scavenging rate of lactone bean curd of Baiyu lactone soymilk and bean curd was only32.1% and 23.2%. According to the comparison, the free radical scavenging ability of soymilk was significantly improved by lactic acid fermentation. This product which had no beany flavor would be beneficial to human health.展开更多
[Objectives]To study the optimum conditions of solid fermentation of natto with antioxidant function as an index.[Methods]Single factor experiment and orthogonal experiment were designed to study the effects of temper...[Objectives]To study the optimum conditions of solid fermentation of natto with antioxidant function as an index.[Methods]Single factor experiment and orthogonal experiment were designed to study the effects of temperature,time,initial pH and inoculum amount on the antioxidant activity of natto solid fermentation.The optimum conditions of natto solid fermentation were determined and the antioxidant ac-tivity of natto extract was compared.[Results]The optimal fermentation conditions were as follows:temperature 32℃,initial pH 7.0,inocu-lation amount 8%,fermentation time 32 h.The hydroxyl radical scavenging rate of natto solid fermentation crude extract was the highest,which was 82.7%.The optimized nato fermentation extract showed stronger scavenging ability for-OH and O,:,and showed obvious dose-effect relationship.ICso was 3.63 and 4.24 mg/mL,respectively,and the scavenging efficiency was 1.3 and 1.9 times higher than that of the unoptimized fermentation extract,respectively.[Conclusions]Natto is rich in nattokinase and other functional factors,and its antioxidant ac-tivity can be improved by optimizing fermentation technology,so that natto products can be widely used,including cosmetic raw materials,nat-to skin care soap,health food and medicine,etc.,and have a broader development prospect.展开更多
文摘Numerical models of trajectories of small aerosol spheres relative to oblate spheroids were used to determine ice crystal scavenging efficiencies. The models included the effects of aerodynamic flow about the ice particle, gravity, aerosol particle inertia and drag and electrostatic effects. Two electric configurations of the ice particle were investigated in detail. The first applied a net charge to the ice particle, of magnitude equal to the mean thunderstorm charge distribution, while the second applied a charge distribution, with no net charge, to the ice particle to model the electric multipole charge distribution. The results show that growing ice crystals with electric multipoles are better scavengers than single ice crystals with net thunderstorm charges, especially in the Greenfield gap (0.1 to 1.0 um), and that larger single crystals are better scavengers than smaller single crystals. The results also show that the low density ice crystals are more effective scavengers with net charges than they are with charge distribution.
基金Supported by Key Technology Research and Development Program of Tianjin(11ZCKNC01800)~~
文摘The DPPH scavenging ability of soymilk fermented with lactic acid bacteria under different fermentation conditions were investigated in this paper. According to the result, the optimal combination of starter species was S. thermophilus, L. plantarum and L. helveticus at a ratio of 2∶1.5∶1.5. The optimal fermentation parameters were temperature of 37 ℃, solids content of 12% and fermentation time of 6 h.Under above conditions, the fermented soymilk showed the highest ability to scavenge DPPH free radicals（84.3%）. Besides, the radical scavenging ability of fermented soymilk was compared with that of Baiyu lactone soymilk and bean curd which were coagulated by chemical method. The result indicated that the scavenging rate of lactone bean curd of Baiyu lactone soymilk and bean curd was only32.1% and 23.2%. According to the comparison, the free radical scavenging ability of soymilk was significantly improved by lactic acid fermentation. This product which had no beany flavor would be beneficial to human health.
基金Supported by 2023 Zhanjiang Non-funded Science and Technology Research Plan(2023B01023)2022 University-level Education and Teaching Reform Project of Lingnan Normal University(LingShiJiaoWu2022154).Junxia SONG,bachelor degree,experimenter,research fields:physical geography.
文摘[Objectives]To study the optimum conditions of solid fermentation of natto with antioxidant function as an index.[Methods]Single factor experiment and orthogonal experiment were designed to study the effects of temperature,time,initial pH and inoculum amount on the antioxidant activity of natto solid fermentation.The optimum conditions of natto solid fermentation were determined and the antioxidant ac-tivity of natto extract was compared.[Results]The optimal fermentation conditions were as follows:temperature 32℃,initial pH 7.0,inocu-lation amount 8%,fermentation time 32 h.The hydroxyl radical scavenging rate of natto solid fermentation crude extract was the highest,which was 82.7%.The optimized nato fermentation extract showed stronger scavenging ability for-OH and O,:,and showed obvious dose-effect relationship.ICso was 3.63 and 4.24 mg/mL,respectively,and the scavenging efficiency was 1.3 and 1.9 times higher than that of the unoptimized fermentation extract,respectively.[Conclusions]Natto is rich in nattokinase and other functional factors,and its antioxidant ac-tivity can be improved by optimizing fermentation technology,so that natto products can be widely used,including cosmetic raw materials,nat-to skin care soap,health food and medicine,etc.,and have a broader development prospect.
