Traditional thermal methods of drying food have often led to loss of flavours, nutrients, vitamins, etc., which encourages non-thermal pretreatments such as osmotic dehydration （OD） and/or high electric field （HEF...Traditional thermal methods of drying food have often led to loss of flavours, nutrients, vitamins, etc., which encourages non-thermal pretreatments such as osmotic dehydration （OD） and/or high electric field （HEF） application to improve the overall product quality. The aim of this study was to evaluate the effect of osmotic dehydration （50% sucrose） with high electric field strengths of 0.5 and 1.0 kV/cm as pretreatments on the drying kinetics and mass transfer of green apples during convective drying at 65 ~C and microwave drying at 1 W/g. The added value of the OD and HEF on the drying kinetics, and the effective mass transfer coefficients of the subsequent drying methods were investigated through this research. The efficacy of these pre-treatments was assessed and compared using cell disintegration index, product texture and thus bring forth new correlations between these pre-treatments and the cell disintegration index using dielectric spectroscopy and its effect on the product texture.展开更多
Dehydration temperatures of serpentine were measured in the pressure range between1. 0 GPa and 5. 0 GPa by using the electrical conductivity method simultaneously at high temperatures and high pressures. The results s...Dehydration temperatures of serpentine were measured in the pressure range between1. 0 GPa and 5. 0 GPa by using the electrical conductivity method simultaneously at high temperatures and high pressures. The results show that with increasing pressure the dehydrationtemperature of antigorite increases slightly below 2. 0 GPa, but drops markedly above 2. 0GPa. This strongly suggests that high pressure would favor the dehydration of serpentine minerals and the water released thereby would be an important source of fluids involved in magmatism in a subduction zone and mantle metasomatism. Meanwhile, the greatly enhanced electricconductivity in the presence of water may be one of the reasons underlying the occurrence of ahigh-conductivity zone in the lower crust.展开更多
Hydrous minerals within the subducting oceanic slab are important hosts for water.Clarification of the stability field of hydrous minerals helps to understand transport and distribution of water from the surface to th...Hydrous minerals within the subducting oceanic slab are important hosts for water.Clarification of the stability field of hydrous minerals helps to understand transport and distribution of water from the surface to the Earth’s interior.We investigated the stability of brucite,a prototype of hydrous minerals,by means of electrical conductivity measurements in both open and closed systems at 3 GPa and temperatures up to 1300 K.Dramatic increase of conductivity in association with characteristic impedance spectra suggests that partial dehydration of single-crystal brucite in the open system with a low water fugacity occurs at 950 K,which is about 300 K lower than those previously defined by phase equilibrium experiments in the closed system.By contrast,brucite completely dehydrates at 1300 K in the closed system,consistent with previous studies.Partial dehydration may generate a highly defective structure but does not lead to the breakdown of brucite to periclase and water immediately.Water activity plays a key role in the stability of hydrous minerals.Low water activity(a H_(2)O)caused by the high wetting behavior of the subducted oceanic slab at the transition zone depth may cause the partial dehydration of the dense hydrous magnesium silicates(DHMSs),which significantly reduces the temperature stability of DHMS(this mechanism has been confirmed by previous study on super hydrous phase B).As a result,the transition zone may serve as a‘dead zone’for DHMSs,and most water will be stored in wadsleyite and ringwoodite in the transition zone.展开更多
The stable fields of hydrous minerals are very important for us to inquire into dia-genesis,magmatism,metamorphic evolution and geochemical process of subduction zone.Until now,the dehydration temperatures of hydrous ...The stable fields of hydrous minerals are very important for us to inquire into dia-genesis,magmatism,metamorphic evolution and geochemical process of subduction zone.Until now,the dehydration temperatures of hydrous minerals at high pressure are mainlydetermined by phase equilibrium experiment,HP-DTA analysis,MD calculation as well展开更多
脉冲电场(Pulsed Electric Field,PEF)作为新型的非热预处理技术,具有耗时短、能耗低、绿色环保等优良特性。本文综述了脉冲电场的作用机理及其作为预处理技术在果蔬干燥领域的应用,如热风干燥、冷冻干燥、微波干燥、渗透干燥、喷雾干...脉冲电场(Pulsed Electric Field,PEF)作为新型的非热预处理技术,具有耗时短、能耗低、绿色环保等优良特性。本文综述了脉冲电场的作用机理及其作为预处理技术在果蔬干燥领域的应用,如热风干燥、冷冻干燥、微波干燥、渗透干燥、喷雾干燥和真空干燥。与未处理相比,PEF预处理可以提高脱水速率,降低生产成本,提高样品中营养成分的保留率,使干燥产品的品质更佳。但PEF存在参数与处理基质之间的特异性,预处理食品的安全性等问题,后续需加强PEF的参数匹配及安全性研究,为PEF预处理在果蔬干燥领域的深入研究提供新的思路和参考。展开更多
文摘Traditional thermal methods of drying food have often led to loss of flavours, nutrients, vitamins, etc., which encourages non-thermal pretreatments such as osmotic dehydration （OD） and/or high electric field （HEF） application to improve the overall product quality. The aim of this study was to evaluate the effect of osmotic dehydration （50% sucrose） with high electric field strengths of 0.5 and 1.0 kV/cm as pretreatments on the drying kinetics and mass transfer of green apples during convective drying at 65 ~C and microwave drying at 1 W/g. The added value of the OD and HEF on the drying kinetics, and the effective mass transfer coefficients of the subsequent drying methods were investigated through this research. The efficacy of these pre-treatments was assessed and compared using cell disintegration index, product texture and thus bring forth new correlations between these pre-treatments and the cell disintegration index using dielectric spectroscopy and its effect on the product texture.
文摘Dehydration temperatures of serpentine were measured in the pressure range between1. 0 GPa and 5. 0 GPa by using the electrical conductivity method simultaneously at high temperatures and high pressures. The results show that with increasing pressure the dehydrationtemperature of antigorite increases slightly below 2. 0 GPa, but drops markedly above 2. 0GPa. This strongly suggests that high pressure would favor the dehydration of serpentine minerals and the water released thereby would be an important source of fluids involved in magmatism in a subduction zone and mantle metasomatism. Meanwhile, the greatly enhanced electricconductivity in the presence of water may be one of the reasons underlying the occurrence of ahigh-conductivity zone in the lower crust.
基金supported by CAS“Light of West China”program(Y9CR026 to X.G.)the National Natural Science Foundation of China(442072051)supported by the Ministry of Education,Culture,Sports,Science,and Technology of the Japanese Government,Grant Numbers,15H05827 and 17H01155 to T.Y.
文摘Hydrous minerals within the subducting oceanic slab are important hosts for water.Clarification of the stability field of hydrous minerals helps to understand transport and distribution of water from the surface to the Earth’s interior.We investigated the stability of brucite,a prototype of hydrous minerals,by means of electrical conductivity measurements in both open and closed systems at 3 GPa and temperatures up to 1300 K.Dramatic increase of conductivity in association with characteristic impedance spectra suggests that partial dehydration of single-crystal brucite in the open system with a low water fugacity occurs at 950 K,which is about 300 K lower than those previously defined by phase equilibrium experiments in the closed system.By contrast,brucite completely dehydrates at 1300 K in the closed system,consistent with previous studies.Partial dehydration may generate a highly defective structure but does not lead to the breakdown of brucite to periclase and water immediately.Water activity plays a key role in the stability of hydrous minerals.Low water activity(a H_(2)O)caused by the high wetting behavior of the subducted oceanic slab at the transition zone depth may cause the partial dehydration of the dense hydrous magnesium silicates(DHMSs),which significantly reduces the temperature stability of DHMS(this mechanism has been confirmed by previous study on super hydrous phase B).As a result,the transition zone may serve as a‘dead zone’for DHMSs,and most water will be stored in wadsleyite and ringwoodite in the transition zone.
基金Project supported by the National Natural Science Foundation of China.
文摘The stable fields of hydrous minerals are very important for us to inquire into dia-genesis,magmatism,metamorphic evolution and geochemical process of subduction zone.Until now,the dehydration temperatures of hydrous minerals at high pressure are mainlydetermined by phase equilibrium experiment,HP-DTA analysis,MD calculation as well
文摘脉冲电场(Pulsed Electric Field,PEF)作为新型的非热预处理技术,具有耗时短、能耗低、绿色环保等优良特性。本文综述了脉冲电场的作用机理及其作为预处理技术在果蔬干燥领域的应用,如热风干燥、冷冻干燥、微波干燥、渗透干燥、喷雾干燥和真空干燥。与未处理相比,PEF预处理可以提高脱水速率,降低生产成本,提高样品中营养成分的保留率,使干燥产品的品质更佳。但PEF存在参数与处理基质之间的特异性,预处理食品的安全性等问题,后续需加强PEF的参数匹配及安全性研究,为PEF预处理在果蔬干燥领域的深入研究提供新的思路和参考。
