摘要:

AbstractThe accurate quantitative determination of free quartz contained in local feldspars and clays was achieved through special methods of differential thermal analysis, and chemical analysis. and chemical analysis. Aswan feldspar and Aswan clays were found to contain varying free quartz contents and were therefore considered as suitable sources of raw materials for the preparation of clay‐feldspar‐quartz ceramic body mixes. Accordingly, no quartz addition was necessary for the production of pottery and porcelain ceramic bod

ISSN:0375-9210    

DOI:10.1002/jctb.5020211201

出版商:John Wiley&Sons, Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractA method is described for the isolation of glucose oxidase from the bacteria Aspergillus niger using sorption on DEAE‐cellulose. The method is rapid by comparison with precipitation methods and results in a preparation having a specific activity of 87‐5 e.u./mg. The preparation contains no detectable catalase or amylase activity and appears to be suitable for most purposes without further treatm

ISSN:0375-9210    

DOI:10.1002/jctb.5020211202

出版商:John Wiley&Sons, Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractAn introduction to a symposium on ‘The evaporation of heat sensitive foodstuff liquids’ is given and a brief historical resume of the subject is presented together with comments on the processes invol

ISSN:0375-9210    

DOI:10.1002/jctb.5020211203

出版商:John Wiley&Sons, Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractA general survey is given of the history of the falling‐film evaporator and its uses in the food industry. An explanation of the reasons for its production is given and is followed by details of operation and an examination advantages and disadvantages met in its use. Examples of specific design‐types are discussed and illustra

ISSN:0375-9210    

DOI:10.1002/jctb.5020211204

出版商:John Wiley&Sons, Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractA description of the plate evaporator is given with particular reference to the A.P.V. products. The difference between the plate evaporator and plate heat exchanger is pointed out. The advantages and disadvantages of this method of evaporation are discussed. The specific requirements of the plate evaporator in dealing with heat sensitive materials are considered.

ISSN:0375-9210    

DOI:10.1002/jctb.5020211205

出版商:John Wiley&Sons, Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractAn historical introduction to the production of fruit juices and their concentrates is provided. The introduction of modern evaporative techniques is examined. The storage properties of concentrates and the evaporation of citrus juices is discussed. It is concluded that with high initial juice quality and the use of volatile recovery satisfactory fruit juice concentrates can be produced by all evaporator types, although those with short residence times give the best effects on flavour except in certain special cases.

ISSN:0375-9210    

DOI:10.1002/jctb.5020211206

出版商:John Wiley&Sons, Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractA description of the theory of the Centri‐Therm evaporator is given, together with illustrations of the parts. The application of the evaporator to a number of heat sensitive foodstuff liquids is examined. Comparison of the cost of operation of the Centri‐Therm evaporator with other comparable evaporation methods is provi

ISSN:0375-9210    

DOI:10.1002/jctb.5020211207

出版商:John Wiley&Sons, Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractThe loss of volatile flavours from food liquids during evaporative drying and freeze‐drying is independent of the relative volatility of the flavours and fully controlled by the rate at which the flavours can migrate to the evaporating surface. This rate of transfer is in solids and liquids without internal circulation directly proportional to the molecular diffusion coefficient of the flavour component. The diffusion coefficients of the flavour components are strongly dependent on water concentration and decrease much more steeply with decrease in water concentration than the diffusion coefficient of water. Below a critical water concentration the system becomes selectively permeable to water and completely impermeable to flavour molecules. The critical moisture content is dependent on the nature of the dissolved solids, and increases with increasing size of the flavour molecule and decreasing temperature.Drying conditions leading to a steep water concentration gradient and a rapid decrease in the water concentration at the liquid‐or solid‐gas interface down to the domain of selective permeability result in high flavour retention. The effect of these process conditions on retention have been studied experimentally for spray drying and freeze d

ISSN:0375-9210    

DOI:10.1002/jctb.5020211208

出版商:John Wiley&Sons, Ltd    

年代:1971

数据来源: WILEY