摘要:

Theories of the process of ultrafiltration and reverse osmosis, that involve permeation of solvent through a membrane in a sense opposite to that which obtains in osmosis, are considered. Factors that affect rates of permeation of solute and of solvent, and hence the selectivity of the membrane, are discussed.The physical structure and chemical composition of membranes are discussed, and the effect of processing variables on structure and composition, and hence on permeation rates and selectivity, are considered. The formation of boundary layers of high solute concentration at the surface of the membrane exposed to the solution has an appreciable effect on permeation; techniques for preventing their formation are mentioned. Some basic considerations relating to the power requirements of membrane processes are defined.

ISSN:1364-727X    

DOI:10.1111/j.1471-0307.1974.tb01683.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

ISSN:1364-727X    

DOI:10.1111/j.1471-0307.1974.tb01684.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Types of ultrafiltration plant are described grouped under tubular and plate and frame concepts. The desirable features of UF plant are defined as low process costs, hygienic operation and precise membrane characteristics and each of these is discussed. In relation to hygienic operation the importance of time and temperature of operation as well as general plant design is stressed and it is concluded that UF plants can be operated hygienically. Applications to whey processing is described and emphasis is placed on lactose ultrafiltration to produce an economically viable process; hydrolysis by beta galactosidase is suggested. Application to skim milk processing is also described.

ISSN:1364-727X    

DOI:10.1111/j.1471-0307.1974.tb01685.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

ISSN:1364-727X    

DOI:10.1111/j.1471-0307.1974.tb01686.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

An examination is made of the influence of the main processing variables in the reverse osmosis (RO) concentration of both whey and skim milk. Up to a solids concentration ceiling ofca.25 per cent, RO offers an economic advantage over thermal evaporation as a concentration technique, in terms of lower operating costs. Furthermore, RO possesses the additional advantage that it concentrates without heat, thereby retaining the native properties of the original raw material before concentration. In particular, there is no heat denaturation of the thermolabile whey proteins and, hence, no reduction of valuable functional properties and no cooked flavour development.Based on these inherent advantages of RO over thermal evaporation, various process and product applications of RO to whey and skim milk utilization have been suggested. Additional features of membrane processing by RO have also been discussed.

ISSN:1364-727X    

DOI:10.1111/j.1471-0307.1974.tb01687.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

The development of electrodialysis is described with its use as a practical process in demineralizing and concentrating solutions of electrolytes. The applications and basic types of ion‐exchange membranes for use in electrodialysis are discussed. Membrane properties such as electrical resistance, permselectivity, ionic capacity, solvent transfer and chemical resistance are given in detail as being particularly important in characterizing electrodialytic properties of ion‐exchange membranes. Demineralization of cheese whey is dealt with fully and various problems and techniques discussed. Variants of electrodialysis ‐ transport depletion, ion substitution and electro osmosis are also given. (Editor's su

ISSN:1364-727X    

DOI:10.1111/j.1471-0307.1974.tb01688.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

ISSN:1364-727X    

DOI:10.1111/j.1471-0307.1974.tb01689.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Whole milk was concentrated by a factor of two by ultrafiltration. It was used directly for making Cheddar and Cheshire cheese, an unripened soft cheese of the Coulommier type, and yoghurt.The yields of hard cheese from the concentrated milk were the same as those from normal whole milk. The cheeses were acceptable though the flavour was milder than that of good quality Cheddar and Cheshire cheese.Medium fat soft cheeses were made from the concentrated milk. The yield of cheese was 41 per cent greater than that made from normal whole milk and the making time was half that of the normal process. The cheeses were consumed fresh or stored in deep freeze.For making yoghurt, the usual reinforcement with skim milk powder was not necessary as the concentrated milk had a high total solids content, nor was it necessary to homogenize the mix. The yoghurt contained 21 per cent total solids and was a very acceptable product.

ISSN:1364-727X    

DOI:10.1111/j.1471-0307.1974.tb01690.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

ISSN:1364-727X    

DOI:10.1111/j.1471-0307.1974.tb01692.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

The types of plastics used for packaging dairy products are reviewed briefly and their advantages for non‐returnable containers discussed. Virtual complete resistance to biodegradation, an important asset in packaging food products, has lead to suggestion of disposal difficulties. Detailed studies have, however, established that plastics currently present no major problems in any of the waste disposal methods used by municipalities and may present some advantages. The litter problem is primarily a social and aesthetic one rather than an ecological one. Attempts are being made to develop plastics which degrade more readily in sunlight. Possibilities for recycling plastics are also being studied. The launch of any product in a non‐returnable pack should be preceded by careful study of likely environmental imp

ISSN:1364-727X    

DOI:10.1111/j.1471-0307.1974.tb01693.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY