Food or edible material: processes – compositions – and products – Processes – Separating a starting material into plural different...
Patent
1989-10-17
1991-07-02
Cintins, Marianne
Food or edible material: processes, compositions, and products
Processes
Separating a starting material into plural different...
426495, 210651, 210490, A23C 114
Patent
active
050284363
DESCRIPTION:
BRIEF SUMMARY
The invention concerns a process for separating the dissolved and undissolved constituents of milk.
The composition of the milk of mammals is well known. The dry content of the cow milk is know to be about 12.7% on average, of which 3.7% are fat components, 3.4% total serum protein. 4.7% lactose and about 0.7% ash. The protein component mainly consists of caseins and whey proteins. Moreover there are a non-proteinaceous nitrogen fraction, protease peptones and minor proteins, which are mainly enzymes.
Ordinarily milk is separated into caseins and whey proteins. This separation is by means of the so-called rennet precipitation in which rennin is added to warmed-up milk (30.degree.-35.degree. C.). The caseins then precipitate, the whey proteins remaining in solution. The same applies to the so-called acid precipitation of the caseins which takes place at the iso-electric point (cow milk pH 4.7). Caseins are heat-resistant, whereas the whey proteins are thermally labile.
It is further known to concentrate milk by reverse osmosis, in which practically pure water is removed from the milk, i.e. all the dissolved and undissolved milk constituents including the salts dissolved in the milk remain in the retentate and the permeate essentially consists of pure water. This is the way essentially in which presently the so-called condensed milk is prepared. However, reverse osmosis also is used to concentrate whey and when making curd-, yogurt-, and sour-milk.
It is further known to treat milk with ultra-filtration. However, only when using skim milk or whey will there be absence of difficulties in the enrichment of the milk proteins. Ultrafiltration of native full-cream milk, on the other hand, results only in incomplete separation. Milk separation by means of conventional membrane filters is impossible.
It is comparatively expensive to secure the whey proteins, which are especially desirable for nutritional and physiological reasons, when using the known methods. Moreover, the whey proteins obtained using the conventional methods as a rule are bacteria-contaminated and contain fat, and further contain the calcium and phosphate ions released upon the separation into caseins and whey proteins.
Accordingly, the object of the invention is to provide an improved process for separating milk into dissolved and undissolved constituents by resorting to membranes.
It was found in surprising manner that milk can be separated into its dissolved and undissolved constituents if it is made to pass through a microporous membrane pretreated with lipids and/or peptides.
Accordingly, the object of the invention is a process for separating the dissolved and undissolved milk ingredients, which is characterized by pretreating a micro-porous membrane with a pore size in the range from 0.1 to 2 microns (u) with lipids and/or peptides, and by separating the milk at the membrane so pretreated.
Advantageously, a fluorocarbon polymer based membrane shall be used. Especially preferred is a polyvinylidene fluoride membrane, for instance a so called DURAPORE membrane made by Millipore Co. (for instance the GLVP or HVLP type).
The membrane's pore sizes are preferably in the range from 0.1 to 1 u, in particular between 0.1 and 0.6 u.
The pretreatment may be with lipids or peptides alone, first with lipids and then with peptides. By means of this pretreatment, a membrane is obtained, which--contrary to the case of an untreated membrane--allows separating the milk into its dissolved and undissolved constituents. No explanation for the effect of pretreatment can be given. Still it might be a polarization effect.
The pretreatment of the membrane is simply carried out by exposing it to a flowing solution, emulsion or dispersion of the lipids and/or peptides in water. As a rule, lipid emulsion of 0.1 to 10%, preferably from 2 to 5% or a peptide solution of 0.01 to 10%, preferably from 0.1 to 5% shall suffice.
Appropriately, the pretreatment takes place at a temperature of 8.degree. to 40.degree. C. in particular from 15.degree. to 35.degree. C.
The duratio
REFERENCES:
patent: 4140806 (1979-02-01), Glimenius et al.
patent: 4203848 (1980-05-01), Grandine, II
patent: 4539117 (1985-09-01), Meyer et al.
patent: 4810384 (1989-03-01), Fabre
patent: 4906379 (1990-03-01), Hodgins et al.
Cintins Marianne
Pratt Helen
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