Food or edible material: processes – compositions – and products – Products per se – or processes of preparing or treating... – Basic ingredient lacteal derived other than butter...
Reexamination Certificate
2000-11-21
2003-04-22
Wong, Leslie (Department: 1761)
Food or edible material: processes, compositions, and products
Products per se, or processes of preparing or treating...
Basic ingredient lacteal derived other than butter...
C210S651000, C426S478000, C426S491000
Reexamination Certificate
active
06551648
ABSTRACT:
This application is a 371 of PCT/FR99/00632 filed Mar. 18, 1999.
The present invention relates to new products with original fat globule distribution characteristics, the method of obtaining such products and the applications thereof. The preferred field of this invention is the dairy product one.
More particularly, the invention relates to a process for selectively separating according to the size thereof without modifying significantly their membrane integrity, fat globules being present in a food or biological medium. In the following text, the invention has been described more in detail by referring to milk treatment. This one is in fact a particularly interesting case of food liquid adapted to be subjected to said process.
Fats contained in milk produced by mammals (cow, goat, sheep, cow-buffalo, mare, she-ass, women, etc.) are present at more than 95% as spherical globules, visible under optical microscope, with a diameter in the range of 0.1 to 20 &mgr;m. As regards cow milk, the average diameter thereof is in the range of 3 and 5 &mgr;m and their gaussian dispersion is mainly comprised between 2 and 12 &mgr;m (Alais, 1984, Science du Lait, Edition Sepaic). Most of the fat globules (80%) have a diameter lower than 0.1 &mgr;m, but only represents a very low proportion in weight of the milk fat material (Keenan et al., 1988, Fundamentals of Dairy Chemistry, Edition Van Nostrand Reinhold). The fat globule size distribution varies slightly according to the species, the feed and the lactation period for dairy cattle (Keenan et al., supra).
Fat globules from cow milk are formed with a membrane having a complex structure comprising numerous protein kinds (20 to 40 according to the authors) with amphiphile properties, like butyrophiline, or enzymatic ones, like xantine oxidase, complex lipids (phospholipids and cerebrosids some of which have also complex glycations, including sialic acid, N-acetylgalactosamine, . . . ) and nucleic acids (Keenan et al., supra) surrounding a droplet of di- and triglycerides, being partially crystallized at room temperature (Alais, supra).
Separation of fat globules from the milk rest, i.e. a so-called phenomenon of skimming, is based upon the volume mass difference (density) existing between globules and the liquid in which they are suspended. Two skimming types are conventionally distinguished: the so-called spontaneous skimming, beforehand quite practiced in manual butter- and cheese-manufacturing, so providing an agglomerated fat globule enriched layer, an operation performed at 5-10° C. during 10-16 hr, and the centrifugal skimming where whole milk subjected to a centrifugal rotation of about 4000 to 5000 rpm within a pile of conical disks (Towler, 1986, Modem Dairy Technology, Edition Robinson) is continuously separated into cream and skimmed milk. The cream being obtained according to such a process and used in the worldwide dairy industry is a milk that is strongly enriched with globular fat material (the most current content thereof is 400 g/kg). Depending upon the equipment being used, the fats content of the skimmed milk is equal to or lower than 0.5 g/kg.
There exists a need in products, in particular dairy products, comprising selected fractions of fat globules as well as products containing calibrated fat globules. The dairy industry is looking more and more for new products meeting customers' needs and amongst them products coming from fat product conversion.
The object of the present invention relates to a new methodology for separating and fractioning through micro-filtration membranes fats contained in a food or biological medium, in particular in the milk produced by dairy females, based not upon volume mass differences between fat globules and skimmed milk like in the prior art, but upon particle size differences of the milk components of mammals.
Thus, the invention does not relate to a total separation of the globular fat material, but to a differential fractioning of said fats according to the globule size so as to implement the surprising properties of the fractions enriched with small and large globules.
The membrane micro-filtration technique is known per se and has been already proposed in the dairy industry in particular. As a pertinent reference, the article of J. L. Maubois titled “Current uses and future perspectives of M. F. Technology in the dairy industry” in Bulletin of the IDF 320, 1997, pp. 37 to 40, that reviews the skilled man knowledge in that field and mentions numerous bibliographic references.
The total whole milk skimming, i.e. the total globule retention by membrane micro-filtration in tangential flow has been proposed by Piot and al. (La Technique Laitiere n° 1016, 1987). The membrane being used with an average diameter of 1.8 &mgr;m led to a retention of about 98% fats that the authors considered as insufficient with respect to the centrifugal skimming and to improve it they proposed to use micro-filtration membranes with a lower pore diameter.
Such an article does not contain any teaching about the production of fat products containing selected fat globule fractions and highlights that the micro-filtration technique, though a priori useable for skimming and bacterial purification of crude whole milk, raises numerous unsolved technical problems.
U.S. Pat. No. 4,140,806 discloses a process for separating milk through tangential micro-filtration into a first fraction containing almost the total fats comprised in the starting product and into a second fraction being practically fat-free, in filtration conditions that do not allow to produce a substantially uniform transmembrane pressure.
Patent FR 95.02939 (publication 2,731,587) describes a process to remove somatic cells from food or biological media consisting in subjecting the medium to be treated to at least a tangential micro-filtration on a membrane having a cut-point threshold higher than 10 &mgr;m, preferably in the range of 10 to 50 &mgr;m. A preferred application for this process is milk treatment, the technical problem in such a case being to produce a milk matching the most severe sanitary quality requirements, i.e. the somatic cell rate of which is very low while keeping the common flora useful in milk conversion, for example cheese. Such prior patent only takes problems associated with the presence of milk somatic cells into account and does not contains any teaching upon the production of fat products containing selected fat globule fractions.
The products produced according such a patent are a micro-filtrate containing less than 10 000 somatic cells/ml and containing the essential starting milk fats as well as a retentate representing 4% in volume of the milk being in contact with the membrane and containing the essential part of the somatic cells and a little fat material.
The present invention has for object a process that allows to separate fat globules selectively according their size and then to produce derivates containing calibrated globules. These ones stay in their native condition, that means their membrane has not been modified and stays with the natural properties thereof.
An object of the invention aims at a process for separating selectively according to their size the fat globules present in a food or biological medium consisting in subjecting the medium to be treated to at least a tangential flow micro-filtration on a membrane with a cut-point threshold comprised between 1.8 and 10 &mgr;m in substantially uniform transmembrane differential pressure conditions and recovering the retentate and permeate being obtained.
In the case of milk, the resulting products are used for preparing milks and creams falling into the conventional conversion processes or the new processes.
The selective separation is performed on micro-filtration membranes with cut-point thresholds in the range between 1.8 and 10 &mgr;m depending upon the selection being looked for. The following illustrative examples demonstrate the interest of selecting membranes with a cut-point threshold higher than 1.8 &mgr;m and lower than 10 &mgr;m. Although the
Fauquant Jacques E
Goudedranche Henri Y M
Maubois Jean-Louis J
Institut National de la Recherche Agronomique
Muserlian Lucas and Mercanti
Wong Leslie
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