FI111902B - Method and apparatus for treating colostrum - Google Patents

Abstract

The invention relates to a method and apparatus for the treatment of raw milk. According to the method is separated from the raw milk under the effect of gravity a cream fraction, which is recovered. According to the invention, an inert gas is fed into the raw milk in order to promote the separation of cream. The apparatus comprises a gas-tight container (1), in the low portion of which there are arranged means (13) for introducing and bubbling gas into the raw milk fed into the container. In the upper portion of the container there is in this case formed a nozzle (11) that can be connected to a source of reduced pressure. According to the invention, a gentle separation of cream (fat) from raw milk is attained. At the same time, oxygen is removed from the raw milk, whereby the preservability of the raw milk and the cream separated can be improved considerably.

Description

1,111,902

Method and apparatus for treating raw milk

The present invention relates to a method for treating raw milk according to the preamble of claim 1.

According to such a method, the fat-rich raw milk is introduced into a container in which a cream fraction is separated from the raw milk by gravity.

The invention also relates to a device for treating raw milk according to the preamble of claim 5.

Separation of raw milk separates fat from the milk to obtain low-fat ("skimmed") milk and a fat-containing cream and / or cream-milk fraction. Separation is complicated by the foaming of raw milk, which is due to milk proteins. It is known that the shelf life of milk and non-acidified milk products is relatively short, and efforts have been made to improve the shelf life of the milk and cream products obtained from separation, for example. pasteurisation.

... 20 It is an object of the present invention to eliminate the drawbacks of the prior art * ·: and to provide a completely novel solution for handling raw milk. order. It is a particular object of the invention to provide a method and apparatus. : to separate raw milk, while improving the preservation of the separated milk and »*» ..: fat fractions.

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The invention is based on the idea that raw milk is fed with an inert gas such as nitrogen to promote separation. The gas is introduced into the milk in the form of small gas bubbles, whereby these bubbles increase the rise of the fat particles emulsified in the milk and accelerate the separation of fat. At the same time, milk and milk products effectively remove oxygen.

The device used in the invention comprises a sealed container having a raw milk feed connection and means for removing milk fractions obtained from separation.

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According to the invention, further means are provided in the lower part of the device for introducing the gas and bubbling it into raw milk fed into the container.

More specifically, the method according to the invention is essentially characterized by what is set forth in the characterizing part of claim 1.

The device according to the invention is characterized in what is stated in the characterizing part of claim 5.

The invention provides considerable advantages. Thus, the invention provides a gentle separation of cream (fat) from raw milk. At the same time, oxygen is removed from the raw milk, thereby significantly improving the preservation of the raw milk and the cream to be separated. The invention can be used in the dairy industry for deoxygenation, to increase the lift, which promotes the separation of cream 15 from raw milk. In addition, the invention is applicable to the preparation of vinegar (aeration) and the smoking of solutions.

The solution of the invention can replace the traditional fat separation by separation. However, it is also possible to combine the process of the invention 20 with conventional separation (i.e., centrifugal separation), whereby separation and separation are performed sequentially.

*; v. The separation may be carried out before or after the separation process according to the invention.

The invention will now be further explored by means of a detailed description with reference to the accompanying drawing. Figure 1a of the drawing is a sectional side elevational view of the basic structure of the apparatus according to the invention.

FIGS. 1b and 1c are top plan views of alternative design solutions for inert gas pipelines.

30: v, The process of the invention relates to raw milk, which is meant

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. ·. Milk, in general, from cows or goats, without significant fat removal. Raw milk is treated by allowing the fat globules emulsified in the aqueous phase to separate from the aqueous phase by gravity. Simply 111902 3 this is done by standing milk. However, it is possible to increase the power of the weight-force separation by the use of centrifugal force (conventional separation technique).

According to the invention, the separation of fat globules is enhanced by bubbling inert gas into the milk in the form of small bubbles, typically about 0.1 to 10 mm in size. Nitrogen or noble gases such as argon may be used as the inert gas. It is also possible to use carbon dioxide, which in this case must be considered inert because it does not react with the milk components as such, or even air from which at least most (at least 80%, preferably at least 90%) of the oxygen has been removed.

Preferably, the inert gas is introduced into the milk under pressure, typically about 110-300 kPa. Because of the vacuum in the container (see below), it is also possible to allow this vacuum to absorb inert gas from a gas source into the milk. Preferably, the proportion of oxygen in the gas fed to the raw milk should be less than 5 vol.%, Preferably less than 2 vol.%.

Since bubbling gas into raw milk can cause milk to foam, it is preferable to perform bubbling under reduced pressure. Typically, the # 20 separation according to the invention is performed at an absolute pressure of about 10 to about 90 kPa. Under reduced pressure, oxygen is removed from milk and milk products and nitrogen gas can be recovered. Vacuum is preferably produced by combining a gas space above the milk with a vacuum source for reducing the pressure with the gases. Vacuum; ..: The gas chamber can be connected to the source by means of a hose or pipe, preferably with a non-return valve.

'· (Teaspoon of the milk to be treated is carried out in a sealed container, typically:': a pressure vessel or similar sealed container fitted with a gas pipe shaped like a circle, a spiral or a grid, so that: '' '; the smoothest possible flow of gas through the raw milk.

:. The tubes may be, for example, sintered or otherwise densely perforated material from which gas flows in small bubbles evenly over the entire bottom surface. The gas (eg nitrogen) is supplied to the pipeline in a controlled manner, i.e. with constant pressure and flow. It is also possible to supply inert gas directly to the milk fed into the separation tank.

The method according to the invention may be implemented as a batch or semi-batch process or as a continuous process. Typically, it operates as a batch process in which the amount of milk to be treated is introduced into the closed separation vessel, the container is depressurized and inert gas is bubbled into the milk. The bubbling is continued until the raw milk is segregated into a fat-enriched surface layer and a bottom layer with a milk fat content of up to about 3 wt%, typically 1-3 wt%. Usually during the process the fat content of the milk has decreased to about 0.1 to 2% by weight. Generally, a fat concentration gradient is formed in the milk, with a cream layer containing a high fat content (20-40 wt%) immediately below the surface and a cream-milk layer containing slightly less fat (5-10 wt%) below it.

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Typical treatment times vary with the amount of milk to be treated, but are generally about 1 minute to 24 hours. At a milk volume of 100 to 10001, the processing time is about 1 to 10 hours.

20 The fat-rich cream layer on the surface of the milk is recovered. Cream and • · · • .; : the creamy milk layers can be sucked from the container from above or removed by decantation and

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:.:: the skimmed milk is drained from the container from below. Products to be recovered: V for further processing.

Fig. 1a shows an embodiment of a device according to the invention. The apparatus comprises a container · · · · * 1, which is, for example, cylindrical or otherwise circular in cross-section so as to prevent the container from forming internal angles which impede separation. The container is closed at both ends to form a pressure vessel 2, 3. The pressure vessel rests on the support members (legs) 4-6 on the base ': 30.

Thus, a vacuum can be provided inside the container to reduce foam formation and enhance cream separation. The bottom 3 of the container 1 is provided with a feed nipple 7 for the raw milk to be processed, where a mechanical can be mounted. 111902 o filter 8 to remove any solid impurities present in the milk to be processed. The wall 9 of the container is provided with an insulator to ensure isothermal operation. The dielectric may also be "" active ", which means that coolant-carrying tubes may be provided on the tank wall.

5 Through the wall of the upper end of the container 2, a tube 10 is inserted into the container, which opens into the container at a desired height from the bottom of the container. The tube can be, for example, a telescopic tube, which makes it easy to adjust the height of the tube end. Cream / cream / milk fractions separated from raw milk are removed through tube 10.

10 At the top end 2 of the tank there is further provided a suction pipe 11 connected to a non-illustrated vacuum source having a non-return valve and a washing system nozzle designated 12 for washing the tank.

As shown in the figure, a hose for supplying milk to the container can be connected to the feeder 7.

As is evident from the above description, according to the invention, a fat-containing emulsion (cream or cream-milk fraction) is separated from the raw milk by supplying to the raw milk an inert gas in the form of small gas bubbles. The gas supply * · «: piping 13 may be arranged on the bottom of the container as shown in Figs. In addition, the invention can be: V applied to: the preparation of vinegar (aeration), the "dissolution" of gas mixtures in liquids and the "flavoring" of liquids with smoke substances.

It is essential that gas is supplied as evenly as possible across the cross-section of the tank. The tubes in the gas supply pipeline are preferably perforated, whereby inert gas flows in the form of small bubbles out of the tubes into the surrounding milk. The pipes should be made of food-compatible material: 30 plastic or metal.

.,.: Alternatively, the inert gas can be fed to the milk inlet, where it is • * ·; effectively mixes with the milk introduced into the container and is released from the vacuum in the container.

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The device according to the figure operates on a batch principle, whereby raw milk is supplied to the container 1 via the inlet 7. The milk is mixed with an inert gas, which gives the fat particles emulsified in the raw milk an additional lift and enhances their separation. The fat rises to the surface of the raw milk, at least typically forming more cream and cream milk fractions, the cream fraction having a fat content of about 25-30% by weight and the creamy milk fraction having about 8-10% by weight, respectively. The remaining milk has a fat content of about 1.1 to 1.3%. The cream and cream-milk fractions can be separated by sucking them from the container by means of a telescopic 10-tube outlet. Through the vacuum tube, a relatively high vacuum is maintained in the container to prevent expansion of the foam layer. The usual vacuum is about 10-90 kPa (absolute pressure). During the separation, the milk is kept cold, preferably at a temperature of about 1 to 10 ° C, most preferably about 2 to 6 ° C.

15 The cream and cream-milk fractions separated from the container are further processed. They have very good shelf life because they have been removed from the air by the inert gas fed to the milk separation, thereby preventing fat oxidation and protein degradation. Preferably, the separated fractions are kept in an inert atmosphere for subsequent removal from the tank.

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The milk separation process can be monitored in different ways. In small - scale activities,. slides can be mounted on the tank wall to detect milk. : Effectiveness of extraction. The tank can be fitted for the needs of large industry; j Liquid specific gravity sensors or electrical conductivity sensors capable of monitoring the density and fat content of fractions rising to the surface.

I t | I · (| · *, "After separation treatment, the fat-containing fractions are separated by means of an outlet and: ·. § are subjected to further processing which may be carried out in the conventional manner. Thus, cream and '' 1; 30 cream milk fractions can be used. Λ, for the production of cream cheese, fat spreads, yogurt, etc. The remaining milk, which contains only one or one and a half percent (w / w) fat, is removed from the container through the milk inlet.

Claims (10)

A method for treating frame milk, according to which a cream fraction utilized is separated from the cow's milk by the action of gravity, characterized by reduced to the frame milk being conducted in a closed container of inert gas to effect the separation of the cream. Process according to claim 1, characterized in that nitrogen is used as inert gas. Method according to claim 1 or 2, characterized in that the frame milk is treated in a closed vessel in which a vacuum is produced. 10 Process according to any of the preceding claims, characterized in that the inert gas is homogeneously conducted into the frame milk in the form of small bubbles, and the supply of the inert gas is continued until a fatty surface layer and the fat content of the milk below the surface layer is formed. at most about 3% by weight, preferably about 0.1-2% by weight. 15 v · 5. Apparatus for treating frame milk, comprising: - a container (1), - a feeding connection (7) arranged in the bottom of the container for ♦ ': frame milk, via which the feed line the frame milk to be treated 1' · 20 can be measured into the container and determines the upper surface of the liquid in the container, and means (10) for removing milk fractions from the upper surface of the liquid, "" poured upon treatment, "" characterized by: "25 - the container Means (13) are arranged in the lower part of the container to conduct and form bubbles of gas in the cow's milk measured into the container, and - in the upper part of the container, the connection (11) is formed, which can be connected to a source of suppression Device patent claim 5, characterized by the means for removing milk fractions from the top surface of the liquid comprising a tube (10) arranged in the upper part of the container, through which a desired cream or cream milk fraction can be sucked from the liquid. 7. Apparatus according to claim 6, characterized in that the means for removing milk fractions comprise a telescopic tube (10), the opening of which can be adjusted to a desired depth relative to the upper surface of the liquid. 8. Apparatus according to any one of claims 5-7, characterized in that the means which conduct gas to the container (13) comprise tubes of densely perforated material from which gas pipes can be homogeneously passed in the form of small bubbles from the bottom surface of the container. 9. Device according to claim 8, characterized in that the tubes (13) are arranged as a cross-work, spirally or circularly in the bottom portion of the container. 10. Apparatus according to any one of claims 5-7, characterized in that the means leading gas to the container comprise a gas supply connection: connected to the milk supply connection to form gas bubbles in the milk which. should be measured into the container. * »· • · * *» »» I · »» I