The present invention relates to a method of producing a fat product containing milk fat with a reduced fat con¬ tent.

The interest for fat products based on milk fat or mix¬ tures of milk fat and vegatable oil is increasing. Up to the present one has often started with butter oil poss¬ ibly mixed with vegetable oil in which fat mixture a water phase is admixed. The water phase may contain casein or caseinate, skim milk powder or milk protein, whey protein and possibly gelatin.

The dry solid content in the water phase which is mixed with the fat phase has been high in order to bind the water in a sufficient degree so that the end product, a water-in-oil emulsion shall be stable and not give off free water.

Processes have also been presented for producing pro- ducts with a low fat content starting from butter, where a water phase is admixed into earlier produced butte ^* <, Such processes are described for example in WO 91/07098 and in EP 368805.

Later there has also been published patent applications which describe processes where products containing milk fat are produced starting from cream without any chur¬ ning step. In EP 376407 there is described a fat product produced from water, melted vegetable oils and cream, Similar processes are described also in EP 385542 and EP 445857. In order to obtain stable emulsions emulsifiers are added to the mixture of cream, vegetable fat and water prior to the phase reversal.

According to the invention there is now proposed a method to produce a fat product containing milk fat with reduced fat content, which fat product is a stable water-in-oil-emulsion free from added emulsifiers.

The method according to the invention is mainly charac¬ terized in that cream is concentrated to a cream product with a fat content of at least 75 % in a centrifugal separator. In connection with the said concentration this cream product is mixed with vegetable oil in an amount of 0-50 % of the total amount of fat in the fat phase which is obtained consisting of cream product and vegetable oil. The fat phase is mixed with the desired amount of pasteurized water phase containing stabilizing means, preferably gelatin, salt and aroma substances. The temperature is kept between 50-80°C during this last-mentioned mixing operation. After the mixing opera¬ tion the mixture is cooled and worked in such a way that phase reversal takes place. The end product which is obtained consists of a stable water-in-oil-emulsion. The product has a fat content of 25-60 % and contains only emulsifiers originally found in the cream. The casein content of the product is below 2 %. Due to the fact that the cream is concentrated to a fat content above 75 % in the centrifugal separator the cream contains so many natural emulsifiers that ordinarily used emulmulsi- fiers are not needed. The emulsifiers naturally found in the cream consist of membrane proteins that is mainly lipo proteins which are found in the membranes around the fat globules in the milk. Due to the fact that the concentration in the centrifugal separator may be carri¬ ed through in such a way that the fat globules in the cream are not injured these membrane proteins are found in the cream phase after the centrifugal separation.

When the expression % is used in the description it relates to weight percent, if nothing else is stated.

According to the invention the concentrated cream is with advantage mixed with so much vegetable oil that the fat content in the obtained mixture of fat and vegetable oil is at least 84 % prior to the mixing with the water phase. Surprisingly it has been found that this opera¬ tion increases the taste of butter in the formed fat product.

The fact that the cream is concentrated to said high level also means that the amount of milk (skim milk) in the cream is low. Consequently, also the content of milk protein, especially casein, is low. A high content of casein in the fat product results in a cheese like, harsh character.

When using the method according to the invention it is possible to obtain fat products with as low casein content as 0.6-0.8 %.

The fat content of the cream product after the centrifu¬ gal separation may, if so is desired, be at least 80 %. Also fat contents above this value (84-85 %) may be obtained if this is considered valuable with regard to the desired compositon of the end product. A hermetic centrifugal separator with a disc stack of insert discs, which are given a special design regarding among all the distance between the discs and the shape of the spacing elements in order to give the fat globules in the cream such a gentle treatment as possible, is preferably used for concentration of the cream.

If the fat phase only consists of a cream product "light butter" with a desired fat content is obtained according to the invention when the cream product is mixed with water.

The temperature during the mixing operation must be so high that it is well above the melting point of the vegetable oil and the solidifying point of the gelatin. It is also important that the water phase is pasteuri- zed. At higher temperatures during the mixing a separate pasteurization of the water phase may be omitted. Tempe¬ ratures in the interval 60-80 ^C C are preferably used during the mixing operation. If the temperature is above 70°C there is obtained a pasteurization of the product which is favourable for the keeping qualities of the end produc .

The vegetable oil which is mixed with the concentrated cream may consist of hardened or unhardened oil or a mixture of such oils. A preferred mixture consists of unhardened vegetable oil in an amount of 0-35 % counted on the total amount of fat in the mixture of cream and vegetable oil.

An admixture of 0 % of vegetable oil consequently means that the end product only consists of milk fat. The interest for products containing only milk fat but with a lower fat content than butter is considered rising, since it is then possible to obtain the many advantage- ous qualities which are present in butter but without its high fat content.

A suitable fat content of an end product produced accor¬ ding to the method of the invention is 40-60 % fat.

For productional reasons it is simplier to add salt and aroma substances to the water phase. Within the scope of the invention it is however possible to add these sub¬ stances to the cream or the oil instead.

After the mixing operation the mixture which consists of an oil-in-water-emulsion is cooled preferably to a temperature below 20°C, suitably below 15°C in the first cooling step. After the cooling the mixture which nor- mally consists of an oil-in-water-emulsion is led to a working step where the mixture during a predetermined holding time is subjected to a gentle mechanical treat¬ ment. During this working crystallization and phase reversal takes place. The crystallization heat given off and added working energy increase the temperature 3-8°C. The mixture is cooled after the working in a second cooling step to a temperature of 12-20°C.

If suitable, further working and cooling steps may be used.

In some connections a mechanical working of a somewhat stronger kind may proceed the last cooling step.

Each cooling step may comprise one or several tube coolers and the gentle mechanical working takes place in one or several pin rotors connected in series possibly complemented with a holding cell/cells in order to obtain an additional holding time at a suitable place during the working.

Examples of production of fat products comprising milk are given below comprising fat according to the inven¬ tion.

Milk fat mixture with 40 % fat

Formula: Rape seed oil 9.56 kg

Concentrated cream 75.3 % fat 40.39 kg Water 46.13 kg

Gelatin 3.01 kg

NaCl 0.80 kg

Aroma substance 0.11 kσ

100 kg

Milk fat 40 % fat

Formula: Concentrated cream 75.3 % fat 53.11 kg

Water 42.98 kg Gelatin 3.00 kg

NaCl 0.80 kg

Aroma substance 0.11 kg

100 kg