FIELD OF THE INVENTION

The present invention relates to butter with a modified nonfat dry matter, and a method for making the same. The butter shows superior properties during frying.

BACKGROUND OF THE INVENTION

It is well known that conventional butter sold at retail will burn and form burnt black particles (burnt black precipitates, black flakes), hereinafter described as crust, when heated to frying temperatures. The crust is mainly com- posed of protein, lactose and milk minerals present in butter. Typically, the crust has undesirable burnt flavour. Frying, heating or grilling of food in butter generally provides an appealing browned surface to the food. Burning of butter, however, may undesirably generate combustion products and even carcinogenic compounds detrimental to health.

There is also clarified butter (also known as "ghee") available at retail, which does not contain protein, carbohydrates or milk minerals but is composed of 100% butter oil. Clarified butter is well suitable for frying and does not burn or blacken. It may thus be seen that frying of food with clarified butter without burning is healthier than frying with conventional butter. However, the desired browning of fat and desired browned flavour intensity and characteristics of milk protein are not achieved with clarified butter.

US 4038436 discloses a margarine-like product which does not burn during normal frying operations and in which the degree of browning during frying is controlled.

We have now found butter which has desirable combined characteristics of conventional butter and clarified butter in which the degree of browning during frying is controlled to the desired level. The butter produced in the invention does not blacken or burn during frying but provides an appealing brown color to a food product during frying. BRIEF DESCRIPTION OF THE INVENTION

An object of the present invention is to provide a method of making a butter product, comprising the steps of:

- providing a butter raw material having a fat content at least 35% by weight, - adjusting the nonfat dry matter of the butter raw material to a range of 0.15% to 1.8% by weight, specifically 0.15% to 1.0% by weight, more specifically 0.15% to 0.5% by weight, even more specifically 0.15% to 0.2% by weight,

- optionally churning the butter raw material to provide butter, - adjusting the pH to provide the butter product having a pH in the range of 4.5 to 8.5.

In the present invention, the term "butter" means a conventional food product described as butter which has a milk fat content of at least 80% by weight. In addition to fat, butter contains an aqueous phase mainly composed of protein, lactose and milk minerals constituting a nonfat dry matter of butter. The term "butter" as used herein complies with the provisions in Codex standard 279- 1971 for butter.

The term "ghee" as used herein complies with the provisions in Codex standard 280-1973 for ghee. The term "clarified butter" as used herein complies with the provisions in Codex standard 280-1973 for butteroil.

While butter is an emulsion of water in oil, ghee and clarified butter (butteroil) are substantially free from water.

It was found in the present invention that modification of the nonfat dry matter of butter and adjustment of the pH of butter provides a butter product which shows beneficial frying, heating and grilling properties. The butter product does not burn but will desirably brown when heated to frying temperatures.

Another object of the invention is to provide butter having a fat content of at least 80% by weight, a nonfat dry matter in the range of 0.15% to 1.8% by weight and a pH in the range of 4.5 to 8.5. DETAILED DESCRIPTION OF THE INVENTION

An object of the present invention is to provide a method of making a butter product, comprising the steps of:

- providing a butter raw material having a fat content at least 35% by weight,

- adjusting the nonfat dry matter of the butter raw material to a range of 0.15% to 1.8% by weight, specifically 0.15% to 1.0% by weight, more specifically 0.15% to 0.5% by weight, even more specifically 0.15% to 0.2% by weight,

- optionally churning the butter raw material to provide butter,

- adjusting the pH to provide the butter product having a pH in the range of 4.5 to 8.5. In an embodiment of the invention, the butter raw material is raw cream having a fat content of about 35% to about 60% by weight. In an embodiment, the cream has a fat content of about 40% by weight. The raw cream can be obtained in a conventional manner by subjecting fresh full fat milk to a centrifugal separator which provides a cream portion and a skimmed milk portion. The cream portion is then churned to provide a butter with a fat content of at least 80% by weight.

Raw cream with a fat content of about 35% to about 60% by weight can also be obtained by subjecting fresh full fat milk to microfiltration to provide a cream portion as a microfiltration retentate and skimmed milk portion as a microfiltration permeate. Microfiltration is appropriately carried out using a membrane with a pore size of about 1.4 μπι whereby milk fat is concentrated in the retentate.

In another embodiment, the butter raw material is clarified butter hav- ing a fat content of about 100% by weight. Clarified butter is typically produced by melting conventional butter whereby milk solids and water are separated by density from the butterfat. The water evaporates, a portion of solids migrates to the surface of the butter and are skimmed off, and rest of the milk solids sinks to the bottom. The upper part is substantially composed of butter fat and is poured off. Commercial methods of production also include direct evaporation but may also be accomplished by decantation and centrifugation followed by vacuum drying; or direct from cream by breaking the emulsion followed by centrifugation.

Ghee is a type of clarified butter made by cooking butter at about 120°C for a prolonged period of time during the separation process of nonfat dry matter. During cooking the milk solids are caramelized resulting in a nutty flavor when they are filtered out.

Butter with extremely low nonfat dry matter, e.g. clarified butter or "ghee", does not get appealing brown colour and desirable browned flavour when heated to frying temperatures. On the other hand, if the nonfat dry matter of but- ter is high, substantial crust (burnt black precipitates, burnt black precipitates, black flakes) formation and taste defects when fried can be observed. In the method of the invention, the nonfat dry matter of the butter raw material is adjusted to a range of 0.15% to less than 1.8% by weight. The adjustment process depends on the nonfat dry matter originally present in the butter raw material. Thus, if the nonfat dry matter of the butter raw material is less than 0.15% by weight, for example 0% by weight, the nonfat dry matter is increased to a range of 0.15% to less than 1.8% by weight by adding an aqueous solution comprising one or more ingredients introducing nonfat dry matter to the butter raw material. Suitable ingredients to increase nonfat dry matter include, but are not limited to, protein(s) and milk minerals. In an embodiment, an aqueous solution comprising one or more ingredients selected from milk protein, carbohydrates, such as lactose, glucose and galactose, and milk minerals is added to the butter preparation.

If the nonfat dry matter of the butter raw material is 1.8% by weight or more, the adjustment is carried out by reducing the original nonfat dry matter of the butter raw material to a range of 0.15% to less than 1.8% by weight. The original nonfat dry matter of the butter raw material can be, e.g., about 2.5% to about 6% by weight. In an embodiment, the nonfat dry matter of the butter raw material is in the range of 2.5% to 4% by weight.

In an embodiment of the invention, the method comprises the steps of:

- providing a butter preparation having a fat content of about 100% by weight and a nonfat dry matter of about 0% by weight,

- adjusting the nonfat dry matter of the butter preparation to a range of 0.15% to 1.8% by weight, specifically 0.15% to 1.0% by weight, more specifically 0.15% to 0.5% by weight, even more specifically 0.15% to 0.2% by weight, by adding an aqueous solution of milk protein to the butter preparation,

- adjusting the pH of the butter preparation with a nonfat dry matter from 0.15% to 1.8% by weight, specifically 0.15% to 1.0% by weight, more specifically 0.15% to 0.5% by weight, even more specifically 0.15% to 0.2% by weight, to a range of 4.5 to 8.5 to provide the butter product.

In an embodiment of the invention, the butter raw material is raw cream. In an embodiment, the method comprises the steps of:

- providing raw cream having a fat content in the range of about 35% by weight to about 60% by weight, specifically about 40% by weight,

- washing the raw cream with a washing liquid to provide a solution of the raw cream and the washing liquid,

- separating the washing liquid from the solution to provide washed cream with a reduced nonfat dry matter content,

- churning the washed cream to provide butter with a nonfat dry matter from 0.15% to 1.8% by weight, specifically 0.15% to 1.0% by weight, more specifically 0.15% to 0.5% by weight, even more specifically 0.15% to 0.2% by weight, - adjusting the pH of the butter with a nonfat dry matter from 0.15% to 1.8% by weight, specifically 0.15% to 1.0% by weight, more specifically 0.15% to 0.5% by weight, even more specifically 0.15% to 0.2% by weight, to a range of 4.5 to 8.5 to provide the butter product.

In an embodiment, the butter product produced by the method of the invention has a fat content of at least 80% (w/w). In another embodiment, the fat content is in the range of 80% (w/w) to about 90% (w/w). In a further embodiment, the fat content is in the range of 80% (w/w) to about 85% (w/w).

In an embodiment, the butter product produced by the method of the invention has a water content in the range of about 10% to 16%.

It is essential that a washing liquid has a low dry matter content. For example, the washing liquid can be water. Moreover, various membrane filtration fractions of a milk-based stream can be used as the washing liquid. The milk- based stream can be, e.g., fresh full fat milk or a milk fraction obtained from pro- cessing of fresh milk, such as skimmed milk, whey obtained from cheese manufacture, or buttermilk from butter manufacture. It is commonly known in the art that components of milk, especially protein, lactose and milk minerals, can be separated into different fractions by successive steps of ultrafiltration, nanofiltration and reverse osmosis. Ultrafiltration permeate of milk is protein-depleted and contains lactose and soluble milk minerals. Nanofiltration permeate of the ultrafiltration permeate is protein and lactose-depleted, and contains soluble milk minerals. Reverse osmosis of the nanofiltration permeate substantially removes soluble milk minerals and provides pure water as a permeate fraction. The nanofiltration permeate with low lactose and protein contents, and reverse osmosis permeate have both a low dry matter content and can be suitably used as washing liquid in the method of the invention. Suitable dry matter content of the washing liquid is less than 5% (w/w). In an embodiment, the dry matter content is at most 4% (w/w). In another embodiment, the dry matter content is at most 1.8% (w/w). In a further embodiment, the dry matter content is at most 1.0% (w/w). In a still further embodiment, the dry matter content is at most 0.2% (w/w).

Whey obtained from cheese manufacture contains whey protein, lactose and milk minerals, among others. Suitable membrane filtrations, such as ultrafiltration and/or nanofiltration of whey provide fractions which have a low dry matter content and are suitable as washing liquid in the present invention. Simi- larly, membrane filtration(s) of buttermilk provide(s) suitable fractions with low dry matter. For example, permeate from ultrafiltration of lactose-depleted but- termilk can be used as washing liquid.

Addition of a washing liquid to raw cream provides a solution of the raw cream and the washing liquid. In an embodiment of the invention, the raw cream is diluted with a washing liquid by a dilution factor of at least 1:10 w/w. In another embodiment of the invention, the raw cream is diluted with a washing liquid by a dilution factor of at least 1:11 w/w. In an embodiment of the invention, the raw cream is diluted with a washing liquid by a dilution factor of at least 1:12 w/w. The washing liquid and the raw cream are gently mixed followed by removal of the washing liquid. The washing liquid can be removed immediately after the raw cream and the washing liquid are thoroughly mixed, or after a short period of time. The washing liquid is separated by a separator. In an embodiment, the washing liquid is water.

After washing, the washing liquid is removed from the solution to provide washed cream. In addition to washing liquid, solid matter, i.e. protein, lactose and milk minerals, are removed from the raw cream. The removal of the washing liquid can be carried out in appropriate manners. In an embodiment, the washing liquid is separated by a centrifugal separator in a conventional manner. In another embodiment, the washing liquid is separated by microfiltration. The pore size of the microfiltration membrane is suitably in the range of 0.8 μιη to 2.0 μιη. In an embodiment, the pore size is 1.4 μιη. The microfiltration is suitably carried out at a temperature from 40°C to 60°C. In an embodiment, microfiltration is carried out at about 50°C.

Washed cream with a reduced nonfat dry matter is then churned in a conventional manner to provide butter with a reduced nonfat dry matter.

In the method of the invention, the pH of is adjusted to a range of 4.5 to

8.5. The pH adjustment can be performed before, during or after the churning. In an embodiment, the pH is adjusted to less than pH 6.5, specifically less than 6, more specifically less than 5.2, by a food grade acid, such as lactic acid. In an embodiment, the pH is adjusted to more than pH 6.5, specifically more than 6.8, by a food grade base, such as sodium or potassium hydroxide. The pH of the butter product affects the extent of Maillard reaction and formation of aroma compounds. Different aroma compounds are formed in acidic pH or in alkaline pH. Browning and flavour of the butter product can be affected by adjusting the amount and composition of nonfat dry matter on one hand, and the pH of the but- ter product on the other hand. Addition of aqueous solution (s) to a fat portion is typically carried out using a high performance mixer, such as Ultra-Turrax, to produce a homogenous water-fat dispersion.

Another object of the invention is to provide butter having a fat con- tent of at least 80% by weight, a nonfat dry matter in the range of 0.15% to 1.8% by weight and a pH in the range of 4.5 to 8.5. In an embodiment, the fat content of the butter is in the range of 80% (w/w) to about 90% (w/w). In another embodiment, the fat content is in the range of 80% (w/w) to about 85% (w/w).

In an embodiment, the nonfat dry matter of the butter of the invention is in the range of 0.15% to 1.8% by weight. In another embodiment, the nonfat dry matter is 0.15% to 1.0% by weight. In a further embodiment, the nonfat dry matter is 0.15% to 0.5% by weight. In a still further embodiment, the nonfat dry matter is 0.15% to 0.2% by weight.

The observable difference between conventional butters and butter of the invention lies in the frying properties. Since the butter of the invention contains less protein, it does not burn and does not form crust when fried. Further, acidic pH improves browning of butter. The frying properties of conventional butter and butters of the invention are illustrated in example 6.

The following examples are presented for further illustration of the in- vention without limiting the invention thereto. The percentages are given on weight basis.

Examples

Reference Example 1

Cream with a fat content of 36% was obtained from full-fat milk by centrifugal separation (Centrifugal Separator, Frau spa Model CN2A). 20 kg of the cream was processed to butter in a conventional manner by ripening the cream at 10°C for 16 hours and then churned in a laboratory churn to provide butter. The composition of the butter ("conventional butter") is shown in Table 1.

Example 1. Butter production from cream washed with water

Cream with a fat content of 40% was used as a butter raw material.

The nonfat dry matter of cream was 4.6% by weight. The cream was obtained from full-fat milk by centrifugal separation (Centrifugal Separator, Frau spa Model CN2A). 10 kg cream was diluted with 110 kg water. The mixture of cream and water was heated to 55°C and separated with the above separator to produce washed cream and washing water. The nonfat dry matter of the washed cream was 0.5% by weight.

The washed cream was pasteurized at 85°C for 20 sec and then ripened at 10°C for 16 hours. The cream was then churned in a laboratory churn for 10 minutes into buttermilk and butter with a modified nonfat dry matter.

The composition of the butter with a modified nonfat dry matter ("invention") is shown in Table 1.

Table 1

The pH of the resultant butter was adjusted to 4.7.

Example 2. Butter production from cream washed with NF permeate

Cream with a fat content of 40% was obtained from full-fat milk by centrifugal separation (Centrifugal Separator, Frau spa Model CN2A). 10 kg cream was diluted with 100 kg nanofiltration (NF) permeate. The NF permeate had a lactose content of 0.04% and a dry matter content of 0.3%. The mixture of cream and the NF permeate was heated to 55°C and separated with the above separator to produce washed cream and washing water.

The washed cream was pasteurized at 85°C for 20 sec and then ripened at 10°C for 16 hours. The cream was then churned in a laboratory churn for 10 minutes into buttermilk and butter. Buttermilk was separated from butter grains. The compositions of the products obtained in the above different steps are given in Table 2.

Table 2

The results show that a substantial portion of protein and lactose are removed from a cream raw material by washing with NF permeate. Thus, the nonfat dry matter of the washed cream is lower compared to that of the cream raw material. Also, the nonfat dry matter of the butter product is lower compared to that of conventional butter.

The pH of the resultant butter was adjusted to pH 7.

Example 3. Butter production from cream washed with water (threefold wash)

Cream with a fat content of 40% was obtained from full-fat milk by centrifugal separation (Centrifugal Separator, Frau spa Model CN2A). 10 kg cream was diluted with 100 kg water. The mixture of cream and water was heated to 55°C and separated with the above separator to produce washed cream and washing water.

The washed cream was diluted again with water ten times the weight of the washed cream. The mixture of cream and water was heated to 55°C and separated with the above separator to produce washed cream and washing water.

The two times washed cream was diluted again with water ten times the weight of the washed cream. The mixture of cream and water was heated to 55°C and separated with the above separator to produce washed cream and washing water.

The three times washed cream was pasteurized at 85°C for 20 sec and then ripened at 10°C for 16 hours. The cream was then churned in a laboratory churn for 10 minutes into buttermilk and butter. Buttermilk was separated from butter grains. The compositions of the products obtained in the above different steps are given in Table 3. The composition of the washing water was analyzed after the third washing cycle of the cream.

Table 3

The results show that intense washing of a cream raw material performed in this example removes a substantial portion of protein and lactose from the cream raw material. Thus, the non-fat dry matter of the washed cream is lower compared with that of the cream raw material. Also, the nonfat dry matter of the butter product is lower compared to that of conventional butter.

The pH of the resultant butter was adjusted to pH 4.5.

Example 4. Butter production from clarified butter

Clarified butter (butteroil) having a nonfat dry matter of 0% was used as a butter raw material. The nonfat dry matter of the butter raw material was increased by adding an aqueous solution containing protein. The aqueous solution of protein was prepared by adding dry ingredients, i.e. 0.12 g of casein, 0.2 g β-lactoglobulin and 0.1 g a-lactalbumin to 9.8 g of deionized water.

The pH-adjusted protein solution (10.22 g) was dispersed to 50 g of the clarified butter using Ultra-Turrax machine.

The pH of the resultant butter was adjusted to 7.2 by adding 3% NaOH solution. The nonfat dry matter of the resultant butter was 0.70% by weight.

Example 5. Butter production from clarified butter

Clarified butter (butteroil) having a nonfat dry matter of 0% was used as a butter raw material. The nonfat dry matter of the butter raw material was increased by adding an aqueous solution containing protein and sugar. The aqueous solution of protein and sugar was prepared by adding dry ingredients, i.e. 0.25 g of whey protein concentrate, 0.025 g galactose and 0.026 g lactose to 9.92 g of deionized water. The pH-adjusted protein solution (10.22 g) was dispersed to 50 g of the clarified butter using Ultra-Turrax machine.

The pH of the resultant butter was adjusted to 7.2 by adding 3% NaOH solution. The nonfat dry matter of the resultant butter was 0.50% by weight. Example 6

The frying properties of conventional butter prepared in reference example 1 (sample 1), and of the butters of the invention prepared in example 1 (sample 2) and example 4 (sample 3) were studied. Butter samples were fried in an oven at 200°C for 30 minutes. The results are shown in table 4.

The color of the samples was measured according to the method described in Campbell et al., Journal of Dairy Science, Volume 96, Issue 12, December 2013, pp. 7404-7413, using a Minolta Chroma meter (CR-410; Konica Minolta Sensing Americas Inc., Ramsey, NJ). Each sample was measured in triplicate. Before measurements were taken, a factory-supplied calibration plate was used to calibrate the instrument. The Hunter CIE L*a*b* color scale (where L* is the lightness of the color, a* is its position between red/magenta and green, and b* is its position between yellow and blue) was used. Reflectance values were taken with a white calibration plate as the background.

Table 4

It was observed that conventional butter formed a substantial amount of crust, whereas the butters of the invention formed less crust. The results shown that formation of crust and resultant burnt flavor could be avoided by reducing the nonfat dry matter of conventional butter. It will be obvious to a person skilled in the art that, as the technology advances, the inventive concept can be implemented in various ways. The invention and its embodiments are not limited to the examples described above but may vary within the scope of the claims.