NL8501878A - MILK POWDER; METHOD FOR PREPARING THEREOF PROCESS FOR PREPARING MILK CHOCOLATE. - Google Patents

Description

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Milk powder; method for preparing it; method for preparing milk chocolate.

The invention relates to a milk powder which is suitable as a raw material for milk chocolate, as well as to a method for preparing such a milk powder by spray drying and to a method for preparing milk chocolate.

5 In the preparation of milk chocolate products, particles of cocoa, sugar and milk powder are ground in a fat phase, whereby the following three process steps can be distinguished: 1. reduction of the particles, 2. taste refinement, 3. shaping.

During comminution, the solid components of cocoa, sugar and milk powder are treated together, i.e. exposed to grinding with the aim of comminuting all particles to such an extent that they are no longer organoleptically detectable in the final product. This means that the maximum particle size is reduced to about 30-50 microns.

During shaping, the virtually finished milk chocolate must of course meet a number of criteria. One is that the viscosity must be low enough for the molding process to proceed smoothly.

It is common for the desired viscosity to be achieved by adding additional cocoa butter to the mass before molding. Since cocoa butter is the most expensive (main) component of chocolate, the aim is always to use methods such that as little cocoa butter as possible is required for this final viscosity reduction.

Influencing factors that are important for minimal cocoa butter consumption include the moisture content of the mixture, the addition of a permitted small amount of lecithin, the properties of the solid components, and the comminution process.

With regard to the properties of the solid constituents, the type of milk powder to be used has been found to have particular influence.

Milk powder is often used in pure form and standardized to a certain fat content (for example 26% or 1%) as a raw material for milk chocolate.

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In the preparation of milk powder, a development has occurred in recent decades, which has proven to be important for chocolate production. The formerly usual roller drying process has increasingly been replaced by the spray drying process.

Therefore, the chocolate maker is faced with the choice between these two types of milk powder. Difficult questions and problems arise with this choice. Within the dairy industry, spray drying is generally regarded as a superior process, partly because the milk powder thus prepared has suffered much less heat damage than roller-dried milk powder, and is much more soluble in water.

Also on the basis of economic and hygienic criteria, the roller dryer usually has to compete with the spray dryer.

In many countries, the drum drying of milk has almost completely disappeared to make way for spray drying.

15 The chocolate maker, who has traditionally been used to roller-dried milk powder and is confronted with spray milk powder, has noticed a difference in taste: the new product has a more natural, less burning taste. This will affect the taste of the chocolate, very generally speaking, in a favorable sense. This is because we now see a very extensive application of spray milk powder in chocolate.

Nevertheless, the new product also has a major objection and with that we return to the chocolate preparation process. Namely, it appears that the viscosity of chocolate prepared with sprayed milk powder is higher than when using roller-dried milk powder. This means that the new product necessitates the addition of more cocoa butter, which is a very serious economic drawback. That is why spray milk powder is often known in the chocolate industry as "cocoa butter eater". No explanation for this difference is known. 30 Of course it has been searched for, but there are a large number of different properties and it is unknown which of these are important for the chocolate viscosity.

For example, the size distribution and shape of both types of powder particles are typically different. But it can also be argued on the basis of the two preparation processes that the mechanical strength and behavior during deformation, fracture and grinding must indeed be strongly increased. 85S13 7 3. * -3- peels. Very well known is the difference in heating and the associated protein denaturation, while differences in milk sugar crystallization may also be important.

Finally, it is said that the high free fat content in roller-dried milk powder contributes to low cocoa butter consumption.

This idea is obvious, because such fat on the outside of milk powder particles can, in a way, replace cocoa butter with chocolate. But this too is at most a partial explanation, because when the fat is brought into free form in spray milk powder (for instance by mixing spray-dried skimmed milk powder with milk fat), only a very limited improvement is achieved.

According to British Patent 637796, sprayed milk powder would be more suitable for processing in chocolate if it has a low porosity, ie a reduced content of vacuoles or air bubbles. However, the improvement achieved as a result is relatively small, and this proposal has therefore not been implemented in practice.

In summary, it can therefore be stated that the virtually dried roller-dried milk powder is commercially attractive in milk chocolate preparation but has problems in terms of taste and that sprayed milk powder tastes excellent, but leads to a high cocoa butter consumption during chocolate preparation and can therefore only be used to a limited extent. are applied.

The object of the invention is therefore to provide a milk powder which has both good properties in it.

Surprisingly, this object has been found to be achieved by a spray milk powder of both high fineness and low porosity. To illustrate the invention, the terms are defined as follows. The fineness of a powder is expressed as the weight average particle size, which indicates that 50% of the powder weight is contributed by smaller diameter particles. The weight average particle size is determined with a Malvern 2600 D partial sizer based on the principle of laser beam diffraction.

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Furthermore, the porosity is defined as a percentage that indicates the average volume fraction of the voids (air bubbles or vacuoles) in the powder particles. Porosity is calculated from the density of the powder, as measured by an Air-5 Comparison. Pycnometer according to Beekman. The following formula is used in the calculation:

Porosity = 100 (^ -) ml / 100 g powder, 1 2 where: D ^ = actual powder density in g / ml D ^ = powder density at a porosity of 10 ml / 100 g powder. For a whole milk powder with 26% fat, this density is 1.28 g / ml.

For the known spray powders, the weight-average particle size is around 80-120 micrometers, while the porosity often ranges between 5 and 40 ml / 100 g powder.

Spray milk powders according to the invention have a weight average particle size of less than 80 micrometers and a porosity of less than 5 ml / 100 g of powder.

According to a preferred form of the invention, these values are 40-70 micrometers and less than 3 ml / 100 g powder, respectively. It is further preferred that the final fat content is adjusted by adding at least a part of the milk fat to the spray-dried milk powder afterwards. Preferably, the amount of fat added afterwards is 20-50% of the final fat content.

The invention is described below with reference to the following examples. The examples demonstrate the effect of the invention on cocoa butter savings. It should be noted that the examples are not intended to be limiting. In the case of milk powders, this also includes other milk-derived chocolate raw materials, such as whey powders, whether or not enriched with protein, or also mixed products obtained by spray-drying, for instance consisting of milk constituents, vegetable fats and added sugars.

Where spray drying is concerned, this should be understood to mean different embodiments of this method, such as, for example, 8S Λ ·? § * 7 · * v "v / ζ> * -V« Ü -5- centrifugal spraying, pressure spraying, floating gas spraying etc.

The term milk chocolate is also used in a broad sense in this context, so that it should also include imitation chocolates, couvertures and the like. After all, in all these cases the technological situation to which the invention relates arises.

Example I

200,000 kg of raw fresh farm milk was standardized to obtain a powder with 26% and 3% moisture, then pasteurized (85 ° C for 30 seconds) and evaporated in a downdraft evaporator.

Subsequently, it was dried in an atomization dryer using a wheel atomizer, with provisions for supplying steam to the atomizer wheel. The steam pressure was 0.5 kg / cm measured in the supply line of the steam to the atomizer wheel. The temperature of the incoming drying air was 185 ° C and that of the outgoing drying air 87 ° C. The revolution speed of the atomizer wheel was 11,000 revolutions per minute. The product obtained was packaged in multi-walled bags in the usual manner. The milk powder thus obtained consisted of particles with a weight average particle size of 64 micrometers and a porosity of 2.3 ml / 100 g of powder.

The milk powder thus obtained was used for the preparation of milk chocolate. The recipe was as follows: cocoa mass 90 g icing sugar 450 g milk powder 230 g 25 cocoa butter 230 g lecithin 4 g

The ingredients (except part of the lecithin, which was added later) were mixed and then rolled in a three-roll Pascall roller. After this, the mass was conched and formed into tablets. The flow properties (viscosity) were measured with a Haake RV12 rotary viscometer, at 40 ° C. The measured values were converted into a Casson viscosity (η) and a Casson yield strength (τ) as described, inter alia, by H. Fincke, Handbuch der Kakaoerzeugnisse, Springer Verlag, Berlin / Heidelberg / Nèw.

The results were: η = 2.3 Pa.S, resp. τ = 9.1 Pa.

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These results were such that the chocolate was suitable for molding, while the cocoa butter content was only 23%, as shown in the above recipe.

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For comparison, from a similarly prepared milk powder, but without adding steam to the atomizing wheel, with a weight average particle size of 95 micrometers and a porosity of 15 ml / 100 g powder, milk-5 chocolate was made according to the above recipe. The viscosity of the product was significantly higher, such that an additional 3.2% cocoa butter had to be added to achieve the same viscosity level as that of the powder described above.

Example II

100,000 kg of raw fresh farm milk was standardized to obtain a powder with 18% fat and 3% moisture, then pasteurized (90 ° C for 1 minute) and evaporated in a trap evaporator. It was then pressure spray dried using nozzles specially selected for preparing a powder with small particles. The sputtering pressure was 25 mPa. Drying air temperatures were 187 ° C (inlet) and 92 ° C (outlet), respectively. The product thus obtained was then mixed in an industrial mixer with milk fat in a mixing ratio of 90 parts powder and 10 parts milk fat, such that the final product had a fat content of 26%. The weight average particle size of this product was 76 micrometers and the porosity was 4.5 ml / 100 g.

The powder thus obtained was processed into milk chocolate, as described in example I. The viscosity of the chocolate was measured, as in example I, with the result: η = 3.1 Pa.S, respectively τ__ = 9.6 Pa, sufficiently low to form the chocolate. A powder prepared in a corresponding manner, but with generally prevailing conditions during the spraying, and with a fat content of the powder immediately after the spraying of 26% fat (no mixing with 30 milk fat), resulted in a chocolate with an identical chocolate preparation process. viscosity such that 2.5% additional cocoa butter was required to match the flow properties of the above powder.

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Claims (9)

Milk powder obtained by spray drying which is suitable as a raw material for the preparation of milk chocolate / characterized in that the weight-average particle size of the milk powder is less than 80 micrometers and the porosity of the milk powder is less than 5 ml / 100 g powder. Milk powder according to claim 1, characterized in that the weight-average particle size of the milk powder is 40 to 70 micrometers. Milk powder according to claim 1 or 2, characterized in that the porosity of the milk powder is less than 3 ml / 100 g powder. 4. Method for preparing milk powder suitable as raw material for the preparation of milk chocolate, characterized in that a milk powder having a weight average particle size of less than 80 micrometers and a porosity of less than 5 ml is prepared by means of spray drying / 100 g of powder. Method according to claim 4, characterized in that the final fat content is adjusted by adding at least a part of the milk fat to the spray-dried milk powder afterwards. 6. A method according to claim 5, characterized in that the amount of milk fat added afterwards is 20% to 50% of the final fat content. Process according to one or more of claims 4-6, characterized in that a milk powder is prepared with a weight average particle size of 40 to 70 micrometers. Process according to one or more of claims 4-7, characterized in that a milk powder is prepared with a porosity of less than 3 ml / 100 g powder. 9. Process for preparing milk chocolate, characterized in that the raw material used is a milk powder obtained by spray drying according to one or more of claims 1 to 3. 5501