FR2583957A1 - MILK POWDER, MANUFACTURING METHOD THEREOF AND RESULTING METHOD FOR MAKING MILK CHOCOLATE - Google Patents

Abstract

THE MILK POWDER OBTAINED IS REMARKABLE IN THAT THE AVERAGE DENSITY OF THE PARTICLES OF THE MILK POWDER IS LESS THAN 80MM AND THE POROSITY OF THE MILK POWDER IS LESS THAN 5ML100G OF POWDER.

Description

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  Powdered milk, its manufacturing process and the process

  resulting die for the production of milk chocolate.

  The present invention relates to a powdered milk which is suitable as a raw material for milk chocolate and further relates to a process for the manufacture of this powdered milk by drying by

  atomization and a process for making milk chocolate.

  For the production of milk chocolate products, particles of cocoa, sugar and powdered milk are ground in a fatty phase during which the following three process stages can be distinguished: 1. Fragmentation of the particles, 2. refinement of the taste

3. Formatting.

  During the fragmentation, the solid constituents, cocoa, sugar and milk powder are treated together, that is to say exposed to a grinding action in order to fragment all the particles so that they are no longer organoleptically noticeable in the final product. This means that the maximum size of the

  particles is reduced to around 30-50upm.

  During shaping, milk chocolate practically

  loan must naturally meet a number of criteria.

  One of them is that the viscosity must be low enough for the shaping process to run smoothly. It is traditional to obtain the desired viscosity by adding additional cocoa butter to the mass before shaping. Since cocoa butter is the most expensive (main) ingredient in chocolate, we always try to achieve processes such that a minimum quantity of cocoa butter is required for this reduction of

final viscosity.

  Among the influencing factors which are important for a minimum consumption of cocoa butter there are inter alia the moisture content of the mixture, the addition of a small authorized quantity of lecithin, the properties of the solid constituents and

the fragmentation process.

  As for the properties of the solid constituents, the type of milk powder to be used has a very particular influence. Milk powder is often used as a raw material for milk chocolate in pure form and standardized to a content

  specific for fat (eg 26% or 1%).

  For the production of milk powder, a development has appeared during the last decade which has proved important for the manufacture of chocolate. The fact is that the once traditional cylinder drying process is increasingly being replaced by the spray drying process. Consequently, the chocolate manufacturer is faced with the choice between these two types of milk in

  powder. This choice is linked to difficult questions and problems.

  In the dairy industry, spray drying is generally considered to be superior, among other things because the powdered milk thus prepared has undergone much less deterioration by heat than the powdered milk dried on cylinders and is much

more soluble in water.

  Also according to economic and hygienic criteria, the cylinder dryer is usually inferior to the atomizer dryer. In many countries, drying on cylinders of milk has therefore practically completely disappeared to leave

place for spray drying.

  The chocolate manufacturer, who has long been accustomed to milk powder dried on cylinders and is confronted with atomized milk powder, will establish a difference in taste; the new product has a more natural, less burnt taste. This will affect the taste of chocolate, that is, speaking in a very general way, in a favorable sense. The point is that we now note a

  very frequent use of atomized milk powder in chocolate.

  However, the new product also has a big drawback

  and in this regard, we return to the process of making chocolate.

  The fact is that the viscosity of chocolate made with atomized powdered milk turns out to be higher than that obtained when using atomized powdered milk. This means that the new product requires the addition of more cocoa butter, which is a very serious economic disadvantage. For this reason, atomized milk powder is very often known in the chocolate industry as a "devourer of cocoa butter". There is no known explanation for this difference. Naturally, we looked for it, but there are a lot of different properties and we don't know which ones

  are important for the viscosity of chocolate.

  The distribution of the size and the shape of the two types of powder particles for example have characteristic differences. However, it can also be noted, taking into account the two manufacturing processes, that the mechanical strength and the behavior during deformation, crushing and grinding must in fact be profoundly different. We know very well the difference in heating and the resulting denaturation of proteins, and moreover the differences relating to

  Milk sugar crystallization could also be important.

  Finally, it is sometimes reported that the high content of free fat in milk powder dried on cylinders contributes to the low consumption of cocoa butter. This idea is obvious because, in a sense, on the outside of the powdered milk particles, this fat can replace the cocoa butter in chocolate. But this, too, is at most only a partial explanation, because when fat is brought into the atomized powdered milk in free form (e.g. by mixing milk with the spray-dried powdered skin with milk fat), you don't get

  only a very limited improvement.

  According to British Patent 637796, atomized milk powder is more suitable for use in chocolate when it has a low porosity, that is to say a reduced content of vacuoles or air bubbles. However, the improvement thus obtained is relatively small, and therefore this proposal did not find acceptance

in practice.

  In summary, it can therefore be said that for the production of milk chocolates, the dried milk powder on rolls which tends to disappear is interesting from the point of view of the commercial economy, but poses problems as to its taste. , and that the atomized milk powder has an excellent taste, but leads to a high consumption of cocoa butter for the manufacture of chocolates and can therefore only be used in this manufacture in a

limited measure.

  The object of the invention is therefore to provide milk powder

  which combines the two good properties.

  gO Surprisingly, it turned out that this objective was achieved thanks to an atomized milk powder having both great finesse and low porosity. In explaining the invention,

  these terms will be defined as follows.

  The fineness of a powder is expressed in the form of average density of the particles which indicates that the particles having a smaller diameter represent 50% of the weight of powder. The average density of the particles is determined using a Malvern 2600 D particle calibrator, based on the principle of diffraction

laser irradiation.

  The porosity is defined by a percentage which indicates the fraction of average volume of the cavities (air bubbles or vacuoles) in the powder particles. The porosity is calculated from the density of the powder, as measured with a Beckman Air Comparison Pycnometer. The following formula is used for the calculation: Porosity = 100 (- 1) ml / 100 g of powder D1 D2 o:

  Dl = real density of powder in g / ml.

  D2 = density of powder at a porosity of 0 ml / 100 g of powder.

  For whole milk powder with 26% fat,

this density is 1.28 g / ml.

  -5-- For known atomized powders, the average density of the particles is about 80-120 µm, and the porosity often varies

between 5 and 40 ml / 100 g of powder.

  The atomized powdered milks according to the invention have an average density of the particles less than 80 juri and a porosity

  less than 5 ml / 100 g of powder.

  According to a preferred embodiment of the invention, these values

  are respectively 40-70 Vm and less than 3 ml / 100 g of powder.

  In addition, it is preferable that the final fat content O10 is adjusted by subsequently adding at least part of the milk fat to the spray-dried milk powder. Preferably, the amount of fat added later

  is 20-50% of the final fat content.

  The invention will be illustrated below by the following examples: the examples show the effect of the invention on the economy of cocoa butter. Note that the examples are not

  limiting. When reference is made to powdered milk, these

  these also include other chocolate raw materials derived from milk, such as powdered serums, whether or not enriched with proteins or mixed products obtained by spray drying, / C cpràenanfedes constituents of milk, vegetable fats, and sugars added. When reference is made to spray drying, various embodiments of this process are included, such as centrifugal atomization, pressure atomization, propellant atomization, etc. Also, the term milk chocolate is used broadly in this regard, so as to also include imitation chocolates, coatings and the like. In fact, the technological situation to which the present invention refers, arises

in all these cases.

Example 1.

  200,000 kg of fresh raw farmer's milk were standardized to obtain a powder with 26% fat and 3% moisture, then pasteurized (for 30 seconds at 85 C) and evaporated in a down draft evaporator. Subsequently, it was dried in a spray dryer using a rotor atomizer where steps were taken to supply steam to the rotor of the atomizer. The vapor pressure was 0.5 kg / cm2 measured in the steam supply line to the rotor of the atomizer. The temperature at the dry air inlet was 185 C and the dry air outlet at 87 C.

  The rotational speed of the atomizer rotor was 11,000 rpm.

  The resulting product was packaged in multi-walled bags in the usual manner. The powdered milk thus obtained consisted of particles having an average density of particles of 64 μm and a porosity of 2.3 ml / 100 g of powder. Powdered milk

  thus obtained was used for the production of milk chocolate.

  The formula was as follows: cocoa mass 90 g powdered sugar 450 g powdered milk 230 g cocoa butter 230 g lecithin 4 g The ingredients (with the exception of part of the lecithin, which was added later ) were mixed and then rolled in a three-roll Pascall rolling mill. Subsequently, the mass was conched and shaped into tablets. The creep properties (viscosity) were measured with a Haake RV12 rotational viscometer at 40 C. The measured values were transformed into a Casson viscosity (ICA) and a Casson pour point (tCA) as it was described by H. Fincke, among others, Handbuch der Kakaoerzeugnisse,

  Springer Verlag, Berlin / Heidelberg / New York.

  The results were: qi CA = 2.3 Pa.S and VCA = 9.1 Pa.

  These results were such that the chocolate was suitable for shaping when the cocoa butter content was only 23%, as shown by the formula above. For comparison, milk chocolate was made from a correspondingly produced powdered milk, but without steam supplied to the rotor of the atomizer, having an average density of particles of

  95 µm and a porosity of 15 ml / 100 g of powder according to the formula below

  - 7 - above. The viscosity of the product was considerably higher, that is to say such that 3.2% more cocoa butter had to be added in order to obtain the same level of viscosity as the powder described above.

Example II.

  100,000 kg of raw fresh farmer's milk were standardized to obtain a powder with 18% fat and 3% humidity, then pasteurized (for 1 minute at 90 C) and evaporated in a down draft evaporator. Subsequently, it was dried by atomization under pressure, using nozzles chosen especially for the manufacture of a powder with small particles. The atomization pressure was 25 mPa. Dry air temperatures were 187 C (inlet) and 92 C (outlet), respectively. The product thus obtained was then mixed in an industrial mixer with the milk fat at a mixing ratio of 90 parts of powder and 10 parts of milk fat so that the final product had a fat content of 26%. The average density of the particles in this product was 76 Vm, and the porosity

was 4.5 ml / 100 g.

  The powder thus obtained was transformed into chocolate with

  milk, as described in Example I. The viscosity of the chocolate

  was measured, as in Example I, with the following result: rICA = 3.1 Pa.S, and t CA = 9.6 Pa, sufficiently low to form the chocolate. A correspondingly produced powder but under generally accepted conditions during atomization and having a fat content of 26% immediately after atomization (no mixing with milk fat) gave in an identical chocolate making process , a chocolate with a viscosity such that 2.5% additional cocoa butter was required to match the flow properties of the powder

mentioned above.

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Claims (9)

CLAIMS.   1. A powdered milk obtained by spray drying and suitable as a raw material for the production of milk chocolate, characterized in that the average density of the particles of the powdered milk is less than 80 μm and the porosity of the powdered milk is less than 5 ml / 100 g of powder. 2. A milk powder according to claim 1, characterized in that the average density of the particles of the milk powder is 40-70 pm.   3. A milk powder according to claim 1 or 2, characterized in that the porosity of the milk powder is lower 3 ml / 100 g of powder.   4. A process for the production of powdered milk suitable as a raw material for the production of milk chocolate, characterized by the production, by spray drying, of a powdered milk having an average density of particles less than 80   Vm and a porosity of less than 5 ml / 100 g of powder.   5. A method according to claim 4, characterized by adjusting the final fat content by subsequent addition of at least a portion of the milk fat to the   spray dried milk powder.   6. A method according to claim 5, characterized in that the quantity of milk fat added later is   20-50% of the final fat content.   7. A method according to one of claims 4-6, characterized   by the production of a milk powder having a density average particle size of 40-70 µm. 9 -   8. A method according to one of claims 4-7, characterized   by making a powdered milk with lower porosity 3 ml / 100 g of powder.   9. A process for the manufacture of powdered chocolate, characterized by the use as raw material of a powdered milk obtained   by spray drying according to one of claims 1-3.