EP1232793B1 - Wheat flours with increased water absorbing capacity and method and apparatus for making the same - Google Patents

Abstract

In the processing of wheat flour, it is ground while dry to increase the water take-up, using a dry stirring ball mill (11) rated at 20-300 kWh of milling energy per tonne of supplied flour, at a temperature of ≤ 60 degrees C or 30-50 degrees C. The wheat flour is milled continuously, in a circuit, or in batches. The mill is cooled by air, liquid nitrogen or liquid carbon dioxide, or the milling assembly is within a double-wall housing forming a cooling water jacket.

Description

Basis of the invention:

The invention relates to wheat flour for dough preparation for the baker's Application but also for other applications inside and outside of the Food processing, a process for the production of these wheat flours and a device for carrying out the method.

During the dough preparation, so much water is added to a flour that a plastic, dry, well-processed dough is produced. The to necessary water addition is in percent based on the initial amount of flour indicated and referred to as water absorption (WA). The objective measurement of Water absorption takes place in the so-called Brabender Farinograph after internationally accepted method ICC standard no. 115/1. The sum of the Water absorption in percent and the underlying flour quantity (with 14% Humidity), the latter is always 100%, is referred to as dough yield (TA).

Other parameters measured in the Farinograph, used to assess the quality Serve flour, dough stability and dough softening. The Dough stability is measured in minutes and is the time starting with the Reaching 500 Brabender Farinogrammeinheiten until falling below 500 Brabender Farinogrammeinheiten. The dough softening is in Brabender farinogram units (FE) measured as the difference between 500 Brabender farinogram units and the value on Brabender farinogram units 12 Minutes after the start of the drop below 500 Brabender Farinogrammeinheiten.

A high water absorption or dough yield of a flour is for bakers Applications first important because they relate to the used Flour high pastry yields allowed.

Because flour has become a rather cheap commodity in recent years and Therefore, the achievable pastry yield has decreased in importance, have other advantages that result from increased water absorption, clearly gained in importance.

Advantages for the end user are about a much better taste of the Pastries, a better relaxation, associated with a larger volume, one prolonged keeping and delay stalemate, thus longer Durability or consumption. Also pasteurized sliced bread, by the Pasteurisation process loses crumb moisture and thus quality of taste, benefits from the highest possible moisture in the crumb, with which the Moisture loss is precompensated.

For users in the baking industry brings the increased water absorbency the flours, when applied the same dough yield as with another flour becomes, drier, less sticky doughs. For pretzels it is e.g. important, to use a firm dough when pretzel slinging and while on it following lye is dimensionally stable. This is usually done by a lower one Wasserschüttung achieved with the result of unsatisfactory freshness of the baked pretzel. An increased water absorption of the flour carries both Necessities (dough strength and good freshness of the pastry) bill and makes a compromise unnecessary. Next, in the dough recipe certain ingredients (shred, oil seeds, dried fruits, etc.) are introduced without resulting in too dry a pastry crumb. These ingredients Normally they must first be swelled with water (in the form of a so-called source or Broth) before they can be added to the dough.

For certain bakery products (for example ciabatta) a very high dough yield is necessary, to produce them in optimal quality. The processing of such doughs is in the Past only possible by hand; since new she can also with special machines whose dough touch surfaces with an anti-stick coating are provided and their elements for portioning and promotion of the dough mechanically stress this only minimally. For doughs with high Water content, which is nevertheless dry and stable, can also be the usual and regularly used in the baking industry facilities are used.

Newer applications require the highest possible water absorption of the doughs. That's how it is now a process for vacuum cooling of pre-baked bread, this naturally removes a certain amount of water and, consequently, drier bread leads if the water loss is not precompensated.

In view of this situation, which exists in principle for a very long time, is already tried have been made to produce flours with increased water intake. It is also known that the Water intake of a flour predominantly through its ingredients protein, pentosan and damaged strength is determined.

State of the art: GB-A-1 265 735 discloses a stirred ball mill having a double-walled ball mill water-cooled housing known.

British Patent No. 1,108,911 describes a process in which high-level flours Proportion of damaged starch. In principle, they are suitable for damage to the starch Roller mills. In the usual production of "light" flour but not at first Strength damage, but an energetically favorable and effective separation of Aspired shell ingredients, with the aim of a low-mineral flour with as possible high yield with a correspondingly low proportion of mineral-rich as possible bran and To win over products. To increase the already given Starch damage is changed in this grinding process, the roller speed. The Relative speed of the rolls of a pair of rolls to each other (overfeed) is increased, The nip is reduced, the contact pressure of the rollers is increased. Continue to be instead of smooth rollers roughened rollers and corrugating rollers used, the corrugation and Anstellwinkel are modified. It will be extremely high Roller relative speeds (lead 1: 8 to 1:80) indicated, wherein the Corrugation constellation is of great importance.

German Auslegeschrift DE-AS 26 22 748 relates to a method by which a Compaction of a rye flour by at least 10 percent, followed by comminution of the compacted material, an improvement of the baking properties of the flour and the To achieve freshness properties of the baked goods to be produced therefrom. Here is the Water absorption of a rye flour considerably increased. Application of the procedure wheat flour affects according to the local revelations in a similar way. The scored Effect was limited due to the change in the protein and the resulting resulting improvement of the adhesive properties to an increase in the Pastries volume. Data on the water absorption of untreated and treated wheat flours are not disclosed, even values for the assumed damage to starch is neither for wheat nor for Rye flours in front. The decisive effect of this method lies beside the Pressure increase in the simultaneous increase in temperature of the goods during the Milling process. The indication of a germ reduction by more than two Decisions of ten indicate a temperature that already causes pasteurization effects leads. This explains a thermal enzyme inactivation and at the same time a incipient starch gelatinization, both of which increased to the observed one Lead to water absorption.

European patent EP 0 919 294 B1 describes a dry one Agitator ball mill for processing cereal flours. That's where it comes from the conditions used do not cause damage to the starch. These intended task is the detachment of the protein from the starch granules, which achieved with very high efficiency. The proteins can be separated by a Separate downstream sighting in high enrichment.

This prior art also indicates that the use of Impact mills for breaking up the flour particles into starch granules and Protein components is known, whereby it by irreversible deformations of the Starch granules comes to damage. Type flours from the Impact milling, however, have a lower starch damage than the corresponding flours from the Walzenstuhlvermahlung, although they are finer. Even with high energy consumption can be with these mills a significant Do not reach starch damage. By the impact milling of flour in the Roll mill method has been manufactured, will increase the water absorption by Max. 10 percent compared to the water absorption of the starting meal reached.

Another method is known from GB 474 359 A.

Disadvantages in the prior art:

Numerous baking companies, but above all finished flour manufacturers, set different Swelling agents in order to increase the water absorption on the by the natural raw material flour to reach previously given limits. Be used in addition to source flours from different cereals Swelling starches and other vegetable hydrocolloids, such as the additives E 412 guar gum, E 411 locust bean gum, E 401 sodium alginate.

With the use of these substances is a "dilution" of the baking effective Grain protein (glue, gluten) accompanied by the separate addition of dried vital adhesive must be compensated. Instead of vital glue can also high protein flours, e.g. by the method according to EP 0 919 294 B1 were used in the mixture. These procedures lead regularly to increased costs, to greater logistical effort and to an extended list of ingredients in which the additives used may have to be identified.

It is well known that there is a general relationship between Strength damage and water absorption. In principle, a high Water absorption desired, a very high starch damage, however also lead to negative effects. These are about diminishing doughs, low Bread volume, coarse pore. Such unwanted effects arise, regardless of the starch damage, even if the increase in Water absorption by very fine grinding of wheat flour from soft Wheat is reached. The quickly absorbed water will over the course of Dough kneading not held, so sticky doughs with a poor state result.

Object and solution of the invention:

The invention relates to a novel wheat flour, which starting from a normal, by means of a conventional roller mill grinding process obtained wheat flour with a likewise claimed as invention Method was modified so that it is compared to the starting flour one order has more than 10 percentage points increased water absorption, the Dough stability and the dough softening of the dough made therefrom the corresponding values of the dough from the starting flour significantly negatively influenced or even improved.

With the flours invention can be extremely comfortable the Solve the problems described at the outset: replacement of source flours, Swelling starches and hydrocolloids from the additive catalog and realization all the benefits for consumers, processors in the baking industry and Subcontractors (finished meal and baking agent manufacturers).

In the flours according to the invention are also doughs with high dough yield, ie high water content, still stable and do not stick, so they despite the use the usual processing plants for an optimal pastry can be processed.

Description of the invention:

The influences caused by the grinding process on those in the Farinographen measured parameters (water absorption, dough stability and dough softening) a flour are not limited to the Starch damage. The protein component can also be changed; here is to think about an oxidative adhesive fortification, but also a damage of the Protein by shear and temperature effects is possible. The fineness of Flour particles produced also play a role. different Milling systems affect the above parameters in different way. In consequence, that means that one Grinding system the strength "selectively" damaged and at the same or even leads to a higher water absorption than another milling system damaging effects on other components, e.g. Proteins and Pentosans lead to lower dough stability and higher dough softening.

Although in the known Walzenstuhlvermahlung a squeezing instead higher strength damage, however, require high contact pressures apparently also shear effects caused by an increase in the relative velocity be achieved. As a result, the already discussed damage is possible, the largely due to thermal problems.

It was found that a treatment of the flours in a dry Agitator ball mill is able to increase the water absorption significantly. Also the values of starch damage, measured according to the internationally recognized Method ICC standard no. 164, are always, sometimes more than 8 Percentage points, much higher than the starting meal. Surprisingly the resulting increase in water intake from the treatment goes in one dry agitator ball mill with the otherwise in other grinding processes observed disadvantages (reducing dough stability and increasing the Dough softening).

The use of a stirred ball mill allowed in the inventive Task a high water absorption at high specific To achieve energy inputs without the known disadvantages occur. By doing the temperature of the treated flour during grinding below 60 ° C, preferably between 30 ° C and 50 ° C, measured at the exit from the Agitator ball mill, is a thermal damage of the protein and the other ingredients excluded. At very high energy input can usefully a direct or indirect cooling of the grinding balls be made, for example, with air, liquid nitrogen or else liquid or solid carbon dioxide. In fact, that was found at the most operating conditions sufficient air cooling of the balls, which already by increasing the reproached in the ball reservoir amount of balls one Extension of the cooling time is achieved.

Surprisingly, it was found that it was with the inventive Agitator ball mill is possible, e.g. commercial baker's flour of the type 550 to change so that compared to the starting flour an increase in the Water absorption of significantly more than the previously known 10 percentage points is reached. By simply adding the appropriate specific energy, the water absorption by up to 29 percentage points increased compared to the starting flour.

Explanation of the drawings:

Diagram 1 clearly shows that in the investigated range the registered specific energy correlates very well linearly with the resulting water absorption of the flour (R = 0.96). Without much difficulty, even higher water absorption can be achieved with a reinforced stirrer drive and additional ball cooling or multiple passage treatment.

The character of the Kugelvermahlung, not the specific energy input and not the fineness of the resulting flour is crucial for the inventive method. Table 1 shows a comparison between different flours, grinded from the same starting flour by means of pin mill (type CW) and by means of a stirred ball mill (type ATR). At about the same registered specific energy and fineness, there are clear differences in water absorption and starch damage in favor of the ground in the agitator ball mill flour. Even with significantly higher enlisted energy, the water-picking effect of the pin mill can not approach that of the ball mill. Effects of pin mill and ball mill treatment Starting flour. pin mill 1 ball mill 1 pin mill 2 ball mill 2 spec. Energy (kWh / t) - 82.3 86.3 183.5 132.2 D 10 (μ) 13.3 6.4 5.3 4.0 4.9 D 50 (μ) 64.7 28.5 21.7 17.4 21.3 D 90 (μ) 174.0 98.8 53.7 47.8 48.8 Water absorption (%) 59.2 61.6 80.3 65.1 88.3 Starch damage (%) 6.1 8.0 9.9 11.4 12.7

In the further evaluation of the Farinogramme the doughs showed in the Ball mill processed flours with the significantly changed flour / water ratio (max difference: 100: 59 to about 100: 88) no significant changes, i.e. Deterioration of dough stability and dough softening over Dough from the starting flour. The increased dough softening at different Try hangs regularly with one by the method of determination given longer kneading time in these cases. Interpretations of the Parameters dough softening may have to take this into account.

Another attempt to increase the water uptake (and starch damage) of a flour was based on a flour made from a wheat mix with a 50% content of very high quality so-called E-Wheat ("Buzzard" variety). Here, however, it was not ground in the "pass" with the ball mill ATR, but in a cycle from which the fine material was discharged by means of a fine-grained ATP. Starting meal and discharged fine meal had the values shown in Table 2: starting flour treated flour Humidity (%) 15.0 9.6 Protein (%) 12.7 12.5 Far. Water absorption (%) 59.6 79.8 Far-dough stability (min.) 10.7 17.6 Color dough softening (BE) 46.0 -16.0 damaged strength ICC 164 7.2 8.8

Although the subject invention by the achieved increase in Water absorption is characterized, are also the achieved Starch damage has been determined by the standard method ICC Standard 164 (Determination of the level of damaged starch by means of the Enzyme kits from Megazym). This method is expected in the future because of their fast, comfortable execution and easily available standardized reagents are the most widely used internationally, so that the values obtained with it for cross-comparison with others Investigations can serve.

Detailed explanation of the embodiments, examples:

In the drawings according to Figures 1 to 3, the invention is based on Embodiments schematically illustrated. Fig. 1 shows the inventive stirred ball mill; Fig. 2 shows a plant scheme with continuous grinding; 3 shows a plant scheme with Kreislaufmahlung.

FIGS. 4 to 6 show the evaluations of the test results in FIG Dough stability diagrams (FIG. 4), the damaged starch (FIG Teigerweichung (Figure 6) for test series each in an inventive Agitator ball mill (Alpine ATR) with steel balls and aluminum oxide balls (Ceramics), and a comparative test series on a pin mill (Alpine CW) According to the state of the art.

1 shows an agitator ball mill type ATR of Hosokawa Alpine AG & Co. OHG. The mill is a continuous or discontinuous, ie batchwise dry agitator ball mill. The agitator ball mill 11 is driven by a drive unit consisting of motor 7, clutch 8 and bevel gear 9 , which is arranged on a bracket 10 .

The drive energy of the motor 7 is introduced via the clutch 8 and the angle gear 9 in the agitator shaft 5 and transferred as grinding energy through the attached to the agitator shaft 5 agitators 6 in the foundry container 1 bed of ground material and grinding balls. The stress of the ground material for comminution in the stirred ball mill 11 takes place in a complex manner by a combination of pressure, shock, shear and shear between the grinding balls. These have a size of preferably less than 7 mm, usually between 1 and 5 mm. Although even smaller grinding balls would be advantageous from a process engineering point of view (higher number of contact points), smaller balls than 1 mm are not used because economic aspects speak against it. Namely, the grinding balls must be separated from the material to be ground in a separating stage following the grinding, for example in a screening machine 14 (FIGS. 2 and 3). For the separation of very fine grinding balls, however, very large, fine-meshed screen surfaces are required, which are very expensive and therefore not very economical.

In the continuous operation of the agitator ball mill 11 , the vertical grinding vessel 1 , which has a tapered lower part 2 of material to be ground and grinding balls, starting from the mill inlet 3 in the direction of the mill outlet 4 flows through evenly, with one at the end of the tapered lower part 2 of the grinding vessel 1 is a horizontal discharge screw 12 is arranged to control the residence time of the material in the grinding vessel 1 . The speed of the discharge screw 12 is variably adjustable via an adjustable worm drive 13 and thus the throughput through the mill in wide ranges adjustable. The speed of the agitator shaft 5 is variably adjustable via the variable motor 7 . The agitator shaft and discharge screw speed determine the specific energy (kWh / t) entered into the material to be ground.

Since the registered energy is converted to a large extent in heat, regrind and balls undergo a significant increase in temperature even in a single pass through the agitator ball mill 11 . In order to keep the temperature in the mill at a low level, on the one hand the grinding vessel 1 is double-walled and flows around of cooling water and on the other hand, the balls are cooled after leaving and before re-entering the agitator ball mill 11 . In the simplest case, an air cooling during the ball transport sufficient to cool the balls sufficiently. More effective, however, is to let the balls stay longer in the sump 15 and to let the sump 15 flow through cold air. In the case of particularly high demands on the cooling capacity, instead of air, other refrigerants such as, for example, liquid nitrogen (LN2) or dry ice (CO ₂ ) can be mixed in the collecting container 15 .

In the continuous operation of the agitator ball mill 11 , a distinction can be made between continuous grinding, as shown in FIG. 2 , and cycle grinding, as shown in FIG . In both cases, the balls are conveyed continuously over the agitator ball mill 11, the discharge screw 12, the screening machine 14, the collecting container 15 and the bucket elevator 24 in the circulation.

In the case of continuous grinding of Fig. 2, the material to be ground can either be placed directly on the agitator ball mill 11 , or it is - as shown - abandoned from a Mahlgutvorrat 25 via a feed screw 26 in the bucket elevator 23 . Together with the balls from the collection vessel 15 reaches the checked ground material through the bucket elevator 24 to the mill inlet 3 of the agitator ball mill 11, the flour treated in a passage in the agitator ball mill 11 is fed by the screw discharge 12 from the lower reaches of the agitator ball mill 11 coming the sieving machine 14 and separated into a fine fraction and a coarse fraction. The fine fraction is tapped off directly at the outlet material outlet 18 and represents the end product. The coarse fraction consists of the balls and is returned to the collecting container 15 . The balls from the collecting container 15 are combined with the newly abandoned grinding material from the ground stock 25 in the area of the bucket elevator 23 and conveyed through the bucket elevator 24 into the agitator ball mill 11 .

In the cycle grinding of Fig. 3, the material to be ground is first transported from a Mahlgutvorrat 25 via a feed screw 26 in the intermediate container 19 . The newly added ground material is mixed in the intermediate container with recirculated coarse material and fed via a feed screw 27 via the bucket elevator 23 to the bucket elevator 24 . Together with the balls from the collecting container 15 , the abandoned ground material mixture passes through the bucket elevator 24 to the mill inlet 3 of the agitating ball mill 11. The flour treated in the agitating ball mill 11 is fed to the screening machine 14 after the screw discharge 12 from the underflow of the agitating ball mill 11 and into a flour fraction and a ball fraction separately. The ball is again fed to the collecting tank 15 , from here the balls as well as the combined with the recirculated coarse material in the intermediate container 19 new ground material in the bucket elevator 23 of the bucket elevator 24 are promoted.

The flour fraction is fed coming from the screening machine 14 by means of conveying air 17 an air classifier 16 and separated there into a fine and a coarse flour fraction. The coarse flour fraction is fed via the coarse material line 28 and the return screw 29 to the intermediate container 19 . As a result, the not yet sufficiently ground coarse regrind is fed back into the cycle process. The air required for air classification is generated by the blower 22 and at the same time conveying air 17 for the sieved on the screening machine 14 Kreislaufgut. The fine flour fraction is guided together with the classifying air into the filter 20 , deposited there and is discharged via the product outlet 21 .

LIST OF REFERENCE NUMBERS

1

grinding vessel

2

conical part

3

mill inlet

4

mill outlet

5

agitator shaft

6

stirrers

7

engine

8th

clutch

9

angle gear

10

console

11

stirred ball mill

12

discharge screw

13

screw drive

14

screening machine

15

Clippings

16

air classifier

17

conveying air

18

Continuous materials outlet

19

intermediate container

20

filter

21

product outlet

22

fan

23

bucket elevator

24

bucket elevator

25

Mahlgutvorrat

26

feed screw

27

feed screw

28

Grobgutleitung

29

Recirculation scroll

Claims (16)

1. Method for treating wheat flours by dry grinding of a starting flour to increase the water absorbing capacity, characterised in that the grinding is carried out in a dry ball mill with a stirring device introducing 20 to 300 kWh of grinding energy per ton of starting flour at a flour temperature of less than 60°C, through which an increase in the water absorbing capacity of more than 10 percentage points is obtained compared with the starting flour.
2. Method according to claim 1, characterised in that the increase in the water absorbing capacity is between 10 and 40 percentage points compared with the starting flour.
3. Method according to claim 1 or 2, characterised in that the wheat flours are ground in the ball mill with a stirring device in a continuous flow-through operation.
4. Method according to claim 1 or 2, characterised in that the wheel flours are ground in the ball mill with a stirring device in a recirculating operation.
5. Method according to claims 1 to 4, characterised in that the grinding is carried out at a temperature of between 30°C and 50°C.
6. Method according to claim 1 or 2, characterised in that the wheat flours are ground in the ball mill with a stirring device in batches.
7. Method according to claims 1 to 5, characterised in that a coolant is added directly to the contents of the ball mill with a stirring device.
8. Method according to claims 1 to 5, characterised in that the ball mill with a stirring device is operated with circulated grinding balls which are cooled by a coolant.
9. Method according to claim 7 or 8, characterised in that the coolant is air, liquid nitrogen or liquid/solid carbon dioxide.
10. Method according to claims 1 to 9, characterised in that the ball mill with a stirring device exhibits a double-walled, water-cooled housing.
11. Method according to one of claims 1 to 10, characterised in that the ball mill with a stirring device contains grinding beads of aluminium oxide or steel.
12. Method according to claim 11, characterised in that the grinding balls exhibit a diameter of less than 7 mm, preferably of 1 mm to 5 mm.
13. Method according to claims 1 to 9, characterised in that the wheat flours are flours of types 405 or 550.
14. Method according to claim 13, characterised in that the wheat flour exhibits a water absorbing capacity of more than 70% and a cracked starch content of more than 8%.
15. Method according to claim 13, characterised in that the wheat flour exhibits a water absorbing capacity of more than 70% and a dough stability of more than 1.3 min.
16. Method according to claim 13, characterised in that the wheat flour exhibits a water absorbing capacity of more than 70% and a dough softening of less than 130 Brabend farino gram units.

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