DE10064437A1 - Processing lupin protein material to give a storable material for use in foods or feed materials includes enzyme-inactivating dry heat-treatment before water extraction - Google Patents

Abstract

Processing of protein material from lupins involves dry heat treatment to inactivate enzymes before the material is subjected to extraction with water.

Description

The invention relates to a method for processing Lupine proteins according to the preamble of claim 1.

Lupins are among the plants that have a high proportion have high-quality vegetable proteins. such Proteins can be a valuable asset in the Represent food and feed production. Not only the bitter lupins containing alkaloid, but also the so-called sweet lupins have antinutritive substances, for example the alkaloids, certain forms of sugar (Oligosaccharides), etc. are to be counted. For separation such anti-nutritional substances and others Processing of the lupine proteins with the desired one Functionality has already been different procedures developed.

For example, EP 0 859 553 describes a method described in which the plant components, in particular the lupine seeds are processed into semolina, which then subjected to two water extractions.

Furthermore, a method is described in DE 198 13 207 described, crushed into flake lupine seeds or deformed and with the help of a solvent, for example hexane. Then also performed an aqueous extraction here.  

In the publication EP 0 522 800 the Processing an isoelectrically prepared Protein concentrate in an aqueous solution at a alkaline pH in predetermined temperature time intervals proposed, but no significant in the processing Shear forces should occur, d. H. the mechanical Procedural measures, such as stirring, centrifuging, etc. should performed with the least possible forces become.

The previous state-of-the-art methods are also used an inactivation of enzymes on the starting product described. To do this, use moist methods such as blanching or steaming suggested. According to the previous view It is essential to ensure that the highest possible proportion of native proteins in the enzyme-inactivated starting product remains. The heat treatment for inactivating enzymes therefore had to be as gentle as possible without denaturing the Proteins take place, which is only comparatively short thermal contact time and therefore, due to the better Heat transfer is only possible in a damp environment. At the Blanching or steaming is due to the moistening of the Starting material with no additional drying corresponding equipment and energy expenditure not possible to add the intermediate after inactivation to store.

The object of the invention is to introduce a method to propose the type mentioned, in which the starting product according to the inactivation of the enzymes can be stored without great effort is.

This is achieved according to the invention in that the herbal raw material before the extraction of a dry heat treatment to inactivate enzymes is subjected.  

In this dry heat treatment, in which the Dwell times due to the compared to wet processes poorer heat transfer must be significantly longer however, a comparatively large proportion of Proteins denatured. However, the invention lies in the surprising finding that it is possible in further procedures without much effort Restructuring of the initially denatured proteins achieve.

Advantageously, as starting products Lupine flour, lupine flakes, lupine grits, etc. used, those from the, if necessary previously peeled, lupine seeds manufactured, e.g. B. be ground. Such one Starting product can be used for enzyme inactivation in a dry heat treatment, e.g. B. toasted with hot air become and is therefore easily over a longer period of time storable. In particular, the starting product can thereby one from the facility to carry out the rest Process separate mill produced and then be toasted. The lupine flour prepared in this way can therefore also as a commercial product for the further implementation of the Process according to the invention for protein processing depending on Needs to be bought.

Finely chopped lupine flour is preferably used as Starting product used. Experiments have shown that when using such flour considerably shorter Response times with improved protein yield in the subsequent process steps can be achieved. This Last but not least, advantages are due to the larger wettable Surface due to the small grain size of the flour as well by the changed due to this small grain size Intermediate consistency achieved. Basically you can these benefits for a given extraction as well  Production of a finely crushed intermediate, e.g. B. with an average particle size ≦ 300 µm during the procedure before this extraction, e.g. B. by wet grinding or the like can be achieved.

The enlarged reaction surface ensures, for example shorter dwell times or a reduction in Extraction stages in the subsequent process steps and thus for a larger throughput or a smaller one Dimensioning of the associated system connected with the corresponding savings in material and energy.

In addition, when using a flour as Starting product or a finely chopped Intermediate product further processing, for example the Extraction, with high mechanical stress, e.g. B. in turbulent environment possible. This facilitates the further Processing enormous. So process parameters, e.g. B. pH values can be set faster for extractions. A better Process control combined with lower protein losses and less denaturation of the proteins possible.

With the previous use of flakes and grits as The starting product was high shear forces or turbulence in the avoid further procedures to avoid the formation of fines excluded. Present due to the invention Use a flour as a raw material or a fine one comminuted intermediate product, on the other hand, can be high Shear forces and turbulence are provided in the further process become. In a turbulent process, for example, the wetting of an exchange area clearly perform more efficiently. As a result, the pH also set more homogeneously, with which in particular also a No more protein damage due to local over-concentration can be done.  

In a method according to the invention, an aqueous Extraction in the acidic and / or alkaline pH range performed.

An acidic water extraction serves, among other things, like this the prior art is known, the removal of the so-called anti-nutritional ingredients of lupins. To especially include the bitter substances (alkaloids) and Multiple sugars (oligosaccharides) that cause bloating.

An alkaline extraction is used for protein extraction and can, depending on the desired end product, also without previous acid Extraction.

The solid refinate is particularly advantageous Embodiment of the extract, i.e. H. with the liquid phase With the help of an ultracentrifuge with acceleration values <3000 g separated. In the known methods with a granular or flaky raw material work, has always been with lower acceleration values worked. The increase in acceleration values in the Separation level improved with the help of an ultracentrifuge especially when using Lupine flour or a finely chopped intermediate, the yield and the quality of the resulting further Intermediates, d. H. of raffinate and extract. As had been particularly advantageous, if possible high acceleration values, which is why the separation advantageously at acceleration values above 5000 g is made. Have good results with Acceleration values of approx. 6000 g are shown, with one further increase in acceleration values is conceivable would.

Acid extraction in the vicinity of the  so-called isoelectric point of the lupine proteins performed to minimize protein loss. The isoelectric point denotes the pH at which the the lowest solubility of the native proteins is present. This isoelectric point is in the range of pH 4.5 to pH 5, so the acidic extraction is not if possible take place outside the pH range between 4 and 5.5 should, provided by the extraction of proteins with a the highest possible proportion of native proteins is assumed. This generally reduces protein losses.

All previous processes require protein-containing Raw materials with high protein solubility (high PDI) in order To be able to produce proteins with high functionality. Due to the new processing of a flour as Starting product or a finely chopped Intermediate product with its large exchange area has Surprisingly, it also showed that proteins with lower Solubility, d. H. with a low PDI value Production of high quality, functional proteins.

This now gives you the opportunity to fine that comminuted intermediate for inactivating enzymes to be subjected to a greater thermal load. So far this thermal treatment was chosen so that a as high a proportion of native proteins as possible Treatment survives. Now, however, is also one Enzyme inactivation and preservation by one with one Denaturation of proteins associated with heat treatment possible, e.g. B. by hot air treatment of a flour, too Called toasting.

In addition, it was again surprisingly shown that with increasing degree of denaturation of the proteins Extraction of the anti-nutritional substances at a higher pH value, for example <pH 5.5, without losses in the  Protein yield can take place. This causes a reduction the amount of acid to adjust the acid extraction and also a reduction of the alkali in a subsequent one Neutralization or a subsequent change to one alkaline environment. Associated with it is still a lower salt content in the end products.

The separation of the raffinate in the above high Centrifugal field causes the liquid extract to be almost is free of solids. This enables easy manufacture a protein concentrate or isolate, which from water-soluble proteins in the acidic pH range.

This creates a previously unknown product the water-soluble ones not used in the previous processes Proteins. Such a protein concentrate or isolate can find use in beverage production, for example.

In addition, by separating out these proteins the extract the so-called BOD content of the extract, d. H. the required oxygen for biodegradation reduced if the extract is disposed of organically got to.

The separation of these proteins, which are soluble in an acidic environment is preferably by means of a membrane separation process performed. Then the proteins are dried, a cleaning level, e.g. Legs Diafiltration, and an evaporation are interposed can.

The above alkaline extraction is preferred at a pH between 8 and 11 can be made to be a good one To achieve protein yield.

In a special embodiment, the alkaline Extraction as a second extraction on the solid raffinate  a first acidic extraction.

In addition to those already described using acid extraction Advantages through the use of Lupine flour or a finely chopped intermediate you can also switch from acid to alkaline Area in a turbulent environment much faster accomplish.

The increased exchange area increases here the protein yield continued to increase to 85% compared to approx. 65% the use of flakes or grits.

The separation of the liquid extract is advantageous of the solid raffinate from the alkaline extraction again with an ultracentrifuge with comparatively high Acceleration values above 3000 g were carried out. The The quality of lupine milk improves the higher the centrifugal field is formed, which is why a Centrifugal field of <5000 g, preferably up to 6000 g recommends.

The result of these high centrifugal fields Lupine milk can be used in various ways.

For example, this lupine milk can be made after one optional concentration and pasteurization by means of an ultra-high temperature heating immediately as End product can be obtained.

The preparation of a lupine milk powder after Concentration using membrane separation processes and / or thermal processes are also possible. The Pasteurization can in turn be done using Ultra high temperature heating with subsequent Spray drying take place.  

In addition, lupine milk can also Fresh products, similar to cow's milk processing, be generated.

With further enzymatic treatment for example, protein hydrolyzates and peptides become. For this manufacture can advantageously first a precipitation with subsequent Concentration and purification of the resulting Protein quarks are placed upstream.

Furthermore, the production of a protein isolate or concentrate, for example, by the following process steps possible. First, the liquid extract or Lupine milk is precipitated. This precipitation will preferably as acid precipitation at the isoelectric point trained, a heat precipitation or a combination of However, heat and acid precipitation are basically also possible.

Here the proteins fall in the form of small, fine and unstable flakes. To then use the proteins separating high yield from whey again advantageously a separation in a high Centrifugal field, d. H. <3000 g, preferably <5000 g and suggested in particular at about 6000 g.

In a further development of this embodiment, in addition during this separation a negative pressure is applied to a possible Advantageously reduce or if necessary, to be avoided completely.

The protein curd resulting from the separation can for example by neutralization and drying into one Protein isolate can be processed. In an advantageous  Embodiment of these process steps is additional thermal treatment of the quark is provided by means of the the functionality of the proteins is affected.

For this, protein extraction and its precipitation downstream thermal treatment is advantageous a so-called tubular reactor is used. In one Tube reactor a plug flow can be realized so that the dwell time and the temperature load are exact is controllable. With this downstream thermal Treatment can also inactivate enzymes that may still be present.

The temperature time treatment depends on the desired functionality and its initial Enzyme activity. It can take up to a few minutes Hour at temperatures from 60 to 120 ° for example be performed.

This treatment results in addition to the one listed above Inactivation of enzymes to modify the proteins and thus to a desired functionality.

If an end product with a high proportion of soluble, the is called native protein is desired, so this can Make a comparatively short-term Ultra high temperature heating without significant denaturation of the proteins are made. About the short stay ensure, for example, a subsequent Relaxation and / or other cooling can be made.

The same applies to the separation of the precipitated protein quark from the Lupine milk obtained from whey can become usable Whey product, for example a whey concentrate are processed. This processing branch can be a Neutralization, concentration, evaporation and / or  Include drying.

Furthermore, from the separation of the liquid extract from solid raffinate after alkaline extraction Solid refinate before that to a high quality functional fiber product is processable. This processing route preferably also includes one Neutralization and drying.

If necessary, additional heating of the raffinate, z. B. be made before neutralization. On the one hand this in turn inactivates any enzymes others may affect functionality when heated become. This process is also used for thermal Treatment preferably uses a tubular reactor, whereby the above-mentioned advantages regarding the length of stay and Temperature control can be achieved. The kind of Temperature time treatment depends on the amount of Protein content, its solubility (PDI value), the initial enzyme activity as well as the desired Functionality of the fiber.

An embodiment of the invention is in the drawing shown and will be explained in more detail below with reference to the figures explained.

In detail shows

Fig. 1 is a block diagram for illustrating the procedure for processing a liquid extract according to a first inventive extraction of lupine flour,

Fig. 2 is a block diagram illustrating the first method steps for Feststoffraffinat from the first extraction,

Fig. 3 is a process chart showing the procedure for the preparation of milk powder,

Fig. 4 is a block diagram for illustrating the procedure for the preparation of a protein isolate, and

Fig. 5 is a block diagram illustrating the process flow in the manufacture of functional dietary fiber.

In Fig. 1, reference number 1 is initially a grinding process for the production of lupine flour with the desired grain size, for. B. with an average grain size or an average grain diameter ≦ 300 microns, from lupine seeds. This flour could, for example, after inactivating the enzymes according to the invention by dry heat treatment, e.g. B. by toasting with hot air, can also be temporarily stored.

This is followed by a first, acidic extraction 2 , so that the flowchart branches at this point. On the one hand, this acid extraction results in a solid refinate 3 , the further processing of which is described with the aid of the following figures.

In addition, the liquid extract is formed from the acidic extraction 2 , which is then in the present embodiment by a concentration 4 , z. B. is further processed by means of a membrane separation process and / or by means of evaporation 5 .

After evaporation 5 , drying 6 takes place, for example in the form of spray drying. The end result is a protein concentrate 7 , the corresponding proteins being soluble in the acidic region since they originated from the liquid phase of the acidic extraction 2 . This protein concentrate 7 represents a novel product and can be used very advantageously in the production of foods in an acidic environment, for example beverages.

Alternatively, after evaporation 5, an organic leaf fertilizer or, by adding 8 additives, a crop protection or plant strengthening agent 9 can be produced. The addition 8 of the additives can serve, for example, for stabilization but also for formulation, ie for adjusting the mode of action. When processing sweet lupins, plant protection agents that are already present in the form of alkaloids when processing bitter lupins can also be added at this point. If no pesticides are added or are present, the end product 9 can also be used as a pure leaf fertilizer.

Fig. 2 shows the subsequent processing of the Feststoffraffinats 3 from the acidic extraction 2. In a further alkaline extraction 10 , the proteins soluble in this pH range are dissolved and then separated from the solid raffinate with a separation 11 . This separation 11 is advantageously carried out with a very strong centrifugal field as described at the beginning, for example of 6000 g. This separation in turn results in a solid refinate 12 which is very high in fiber and whose further processing will be explained later with reference to the following figures.

The protein milk in the form of the liquid extract can now continue in different procedures are processed as shown by the branch in For example, three process branches are indicated.

So can in a manner not shown for example by enzymatic treatment or other Processing as known from cow's milk processing is fresh produce or similar foods become.

A method for producing milk powder from protein milk 13 is explained with reference to FIG. 3. Thus, protein milk 13 is first subjected to neutralization 14 with subsequent concentration 15 . The neutralization 14 is carried out with the addition of acid until a neutral pH is reached, while the concentration 15 is again carried out, for example, with the aid of ultrafiltration. Enclosing evaporation 16 provides a further increase in protein concentration. After pasteurization 17 and drying 18 , milk powder 19 is finally available as the end product.

According to FIG. 4, the milk protein 13 can also by a precipitation are processed for example by an acid or heat precipitation. The solids precipitated during the precipitation 20 are then separated from the liquid whey in a separation 21 . This separation 21 is in turn preferably carried out in a very high centrifugal field as mentioned at the beginning, for example at 6000 g. If necessary, a vacuum can also be used at this point to prevent any problems caused by foam formation.

This separation 21 results in a whey 22 , the processing of which is explained further below.

In the present exemplary embodiment, the protein curd resulting from the separation 21 is subjected to heating 23 with subsequent time / temperature treatment 24 . This time / temperature treatment 24 is preferably carried out in a tube reactor in a so-called plug flow, so that the dwell time during the temperature treatment can be precisely controlled. The heating 23 and the time / temperature treatment primarily serve to influence the functionality of the proteins.

After a subsequent neutralization 25 and drying 26 , a protein isolate 27 is thus obtained. The neutralization 25 can alternatively be carried out between the separation 21 and heating 23 . Drying 26 is again preferably carried out by spray drying.

Fig. 5 is used to illustrate the processing of the whey 22nd In the present exemplary embodiment, this is first subjected to a neutralization 28 with subsequent concentration 29 , for example by ultrafiltration. After subsequent evaporation 30 and drying 31 , a whey concentrate is obtained which can also be used in food production.

The process sequence for further processing of the solid refinate 12 from the alkaline extraction 10 is explained in more detail in FIG. 6. If necessary, heating 33 is carried out with a subsequent time / temperature treatment 34, for example again in a tubular reactor with a plug flow, for precise control of the time and temperature parameters. The heating 33 and the time / temperature treatment 34 can be provided to influence the functionality of the end product. This is followed by neutralization 35 and drying 36 , so that functional fiber 37 results as the end product.

The processing of the individual intermediate products can also be based on other known ways take place. Essential to the Invention is that by inactivating the enzymes by a dry heat treatment of the starting product this starting product can be stored without additional effort is, so that if necessary on one of the system for the The rest of the process is made and stored in a separate system can be.  

LIST OF REFERENCE NUMBERS

1

grinding

2

acid extraction

3

Feststoffraffinat

4

concentration

5

evaporation

6

desiccation

7

protein concentrate

8th

encore

9

foliar fertilizer

10

alkaline extraction

11

separation

12

Feststoffraffinat

13

protein milk

14

Neutralization

15

concentration

16

evaporation

17

pasteurization

18

desiccation

19

milk powder

20

precipitation

21

separation

22

whey

23

heating up

24

Time / temperature treatment

25

Neutralization

26

desiccation

27

protein isolate

28

Neutralization

29

concentration

30

evaporation

31

desiccation

32

whey concentration

33

heating up

34

Time / temperature treatment

35

Neutralization

36

desiccation

37

dietary fiber

Claims (32)

1. Process for the processing of vegetable proteins from lupins, an extraction with water being carried out, characterized in that the vegetable starting product is subjected to a dry heat treatment to inactivate enzymes before the extraction. 2. The method according to claim 1, characterized in that as a starting product, a flour from the lupine seeds is ground becomes. 3. The method according to claim 2, characterized in that the starting product is toasted by hot air treatment. 4. The method according to any one of the preceding claims, characterized characterized in that the separation of the solid refinate from the liquid extract in an ultracentrifuge Acceleration values <3000 g are made. 5. The method according to any one of the preceding claims, characterized characterized in that the separation of the solid refinate at an acceleration of <5000 g is carried out. 6. The method according to any one of the preceding claims, characterized characterized in that the separation of the solid refinate at an acceleration of about 6000 g is made. 7. The method according to any one of the preceding claims, characterized characterized that extraction for extraction anti-nutritive substances in an acidic pH range and / or for protein extraction at an alkaline pH Value range is made.   8. The method according to any one of the preceding claims, characterized characterized that the pH of the extraction between 4 and 5.5. 9. The method according to any one of the preceding claims, characterized characterized that the extraction at a pH ≧ 5.5 is carried out. 10. The method according to any one of the preceding claims, characterized characterized that the liquid extract into a Protein concentrate or isolate is worked up. 11. The method according to any one of the preceding claims, characterized characterized in that when concentrating the Extract liquid obtained to an organic Foliar fertilizer is processed. 12. The method according to any one of the preceding claims, characterized characterized that the alkaline extraction at a pH Value in the range between 8 and 11 is made. 13. The method according to any one of the preceding claims, characterized characterized that the alkaline extraction second Extraction on the solid refinate from a first, acidic Extraction is made. 14. The method according to any one of the preceding claims, characterized characterized that a separation of the solid refinate of the alkaline extraction in an ultracentrifuge Acceleration values <3000 g are made. 15. The method according to any one of the preceding claims, characterized characterized in that the separation of the solid refinate of the alkaline extraction at acceleration values <5000 g is made.   16. The method according to any one of the preceding claims, characterized characterized in that the separation of the solid refinate of the alkaline extraction with an acceleration of approx. 6000 g is made. 17. The method according to any one of the preceding claims, characterized characterized that the obtained as a liquid extract Protein milk is concentrated and / or pasteurized. 18. The method according to any one of the preceding claims, characterized characterized that the obtained as a liquid extract Protein milk is processed into milk powder. 19. The method according to any one of the preceding claims, characterized characterized that the obtained as a liquid extract Protein milk is subjected to precipitation. 20. The method according to any one of the preceding claims, characterized characterized that by a third separation the whey from the curd produced by precipitation using a Ultracentrifuge is separated. 21. The method according to any one of the preceding claims, characterized characterized that the separation of the whey at Acceleration values <3000 g are made. 22. The method according to any one of the preceding claims, characterized characterized that the separation of the whey at Acceleration values <5000 g is carried out. 23. The method according to any one of the preceding claims, characterized characterized that the separation of the whey at Acceleration values of approx. 6000 g are made.   24. The method according to any one of the preceding claims, characterized characterized that the separation of the whey at negative pressure is carried out. 25. The method according to any one of the preceding claims, characterized characterized that the present after the separation Protein curd through neutralization and drying into one Protein isolate is processed. 26. The method according to any one of the preceding claims, characterized characterized that a heat / time treatment of the Protein quarks is provided. 27. The method according to any one of the preceding claims, characterized characterized that the protein curd one Ultra high temperature heating without significant denaturation of the proteins with a correspondingly short residence time is then subjected to relaxation and / or cooling. 28. The method according to any one of the preceding claims, characterized characterized that the obtained by ultracentrifugation Whey is processed into a whey concentrate. 29. The method according to any one of the preceding claims, characterized characterized in that the raffinate from the second alkaline Extraction by neutralization and drying into one functional fiber is processed further. 30. The method according to any one of the preceding claims, characterized characterized in that heating of the raffinate is provided is. 31. The method according to any one of the preceding claims, characterized characterized by heat / time treatment of the raffinate is provided from the second extraction.   32. The method according to any one of the preceding claims 28 or 33, characterized in that the heat / time treatment the protein curd according to claim 26 and / or the raffinate is carried out according to claim 29 in a tubular reactor.