METHOD FOR PREPARING FOOD PRODUCTS BY MEANS OF CO-EXTRUSION, VISCOUS GELLING SOLUTION AND SYSTEM FOR CO-EXTRUSION OF FOOD PRODUCTS

Abstract

The invention relates to a method for preparing food products by means of co-extrusion, wherein at least two casing material components are mixed to make a viscous gelling solution. This viscous gelling solution is subsequently co-extruded whereby the gelling solution is forming the external layer of an extruded strand of food dough. The invention also relates to a viscous gelling solution obtainable by such method as well as a system for co-extrusion of food products.

Claims

1.-25. (canceled)

26. A method for preparing food products by means of co-extrusion, comprising the steps of: a) providing at least two casing material components; each of which components in itself is not suitable for extrusion as an external layer; b) mixing the casing material components provided during processing step a) to make a viscous gelling solution; and c) feeding the viscous gelling solution of processing step b) to the co-extrusion process of a food product to be co-extruded whereby the gelling solution is forming the external layer of an extruded strand of food dough, wherein the time range of the time window between the moment of mixing of the casing material components to make the viscous gelling solution and the moment of the co-extrusion of the viscous gelling solution is a time window within a time range of [0, 48] hours to maintain the viscoelasticity of the viscous gelling solution at the moment of the co-extrusion within a predetermined range such that the grammage of the external layer of the food product prepared does not exceed 200 g/m.sup.2.

27. The method according to claim 26, wherein the grammage of the external layer of the food product prepared does not exceed 150 g/m.sup.2.

28. The method according to claim 26, wherein the grammage of the external layer of the food product prepared is about [25, 75] g/m.sup.2.

29. The method according to claim 26, wherein the time range of the time window between the moment of mixing of the casing material components to make the viscous gelling solution and the moment of the co-extrusion of the viscous gelling solution is a time window within a time range of [0, 24] hours.

30. The method according to claim 26, wherein during processing step b) an acidic buffer solution is added.

31. The method according to claim 30, wherein the pH of the acidic buffer solution is about [2.0, 5.0].

32. The method according to claim 26, wherein the time range of the time window between the moment of mixing of the casing material components to the viscous gelling solution and the moment of the co-extrusion of the viscous gelling solution is controlled automatically.

33. The method according to claim 26, wherein one or more of the components provided during processing step a) is chosen from the group consisting of: water, alginate powder, alginate gel, collagen powder, collagen gel, strong acidic solution, weak acidic solution, strong alkaline solution and weak alkaline solution.

34. The method according to claim 26, wherein the viscous gelling solution comprises alginate.

35. The method according to claim 26, wherein during processing step b) at least one dry gelling agent is mixed with at least one aqueous medium.

36. The method according to claim 26, wherein during processing step b) at least one acidic component is mixed with at least one aqueous medium.

37. The method according to claim 26, wherein during processing step b) at least two dry gelling agents are mixed, and subsequently the dry gelling agent mix is mixed with the aqueous medium.

38. The method according to claim 26, wherein information on the properties of one or more of the casing material components provided during processing step a) is used for regulating the proportions of the components provided.

39. The method according to claim 26, wherein information on the properties of the food dough and/or the food product to be co-extruded is measured automatically.

40. The method according to claim 26, wherein information on the properties of the food dough and/or the food product to be co-extruded is measured manually.

41. The method according to claim 26, wherein the casing material components provided during processing step a) comprise an additive that is selected from an emulsifying agent, a buffer solution, a structure improver, a strengthening agent, a thickener agent and/or combinations thereof.

42. The method according to claim 26, wherein the viscous gelling solution is composed according to a pre-set recipe.

43. The method according to claim 26, wherein the mixing of the casing material components to a viscous gelling solution during step b) comprises mechanical emulsifying of the mixture.

44. The method according to claim 26, wherein the average temperature of the casing material components provided during processing step a) is [0, 24] C.

45. The method according to claim 26, wherein the method also comprises the steps of: d) treating the exterior of the food strand with an aqueous salt solution; and e) dividing the food strand into separated parts.

46. The method according to claim 26, wherein the mixing of the casing material components to a viscous gelling solution according to processing step b) comprises plural mixing phases; a first mixing phase wherein a first dry powder gelling agent is mixed with an aqueous medium wherein the components are mixed at a relative low speed; a second mixing phase wherein the obtained semi-manufactured viscous gelling agent is mixed at a higher speed than the mixing speed during the first mixing phase, which second mixing phase takes place under a gas pressure of less than 0,2 bar, preferably a gas pressure of less than 0,1 bar, during a period of [2, 4] minutes.

47. The method according to claim 46, wherein the method in between the first mixing phase and the second mixing phase also comprises an intermediate mixing phase wherein a second dry powder gelling agent is mixed with the semi-manufactured viscous gelling solution resulting from the first mixing phase and the mixing speed during the intermediate mixing phase is higher than during the first mixing phase but lower than during the second mixing phase.

48. The method according to claim 46, wherein the period of mixing the obtained aqueous solution during processing step b) is [2.5, 3.5] minutes.

49. Viscous gelling solution obtainable by the method according to claim 26.

50. System for co-extrusion of food products, the system comprising: a co-extrusion unit for extruding a strand of food dough at least partially enclosed by a simultaneously extruded layer of viscous gelling solution, the co-extrusion unit having a food dough inlet and a casing material inlet; and at least one mixing unit for receiving and mixing a plurality of casing material components, which casing material components in themselves are not suitable for extruding a layer of viscous gelling solution, wherein the mixing unit is provided with at least two casing material component supplies and a viscous gelling solution outlet, and wherein the viscous gelling solution outlet of the mixing unit is connected to the casing material inlet of the co-extrusion unit, wherein the system further comprises an intelligent control unit including a timer that controls the time window between the moment of mixing of the casing material components to the viscous gelling solution and the moment of the co-extrusion of this viscous gelling solution as a layer of viscous gelling solution on the strand of food dough, wherein the time window is within a time range of [0, 48] hours such that the grammage of the external layer of the food product prepared does not exceed 200 g/m.sup.2.

Description

[0024] The present invention will be further elucidated on the basis of the non-limitative exemplary embodiments shown in the following figures. Herein:

[0025] FIG. 1 shows a schematic view on a system for co-extrusion of food products according the present invention;

[0026] FIG. 2 shows a schematic top view on an alternative embodiment of a system for co-extrusion of food products according the present invention.

[0027] FIG. 1 shows an in-line system 1 for co-extrusion (P1) of food products 2 (e.g. sausages). The system comprises a co-extrusion unit 3 for extruding a strand of food dough 4 enclosed by a simultaneously extruded layer of viscous gelling solution 5. The co-extrusion unit 3 has a food dough inlet 6 and a viscous gelling solution inlet 7. The food dough inlet 6 connects to a food dough feeder 8 (e.g. a meat mass hopper), for example via a pump (not shown), while the viscous gelling solution inlet 7 connects (in-line) to a mixing unit 9 for the preparation of the viscous gelling solution (casing material), for example via a pump (not shown). The mixing unit 9 is fed by a plurality of casing material supplies 10-13, each providing a different type of casing material component. It is however also possible that two (or even more) casing material supplies 10-13 feed an identical casing material component for instance to enable continuous feed of the specific casing material component from holders/drums/packages that require exchange. In the figure shown two material supplies 10, 11 connect to casing material component hoppers 14, 15 that e.g. can feed a dry powder casing material components, a third material supply 12 that connects to a drum 16 for feeding a liquid casing material component and a fourth material supply 13 that connects to a pipe 17 (e.g. a water pipe) to feed a further liquid (e.g. water). In the mixing unit 9 a selected number of the possible casing material components are mixed to a viscous gelling solution with specific process conditions at a moment in time T.sub.mix. The moment when the mixed viscous gelling solution is extruded in the co-extrusion unit is moment T.sub.coex. For operating the system 1 a control unit 18 is provided that connects to the co-extrusion unit 3, food dough feeder 8, mixing unit 9, casing material component hoppers 14, 15, a pump 19 connecting to drum 16 and a valve 20 in the pipe 17. The control unit 18 regulates the mixing operation to produce the viscous gelling solution from the various casing material components to be fed to the co-extrusion unit 3. With the control unit 18 the time window between the moment of mixing of the viscous gelling solution (T.sub.mix) and the moment of co-extrusion of food products 2 (T.sub.coex) is controlled within a within a set time window to maintain the viscoelasticity of the viscous gelling solution at the moment of the co-extrusion within a predetermined range.

[0028] FIG. 2 shows a schematic top view on an alternative embodiment of a system 30 for co-extrusion (P2) of food products 31 wherein the reference signs to parts that correspond with parts of the system 1 as shown in FIG. 1 are referred to with identical reference signs. The system 31 comprises a co-extrusion unit 3 for extruding a strand of food dough 4 enclosed by a layer of viscous gelling solution 5. The co-extrusion unit 3 has a food dough inlet 6 and a casing material inlet 7. The food dough inlet 6 connects to a food dough feeder 8 (e.g. a meat mass hopper) while the viscous gelling solution inlet 7 connects to a viscous gelling solution feeder 32. The viscous gelling solution fed to the viscous gelling solution feeder 32 is pre-mixed in a separate mixing unit 33 which is off line with the co-extrusion unit 3. The separate mixing unit 33 is fed by three casing material supplies 34-36, each providing a different type of casing material component. Two of the material supplies 34, 35 connect to casing material component hoppers 37, 38, a third material supply 36 connects to a pipe 39 (e.g. a water pipe) to feed a further liquid (e.g. water). The viscous gelling solution mixed in the separate mixing unit 33 may be fed in batches 40 (see arrows P.sub.3, P.sub.4) to the co-extrusion unit 3. The time to be controlled according the present invention in this system 30 for co-extrusion (P2) of food products 31 is the moment of mixing of the viscous gelling solution (T.sub.mix) in the separate mixing unit 33 to the moment of co-extruding the strand of food dough 4 enclosed by a layer of viscous gelling solution 5 in the co-extrusion unit 3.