Foamed Plant Protein Meat Analogues Pore Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional extrusion methods for producing plant protein-based meat analogs fail to achieve a controlled and reproducible ratio of open to closed pores, leading to inconsistent texture and absorption properties, which affects sensory qualities and processing characteristics.
Innovation Solution
A method and device that utilize a combination of high moisture extrusion cooking (HMEC) with micro-foaming and specific pore opening technologies, such as flash-pores opening, cut-extrusion, penetration, forced secondary mixed flow, and freeze structuring, to adjust the ratio of closed to open pores in the extruded products, allowing for a defined degree of pore opening and improved fluid absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional extrusion methods are used to produce plant protein-based meat analogs, then the production process is simple, but the ratio of open to closed pores cannot be controlled and reproduced, leading to inconsistent texture and absorption properties
Solution Approach 1:
The extrusion device is divided into multiple functional zones: a foaming zone with injection molding cavities for bubble formation, a compression zone for compacting the foam structure, and a drying zone for moisture removal. This segmentation allows independent control of pore formation and consolidation processes, enabling precise control over the open-to-closed pore ratio while maintaining reproducible texture and absorption properties
Solution Approach 2:
Gas bubbles are introduced and distributed throughout the plant protein material before the extrusion process begins. The foaming zone pre-forms the foam structure with controlled bubble size and distribution, which is then consolidated in the compression zone. This preliminary foam formation allows precise control over the final pore structure and ratio of open to closed pores
2Quantity of substance
If foam bubbles are introduced to create porous structure, then absorption properties improve, but the structural stability and dimensional accuracy of the extruded product deteriorate
Solution Approach 1:
The extrusion device creates different foam structures in different regions: the compression zone applies high pressure to consolidate the foam and create a stable, load-bearing structure with primarily closed pores for structural integrity. The drying zone then selectively opens certain pores and removes moisture to create channels for fluid absorption. This local differentiation of pore quality allows the product to simultaneously achieve high absorption capacity and structural stability
Solution Approach 2:
The device intentionally creates a dual-pore structure: closed pores provide structural stability and prevent collapse during handling and cooking, while selectively opened pores provide fluid absorption pathways. The controlled foam consolidation process ensures that the porous structure maintains its shape and dimensional accuracy while enabling enhanced absorption of liquids and flavorings
3Manufacturing precision
If high pressure is applied to compact the foam structure, then dimensional accuracy improves, but the degree of pore opening decreases
Solution Approach 1:
The extrusion process employs periodic pressure variations: the compression zone applies cyclic high pressure to compact the foam and establish dimensional accuracy, followed by a pressure release phase in the drying zone that allows pores to reopen. This periodic pressure action sequence ensures that the product achieves both high dimensional accuracy and sufficient pore opening degree for fluid absorption
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method enables the production of foamed meat analogs with adjustable sensory and nutritional attributes, enhancing tenderness, juiciness, and cooking properties by optimizing the ratio of open to closed pores, allowing for better absorption of liquids and incorporation of flavor and nutritional components.
Implementation Method 1
gas is metered in under atmospheric or excess pressure, mixed/dispersed and/or partially or fully dissolved under excess pressure
Implementation Method 2
is then released again by pressure release and remains partially or fully incorporated in the viscous mass to form a foam
Implementation Method 3
a static pressure build-up occurs, which in the nozzle is reduced again to atmospheric pressure at the extruder nozzle outlet with the nozzle cross-section being kept more or less constant via the flow shear stresses prevailing there due to wall friction and inner fluid friction. The pressure build-up in the nozzle inlet zone (before entry into the nozzle) compresses the gas trapped in the foam bubbles
Implementation Method 4
the pressure reduction in the extruder nozzle down to the outlet atmospheric pressure allows the gas in the foam bubbles to expand again and thus enlarges the foam bubbles
Implementation Method 5
The maximum wall shear rate present in the fluid layer in contact with the wall (=speed of the fluid film under consideration close to the wall on its side facing the center of the nozzle channel divided by the fluid film thickness) usually causes the formation of a boundary layer close to the wall. If the fluid system contains disperse components, these disperse components are set in rotation as a result of the wall shear rate effective in the fluid layer under consideration close to the wall, and experience a dynamic buoyancy force (lift force), which causes the disperse components to separate away from the wall towards the middle of the nozzle channel
Implementation Method 6
In an aqueous protein melt produced under these conditions, protein denaturation occurs in the form of protein fibrils that form, which are oriented in the direction of flow in the extruder nozzle inlet flow as a result of the elongational flow components that are effective there
Implementation Method 7
are solidified in this oriented structural state by subsequent cooling (to approx. 60° C.) in a long (≥approx. 1 m) extruder cooling nozzle
Implementation Method 8
constricted to a position which allows adjusting the static pressure before entry into the constricted slit gap to a value of ≥approx. 1.5-2 bar of the static pressure prevailing after exiting the slit gap, which is typically atmospheric pressure. This brings about a preferred gas pressure release in the product cross-sectional direction and thus towards the product surface
Implementation Method 9
In the diverging outlet flow after the constriction, the previously stored elastic tensile stresses partially relax again through elastic reverse deformation of the viscoelastic fluid. Small flow asymmetries or the stochastic variance of the elastic deformation cause the formation of a periodic, sinusoidally oscillating, roller-like flow disturbance. This so-called secondary flow causes the foam bubbles to be moved towards the product surface and, in combination with the simultaneous breaking up of the skin layer, results in the formation of persistent pores/pore channels that are open towards the surface
Implementation Method 10
The characteristics of the viscoelastic secondary flow effect used for POT-4 can lead to an almost complete disintegration of the extrudate strand. In plastics technology, this undesirable elastic phenomenon is also referred to as 'melt fracture'. For its avoidance, the VSDA device is installed according to the invention >0.2 LD (nozzle length) before the end of the extruder nozzle. As a consequence, the extrudate strand, in the event of partial disintegration, 'heals' again in the undisturbed nozzle flow after passing through the VSDA
Data Source
AI summary
The invention relates to a product having a foam structure with a set ratio of gas pores open to the product surface and closed to the product surface. The invention also relates to a method with four embodiments according to the invention for the defined mechanical opening of closed foam pores. Furthermore, the invention relates to a device having four embodiments according to the invention for the defined mechanical opening of closed foam pores. The invention also relates to the use of products designed according to the invention as meat analogs or plant protein-based textured multiphase foods, more particularly vegetable or fruit composites. Particular advantages of the invention relate to the targeted influencing of the deformation and texture properties of foamed products and their accessibility from the outside for quick and easy filling of the open pores with fluid systems which introduce additional functionalities into the product.