Periodic Reporting for period 1 - EVALUATOR (EVALUation of heAlthy-susTainable fOod pRoteins)
Reporting period: 2023-06-01 to 2025-09-30
Access to healthy and sustainable foods is an existential priority as recognized by the UN, WHO, and EU. Replacing animal-based proteins with their plant-based counterparts or even with other potential (more sustainable) ingredients is expected to be a major step forward. In order to speed up this transition, methods need to become available to allow for high throughput evaluation of ingredients, in terms of technical functionality that rules food properties, and physiological functionality that ultimately decides on effects taking place in the body. The EVALUATOR project focusses on ingredient properties in colloidal emulsions (oil (droplets)-dispersed in-water systems), for which a tailor-made microfluidic platform was applied to dynamically assess technical emulsion stability (ingredient ability to form and stabilize the droplets) and digestibility.
The microfluidic platform allows real-time investigation at micro- and nano- meter levels, the scales at which basic food structure elements are formed and degraded, and within very short time spans mimicking natural process conditions via high-speed recording. With this, the EVALUATOR project not only led to the design of healthier and greener food systems but also supply a versatile microfluidic platform that allows design from first principles, i.e. the actual ingredient properties as they are relevant for food production and digestion. This brings food design, that currently revolves around trial and error, into a completely different realm, and even more important, establishes the currently missing link between technological functionality and digestion.
All of the above is highly relevant from a scientific perspective, but not only that, the use of these tiny devices may also have a broader and larger impact. By using the microfluidic platform, ingredient screening can be done with small sample sizes and reduced amount of chemicals, making a substantial contribution to environmental sustainability and the exploration of novel food sources.
The microfluidic platform allows real-time investigation at micro- and nano- meter levels, the scales at which basic food structure elements are formed and degraded, and within very short time spans mimicking natural process conditions via high-speed recording. With this, the EVALUATOR project not only led to the design of healthier and greener food systems but also supply a versatile microfluidic platform that allows design from first principles, i.e. the actual ingredient properties as they are relevant for food production and digestion. This brings food design, that currently revolves around trial and error, into a completely different realm, and even more important, establishes the currently missing link between technological functionality and digestion.
All of the above is highly relevant from a scientific perspective, but not only that, the use of these tiny devices may also have a broader and larger impact. By using the microfluidic platform, ingredient screening can be done with small sample sizes and reduced amount of chemicals, making a substantial contribution to environmental sustainability and the exploration of novel food sources.
The EVALUATOR activities were performed according to three specific objectives (O).
O1. Evaluate the techno-functionality of emulsions.
Here, we used the EDGE (Edge-based Droplet GEneration) device to assess the dynamic interfacial tension (related to the adsorption of emulsifiers) between oil-water and air-water interfaces during droplet formation. Those interfaces were covered either by conventional surfactants (as model systems), whey or plant proteins subjected to different processing (e.g. temperature) conditions. This step was really important to understand the behaviour of different emulsifiers in adsorbing and stabilizing interfaces in conditions as would occur during food production. Additionally, we also used the coalescence-cell and the concentrator chip to quantify the re-coalescence of emulsions (including also particle-stabilised droplets, also known as Pickering emulsions). The coalescence-cell and the concentrator chip enable the measurement of the droplets merging at timescales relevant to food production, providing information on interfacial phenomena and emulsion stability that can be correlated with standard emulsification techniques. The use of the EDGE chip together with the coalescence-cell (or the concentrator chip) is an interesting strategy as it allows determining sequential steps during droplet formation/stabilization: the adsorption of the stabilizers at the oil-water interface during droplet generation and the coalescence of the droplets after such stabilizers have been deposited at the droplet surface. With all these devices combined, we were able to identify interfacial phenomena and potential coalescence, visualizing events as they occur in a dynamic fashion (sub-millisecond and micrometre scale). Such conditions are extremely relevant for food production.
O2. Evaluate the physiological functionality of emulsions.
Here, we used pre-developed microfluidic devices to evaluate digestibility of emulsions stabilised by conventional surfactants, (plant) proteins or particles. We also used a novel approach to investigate the physiological functionality of emulsions based on the rheology chip. Such technique allowed us to understand the adsorption/desorption kinetics of materials at oil-water interfaces under physiologically relevant conditions.
O3. Develop a microfluidic digestive system.
Here, we built up microfluidic systems to simulate gastrointestinal conditions, which are suitable for very systematic high throughput testing of new food systems. In this context, we developed a new glass chip where fluid dynamics (flow rate and residence time) and secretion fluids (pH, enzymes, salts) have been adapted to simulate digestion phases. These chips can accommodate single or multiple droplets where the oil digestibility (based on droplet size reduction) can be assessed. Since Pickering emulsions are more stable, their digestibility was also investigated, in addition to conventional surfactant- and (plant) protein-stabilised emulsions.
O1. Evaluate the techno-functionality of emulsions.
Here, we used the EDGE (Edge-based Droplet GEneration) device to assess the dynamic interfacial tension (related to the adsorption of emulsifiers) between oil-water and air-water interfaces during droplet formation. Those interfaces were covered either by conventional surfactants (as model systems), whey or plant proteins subjected to different processing (e.g. temperature) conditions. This step was really important to understand the behaviour of different emulsifiers in adsorbing and stabilizing interfaces in conditions as would occur during food production. Additionally, we also used the coalescence-cell and the concentrator chip to quantify the re-coalescence of emulsions (including also particle-stabilised droplets, also known as Pickering emulsions). The coalescence-cell and the concentrator chip enable the measurement of the droplets merging at timescales relevant to food production, providing information on interfacial phenomena and emulsion stability that can be correlated with standard emulsification techniques. The use of the EDGE chip together with the coalescence-cell (or the concentrator chip) is an interesting strategy as it allows determining sequential steps during droplet formation/stabilization: the adsorption of the stabilizers at the oil-water interface during droplet generation and the coalescence of the droplets after such stabilizers have been deposited at the droplet surface. With all these devices combined, we were able to identify interfacial phenomena and potential coalescence, visualizing events as they occur in a dynamic fashion (sub-millisecond and micrometre scale). Such conditions are extremely relevant for food production.
O2. Evaluate the physiological functionality of emulsions.
Here, we used pre-developed microfluidic devices to evaluate digestibility of emulsions stabilised by conventional surfactants, (plant) proteins or particles. We also used a novel approach to investigate the physiological functionality of emulsions based on the rheology chip. Such technique allowed us to understand the adsorption/desorption kinetics of materials at oil-water interfaces under physiologically relevant conditions.
O3. Develop a microfluidic digestive system.
Here, we built up microfluidic systems to simulate gastrointestinal conditions, which are suitable for very systematic high throughput testing of new food systems. In this context, we developed a new glass chip where fluid dynamics (flow rate and residence time) and secretion fluids (pH, enzymes, salts) have been adapted to simulate digestion phases. These chips can accommodate single or multiple droplets where the oil digestibility (based on droplet size reduction) can be assessed. Since Pickering emulsions are more stable, their digestibility was also investigated, in addition to conventional surfactant- and (plant) protein-stabilised emulsions.
The results that go beyond the state of the art are mainly related to two different aspects:
i) Evaluation of the adsorption/desorption of components at oil-water interfaces of emulsions and air-water interfaces of foams at extremely short timescales (in the order of milliseconds). With this, new information could be obtained which can be further used in the context of developing and assessing the functionality and digestibility of new food ingredients.
ii) A new microfluidic device to simulate gastrointestinal conditions were developed and validated, which is currently readily available to use.
i) Evaluation of the adsorption/desorption of components at oil-water interfaces of emulsions and air-water interfaces of foams at extremely short timescales (in the order of milliseconds). With this, new information could be obtained which can be further used in the context of developing and assessing the functionality and digestibility of new food ingredients.
ii) A new microfluidic device to simulate gastrointestinal conditions were developed and validated, which is currently readily available to use.