Final Report Summary - WHEY2FOOD (Enhanced protein fractionation from protein sources for their use in special food applications)
Executive Summary:
Whey proteins have gained major attention for applications in infant formula, sports and clinical nutrition due to their health and nutritional benefits, large availability as a by-product from cheese-making and low raw material cost. Moreover, whey proteins fractions have extraordinary techno-functional properties, including foaming, emulsifying, gelling and water-binding potential.
Currently, only 25% of liquid whey is transformed into food and human nutrition products in Europe. Sixty percent of the whey produced is disposed in municipal sewage systems, creating serious environmental problems. Current technologies for protein fractionation and concentration are still laborious and require several processing steps, the use of chemicals, large amounts of eluents or buffers or need huge cleaning efforts due to membrane fouling and have high membrane replacement costs (e.g. ultrafiltration). In addition, acids, alkalis and high temperatures are often needed to achieve separation, causing protein denaturation and diminishing product quality. In general, these technologies are difficult to up-scale and are associated with additional environmental problems due to disposal of chemicals and the large amounts of waste water generated. Therefore, an economic and sustainable solution for the valorization of whey is urgently needed.
The Whey2Food project aims to develop a highly efficient, selective, gentle and economically attractive Electro Membrane Filtration (EMF) technology to enhance separation and concentration of proteins and peptides from whey. This technique combines an electric field with mechanical membrane filtration. The driving gradient for the material transport across the membrane can be generated both by the transmembrane pressure and the electric field applied. This enables the separation both on the basis of the electric charge and the particle size. Fraction purity and economic yields are increased due to the ability of EMF to increase the filtration flow rate and minimize membrane fouling, cleaning efforts and membrane replacement costs.
During this project, enriched whey protein fractions are obtained by selecting appropriate electrode material and cell configuration parameters, including placement of filtration membranes and electrode shielding membranes, electric field strength, pH, fluid temperature, fluid pressure gradient and membrane cut off (pore size). The aim is to obtain a full understanding of the EMF process and its interferences with whey and the contained compounds to create a knowledge base that supports the development of an optimal system configuration at laboratory level and enables the scale up of the process and into a demonstration prototype suitable for use at an industrial relevant environment.
The project focused on the enrichment of a whey protein suspension containing Casein Macro Peptide (CMP), the hydrophilic fraction of κ-Casein that remains in the whey.
Separation of CMP from α-Lactalbumin (α-La) and β-Lactoglobulin (β-Lg) requires a fine adjustment and monitoring of parameters due to the narrow range at which the isoelectric points of them are found. However, as the molecular weight of both α-La and β-Lg at least double that of CMP, the electric field applied is able to retain them at the retentate side while CMP is transmitted to the permeate under the influence of the transmembrane pressure. Commercial benchmark formulas report a CMP concentration ranging from 75 to 85% of total protein. Accordingly, our laboratory trials successfully enriched CMP to a concentration of 81% of total proteins transmitted to the permeate, increasing over 10-fold the CMP/ β-Lg ratio in a single step.
After process optimization at laboratory level, a pilot unit was developed. The core of this unit is an optimized EMF cell, which takes into account an optimum distribution of electric field, minimizes pH-shifts and ensures the adjustment of the crossflow and transmembrane pressure to the required range. The unit operates in semi-batch mode (feed and bleed) with feed flow of 1000 L/h at optimum transmembrane pressure conditions. Validation of the process up-scale will continue.
Project Context and Objectives:
The goal of the Whey2Food project is to develop and establish a highly efficient, selective, gentle and economically attractive electro-membrane filtration (EMF) technology to enhance separation and concentration of proteins and protein peptides from whey. The EMF technology combines the ultrafiltration technique with the migration of charged species in an electric field enables the separation of molecules with similar molecular weight but different electric charge. Compared to state-of-the-art ultrafiltration, EMF significantly increases filtration yields and reduces membrane fouling, therefore reducing cleaning efforts and membrane replacement costs.
Whey is a by-product of the manufacture of cheese or casein and is considered a promising raw material for various commercial applications due to its high-value components like proteins. The separated protein fractions are of high interest in food (infants or sports), medical, and personal care applications. However, most of the produced whey is currently disposed and not used for further processing.
The efficient recovery of functional protein fractions through EMF technology will provide an important source of high-value natural food emulsifiers and protein supplements for various food formulations and nutritional applications, while providing an economic alternative to whey disposal and reducing the environmental impact of European SME dairies. The key innovations of the Whey2Food project are:
• A novel large scale EMF technology to process whey
• A process that can be tailored to adjust and control the output protein fractions. This can be reached due to the fact that EMF separates not only by the molecular weight, but also by the electric charge of the proteins under interest.
• An electro-membrane filtration unit with automated function and minimal maintenance requirements. Membrane cleaning can be performed not only by applying a backpressure, but also by reversing the cell voltage.
• A method to produce proteins of specific functionality or to enrich specific proteins
• A cost effective, flexible in production and easy to operate system for small-scale cheesemakers • A process with a wide range of potential applications in biotechnological downstream processes Scientific objectives of the Whey2Food project will be:
• Understanding of the electric field distribution in the Whey2Food reactor and its effect on the transport of the proteins across the filtration membrane
• Understanding the effect of key operation parameters on the separation yield and efficiency
• Characterization of the functional properties of protein and peptide fractions in model and food application
The Whey2Food project therefore combines scientific research with industry-relevant applications.
The work performed in the project will cover the physical modelling of the EMF process and cell, the development and fabrication of a novel cell with improved performance, the integration of this cell into an industrial relevant process concept for the separation of proteins from whey, the analysis of the proteins, the demonstration of the running system in real-time applications and the analysis of promising markets and applications of our technology.
Based on these project targets and work, the consortium of the Whey2Food project has been formed:
The consortium consists of experts on electro-physical separation processes, dairy technology and analysis, design and fabrication of reactor cells and its components, automation, and application in the whey and milk product industry. The partners therefore form a complete supply chain from the system development to demonstration and application.
Project Results:
During this project, a technical-economic analysis of different protein fractions in the whey and their market potential was conducted. Specific target proteins were identified and a corresponding separation concept based on the EMF technique was developed.
Enriched whey protein fractions were obtained by selecting appropriate electrode material and cell configuration parameters, including placement of filtration membranes and electrode shielding membranes, electric field strength, pH, fluid temperature, fluid pressure gradient and membrane cut off (pore size). The aim was to obtain a full understanding of the EMF process and its interferences with whey and the contained compounds to create a knowledge base that supports the development of an optimal system configuration at laboratory level and enables the scale up of the process and into a demonstration prototype suitable for use at an industrial relevant environment.
Life Cycle Assessment
A life cycle assessment (LCA) study was conducted to verify the economic-ecological significance of the Whey2Food concept as an efficient alternative for the recovery of protein fractions from whey. Experimental data and modeling of the product system collected during the first phase of the project were fed to quantify the impact of the baseline technology and to compare it with the SoA UF technology (Ultrafiltration). This LCA study is a “cradle-to-grave” assessment that consists of the following four stages:
1. Raw materials: production of components and transportation
2. Manufacture and spare parts: manufacturing the treatment technology (i.e. Whey2Food technology and conventional ultrafiltration) and providing spare parts, e.g. membranes
3. Use: recovery of the targeted mixture of proteins
Included processes: production of consumed electricity and production of reagents consumed by the processes, namely electrode rinse solution (buffer solution), cleansing agent and water. This sub-system comprises extraction of resources and transport to the treatment place.
4. End of life: disassembly and final disposal
The technology comparison relied on the following sources:
- Results obtained in laboratory and bench scale tests carried out during the Whey2Food project (e.g. energy and mass balance assessment of the processes, emissions to air, discharges to water and soil)
- Databases from the GaBi6 Software for generic information
- Information obtained from technical publications and professional journals
- Technical information obtained from suppliers
The analysis was conducted according to the standards DIN EN ISO 14040 and DIN EN ISO 14044 and was made on a common basis, defined by the functional unit.
To ensure comparability of the LCA results and obtain reliable data information, the experimental setup was designed in a way that allows modifications to enable the operation of the regarded SoA process in the same setup as the newly developed Whey2Food process.
To assess the foreground system, which corresponds to the operation of the technology, the following information related to the functional unit (FU) was gathered for both scenarios:
- Type and amount of required consumables: electrodes, membranes, electrode rinses (sodium sulphate) and cleansing agent (sodium hydroxide)
- Electricity consumption
All the presented data on consumption are gathered for an Experimental setup of 1 l/h of permeate, treating 30l of fresh whey in one experiment. It was then upscaled to a unit with a larger membrane stack, producing 100 l/h and the respective amounts were calculated for the functional unit. The production and transportation of the consumables was also included.
To enable the Life Cycle Assessment, four impact categories were found to present sufficiently distinctive results to compare and evaluate the Whey2Food technology and the state of the art process respectively:
- Climate: Global Warming Potential (GWP) by green-house gases, in kg CO2-Equivalents (CO2 = carbon dioxide)
- Elementary Resources: Abiotic depletion elementary resources (ADP elements), in kg Sb-Equivalents (Sb = antimony)
- Fossil Resources: Abiotic depletion of fossil resources (ADP fossil), in MJ (average mix of typical fossil energy carriers)
- Water toxicity: Marine Aquatic Ecotoxicity Potential (MAETP) in kg DCB-Equivalents (DCB = dichlorobenzene2)
The analysis of the newly developed Whey2Food process, when regarding the complete Life Cycle of the system, resulted in the emission of 35.9 kg of CO2-Equivalents, the depletion of 1.35*10-5 kg of Sb-Equivalents, the use of 415 MJ of fossil resources and production of 4500 kg of Dichlorobenzene (DCB)-Equivalents per 1 m³ of protein concentrate. For all regarded processes, the comparison shows that the electricity consumption has the most relevant impact in the LCA in all four impact categories. The materials needed for construction and the end of life have a relatively small influence that further decreases with increasing production rate during the lifetime of a system. This can be seen from the fact that in the SoA, which consumes more material and has a lower production, the influence of manufacturing and end of life processes is stronger than for the Whey2Food system. The impact of these processes can be seen especially in the categories describing depletion of elementary resources and water toxicity. Transportation processes, the use of consumables and water have only very small influence. An impact can be seen partly in the category for depletion of elementary resources.
The functional unit to enable this assessment was defined as one m³ of protein concentrate, a mixture of proteins containing at least 60% of CMP (caseinomacropeptide) per gr of Total Whey protein recovered in the concentrate of the first process stage.
This analysis and the comparison of results show that the Whey2Food process at this stage is at a similar level with the state of the art process already. However, the Whey2Food technology has a clear potential to surpass the standard ultrafiltration. Beyond the ecological aspects the electro membrane filtration has already clear benefits over the state of the art, especially when it comes to the required effort in maintenance and the connected production downtimes, which have to be avoided by any means in an environment of industrial production.
Process parameter studies and development of cell
A 4-compartment cell was developed and a process parameter study of the cell was conducted. The work included the selection of suitable electrode rinse solutions (e.g. sodium sulphate) and the optimization of the process parameters, e.g. flow rates and cell voltages.
A wide range of electro membrane contactor tests were conducted, with different membranes and at different voltages and pH’s. The initial aim was to split lactoferrin from the other proteins present in whey, based on its high iso-electrical point (IEP). However, it was concluded that the selective isolation of lactoferrin from fresh whey is not straightforward by means of an electrical field. It is assumed that the interaction between the positively charged LF and the negatively charge whey proteins (e.g. α-Lactoalbumin and β-Lactoglobulin) causes this effect. More research efforts are needed to overcome this issue.
The project focused switched further focus on the enrichment of a whey protein fraction containing Casein Macro Peptide (CMP). CMP is the hydrophilic fraction of κ-Casein that remains in the whey after the Lab-induced formation of curd during the cheese-making process. Its concentration in whey is around 1.5 g/l. This peptide has proven immunomodulatory, health promoting properties and is currently being commercialized for clinical foods and infant nutrition formulas. CMP has also extraordinary foaming and emulsifying properties that widens its area of application in foods. Commercial benchmarks report a CMP concentration of 75 to 85% of total protein. Accordingly, research activities focused on a strategy to obtain a similar concentration of CMP in the enriched fraction.
The main challenge is to separate CMP from α-Lactalbumin (α-La) and β-Lactoglobulin (β-Lg), whose isoelectric points are found within a very narrow range. Therefore, a fine adjustment and monitoring of pH, transmembrane pressure, crossflow and the conductivity is necessary. Because the molecular weight of α-La and β-Lg at least double that of CMP, the electric field applied was able to retain them at the retentate side while CMP was rather transmitted to the permeate under the influence of the transmembrane pressure applied. During laboratory trials CMP was successfully enriched in the permeate to a concentration of up to 81% with respect to the sum of all protein fractions transmitted. With this process the CMP/ β-Lg ratio from the feed solution was shifted to ca. 6.2 in the enriched permeate, increasing over 10-fold.
During the project, only electrodes of Titanium -platinum material were used because they are FDA approved. According to previous experiences, oxidation of the electrodes do not occur at operational conditions (15 to 40°C). Studies conducted by Tzedakis et al (1999) to estimate the electrochemical reaction rate during ohmic sterilization using Titanum-Platinum electrodes to heat foods up to130°C at a frequency of 50Hz examined the redox behaviour of several commercial foods in contact with various electrodes. The latter confirmed that no significant electrocatalytic properties towards foods occurred. Based on this scientific evidence, it was recommended to keep using this material.
Whey2Food System Up-Scaling
After first trials, cell design parameters were updated and limitations were corrected to enable up-scaling and design of pilot cell.
After process optimization at laboratory level, a pilot unit was developed. The core of this unit is an optimized EMF cell, which takes into account an optimum distribution of electric field, minimizes pH-shifts and ensures the adjustment of the crossflow and transmembrane pressure to the required range. The unit operates in semi-batch mode (feed and bleed) with feed flow of 1000 L/h at optimum transmembrane pressure conditions.
To this end, scientific data was evaluated to transfer application of parameters control requirements. Knowledge on which parameters to measure was established. A P&ID was defined and the corresponding sensors were specified and selected. Furthermore, control system and corresponding algorithms were defined. Control panel with data logging and software requirements were planned and implemented.
Furthermore, process harzards and critical control points (HACCP) were assess and reported and a risk assessment was conducted. This enabled the correct configuration of the process control. The risk evaluation was done using SaveExpert ® software commercial software and outlined. Mechanical design & scenario evaluation of complete system, including peripherals (tanks, pumps, in-line measurements, transmitters, piping, etc.) was then finalized. Parts were purchased and assembled.
Performance tests, including membrane & electrode performance to understand the key reliability/maintenance issues were conducted at Fraunhofer and the function of in-situ membrane cleaning in the scaled-up cells was verified. Specific guidelines for hygienic design, HACCP and Good Manufacturing Practices were implemented.
Pilot studies
Milk protein fractionation study were conducted using the pilot scale cell at UHOH dairy plant to confirm lab results with model and whey solutions. Techno-functional and emulsifying properties of fractions from real and model samples were confirmed and the suitability of milk protein fractions for formulations in foods was defined. Trials were conducted in parallel at Fraunhofer and included assessment of evolution of trans-membrane pressure during production cycles and the monitoring of electric field and power consumption.
Membrane used for trials was based on optimum laboratory results. When comparing the protein fraction values in the feed and permeate sample it could be shown for both trials that CMP was transmitted through the UF-membrane. Results on protein fractions revealed a better transmission of CMP by running the closed cycle (68.7%) than the open cycle (48.7%). These results are in accordance with laboratory trials. However adjustments in the system are still required to ensure higher CMP transmition rates. Benchmark levels of 75-85% CMP of total protein content have been reported in commercial formulas. With the developed system, CMP concentrations of up to 81% were reached at laboratory level.
Few weeks of continuous operation (production and cleaning cycles) of the pilot unit to evaluate all relevant parameters (flow rate, voltage, TMP) including the analysis of protein fractions were conducted. Membranes and electrodes were visually examined after trials.
Conclusions
At pilot level same as at laboratory level, a maximum flux of 10 L/h.m2 can be defined. Above this value the TMP increase considerably due to fouling. To evaluate the performance of the electrical field and the distribution in the new pilot cell, a voltage/current curve was performed. At laboratory level voltages of 10V or either 15V were required to have enough current distribution, but with the new cell design (bigger surface area and reduced distance between electrodes) lower voltages (ca. 8V ) are enough to have a current density between 15 – 20 mA/cm2. On the whole, following conclusions can be outlined:
1. A close understanding of the EMF process itself was achieved
2. 4-compartment EMF cell was successfully demonstrated
3. Successful selective concentration of CMP in whey based on size exclusion and electrical field application: Selectivity ratio CMP/β-Lg: 5 to 7.
4. Positive effect of voltage on TMP
5. Positive effect of voltage on fouling: longer runs with less cleaning are possible
6. The relative CMP content achieved is comparable to that of commercial products (74 – 85%)
7. a-La and b-Lg can be efficiently retained due to electrical field
8. For pH stabilization, buffer effects need to be taken into account
9. A flux of 10 l/m².h will be maximal to stay under the critical value of gel layer formation. Further experiments and improvements at pilot scale are necessary
10. Based on lab results, a higher transmission of CMP is achieved with cross flows of around 0.5 m/s. Lower cross-flows have a negative impact in membrane fouling and higher cross flows have a negative impact in CMP separation due to turbulence.
11. Efforts to improve the capacity of the current EMF-cell and to reduce investment and operational costs should be done, in order to obtain a profitable technology in comparison with current technologies for protein fractionation. Specifically efforts has to be focused on reduce electric consumption and process of the electrodes.
12. Efforts to improve the cleaning protocol in order to reduce the cleaning time and water and chemicals consumption. For the cleaning the possibility to connect a CIP unit has to be considered and tested.
Outlook
Technical guidelines for industrial design and operation have been outlined, including an outline of risk assessment and HACCP. A first economic evaluation based on phase I trials was conducted.
Recommendation protocols reflect combined results from trials at UHOH and Fraunhofer IGB, and are robust enough to draw conclusions. However, further field trials will be performed as part of post-project activities. Assessment and recommendation will be verified and /or updated at a later stage.
In terms of exploitation of results, and exploitation agreement has been prepared and circulated to the partners for their acceptance. The Document has been dully signed and distributed to all partners. Selection of topics to be published (peer reviewed) has been agreed. Finally, financial opportunities and business models to enter the market have been proposed.
Relevant results have been transferred from RTD to the SME partners by various communication channels
An overview of the internal dissemination activities of the project results carried out within the whole period of the project is given in Deliverable 7.6. Three Workshops were undertaken during project time as a knowledge transfer exercise to ensure that all relevant knowledge generated by the RTD performers is transferred to the SME participants and their staff. As part of post-project activities, partners will continue exchanging information on system performance, aiming at future progress into the market.
Potential Impact:
Consumers are increasing their awareness towards health and wellness, thus driving market growth of food protein ingredients worldwide. Accordingly, whey proteins have gained major attention for applications in infant formula, sports and clinical nutrition due to their health and nutritional benefits, large availability as a by-product from cheese-making and low raw material cost. Moreover, whey proteins fractions have the potential to replace chemical additives in formulations due to their extraordinary techno-functional properties, including foaming, emulsifying, gelling and water-binding potential.
Whey is a by-product of the manufacture of cheese or casein and is considered a promising raw material for various commercial applications due to its high-value components (e.g. proteins) and its large availability. Around 81 million tons of liquid whey was produced by the approximately 150,000 European cheese makers in EU-27 in 2011. However, according to the European Whey Products Association (EWPA), only 40% of the liquid whey in Europe is being processed for its utilization in food and human nutrition or in feed applications, while the rest is still being dumped into municipal sewages, mainly by SME dairies. This is neither ecologically nor economically reasonable.
Current technologies for protein fractionation and concentration are still laborious and require several processing steps, the use of chemicals, large amounts of eluents or buffers or need huge cleaning efforts due to membrane fouling and have high membrane replacement costs (e.g. ultrafiltration). In addition, acids, alkalis and high temperatures are often needed to achieve separation, causing protein denaturation and diminishing product quality. In general, these technologies are difficult to up-scale and are associated with additional environmental problems due to disposal of chemicals and the large amounts of waste water generated. Therefore, an economic and sustainable solution for the valorization of whey is urgently needed.
The Whey2Food project resulted in a novel large scale EMF technology to process whey. For this purpose, an EMF cell reactor including suitable electrodes and membranes were specified, developed, fabricated, and tested with model and real whey solutions. The effect of process parameters like cell voltage, transmembrane pressure and cross flow velocity was analyzed in order to optimize the process performance. The Whey2Food project also provided detailed information on different market applications which can be targeted using the developed technology.
The system developed in the Whey2Food project is able to meet these requirements: Compared to state-of-the-art ultrafiltration technology, the EMF is expected to reach higher separation yields with low energy consumption and reduced electrode and membrane fouling, resulting in less cleaning efforts and therefore reduced operation costs.
The results of the project will therefore have a significant technical, economic and ecological impact. The technology developed in this project will provide a cost-effective method to separate protein fractions from whey, which will in the end increase the competitiveness of European SME cheese makers.
List of Websites:
www.whey2food.eu
Whey proteins have gained major attention for applications in infant formula, sports and clinical nutrition due to their health and nutritional benefits, large availability as a by-product from cheese-making and low raw material cost. Moreover, whey proteins fractions have extraordinary techno-functional properties, including foaming, emulsifying, gelling and water-binding potential.
Currently, only 25% of liquid whey is transformed into food and human nutrition products in Europe. Sixty percent of the whey produced is disposed in municipal sewage systems, creating serious environmental problems. Current technologies for protein fractionation and concentration are still laborious and require several processing steps, the use of chemicals, large amounts of eluents or buffers or need huge cleaning efforts due to membrane fouling and have high membrane replacement costs (e.g. ultrafiltration). In addition, acids, alkalis and high temperatures are often needed to achieve separation, causing protein denaturation and diminishing product quality. In general, these technologies are difficult to up-scale and are associated with additional environmental problems due to disposal of chemicals and the large amounts of waste water generated. Therefore, an economic and sustainable solution for the valorization of whey is urgently needed.
The Whey2Food project aims to develop a highly efficient, selective, gentle and economically attractive Electro Membrane Filtration (EMF) technology to enhance separation and concentration of proteins and peptides from whey. This technique combines an electric field with mechanical membrane filtration. The driving gradient for the material transport across the membrane can be generated both by the transmembrane pressure and the electric field applied. This enables the separation both on the basis of the electric charge and the particle size. Fraction purity and economic yields are increased due to the ability of EMF to increase the filtration flow rate and minimize membrane fouling, cleaning efforts and membrane replacement costs.
During this project, enriched whey protein fractions are obtained by selecting appropriate electrode material and cell configuration parameters, including placement of filtration membranes and electrode shielding membranes, electric field strength, pH, fluid temperature, fluid pressure gradient and membrane cut off (pore size). The aim is to obtain a full understanding of the EMF process and its interferences with whey and the contained compounds to create a knowledge base that supports the development of an optimal system configuration at laboratory level and enables the scale up of the process and into a demonstration prototype suitable for use at an industrial relevant environment.
The project focused on the enrichment of a whey protein suspension containing Casein Macro Peptide (CMP), the hydrophilic fraction of κ-Casein that remains in the whey.
Separation of CMP from α-Lactalbumin (α-La) and β-Lactoglobulin (β-Lg) requires a fine adjustment and monitoring of parameters due to the narrow range at which the isoelectric points of them are found. However, as the molecular weight of both α-La and β-Lg at least double that of CMP, the electric field applied is able to retain them at the retentate side while CMP is transmitted to the permeate under the influence of the transmembrane pressure. Commercial benchmark formulas report a CMP concentration ranging from 75 to 85% of total protein. Accordingly, our laboratory trials successfully enriched CMP to a concentration of 81% of total proteins transmitted to the permeate, increasing over 10-fold the CMP/ β-Lg ratio in a single step.
After process optimization at laboratory level, a pilot unit was developed. The core of this unit is an optimized EMF cell, which takes into account an optimum distribution of electric field, minimizes pH-shifts and ensures the adjustment of the crossflow and transmembrane pressure to the required range. The unit operates in semi-batch mode (feed and bleed) with feed flow of 1000 L/h at optimum transmembrane pressure conditions. Validation of the process up-scale will continue.
Project Context and Objectives:
The goal of the Whey2Food project is to develop and establish a highly efficient, selective, gentle and economically attractive electro-membrane filtration (EMF) technology to enhance separation and concentration of proteins and protein peptides from whey. The EMF technology combines the ultrafiltration technique with the migration of charged species in an electric field enables the separation of molecules with similar molecular weight but different electric charge. Compared to state-of-the-art ultrafiltration, EMF significantly increases filtration yields and reduces membrane fouling, therefore reducing cleaning efforts and membrane replacement costs.
Whey is a by-product of the manufacture of cheese or casein and is considered a promising raw material for various commercial applications due to its high-value components like proteins. The separated protein fractions are of high interest in food (infants or sports), medical, and personal care applications. However, most of the produced whey is currently disposed and not used for further processing.
The efficient recovery of functional protein fractions through EMF technology will provide an important source of high-value natural food emulsifiers and protein supplements for various food formulations and nutritional applications, while providing an economic alternative to whey disposal and reducing the environmental impact of European SME dairies. The key innovations of the Whey2Food project are:
• A novel large scale EMF technology to process whey
• A process that can be tailored to adjust and control the output protein fractions. This can be reached due to the fact that EMF separates not only by the molecular weight, but also by the electric charge of the proteins under interest.
• An electro-membrane filtration unit with automated function and minimal maintenance requirements. Membrane cleaning can be performed not only by applying a backpressure, but also by reversing the cell voltage.
• A method to produce proteins of specific functionality or to enrich specific proteins
• A cost effective, flexible in production and easy to operate system for small-scale cheesemakers • A process with a wide range of potential applications in biotechnological downstream processes Scientific objectives of the Whey2Food project will be:
• Understanding of the electric field distribution in the Whey2Food reactor and its effect on the transport of the proteins across the filtration membrane
• Understanding the effect of key operation parameters on the separation yield and efficiency
• Characterization of the functional properties of protein and peptide fractions in model and food application
The Whey2Food project therefore combines scientific research with industry-relevant applications.
The work performed in the project will cover the physical modelling of the EMF process and cell, the development and fabrication of a novel cell with improved performance, the integration of this cell into an industrial relevant process concept for the separation of proteins from whey, the analysis of the proteins, the demonstration of the running system in real-time applications and the analysis of promising markets and applications of our technology.
Based on these project targets and work, the consortium of the Whey2Food project has been formed:
The consortium consists of experts on electro-physical separation processes, dairy technology and analysis, design and fabrication of reactor cells and its components, automation, and application in the whey and milk product industry. The partners therefore form a complete supply chain from the system development to demonstration and application.
Project Results:
During this project, a technical-economic analysis of different protein fractions in the whey and their market potential was conducted. Specific target proteins were identified and a corresponding separation concept based on the EMF technique was developed.
Enriched whey protein fractions were obtained by selecting appropriate electrode material and cell configuration parameters, including placement of filtration membranes and electrode shielding membranes, electric field strength, pH, fluid temperature, fluid pressure gradient and membrane cut off (pore size). The aim was to obtain a full understanding of the EMF process and its interferences with whey and the contained compounds to create a knowledge base that supports the development of an optimal system configuration at laboratory level and enables the scale up of the process and into a demonstration prototype suitable for use at an industrial relevant environment.
Life Cycle Assessment
A life cycle assessment (LCA) study was conducted to verify the economic-ecological significance of the Whey2Food concept as an efficient alternative for the recovery of protein fractions from whey. Experimental data and modeling of the product system collected during the first phase of the project were fed to quantify the impact of the baseline technology and to compare it with the SoA UF technology (Ultrafiltration). This LCA study is a “cradle-to-grave” assessment that consists of the following four stages:
1. Raw materials: production of components and transportation
2. Manufacture and spare parts: manufacturing the treatment technology (i.e. Whey2Food technology and conventional ultrafiltration) and providing spare parts, e.g. membranes
3. Use: recovery of the targeted mixture of proteins
Included processes: production of consumed electricity and production of reagents consumed by the processes, namely electrode rinse solution (buffer solution), cleansing agent and water. This sub-system comprises extraction of resources and transport to the treatment place.
4. End of life: disassembly and final disposal
The technology comparison relied on the following sources:
- Results obtained in laboratory and bench scale tests carried out during the Whey2Food project (e.g. energy and mass balance assessment of the processes, emissions to air, discharges to water and soil)
- Databases from the GaBi6 Software for generic information
- Information obtained from technical publications and professional journals
- Technical information obtained from suppliers
The analysis was conducted according to the standards DIN EN ISO 14040 and DIN EN ISO 14044 and was made on a common basis, defined by the functional unit.
To ensure comparability of the LCA results and obtain reliable data information, the experimental setup was designed in a way that allows modifications to enable the operation of the regarded SoA process in the same setup as the newly developed Whey2Food process.
To assess the foreground system, which corresponds to the operation of the technology, the following information related to the functional unit (FU) was gathered for both scenarios:
- Type and amount of required consumables: electrodes, membranes, electrode rinses (sodium sulphate) and cleansing agent (sodium hydroxide)
- Electricity consumption
All the presented data on consumption are gathered for an Experimental setup of 1 l/h of permeate, treating 30l of fresh whey in one experiment. It was then upscaled to a unit with a larger membrane stack, producing 100 l/h and the respective amounts were calculated for the functional unit. The production and transportation of the consumables was also included.
To enable the Life Cycle Assessment, four impact categories were found to present sufficiently distinctive results to compare and evaluate the Whey2Food technology and the state of the art process respectively:
- Climate: Global Warming Potential (GWP) by green-house gases, in kg CO2-Equivalents (CO2 = carbon dioxide)
- Elementary Resources: Abiotic depletion elementary resources (ADP elements), in kg Sb-Equivalents (Sb = antimony)
- Fossil Resources: Abiotic depletion of fossil resources (ADP fossil), in MJ (average mix of typical fossil energy carriers)
- Water toxicity: Marine Aquatic Ecotoxicity Potential (MAETP) in kg DCB-Equivalents (DCB = dichlorobenzene2)
The analysis of the newly developed Whey2Food process, when regarding the complete Life Cycle of the system, resulted in the emission of 35.9 kg of CO2-Equivalents, the depletion of 1.35*10-5 kg of Sb-Equivalents, the use of 415 MJ of fossil resources and production of 4500 kg of Dichlorobenzene (DCB)-Equivalents per 1 m³ of protein concentrate. For all regarded processes, the comparison shows that the electricity consumption has the most relevant impact in the LCA in all four impact categories. The materials needed for construction and the end of life have a relatively small influence that further decreases with increasing production rate during the lifetime of a system. This can be seen from the fact that in the SoA, which consumes more material and has a lower production, the influence of manufacturing and end of life processes is stronger than for the Whey2Food system. The impact of these processes can be seen especially in the categories describing depletion of elementary resources and water toxicity. Transportation processes, the use of consumables and water have only very small influence. An impact can be seen partly in the category for depletion of elementary resources.
The functional unit to enable this assessment was defined as one m³ of protein concentrate, a mixture of proteins containing at least 60% of CMP (caseinomacropeptide) per gr of Total Whey protein recovered in the concentrate of the first process stage.
This analysis and the comparison of results show that the Whey2Food process at this stage is at a similar level with the state of the art process already. However, the Whey2Food technology has a clear potential to surpass the standard ultrafiltration. Beyond the ecological aspects the electro membrane filtration has already clear benefits over the state of the art, especially when it comes to the required effort in maintenance and the connected production downtimes, which have to be avoided by any means in an environment of industrial production.
Process parameter studies and development of cell
A 4-compartment cell was developed and a process parameter study of the cell was conducted. The work included the selection of suitable electrode rinse solutions (e.g. sodium sulphate) and the optimization of the process parameters, e.g. flow rates and cell voltages.
A wide range of electro membrane contactor tests were conducted, with different membranes and at different voltages and pH’s. The initial aim was to split lactoferrin from the other proteins present in whey, based on its high iso-electrical point (IEP). However, it was concluded that the selective isolation of lactoferrin from fresh whey is not straightforward by means of an electrical field. It is assumed that the interaction between the positively charged LF and the negatively charge whey proteins (e.g. α-Lactoalbumin and β-Lactoglobulin) causes this effect. More research efforts are needed to overcome this issue.
The project focused switched further focus on the enrichment of a whey protein fraction containing Casein Macro Peptide (CMP). CMP is the hydrophilic fraction of κ-Casein that remains in the whey after the Lab-induced formation of curd during the cheese-making process. Its concentration in whey is around 1.5 g/l. This peptide has proven immunomodulatory, health promoting properties and is currently being commercialized for clinical foods and infant nutrition formulas. CMP has also extraordinary foaming and emulsifying properties that widens its area of application in foods. Commercial benchmarks report a CMP concentration of 75 to 85% of total protein. Accordingly, research activities focused on a strategy to obtain a similar concentration of CMP in the enriched fraction.
The main challenge is to separate CMP from α-Lactalbumin (α-La) and β-Lactoglobulin (β-Lg), whose isoelectric points are found within a very narrow range. Therefore, a fine adjustment and monitoring of pH, transmembrane pressure, crossflow and the conductivity is necessary. Because the molecular weight of α-La and β-Lg at least double that of CMP, the electric field applied was able to retain them at the retentate side while CMP was rather transmitted to the permeate under the influence of the transmembrane pressure applied. During laboratory trials CMP was successfully enriched in the permeate to a concentration of up to 81% with respect to the sum of all protein fractions transmitted. With this process the CMP/ β-Lg ratio from the feed solution was shifted to ca. 6.2 in the enriched permeate, increasing over 10-fold.
During the project, only electrodes of Titanium -platinum material were used because they are FDA approved. According to previous experiences, oxidation of the electrodes do not occur at operational conditions (15 to 40°C). Studies conducted by Tzedakis et al (1999) to estimate the electrochemical reaction rate during ohmic sterilization using Titanum-Platinum electrodes to heat foods up to130°C at a frequency of 50Hz examined the redox behaviour of several commercial foods in contact with various electrodes. The latter confirmed that no significant electrocatalytic properties towards foods occurred. Based on this scientific evidence, it was recommended to keep using this material.
Whey2Food System Up-Scaling
After first trials, cell design parameters were updated and limitations were corrected to enable up-scaling and design of pilot cell.
After process optimization at laboratory level, a pilot unit was developed. The core of this unit is an optimized EMF cell, which takes into account an optimum distribution of electric field, minimizes pH-shifts and ensures the adjustment of the crossflow and transmembrane pressure to the required range. The unit operates in semi-batch mode (feed and bleed) with feed flow of 1000 L/h at optimum transmembrane pressure conditions.
To this end, scientific data was evaluated to transfer application of parameters control requirements. Knowledge on which parameters to measure was established. A P&ID was defined and the corresponding sensors were specified and selected. Furthermore, control system and corresponding algorithms were defined. Control panel with data logging and software requirements were planned and implemented.
Furthermore, process harzards and critical control points (HACCP) were assess and reported and a risk assessment was conducted. This enabled the correct configuration of the process control. The risk evaluation was done using SaveExpert ® software commercial software and outlined. Mechanical design & scenario evaluation of complete system, including peripherals (tanks, pumps, in-line measurements, transmitters, piping, etc.) was then finalized. Parts were purchased and assembled.
Performance tests, including membrane & electrode performance to understand the key reliability/maintenance issues were conducted at Fraunhofer and the function of in-situ membrane cleaning in the scaled-up cells was verified. Specific guidelines for hygienic design, HACCP and Good Manufacturing Practices were implemented.
Pilot studies
Milk protein fractionation study were conducted using the pilot scale cell at UHOH dairy plant to confirm lab results with model and whey solutions. Techno-functional and emulsifying properties of fractions from real and model samples were confirmed and the suitability of milk protein fractions for formulations in foods was defined. Trials were conducted in parallel at Fraunhofer and included assessment of evolution of trans-membrane pressure during production cycles and the monitoring of electric field and power consumption.
Membrane used for trials was based on optimum laboratory results. When comparing the protein fraction values in the feed and permeate sample it could be shown for both trials that CMP was transmitted through the UF-membrane. Results on protein fractions revealed a better transmission of CMP by running the closed cycle (68.7%) than the open cycle (48.7%). These results are in accordance with laboratory trials. However adjustments in the system are still required to ensure higher CMP transmition rates. Benchmark levels of 75-85% CMP of total protein content have been reported in commercial formulas. With the developed system, CMP concentrations of up to 81% were reached at laboratory level.
Few weeks of continuous operation (production and cleaning cycles) of the pilot unit to evaluate all relevant parameters (flow rate, voltage, TMP) including the analysis of protein fractions were conducted. Membranes and electrodes were visually examined after trials.
Conclusions
At pilot level same as at laboratory level, a maximum flux of 10 L/h.m2 can be defined. Above this value the TMP increase considerably due to fouling. To evaluate the performance of the electrical field and the distribution in the new pilot cell, a voltage/current curve was performed. At laboratory level voltages of 10V or either 15V were required to have enough current distribution, but with the new cell design (bigger surface area and reduced distance between electrodes) lower voltages (ca. 8V ) are enough to have a current density between 15 – 20 mA/cm2. On the whole, following conclusions can be outlined:
1. A close understanding of the EMF process itself was achieved
2. 4-compartment EMF cell was successfully demonstrated
3. Successful selective concentration of CMP in whey based on size exclusion and electrical field application: Selectivity ratio CMP/β-Lg: 5 to 7.
4. Positive effect of voltage on TMP
5. Positive effect of voltage on fouling: longer runs with less cleaning are possible
6. The relative CMP content achieved is comparable to that of commercial products (74 – 85%)
7. a-La and b-Lg can be efficiently retained due to electrical field
8. For pH stabilization, buffer effects need to be taken into account
9. A flux of 10 l/m².h will be maximal to stay under the critical value of gel layer formation. Further experiments and improvements at pilot scale are necessary
10. Based on lab results, a higher transmission of CMP is achieved with cross flows of around 0.5 m/s. Lower cross-flows have a negative impact in membrane fouling and higher cross flows have a negative impact in CMP separation due to turbulence.
11. Efforts to improve the capacity of the current EMF-cell and to reduce investment and operational costs should be done, in order to obtain a profitable technology in comparison with current technologies for protein fractionation. Specifically efforts has to be focused on reduce electric consumption and process of the electrodes.
12. Efforts to improve the cleaning protocol in order to reduce the cleaning time and water and chemicals consumption. For the cleaning the possibility to connect a CIP unit has to be considered and tested.
Outlook
Technical guidelines for industrial design and operation have been outlined, including an outline of risk assessment and HACCP. A first economic evaluation based on phase I trials was conducted.
Recommendation protocols reflect combined results from trials at UHOH and Fraunhofer IGB, and are robust enough to draw conclusions. However, further field trials will be performed as part of post-project activities. Assessment and recommendation will be verified and /or updated at a later stage.
In terms of exploitation of results, and exploitation agreement has been prepared and circulated to the partners for their acceptance. The Document has been dully signed and distributed to all partners. Selection of topics to be published (peer reviewed) has been agreed. Finally, financial opportunities and business models to enter the market have been proposed.
Relevant results have been transferred from RTD to the SME partners by various communication channels
An overview of the internal dissemination activities of the project results carried out within the whole period of the project is given in Deliverable 7.6. Three Workshops were undertaken during project time as a knowledge transfer exercise to ensure that all relevant knowledge generated by the RTD performers is transferred to the SME participants and their staff. As part of post-project activities, partners will continue exchanging information on system performance, aiming at future progress into the market.
Potential Impact:
Consumers are increasing their awareness towards health and wellness, thus driving market growth of food protein ingredients worldwide. Accordingly, whey proteins have gained major attention for applications in infant formula, sports and clinical nutrition due to their health and nutritional benefits, large availability as a by-product from cheese-making and low raw material cost. Moreover, whey proteins fractions have the potential to replace chemical additives in formulations due to their extraordinary techno-functional properties, including foaming, emulsifying, gelling and water-binding potential.
Whey is a by-product of the manufacture of cheese or casein and is considered a promising raw material for various commercial applications due to its high-value components (e.g. proteins) and its large availability. Around 81 million tons of liquid whey was produced by the approximately 150,000 European cheese makers in EU-27 in 2011. However, according to the European Whey Products Association (EWPA), only 40% of the liquid whey in Europe is being processed for its utilization in food and human nutrition or in feed applications, while the rest is still being dumped into municipal sewages, mainly by SME dairies. This is neither ecologically nor economically reasonable.
Current technologies for protein fractionation and concentration are still laborious and require several processing steps, the use of chemicals, large amounts of eluents or buffers or need huge cleaning efforts due to membrane fouling and have high membrane replacement costs (e.g. ultrafiltration). In addition, acids, alkalis and high temperatures are often needed to achieve separation, causing protein denaturation and diminishing product quality. In general, these technologies are difficult to up-scale and are associated with additional environmental problems due to disposal of chemicals and the large amounts of waste water generated. Therefore, an economic and sustainable solution for the valorization of whey is urgently needed.
The Whey2Food project resulted in a novel large scale EMF technology to process whey. For this purpose, an EMF cell reactor including suitable electrodes and membranes were specified, developed, fabricated, and tested with model and real whey solutions. The effect of process parameters like cell voltage, transmembrane pressure and cross flow velocity was analyzed in order to optimize the process performance. The Whey2Food project also provided detailed information on different market applications which can be targeted using the developed technology.
The system developed in the Whey2Food project is able to meet these requirements: Compared to state-of-the-art ultrafiltration technology, the EMF is expected to reach higher separation yields with low energy consumption and reduced electrode and membrane fouling, resulting in less cleaning efforts and therefore reduced operation costs.
The results of the project will therefore have a significant technical, economic and ecological impact. The technology developed in this project will provide a cost-effective method to separate protein fractions from whey, which will in the end increase the competitiveness of European SME cheese makers.
List of Websites:
www.whey2food.eu
