By: Christian Diener *
Ongoing consumer interest in personal health and fitness has been great news for the protein market. Indeed, according to Grand View Research, the global protein ingredients market was valued at $25.62 billion in 2016 and is expected to enjoy CAGR growth of more than 7 percent until 2025.1) While the key drivers for this market buoyancy have been functional foods and dietary supplements, proteins are used in many other market sectors, from agriculture to cosmetics and personal care. Thanks to innovative processing technologies, it is now possible to obtain proteins from a variety of sources for different purposes in an efficient and sustainable way. The right expertise and equipment allows as much protein as possible to be extracted from the raw material, securing high purity output and saving resources at the same time.
Diverse demands require technical expertise Obtaining high quality proteins from raw materials – whether they are of plant or animal origin – requires innovative process solutions that are able to cope with a broad range of demands. Not only might proteins of different origins have significantly different features, but the attributes of the protein end products may have to meet very individual demands too. As an expert in the processing of liquid products, Ruland Engineering & Consulting develops tailored plant components and solutions that can optimise all types of protein extraction, processing and refining.
Purification at the initial stage
The first step in protein processing is to separate and purify distinct components from a liquid mixture consisting of fats, water and proteins. Using decanters and separators, coarse solids and fats are removed – the latter often being used in the animal feed industry.
After passing through a centrifuge, turbid elements and residual fats are separated from the protein mixture. The length of the amino acid chains and process parameters such as temperature and pH means that particular expertise is required here. All equipment has to be set up to handle the specific products and parameters of each type of protein: The quality of the outcome is highly dependent on the use of membranes with appropriate pore diameters and suitable filters. For long-chain proteins, in most cases, conventional filters are used because the proteins are too long to pass through fine-pored membranes, which would become clogged.
On the other hand, fine-pored membrane technology is ideal for short-chain and hydrolysed proteins, and it helps to remove the remaining turbid elements from the protein mixture. In fact, this method produces significantly better results in terms of turbidity (NTU-value) than standard filters. This preliminary cleaning step is one of the most important aspects of the protein extraction and refining process because it determines the quality of the final output.
After it has been cleaned, the solution is desalinated and concentrated. Depending on the protein source, membrane technology will once again be used, in many cases combined with an evaporation system.
Partial desalination is required for some products and grades, and specialist ion exchangers and membranes are used to achieve this. Ultrafiltration and nanofiltration membranes remove mono- and polyvalent salts as well as bitter compounds and other flavours and odourants. An additional diafiltration stage can wash even more salt out of the product.
Diafiltration combines the features of dialysis and ultrafiltration. During this process, a solvent is continuously added to the pre-concentrated protein solution until the old solvent has been completely replaced via the membrane. The volume of the suspension remains unchanged.
Efficient use of plant
Depending on the pretreatment methods used, the main process is carried out in either one or two steps. If the proteins are highly hydrolyzed and of a short chain length, the solution can be concentrated using membranes up to the required level and then spray dried. For long-chain proteins, the final concentration can be reached by means of an additional evaporation stage.
The combination of membranes and evaporation equipment for the processing of long-chain proteins offers the advantage of allowing the processor to choose the optimal transition point. Not only does this relieve the membranes, but it also allows a single or multi-stage evaporation plant to be downsized. This results in optimal allocation of resources at the same time as achieving the best quality output.
Filtering by molecular size
In order to obtain a protein hydrolysate with a clearly defined range of chain lengths, protein fragments need to be separated according to their molecular size. A multistage filtering process involves initial filtering of large, long-chained particles through an open membrane, followed by the separation of short-chained proteins via membranes with narrow pores. Thus, different chain lengths for various application fields can be obtained.
Investing in cleaning improves results
When it comes to plant efficiency, cleaning is of paramount importance. Ruland’s experts are dedicated to reviewing and optimizing the cleaning systems at all production sites.
Cleaning-in-Place (CIP) plants are deployed whenever pipelines and tanks need to be cleaned. Depending on the level of production output, either central CIP plants with multiple tanks and chambers or local mobile CIP plants are installed. It is also possible to extend the system with a Sanitary-in-Place (SIP) process when cleaning has to be followed by sterilization.
Alternatively or in addition to classic pigging technology, whirlwind technology can be deployed in order to minimise product loss and maximise yield. Draining a pipeline using whirlwind technology comprises two steps. The power of a turbulent air flow is used to remove product residues from the pipelines efficiently. Extended by a basic module, this technology can also take care of chemical cleaning and rinsing. It requires a minimum amount of water and cleaning agents and is especially suitable for when fast product switches with minimal product losses are required.
While the primary objective of every protein processor should be to utilize all available raw material exhaustively and produce the maximum output, it is not the only aim. Another essential requirement when extracting and refining proteins is optimal resource allocation so that fresh water and electricity usage are kept as low as possible and wastewater output is minimized.
Protein processing is extremely waterintensive. For this reason, effective water treatment or early reduction of water use are particularly important. Drinking water first needs to be softened in a complex process. After it has been used in processing, however, specialist treatment technology enables a large percentage of the water to be recycled, reducing the amount of organically polluted wastewater that reaches the sewage system. To achieve this, water streams are joined, mixed and subsequently treated with filtering and membrane equipment. Today, up to 80 percent of the water used in protein processing can be recycled in this way.
Tailored for superiority
Whatever technology is used, it has to be practical, safe and efficient. Sustainability is also important. Production plants and technologies must be high performance, durable and able to deliver consistent high quality; additionally, they need to meet the current demand for conserving resources and reducing rejects. Whether it’s a centrifuge, a decanter, membrane technology or a cleaning agent, all components need to complement each other perfectly to ensure smooth and reliable performance. Ruland Engineering & Consulting has extensive expertise in liquid processing as well as in-depth knowledge of its specific demands. To ensure best results in all cases, the Ruland team works closely with clients in order to find optimal solutions that are the best fit for every requirement.