Valorisation of Residual Streams

Valorisation of residual streams is a hot topic in the food industry, where drying processes often play an important role with regard to raw materials and energy consumption. Daan Goris, Team Manager Food & Feed at Hosokawa Micron, states that companies can recover valuable nutrients or other high-quality raw materials and make their business processes greener.

"We often get questions from companies, mainly in the food industry, about how they can add value to waste streams from their production process. They are often liquids, pastes or wet powders which are interesting from a nutritional point of view because they contain proteins or have other functional properties. Think of residual products in the processing of meat or fish, vegetable or fruit peels and side streams from bakeries, breweries and biorefining plants. Awareness is growing that products that are now being disposed of or used for low-value applications can be upgraded to high-quality products."

Drying temperature sentive products, efficiently

"Companies ask us how they can dry these side streams efficiently while maintaining nutritional value and/or functional properties. Whether that is profitable depends largely on the balance between the value of the (residual) product and the (energy) costs of the drying process. An important aspect here is that food products are often temperature sensitive. In many cases, the product quality and functionality will decrease at product temperatures above 80 °C. You need to take that into account when developing a dryer system."

Valorisation of residual streams - Whey protein powder

"If the business case is good, the valorisation of waste streams can even become a core competency. One success story involves drying a residual stream in the production of cheeses to whey powder. This product has great nutritional value and, according to experts, is at least as important as the production of the cheese itself. Another example concerns the side streams from fish and shrimp processing. Dried and ground they serve as basic raw materials for food and feed products. Like these, there are other specialist residual products that can be marketed very well because they can be engineered upstream in the production process according to particular product specifications. This principle of raw material recovery and use in new processes is a trend you see reflected in the entire food industry."

Improve feasibility and profitability

"Whether reclaiming raw materials is possible and profitable, we can estimate in many cases based on our experience. Our database is an excellent source of information for this. Many natural waste streams typically contain 15 to 40% solids. A large part of the water present will therefore have to be evaporated. Of course, energy costs are decisive in the feasibility study of drying processes."

"When developing drying processes, we recommend to dewater mechanically first. We therefore work together with suppliers of presses, separators and centrifuges on a project basis. Mechanical dewatering is not only interesting from an energy saving perspective, but also because you can extract oil and fat from the waste stream. These are not only valuable, but can also disrupt the drying processes. Oil and fat are easy to separate beforehand, leaving you with a good composition of the feed material for your drying process. Selecting the right drying technique can save a lot of energy."

"A good example is using a Micron flash dryer instead of a spray dryer, especially if the raw material can be dewatered mechanically. When using a spray dryer, the product must be liquid to be sprayed, so a lot of water has to be evaporated. With Hosokawa's flash dryer the product is fed as dry as possible, so less thermal energy is required for the drying process. An additional advantage of this type of dryer is that it combines drying, grinding and classifying in one single device. Also, the thermal impact to the product is limited because of a controlled, short residence time."

Drymeister (DMR) flash dryer

Reduce your environmental footprint

"It is always possible to economize further, but drying processes will not be reinvented. You can not change the laws of nature. You can, however, ensure less energy loss when developing a dryer system. We currently observe a lot of interest in heat recovery systems, so hot air of 70-80°C no longer disappears through the chimney. It is smart to use the energy that is released during the drying process to heat parts of your process that must remain above a critical temperature for hygienic reasons. This allows you, for example, to preheat a food product that must remain at 80°C on the way to the dryer."

"Although the investment in heat recovery is still a challenge with current energy prices, keep in mind that energy bills will only get higher in the future. And payback periods are often not the only consideration. Achieving environmental goals is becoming increasingly important. A good example is Unilever, who aim to halve their environmental footprint by 2030 within a growth scenario."


Hosokawa Micron B.V. is a 'go-to' source of expertise for drying of residual streams in the food processing industry, working at every level of development with customers to achieve the best, commercial outcome. Let us help you improve the profitability of your process!

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