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Low temperature spray drying and its biggest benefits

low temperature

The benefits of using a low temperature spray dryer over more traditional heat drying technology brings with it a host of benefits, not least of which is extended shelf life.

Only a decade ago the technology which now creates the foundation for Spraying Systems’ Fluid Air spray drying machinery was still in its infancy, but in that short time the results have proven positive for all that have taken it on board.

Head of global research at Fluid Air, Dr Bogan Zisu, spoke to Food & Beverage Industry News about how its spray drying technology is all about creating greater quality, over quantity.

“It’s essentially a spray drying technology, but it doesn’t compete with a traditional spray dryer because a traditional spray dryer works at very high temperatures,” he said.

“These high temperatures mean that the traditional dryers can produce a lot of throughputs with high quantities of powder, we aren’t working on high quantity, instead we are working on quality. That high temperature is detrimental to functionality.”

When Zisu mentions functionality, he is referring to biological functionality.

“Things that are killed off or denatured by heat, proteins and living cells for example, will die off in a traditional spraying heat dryer,” he said.

“We work at much lower temperatures, half the drying temperatures in terms of degrees Celsius.

“Those lower temperatures pretty much allow us to dry a quality product without killing off living cells or destroying biological activity in high value products, like lactoferrin in dairy, for example.”

In relation to the dairy example, being able to retain a particular biological element of Lactoferrin, is a major benefit for high quality and high value dairy products.

“Lactoferrin is highly sought after for its health promoting properties and is used widely in infant formulations, for example, which is a significant contributor for Australian dairy and exports,” said Zisu.

“With the industry moving as a whole towards a more health-conscious aspect, that’s where it’s important to maintain that biological element of the proteins, rather than just adding a protein to a product. This is where it is critical to preserve its health promoting functions.

“Lactoferrin is an ingredient that is blended into infant formulation and it’s critical to have that as a functional protein.”

low temperature

Baby formula produced in Australia is, for the most part, exported to foreign shores which means the longer its shelf life, the better.

“The technology can be used for drying infant formulation in the final product and again because of lower temperatures it has those benefits in the formula itself, preserving biological activities and other benefits which are associated with low temperature,” said Zisu.

“The high heat also generates further reactions in storage, usually browning, which ultimately creates a shorter shelf life.

“Because we are working with a much lower temperature, these browning reactions that limit shelf life are reduced significantly. Again, this is about quality products and extended shelf life.”

Because products which are exported experience a variety of external factors, such as extreme temperatures, the longer the product can withstand these conditions the better it is in the long run for the producer.

“Product is put on a container ship and sits in storage for a long time and during this time there are temperatures abuses which accelerate the deterioration and quality breakdown and ultimately the shelf life of the powder suffers,” said Zisu.

“But with our lower temperature treatment there are fewer of these reactions and it’s not as critical, we have a longer window of opportunity to transport and store that product before it meets the end of its shelf life.”

Another factor which helps to create an extended shelf life for products is through the use of nitrogen to create an oxygen free environment during the drying process.

“We spoke about heat and the preservation effect because of lower temperatures but there is also oxidative breakdown, which accelerates product loss through oxidation reactions,” said Zisu.

“Our drying technology also works in a nitrogen environment, and nitrogen displaces oxygen, limiting the oxidative breakdown.”

At the same time, the technology uses an electrical current during the drying process to further combat the presence of oxydation.

“The electrical current drives some of the surface fat, which is responsible for oxidative breakdown, to the core of the particle and together with the oxygen free environment you have a longer shelf life when it comes to oxidative stability,” said Zisu.

An oxygen free environment means we have fewer oxidative breakdown reactions and oxidative stability is significantly improved.

“We also have all the relevant data to back up our technology in terms of all of these benefits.”

The development of the spray drying technology has been more than a decade in the making but since hitting the market it has been making inroads.

“Going back about ten years when this was a concept in the USA. At that time these low temperature electrostatic spray dryers didn’t exist, what did exist was the electrostatic spray nozzle,” said Zisu.

“The way this began was working in partnership with a US company and this company provided IP and support for product development and guide our team in developing the dryer around the electrostatic nozzle and how it should work, what it should do, and so on.

“The design and concept became reality after consultation, and it wasn’t an overnight thing. It took some years to manufacture the dryer around industry needs.”

In the years since low temperature spray drying was brought to the market, it has found success with the companies that have made the decision to test it out.

“There are companies who have bought more dryers after seeing what the technology can do for them, and their business and an Australian customer has plans for expansion with at least another one or two larger units,” said Zisu.

Spraying Systems Australia and Fluid Air also offer a flexible approach for customers looking to employ their technology for the first time.

“We have a range of dryers from the very small benchtop feasibility unit to the largest commercial dryer that we have, which has the capacity to remove 200kg of water per hour, but we can also scale up to meet demand,” said Zisu.

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