Research to benefit dairy ingredient manufacturers

COLLABORATIVE efforts between researchers and scientists from South Dakota State University (SDSU) in the United States and the Monash University in Australia hope to simplify the process of changing formulations as well as of developing new dairy ingredients.

The success of this project would eventually help manufacturers of dairy ingredients and milk powders achieve the exact powder characteristics needed in their products without having to rely on trial and error or past experience in finding the right drying conditions.

Dairy researchers from the SDSU are using a bench-scale single-droplet dryer to predict dairy ingredient properties. They are contributing knowledge in manufacturing and functionality to this project, according to lead researcher, Professor Lloyd Metzer.

While at Monash University near Melbourne, Professor Cordelia Selomulya and her team will use the data on the drying behavior of different materials to develop a computational fluid dynamics model to predict the range of drying parameters needed to produce a powder with those properties in a spray dryer.

The right properties

In spray-drying, any number of conditions can affect powder properties, including the characteristics of the material being dried, the nozzle type and amount of pressure behind nozzle, the fluid pre-heat temperature and the air inlet and outlet temperature, said Professor Metzger.

He also said that the desired powder properties will also vary for different products like coffee creamer, where the powder must dissolve very quickly in hot coffee and it may be required to foam. In other applications like infant formula, the density of the powder is critical to ensure that each scoop of powder has the correct nutrient content.

The industry relies on difficult trial and error and past experience to adjust drying conditions. Professor Selomulya said that “both are complex systems in their own right, so the drying history will be different for each dryer. With the variation of feed formulation in dairy, trial and error is not an effective approach.”

A more efficient approach is to use a predictive model, one which the teams from SDSU and Monash are working on. Professor Selomulya and her team will calculate the drying rate of the material using experimental data, such as changes in mass, droplet temperature and size, along with morphological changes, such as skin formation, from the single-droplet dryer combined with a reaction engineering modeling approach. The results will then be used in a computational fluid dynamics model to predict what will happen inside an industrial spray dryer.

“It’s all about trying to simulate on a small scale with the single-particle dryer and relate that to what happens in the big dryer,” Professor Metzger said. The semicommercial-scale dryer at the Davis Dairy Plant will be used to validate the methodology and scale up the models developed.

Together the teams aim to streamline the process of changing formulations and developing new dairy ingredients—and that could translate into huge savings for the dairy industry. It will benefit makers of milk powders, and ingredients such as whole milk powder, whey and milk protein concentrates and isolates and infant formula.

The project was initiated by former assistant professor Hasmukh Patel, who has now moved on to become senior principal scientist at Land O’Lakes in Minneapolis.

The SDSU portion of the three-year project, which began in 2014, is supported by the Dairy Management Inc. grant for more than $250,000.