Fluids technology helps to mix it up

Fluid engineering can also provide enhanced properties to the end products through processes which distribute very small particles and gases in liquids used to make them, claimed David Brown, process research business manager at consultancy BHR Group (BHRG), formerly the British Hydromechanics Research Association.

Brown said food firms could learn much from mixing and dispersing techniques developed in other sectors, such as pharmaceuticals, personal care, paint and polymer manufacture.

“The technologies they use to make their products are often very, very similar and sometimes companies in the food industry think their processing problems just belong to them,”​ said Brown.

BHRG, which carries out contract consultancy and consortia research for industry, is already working with around four or five blue-chip food companies in areas such as soft drink processing, ice cream and potato chip manufacture to optimise processes used to distribute fine particles in liquids that are stable and do not separate out over their shelf-life.

Work ​

This work ranges from physical modelling: constructing and testing experiments with relevant equipment, to desk-based consultancy and computational fluid dynamic modelling.

Projects have investigated whether products such as crisps were uniformly cooked to ensure end product consistency, while others have examined the consistency of bottled juice and ketchup; carbonated soft drink concentration preparation, and the dispensing of coffee. In another project, BHRG examined the uniform dispersion of fruit in a juice.

“I’m mostly working in one way or another with food mixing, which includes a lot of the nano-dispersion type work and processing of liquids in one form or another,”​ said Brown.

Consortia research projects range from one called FMP (fluid mixing processes) to another called Domino, which covers the dispersion of micro- and nano-particles in liquids, said Brown.

Very strongly dependent ​

“We’ve done work looking at dispersions of quite small volume fractions of nano-type materials and powders and their rheology,”​ Brown added. “This examined how thick the product is and how it flows. What materials feel like is very, very strongly dependent on what they are dispersed in.”​

A lot of the work for the food industry in particular has involved characterising and understanding the equipment used to disperse micro and nano-type materials, he said. Often the materials that are added start off as agglomerates of nano-particles.

“The degree to which those agglomerates are broken down is the interesting question; and how you scale that up from the lab,”​ said Brown.

“We have also looked at things like the heat transfer processes for chilled foods and frozen products, looking at the product structure and mouthfeel.”​