Supercritical CO2 to offer novel whey ingredients for food?

Using supercritical carbon dioxide (scCO2) processing, researchers from the University of Tennessee report in the Journal of Dairy Science that a range of novel whey protein ingredients with increased gel strength.

"The results suggest that functionalities of whey proteins can be improved by scCO2 treatment to produce novel ingredients," wrote Qixin Zhong and Mei Jin.

Whey proteins from cow's milk are used as emulsifiers in a broad range of food products including ice creams, beverages, salad dressing and sports supplements, and are classified as either concentrates (protein content between 25 and 80 per cent) or isolates (more than 90 per cent protein).

The global whey protein concentrates and isolates market is estimated at 395,000 MT in 2004 representing a value of just over $1bn.

The US remains the biggest producer at 187,000 MT followed by Europe with 159,000.

The new study adds to other attempts to impact the functionality of whey proteins, previously achieved by forming complexes with carbohydrates, using enzymes to cross-link proteins, or using hydrolysis.

Zhong and Jin treated commercial whey protein isolates (WPI) and whey protein concentrates (WPC) with supercritical CO2.

They treated WPI and WPC powders with at 65 degrees Celsius and 10 or 30 MegaPascal (MPa) for one hour, and a WPI solution (10 per cent) at 40 degrees Celsius and 10 MPa for one hour.

"Compared with the unprocessed samples and samples processed with nitrogen under similar conditions, supercritical CO2-treated WPI, whether dispersed in water or in the powder form during treatments, formed a gel with increased strength," wrote the authors.

They added that the gelling improvements were most pronounced for the supercritical CO2-treated WPC.

According to an interpretive summary by the journal, the supercritical CO2 treatment led to "improved visual appearance of powders and enhanced gelling properties."

This purely physical approach may lead to a range of whey proteins with enhanced functionalities that could offer specialty ingredients to food formulators.

Recently, this website reported on research from scientists at the Southeast Dairy Foods Research Center at North Carolina State University that reported a modified whey protein concentrate (mWPC) combined with calcium could enhance the control of food formulations, especially under cold processing conditions.

The study, published in the Journal of Agricultural and Food Chemistry (Vol. 55, pp. 10932-10940), reported that the addition of calcium increased the thickening capacity of the protein solution, and led to increased water-holding capacity of the gel.

A recent survey by Danish 3A Business Consulting on whey and lactose ingredients, suggested that food makers are increasingly viewing whey and lactose products as an ideal means of achieving added value.

As such the global whey protein concentrates and isolates market is estimated at 395,000 MT in 2004 representing a value of just over $1bn.

Source: Journal of Dairy Science February 2008, Volume 91, Pages 490-499 "Enhanced Functionalities of Whey Proteins Treated with Supercritical Carbon Dioxide" Authors: Q. Zhong and M. Jin