Micro-particles of whey protein could help manufacturers cut calories in food products by replacing starch and fat, suggest researchers.
The new study systematically examined the potential of micro-particulated whey protein (MWP) as a replacer of fat and starch granules in reduced calorie foods by assessing the impact of MWP addition on the physicochemical properties of model food emulsions.
Led by Professor David Julian McClements from the University of Massachusetts - in collaboration with ConAgra foods - the new study assessed the potential for MWP to mimic fat in reduced calorie model sauces and dressings - finding the commercially available MWP ingredient has potential applications as a fat replacer due to its ability to bring a lightness to reduced calorie food emulsions like sauces, dressings, and desserts.
"This study highlights conditions where MWP can be used as potential fat replacers in low calorie food emulsions," said the researchers, who noted that the ingredient "increases the lightness and viscosity of products, thereby mimicking some of the desirable characteristics of fat droplets."
McClements and his colleagues tested the influence of solution composition (pH and salt) and processing (homogenization and heating) on the properties of MWP at a variety of concentrations ranging from 0% to 20%.
The team found that high-pressure homogenization (6000 psi, 1 pass) of MWP suspensions significantly reduced protein particle size and improved their stability to sedimentation.
"The lightness and viscosity of the suspensions increased with MWP concentration, which was attributed to the influence of the protein particles on light scattering and fluid flow," said the authors.
Meanwhile thermal treatment (90 °C for 5 minutes) of the MWP suspensions was revealed to increase viscosity - which was associated with increased protein aggregation, said the team.
"The large aggregates formed after heating were highly unstable to sedimentation, which would limit their use in low viscosity food and beverage products," the team added - who added that unlike heat-denatured whey protein molecules, the addition of calcium chloride after heat treatment did not have a significant effect on the rheological properties of the MWP suspensions.
"Solution pH (2–8) also had an impact on the particle size and microstructure of the MWP suspensions, which was attributed to changes in particle charge: the charge went from negative to positive with decreasing pH, with an isoelectric point around pH 4.5."
Source: Food Research International
Volume 56, February 2014, Pages 136–145, doi:10.1016/j.foodres.2013.11.034
"Development of Reduced-calorie foods: Microparticulated whey proteins as fat mimetics in semi-solid food emulsions"
Authors: Cheryl Chung, Brian Degner, David Julian McClements