Published in the Journal of Dairy Science the study provides an approach to create stable, aerated gels by adjusting the polysaccharide (PS) type and use level.
“High-charge-density PS, at concentrations that provide adequate viscosity, are needed to achieve stability while also maintaining dispersion overrun capabilities,” the study said.
“This can be applied to dairy-based gels set by acid or calcium such as yoghurt or mousses where aeration can increase their appeal by creating novel textures and reducing calories by volume.”
The study hopes to provide a greater understanding of how heated complex additions can be used to maintain product stability while manipulating properties such as overrun and yield stress.
For example, aerated whey protein gels could provide a stabilisation mechanism in food such as soufflés, ice cream, and whipped cream, which rely on fat molecules to support the aerated network.
In trying to reduce fat content, the use of whey protein may well be a viable substitute.
“The functional properties of whey protein can be exploited to prevent system destabilisation such as drainage, coalescence, or disproportionation,” the researchers said.
“As well as reducing calorie content the use of aerated gels could also be used in the controlled release of minerals.”
Protein power
Led by Emily O'Chiu and Bongkosh Vardhanabhuti from the division of food systems and bioengineering at the University of Missouri, three PS' with different charge densities were chosen. These were low-methoxyl pectin, high-methoxyl type D pectin and guar gum.
Next, heated complexes were created by heating the mixed dispersions that consisted of 8% protein and zero to 1% of the selected PS.
To form an aerated gel, the researchers added 2% glucono-δ-lactone and skimmed milk powder to the heated complex dispersion. The mixture was them whipped to create a foam.
Once the foam set into a gel, it was analysed for overrun, drainage, gel strength and viscoelastic properties.
Findings revealed that the overrun of aerated gel decreased by up to 73% as PS concentration increased from 0.105 to 0.315%.
The team believed this was due to increased viscosity, which limited air incorporation.
The researchers also found that when percentage drainage increased the dispersion viscosity decreased.
However, comparing drainage against dispersion viscosity using the different PS types showed that samples with high-charge-density such as the low-methoxyl pectin, showed the most stability.
High-methoxyl type D pectin, the PS with a low-charge-density, closely followed with aerated gels with no charge (guar gum) showing no improvement to stability.
“Stronger interactions between whey protein and high-charge-density PS were likely responsible for increased stability,” the study found.
“Stable dairy aerated gels can be created from whey protein-PS complexes. High-charge-density PS', at concentrations that provide adequate viscosity, are needed to achieve stability while also maintaining dispersion overrun capabilities.”
Food industry applications
The food industry, particularly in the dairy sector, have long focused efforts in improving dairy-based gels set by acid or calcium such as yogurt or mousses.
Increasing aeration could, for example increase their appeal by creating novel textures and reducing calories by volume.
Whey protein has become a popular focus for the food industry as it has been shown to suppress gastrointestinal hormones to further improve satiation.
Furthermore, adding bubbles to snack foods such as chocolate or cheese puffs introduces a novelty factor and has been shown to decrease energy intake by increasing the total food volume per calorie.
Future applications in using aerated gels could also include flavour encapsulation or release (or both), delivery of bioactive molecules, control of satiety, and creation of gastronomic structures.
Source: Journal of Dairy Science
Published online ahead of print: doi.org/10.3168/jds.2016-12053
“Utilizing whey protein isolate and polysaccharide complexes to stabilize aerated dairy gels.”
Authors: Emily O'Chiu, Bongkosh Vardhanabhuti