The research, published in Food Hydrocolloids, investigated a method for producing protein micro-particles using a two step emulsification process. The methods allow the use of various protein sources and concentrations for the particle ‘inside’, and various stabilizers for use on the particle surface.
The authors, from the department of agrotechnology and food sciences at Wageningen University in The Netherlands, said that using a prefabricated protein structure may help to create products with better sensory properties, and to overcome problems such as proteins sticking together (aggregation) when formulating novel products.
“We have shown that high protein micro-particles, as a possible structure element, could be prepared using a process based on two-step emulsification,” said the authors, led by Paul Venema assistant professor at Wageningen.
“Besides the use as a food ingredient, these particles could be useful also for other applications such as encapsulation and controlled release,” they added
Protein power
Research has indicated that food products with increased protein content have important health benefits, including strong satiating effects that may be of use for weight control.
Previous studies have also emphasized the importance of proteins in the diets of elderly; is has been suggested that protein intake larger than the recommended dietary allowance (RDA) may help against chronic loss of muscle mass – an important aging-related disease.
However, proteins do not just have nutritional value in foods, but are also important because of their contribution to structure and texture.
As a result of heat-induced protein aggregation, several problems related to food structure and texture may occur in protein enriched foods, said the authors.
“The development of stable and consumer appealing protein-rich foods is a challenging field, in which unwanted protein aggregation plays a prominent role … Current knowledge on protein aggregation in concentrated protein systems, and on ways to control and prevent it, is very limited, hampering development of successful high protein food products,” said Venema and his colleagues..
“Ideally, one would like to be able to control the protein content of foods independently from the other important attributes such as sensory properties and stability … A possible route to achieve such uncoupling of protein content from the effects of proteins on structuring is to use prefabricated “protein structure elements”. An example to such structure elements can be dense protein micro-particles,” they explained.
Study details
The authors explained that commercially available protein particles are produced by heating protein concentrate at low pH and under high-shear treatment, in a process known as microparticulation. In comparison to microparticulation the new method offers a larger flexibility in protein concentration, pH and protein source.
Protein dense micro-particles were prepared using a two-step emulsification procedure. Protein particles prepared through this method were reported to be spherical in shape and had an average diameter of “few microns.”
The researchers said that the size distribution of particles “could be controlled to some extent by changing applied shear rate in the primary emulsification step.”
“The method that we have developed to prepare internally dense protein micro-particles is versatile and robust: we expect that it should be possible to extend it in various ways,” said Venema and his colleagues.
Such extensions which may be important for future use include the use different protein types, higher concentrations of proteins, and different types of stabilizers, the explained.
“A next step will be to start studying the physical properties and functionality of these protein micro-particles in food (model) systems,” indicated the researchers.
Source: Food Hydrocolloids
Volume 25, Issue 5, Pages 1139-1148, doi: 10.1016/j.foodhyd.2010.10.011
“Preparation of high protein micro-particles using two-step emulsification”
Authors: D. Sağlam, P. Venema, R. de Vries, L.M.C. Sagis, E. van der Linden