Whey protein promises nano-encapsulation of omega-3
Israeli researchers report that the whey protein may be a nano-vehicle for DHA, and nano-complexes with pectin produced transparent dispersion with extended shelf-life for the ingredient. They report their results in an upcoming issue of Food Hydrocolloids.
“The new technology presented herein may serve to enhance the health promoting properties of beverages and foods while maintaining transparency and providing substantial protection to the encapsulant against deterioration during product shelf life,” wrote Patricia Zimet and Yoav Livney from the Israel Institute of Technology in Haifa.
Zimet and Livney also note that this is the first time that the spontaneous binding of an omega-3 fatty acid to beta-lactoglobulin has been reported.
Omega-3 fatty acids are one of the success stories in health and wellness circles. However, their use in foods is limited by their low solubility in water and their sensitivity to spoilage by oxygen. Encapsulation is one method or protecting the oils.
For the new study, the Haifa-based researchers investigated the potential of beta-lactoglobulin to spontaneously bind to DHA and to act as a carrier for the fatty acid.
In combination with low-methoxy pectin, colloidally stable nanocomplexes of DHA-and beta-lactoglobulin were produced. An excess of pectin led to the formation of particles containing 166 times more DHA than the surrounding solution, added Zimet and Livney.
Moreover, the particles were transparent and their average size was about 100 nanometres.
Further experiments studied the stability and shelf-life of the resulting nano-complexes. An accelerated stress test (100 hours at 40 degrees Celsius) showed that only between 5 to 10 per cent of the DHA was degraded when bound with the whey protein. On the other hand, about 80 per cent DHA degradation is observed for unprotected DHA, report the researchers.
“The first evidence for the binding of an omega-3 polyunsaturated fatty acid, DHA, to beta-lactoglobulin has apparently been presented in this study,” they added.
The next stage in the development of this encapsulation technology is to study the heat stability of the nano-complexes, said the researchers. This would ensure that the complexes could be used in industrial beverages that undergo pasteurisation and/or cold storage.
Questions over how the nano-complexes may affect the sensory attributes of the beverages, and the bioavailability of the DHA (or other hydrophobic ingredients) also need answered.
Food manufacturers are increasingly turning to encapsulation technologies as a way of achieving much-needed differentiation and enhancing product value. Tapping into key and emerging consumer trends with innovative techniques is becoming increasingly important for food manufacturers.
While the majority of focus has been on microencapsulation, more and more research is looking at the potential of nanoencapsulation.
Source: Food HydrocolloidsVolume 23, Issue 4, Pages 1120-1126"Beta-lactoglobulin and its nanocomplexes with pectin as vehicles for ω-3 polyunsaturated fatty acids"Authors: P. Zimet, Y.D. Livney