Nanoencapsulation of omega-3 fatty acids using caseinate-pectin based complexes: FTIR, DSC, particle size, and encapsulation efficiency

A protein-polysaccharide complex can be used to produce nanocapsules containing nutrients and active compounds. This study determined optimum conditions for producing caseinate-pectin based nanocomplexes containing omega-3 fatty acids with minimal particle size and size distribution and evaluated the stability and encapsulation efficiency of this system. Caseinate-pectin nanocapsules were formed by the addition of electrolyte salts into the caseinate solution (0. 5%، 1%، 1. 5%) containing omega-3 and pectin solution (0. 2%، 0. 45%، 0. 7%) into the system. The pH was then adjusted to below the isoelecteric point of the protein. Determination of the size and size distribution was done using the laser light scattering method. Infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) were used to detect complex formations and the types of interaction between the biopolymers and omega-3 and the thermal behavior of the complexes. Gas chromatography (GC) was used to determine the encapsulation of omega-3. A three-level four-factorial Box-Behnken experimental design was employed using Minitab 15 software to analyze particle size. The complex containing 1% sodium caseinate and 0. 45% pectin at pH = 4. 1 had a the smallest particle size (86 nm) and turbidity; with omega-3 capsulation، the particle size increased to 118 nm. FTIR results showed complex formation and interaction (electrostatic and hydrophobic) between the biopolymers and omega-3 and DSC results showed formation of new structures. Gas chromatography results showed an encapsulation efficiency of 12%-76% for the different formulations. The results showed that pH، pectin، and caseinate biopolymer concentrations played important roles on the particle size of the complex، stability، and encapsulation efficiency. This system can be used to encapsulate omega-3 in beverages having relatively acidic pH values.