Characterization and oxidation stability of spray-dried emulsions with omega-3 oil and buttermilk processed by ultra-high-pressure homogenization (UHPH).

Integrating functional ingredients, such as buttermilk and omega-3 rich oils, in spray-dried emulsions (SDE) is a suitable way to incorporate these ingredients in dairy products to substitute dairy fat and increase their added value. Ultra-high-pressure homogenization (UHPH) processing of liquid emulsions considerably improves stability compared to the conventional homogenization (CH) process. With this premise, SDE were produced while comparing CH (30 MPa) and UHPH (100 or 200 MPa) processing of feeding emulsions. Emulsions were formulated with (50:50 chia:sunflower) oil, whole commercial buttermilk (BM), and maltodextrin (MD) as wall materials. Further spray drying of emulsions was then conducted. Obtained SDE were characterized in terms of water content, Aw (water activity), flowing properties, water solubility, encapsulation efficiency (EE), color, and microstructure. Oxidation stability of SDE was analyzed in accelerated oxidation conditions at 50 °C for one month for primary and secondary oxidation analysis evolution on days 1, 7, 14, and 31 of storage. Results showed better ability of BM as encapsulating agent in UHPH-processed emulsions with 7% of BM. This improvement was especially observed in the flowing properties and encapsulating efficiency. Seven percent BM UHPH-treated SDE showed the best primary oxidation stability during storage, while the 4% BM-UHPH-treated SDE exhibited better secondary oxidative stability.