Production of alginate‐based emulsion microgel particles to encapsulate soybean oil emulsions stabilized by whey protein aggregates using an air‐atomization system

Encapsulation is a popular approach used to incorporate lipophilic bioactive molecules in food matrices. In the present work, soybean oil emulsions with different oil volume fractions ( ϕ = 0.17 and ϕ = 0.26) stabilized by whey protein aggregates (WPAg), were mixed with sodium alginate (SA) suspensions and atomized over a calcium gelling bath using an airbrush atomization system to obtain emulsion microgel particles (EMP). Rheological measurements of the mixtures of microgel‐stabilized emulsions and SA suspensions showed a significant increase in viscosity when the oil volume fraction was increased. The analysis of the flow curves showed that viscosity decreased with the increase of shear rate for both systems indicating shear thinning behavior. No difference in the size distribution curves of EMP obtained with different oil fractions was observed. The average and span values were 509 ± 56 μm, 1.14 ± 0.08 ( ϕ = 0.17), and 527 ± 51 μm, 1.19 ± 0.06 ( ϕ = 0.26). The encapsulation efficiency in both cases was acceptable (89 ± 5% for ϕ = 0.17 and 74 ± 8% for ϕ = 0.26), and none of the microparticles showed oil release after 2 months of storage. Results showed that the airbrush atomization system to obtain alginate‐based EMP is simple, low‐cost, and does not require heating, making it appropriate for the effective encapsulation of labile lipophilic compounds in the food industry.