Correlating emulsion properties to microencapsulation efficacy and nutrients retention in mixed proteins system

Abstract

This study investigated six different combinations of proteins as emulsifiers and wall materials in a pilot scale. The potential correlations among formulations, emulsion properties, and microencapsulation stabilities were studied using principal component analysis (PCA). Dairy proteins (milk protein concentrate or sodium caseinate) dominate the overall properties when they are mixed with vegetable proteins (soy protein isolate and pea protein isolate). The presence of sodium caseinate (NaCas) in the formula is positively correlated with higher Vitamin A retention (P < 0.001), which could be associated with its excellent emulsifying properties and molecular flexibility. An improvement in Vitamin A retention of up to 13.93% was found with NaCas samples as compared to milk protein concentrate (MPC) samples. Pea protein isolate (PPI) samples showed significantly higher thermal stability by preventing droplet coalescence. Droplet sizes of all samples increased significantly after thermal treatment. However, only 54% size evolution was found with PPI samples, while the percentages of size increase using other protein blends were ranging from 95 to 150%. The formulas containing PPI show good oxidative stability after 180 days of accelerated temperature storage, which could attribute to its anti-oxidative properties that helped retain the stability of core materials. NaCas showed promising synergistic effects with PPI. The protein combinations of NaCas + PPI has a smaller droplet size and better emulsion thermal stability of liquid emulsion which resulted in the best microencapsulation efficiency (ME%) at 96.08% and highest nutrient retention of powder microcapsule. Overall, this combination is featured as a better wall material.