Effect of Combining Surfactants with Potato Protein Hydrolysates on Their Emulsifying and Antioxidant Properties in Fish-Oil-in-Water Emulsions

This study investigated the emulsifying and antioxidant properties of potato protein hydrolysates (PPHs) obtained through enzymatic hydrolysis with trypsin, aiming to utilize them as natural emulsifiers in 5 wt% fish-oil-in-water emulsions. Unfractionated and fractionated PPH fractions (>10 kDa, 5-10 kDa, 0.8-5 kDa, and <0.8 kDa) in combination with surfactants (Tween 20 or DATEM) were evaluated. Unfractionated PPH alone resulted in unstable emulsions; however, combining it with 67 wt% DATEM or Tween 20 improved physical stability. Smaller PPH fractions (<10 kDa) produced smaller droplet sizes (0.352-0.764 μm) with DATEM, whereas for Tween 20-stabilized emulsions, the smallest droplet size was observed with unfractionated PPH (1.051 ± 0.015 µm). Notably, the 5-10 kDa fraction exhibited the best oxidative stability when combined with Tween 20, likely due to its antioxidant properties. While further refinement is necessary to improve PPHs' effectiveness as standalone emulsifiers, their potential is evident.