Effect of Porcine Plasma Protein with Limited Hydrolyzation Coupled with Tween 20 on the Physical and Oxidative Stability of Oil-in-Water Emulsions

This study investigated the potential effect of porcine plasma protein hydrolysates (PPPH) coupled with Tween 20 on the physical and oxidative stability of canola oil-in-water emulsions (10% wt. lipid, pH 7.0). The PPPH obtained via limited alcalase-hydrolysis (60 min) possessed the highest emulsifying activity index and emulsion stability index (P < 0.05). Emulsions stabilized with PPPH alone were less stable than those prepared with PPPH and Tween 20. However, a lower concentration of PPPH (2.5 mg/mL) combined with Tween 20 formed the most stable emulsions, which is mainly due to competitive adsorption present at the interface. Additionally, compared with PPPH-free emulsions, the addition of PPPH was able to retard lipid oxidation, showing up to an 8.51% decrease in the formation of conjugated dienes and a 22.08% decrease in thiobarbituric acid-reactive substances after 10 days of storage (P < 0.05). This is mainly attributed to distinct antioxidant amino acid profiles and the distribution of peptides at the interface. Therefore, our results indicate that PPPH derived from limited hydrolysis could be used as both co-emulsifiers and antioxidative compounds in food emulsions.