Stability of Oil‐in‐Water Emulsions Fortified with Enzymatic Hydrolysates from Porcine Plasma Protein

Abstract

The oxidative and physical stability of oil‐in‐water emulsions affected by the addition of porcine plasma protein hydrolysates (PPPH) is investigated. The emulsions are prepared by combining a 10 wt.% oil phase with a 90 wt.% aqueous phase containing 1.25 wt.% Tween 20 and PPPH (0, 2.5, 5, 10, and 20 mg mL−1 in the final emulsion). The results show that PPPH effectively inhibited the formation of hydroperoxides, thiobarbituric acid reactive substances, and conjugated dienes (P < 0.05), enhancing the oxidative stability of oil‐in‐water emulsions. Meanwhile, the addition of PPPH results in a remarkable increase in the ζ‐potentials and viscosities (P < 0.05) as well as a significant decrease in the particle sizes (P < 0.05), which is verified by an optical microscope. During storage, PPPH prevents oil droplets from colliding and hinders their coalescence and aggregation, leading to better emulsion stability. These results suggest that the addition of PPPH results in an improvement in the oxidative and physical stability of emulsions.Practical Applications: Food emulsions are thermodynamically unstable systems, so they often lean toward separation into an aqueous and oil phase during storage. Therefore, food manufacturers are challenged to seek desirable ingredients in order to stabilize food emulsion systems. In a previous study, the authors demonstrate that PPPH shows strong radical‐scavenging and Cu2+‐chelation ability. In this present study, it is found that the addition of PPPH reduces lipid oxidation and increases the ζ‐potential and viscosity of emulsions, enhancing the oxidative and physical stability of oil‐in‐water emulsions. Thus, PPPH has the potential for use as a natural antioxidant and stabilizer in food emulsions.PPPH is added to oil‐in‐water emulsions and the stability of the emulsions is investigated. The results show that the addition of 20 mg mL−1 PPPH results in the lowest thiobarbituric acid reactive substances (TBARS) value. The size of oil droplets in the emulsion without PPPH is larger than the emulsion with 20 mg mL−1 PPPH during storage. Therefore, the addition of PPPH improves the stability of emulsions.