Changes in Emulsifying and Physical Properties of Shrimp Oil/Soybean Oil‐in‐Water Emulsion Stabilized by Fish Myofibrillar Protein during the Storage

Abstract

AbstractProperties of shrimp oil/soybean oil (30:70)‐in‐water emulsion stabilized using fish myofibrillar protein (FMP) at different concentrations (15, 30, and 45 mg mL−1) are investigated. When FMP concentration increases, emulsion activity index decreases (p < 0.05). Conversely, emulsion stability index, adsorbed protein, and interfacial protein contents are augmented (p < 0.05). During storage of 15 days, emulsion added with FMP at 45 mg mL−1 (FMP‐45) has the highest turbidity, zeta potential, viscosity, and viscoelastic properties (G′ and G″) than the others (p < 0.05). Emulsions show shear‐thinning and non‐Newtonian behavior. The emulsion added with FMP at 15 and 30 mg mL−1 (FMP‐15 and FMP‐30, respectively) has dominant viscous properties (G′ < G″), whereas FMP‐45 shows elastic gel‐like behavior (G′ > G″) (p < 0.05). Lower droplet size (d32 and d43), polydispersity index (PDI), flocculation (Fi), and coalescence (Ci) are observe in FMP‐45 (p < 0.05). Microstructure reveals smaller droplet size and smaller increase in droplet size of FMP‐45 after storage. Overall, all emulsions remain stable with no obvious phase separation throughout the storage. Confocal laser scanning microscopic images show that increase in FMP concentration can yield monodisperse emulsion. Therefore, fish myofibrillar protein exhibits excellent emulsifying property and stability for shrimp/soybean oils‐in‐water emulsion.Practical Applications: Oil from shrimp hepatopancreas, a byproduct from hepatopancreas free whole shrimp, is well known for their health benefits. It can be used to produce functional food emulsion such as mayonnaise. The use of fish myofibrillar protein is proven to be a potential emulsifier, which can improve emulsifying properties. The obtained emulsion is stable without no phase separation during the extended storage. This finding can be beneficial for food industries to produce food emulsion rich in high quality protein and polyunsaturated fatty acid. Also, hepatopancreas can be fully exploited.