Ultrasound treated fish myofibrillar protein: Physicochemical properties and its stabilizing effect on shrimp oil-in-water emulsion

Effects of ultrasonication at different amplitudes (40% and 60%) and time (5, 10, and 15 min) on the physicochemical and emulsifying properties of the fish myofibrillar protein (FMP) were investigated. Solubility, surface hydrophobicity, and emulsifying properties were augmented when FMP was subjected to ultrasonication at 40% amplitude for 15 min (p < 0.05). Protein pattern study revealed that augmenting amplitude and duration of ultrasound treatment reduced band intensity of myosin heavy chain. Ultrasound treatment facilitated the adsorption of FMP on oil droplets as indicated by the increases in both adsorbed and interfacial protein contents (p < 0.05). Ultrasound-treated FMP (UFMP) sample showed the alteration in chemical bonds as depicted by Fourier transform infrared (FTIR) spectra. Ultrasound treatment altered the & beta;-sheet and random coil of FMP. During storage for 30 days at 30 degrees C, UFMP stabilized shrimp oil (SO)-in-water emulsion had higher turbidity but lower d32, d43, and polydispersity index than emulsion stabilized by untreated FMP (p < 0.05). Furthermore, emulsion stabilized by UFMP had lower flocculation and coalescence indices (p < 0.05). Microstructure observation revealed smaller droplet sizes and higher stability of droplets in emulsion stabilized by UFMP. Confocal laser scanning microscopic images demonstrated a monodisperse emulsion stabilized by UFMP. This coincided with higher viscosity and modulus values (G' and G & DPRIME; ). Emulsion stabilized by UFMP exhibited viscous, shear-thinning, and non-Newtonian behavior and no phase separation occurred during storage. Therefore, ultrasonication was proven to be a potential method for enhancing the emulsifying properties of FMP and improving the stability of SO-in-water emulsion during prolonged storage.

Automated summary

This study investigated the effects of ultrasonication on the physicochemical and emulsifying properties of fish myofibrillar protein (FMP) at different amplitudes and durations. The results showed that ultrasonication at 40% amplitude for 15 minutes significantly improved the solubility, surface hydrophobicity, and emulsifying properties of FMP. Protein pattern analysis revealed changes in the myosin heavy chain. Ultrasound treatment also increased the adsorption of FMP on oil droplets and altered the chemical bonds. Furthermore, emulsion stabilized by ultrasound-treated FMP exhibited higher stability, smaller droplet sizes, and altered rheological behavior.