Fabrication and Physicochemical Characterization of Pseudosciaena crocea Roe Protein-Stabilized Emulsions as a Nutrient Delivery System

Abstract: The aim of this study was to develop a protein emulsifier that can be used to construct a nutrient delivery system. Pseudosciaena crocea roe protein isolate (PRPI) was prepared and tested for its emulsifying properties. Benzyl isothiocyanate (BITC) was used as a model delivery nutrient in the constructed emulsions. The average particle size, zeta potential, and BITC retention rate of the emulsions were used as the main evaluation indexes, and confocal laser scanning microscopy was used to test the storage stability of the emulsions (composition: 5 mg/mL protein, 5% oil, 0 to 5 mg/mL BITC, pH 8). After storing at 20 °C for 7 days, the largest particle size of the emulsion at pH 8 increased from 274.27 to 280.82 nm. Storing at higher temperatures had a negative impact on the particle size and BITC retention rate. On the seventh day, the average particle size at 20 and 4 °C was 289.63 nm and 275.67 nm, respectively, and the BITC retention rate at 20 °C (83.30%) was found to be 15.50% lower than that at 4 °C (98.58%). These results demonstrate that the PRPI-based emulsion system is effective in protecting nutrients and has excellent stability at 4 °C. Practical Application: This study provides some useful information for the food industry to develop a nutrient delivery system emulsified with fish roe protein isolate. The properties of the isolated protein and its protective effect on nutrients are discussed.