Process Optimisation， Structural Characterisation and Stability Analysis of Soybean Isolate Protein-curcumin Nanoparticle Preparation

The application of curcumin in the food industry is limited due to its poor water dispersibility and instability. To overcome this limitation， in this study， a pH-driven method was used to construct soybean isolate protein-curcumin nanoparticles (SPI-Cur) using soybean isolate protein as the packaging material (SPI)， and the loading rate was used as the evaluation index， and the three major factors affecting the loading rate of soybean isolate protein-curcumin nanoparticles (protein concentration， curcumin addition concentration， and pH-driven combinations) were respectively subjected to one-factor experimental analysis and response surface condition optimization， the optimal preparation process for SPI-Cur nanoparticles was determined to be: protein amount concentration of 50 mg/mL， curcumin addition mass concentration of 0.4 mg/mL， and pH-driven combination of pH value adjusted back from 13.0 to 7.0. By the optimal process obtained SPI-Cur nanoparticles were evaluated in terms of the particle size， ζ-potential， PDI dispersibility index， appearance and morphology，Fourier infrared spectroscopy (FTIR) and x-ray diffraction， it was concluded that curcumin was successfully loaded into the SPI nanocomplexes and was captured in an amorphous form in the soybean isolate protein matrix. In addition， the stability analysis results concluded that SPI could effectively improve the thermal and gastrointestinal stability of curcumin， and had a better protective effect on curcumin. This study provides an optimal process for the preparation of SPI-Cur nanoparticles by pH-driven method and also shows that SPI can be used as a delivery matrix for hydrophobic bioactives. © 2024 Chinese Institute of Food Science and Technology. All rights reserved.