Development of Carrageenan-Based Edible Films Via Ultrasonication-Assisted Soybean Oil High Internal Phase Emulsion (HIPE) Incorporation

The development of edible films based on natural biopolymers, such as carrageenan, represents an effort to create environmentally friendly food packaging. The objective of this study was to develop a carrageenan-based edible film with the incorporation of High Internal Phase Emulsion (HIPE), which has been stabilized through ultrasonication with a view to enhancing the stability and functional properties of the film. The HIPE formulation employed alginate and soy protein isolate (SPI) as natural stabilizers, with soybean oil as the internal phase. The effects of sonication time (0–10 minutes) on the resulting droplet size and stability were investigated, and it was determined that 7 minutes was the optimal duration for achieving the best results. This condition was found to result in HIPE with high storage and centrifugal stability. The incorporation of HIPE into carrageenan matrix resulted in an increased film thickness, decreased water content and solubility, and increased the water contact angle, indicating improved moisture barrier properties. Mechanically, the increasing HIPE concentration reduced tensile strength, yet increased elongation at break, rendering the film more flexible. Scanning Electron Microscopy (SEM) analysis demonstrated homogeneous globule distribution, whilst FTIR confirmed the presence of hydrogen, electrostatic, and hydrophobic interactions between the components. Thermogravimetric Analysis (TGA) results indicated enhanced thermal stability, with an observed increase in antioxidant activity up to 68% at the optimum HIPE concentration. The findings of this study demonstrate that the incorporation of ultrasonically stabilized HIPE leads to a notable enhancement of carrageenan films, enhancing their potential as safer, sustainable food packaging.