Influence of Microfluidization Process and Oil Type on the Physicochemical Properties of Nanoemulsions and Their Films

This study aimed to evaluate the influence of microfluidization cycles and oil type on the physicochemical characteristics of nanoemulsions and the properties of alginate-based edible films. Two types of oil (1%), coconut oil and coconut testa oil, were used for nanoemulsion preparation with Tween 80 and Span 20 (3:2). The emulsions were processed using different numbers of microfluidization cycles (0, 1, 2, and 3) and subsequently mixed with 2% sodium alginate in a 1:1 ratio to obtain film-forming solutions. The film-forming solution containing testa oil showed a particle size of 135.60 ± 37.87 nm, zeta potential of -22.14 ± 3.09 mV, whiteness index of 79.92 ± 2.20, and a creaming index of 0%. These systems produced flexible edible films with significantly (<i>p</i> < 0.05) higher elongation at break (1.35 ± 0.17%) and puncture force (2.40 ± 0.32 N), as well as lower water vapor permeability (4.7 × 10^-7 ± 0.56 × 10^-7 g m^-1 h^-1 Pa^-1). Fourier Transform Infrared (FTIR) spectroscopy and Scanning Electron Microscopy (SEM) analyses indicated that both the number of microfluidization cycles and the type of oil significantly (<i>p</i> < 0.05) influenced the structural and physicochemical characteristics of the resulting edible films.