Abstract
In this study, an I-optimal design was used to select an optimal muña essential oil nanoemulsion (MEO-NE) for application in active starch-based films. Four independent variables were used to optimize the process: emulsifier concentration (X(1)) (% w/w), sonication time (X(2)) (min), essential oil concentration (X(3)) (% w/w), and emulsifier type (X(4)) (Tween 80 or sapote gum). Results revealed that MEO-NE containing 5.24% of MEO, 6% Tween(®) 80, and 9 min of ultrasound treatment exhibited a small droplet size (Y(1)) (48.6 nm), moderate ζ-potential (Y(2)) (-15 mV), and DPPH inhibition (Y(3)) (95.6%). Starch-based films were incorporated with optimized MEO-NE at 5% (F(1)) and 10% (F(2)) and compared with control films (F(0)). F(1) and F(2) exhibited lower moisture content, water solubility, and water vapor permeability than F(0); however, their contact angles were higher. The addition of MEO-NE into the polymeric matrix increased the stiffness of F(1) and F(2); however, the elongation at yield was slightly lower than that of F(0), resulting in less stretchable composite films. All films were disintegrated by more than 90% after 5 days of burial under composting conditions. The incorporation of MEO-NE into composite films significantly enhanced their properties, suggesting their potential use as eco-friendly packaging.