Enriched oil-in-water emulsions as bioactive agents for locust bean gum films: A comparative investigation

Abstract

In this study, pracaxi oil (PO) and olive oil (OO) emulsions, enriched with turmeric powder (Cur) and stabilized by nanofribrillated cellulose (NFC), were developed and incorporated to glycerol-plasticized locust bean gum (LBG) dispersions. Films were obtained by solution casting, and their properties were compared, aiming to expand PO application as a potential constituent of active food packaging. The films were characterized for their morphological, structural, transparency, gas permeability, wettability, thermal, mechanical, and antioxidant properties. In relation with the plasticized LBG film, both emulsion films showed improved humidity content, surface wettability, oxygen barrier capacity, thermal stability, and mechanical properties. As for wettability, while the initial water contact angle for the LBG film was θ0 = 93.4°, values of θ0 = 105.5° and θ0 = 99.2° were determined for the LBG films incorporated with PO- and OO-based emulsions, respectively. In comparison with the LBG film, the incorporation of PO-based droplets led to an approximately 8.0% reduction in the water vapor transmission rate values. Also, in comparison with the LBG film, the LBG/NFC/PO-Cur and LBG/NFC/OO-Cur films were capable of reducing the peroxidation value of sunflower oil by 16% and 11%, respectively. Enhancements in tensile strength values of 44% and 49% were determined for the PO- and OO-based emulsion films. The emulsion films presented similar antioxidant properties and better preservation of strawberry model food than LBG and polyethylene films. The results of the comparative experiments suggested that the use of PO may be expanded as a component of active food packaging.