Effects of Candelilla and Carnauba Wax Incorporation on the Functional Properties of Edible Sodium Caseinate Films.

Sabina Galus,Frédéric Debeaufort,Hanna Kowalska,Margaux Gaouditz

doi:10.3390/ijms21249349

Abstract

The aim of this study was to evaluate the effects of candelilla (CAN) or carnauba wax (CAR) incorporation on functional properties of edible sodium caseinate (CAS) films. Glycerol and Tween-80 were used as the plasticizer and the emulsifier, respectively. The results showed that the incorporation of waxes increased film opacity, total color differences (∆E), and mechanical resistance and reduced film lightness, water vapor permeability (WVP), and elongation at break. Scanning electron microscopy showed heterogeneous structure of emulsion films with regular distribution of lipid particles. A different internal arrangement was observed as a function of the film composition with both layered and incorporated film structure. Films containing candelilla wax exhibited more regular lipid reorganization, which resulted in better water vapor barrier efficacy and mechanical resistance in comparison to control films. The presence of Tween-80 resulted in better dispersion of lipid particles in film-forming solutions and lower water solubility, lightness, film opacity, and water vapor permeability, whereas the total color differences (∆E) were significantly larger and the improvement in mechanical properties was also achieved.

Highlights

Development of edible films for application as packaging materials is a subject of great interest due to the partial replacement of synthetic polymers
The candelilla and carnauba waxes showed a greater decrease in the water vapor permeability values of sodium caseinate films due to the highly hydrophobic nature of the waxes
The incorporation of the candelilla and carnauba wax caused a significant decrease in the elongation at break of the analyzed films and increased the tensile strength and Young’s modulus, indicating that wax addition provided more resistant films

Summary

Introduction

Development of edible films for application as packaging materials is a subject of great interest due to the partial replacement of synthetic polymers. This approach may offer opportunities that would benefit both consumers and manufacturers by providing environmentally friendly packaging and less waste from the packaging industry. Edible films, when used as protective coatings, can control mass transfer of substances (i.e., water vapor, oxygen, carbon dioxide, lipid, flavor, and/or aroma) with a resulting increase in quality and shelf life of food products. Edible films and coatings are traditionally used to improve the appearance and the preservation of food products [1]. The coating composition is chosen as a function of the desired application, and this composition is very important to determine the functional properties of the film in the product to be coated [3,4]

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