Edible carboxymethyl cellulose films containing natural antioxidant and surfactants: α-tocopherol stability, in vitro release and film properties

Abstract

Edible carboxymethyl cellulose films containing α-tocopherol (TC) and a mixture of polysorbate 80 (T80) and lecithin were prepared and characterized physicochemically. The stability of TC into the CMC matrix over time, the physicochemical properties of the films, in vitro release profile of TC from films and its antioxidant capacity were investigated. Films containing each one or both surfactants were more homogenous and no phase separation was observed during the drying. TC-loaded CMC films were stable over a period of 8 weeks, regardless of surfactant type. The addition of T80 in CMC films provided a plasticizing effect, reducing Young's modulus and elongation-at-break. Conversely, the presence of lecithin together with the T80 reduced the water vapor permeability to values close to pure CMC (4 × 10−7 g/h m Pa), improving the mechanical properties of the films. Lecithin-based films were able to release approximately 5 times more TC than T80-based films, probably due to differences in the interaction between surfactant and matrix. These findings also explain the higher antioxidant effect of lecithin-based films. Moreover, lecithin chemically interacts with TC, slowing down its degradation. The main contribution of this study is that combinations of surfactants are more effective to stabilize TC in a hydrophilic matrix, protecting it against degradation.