Antioxidant films and coatings based on starch and phenolics from Spondias purpurea L.

The objective of this study was to prepare, for the first time, active films and coatings from fruit starch (SPFS) and phenolic stem bark extract (SBPE) from Spondias purpurea L. Starch film formulations were prepared with different SBPE contents (5-20 wt% on starch), then cast and dried into films. SBPE showed higher antioxidant activity and antimicrobial activity against both Gram-negative and Gram-positive bacteria. Chemical, morphological, thermal, optical, mechanical, and barrier properties were studied for SPFS-SBPE films. In general, the phenolic extract caused significant changes in starch films (especially when in excess), such as gradual reduction of elastic modulus and tensile strength, increased elongation, opacity, and thermal properties (e.g. glass transition and melting enthalpy). On the other hand, SBPE provided the films with active properties (antioxidant and UV-absorbing). Coatings were applied to minimally processed mangoes (MPM), which were stored for 10 days at 12 °C. SBPE-containing coatings provided better protective action, reducing the total color difference (∆E) and delaying the browning index (BI) during storage as well as reducing fungus attack. The active SPFS-SBPE films showed great potential as environmentally friendly active films and coatings.