Boldo (Peumus boldus) leaf's hydroethanolic extracts on gelatin-based active films

Biopolymer based active films can present several types of activity, such as the antioxidant activity. It can be produced by adding plant extract, usually rich in phenolic compounds, in its formulation. Boldo is a plant not studied as raw material in active film technology. The aims of this study were to evaluate the antioxidant activity (AA) of the boldo leaf's hydroethanolic extracts (BLHE) produced with solvents at different water:ethanol ratios and to study the effect of their addition on properties of gelatin-based films. Solvents prepared with 0:100-100:0 water:ethanol ratios were used to produce BLHE, which were analyzed for AA, color, pH and total phenolic content. Gelatin-based films were produced with 0-50-150g BLHE/100g gelatin. The BLHE produced using pure water presented a yellowish-red aspect; while using pure ethanol, it presented a greenish-yellow aspect. The pH varied between 5.1-5.7. The BLHE produced using pure ethanol had 3.6 mg Gallic acid/mL extract, but this value increased to 7.3 mg Gallic acid/mL extract for BLHE produced with 100:0. The AA of BLHE was not affected by the water:ethanol ratio. The addition of BLHE into film did not affect its main properties. The BLHE did however affect the film color and UV/visible light barrier properties. Delta E* was higher when 150% of BLHE produced with more ethanol into solvent was applied into films. All films presented high barrier to UV and moderate barrier to visible light. All films with 150% of BLHE presented good AA. This material looks interesting to be applied as package of fat rich foods. Novelty impact statement Active films were produced by addition of Boldo leaf's hydroethanolic extracts (BLHE) in its formulations. Several BHLE were produced using solvents prepared with 0:100-100:0 water: ethanol ratios. All films presented antioxidant activity and complete UV light barrier without effect of solvents used to produce BLHE. Nevertheless, the visible light barrier was higher when high proportion of ethanol into solvent was used to produce BLHE.