Olive Leaves Addition on Starch-Pectin Films: Optimization, Characterization, and Evaluation as Edible Hydrosoluble Sachets
摘要
Olive oil production generates 6.23 kg/L of olive leaf residues, which are rich in macromolecules and bioactive compounds. The aim of this study was to (i) develop and characterize starch-pectin films with olive leaves in powder form; (ii) optimize the formulations using a central composite rotatable design; and (iii) use the optimized film as edible, hydrosoluble sachets with spices for seasoning rice or olive leaves for infusion and analyze sensory acceptability. The response values ranged from 2.7 to 7 MPa for tensile strength, 8 to 13% for elongation at break, 4.1 to 8 mm−1 for opacity, and 34 to 88% for water solubility. The optimized film showed UV protection (above 90%) with a moisture content of 11.4 ± 0.4%, water solubility of 83 ± 9%, water vapor permeability of 1.48 ± 0.04 g mm h−1 m−2 kPa−1, water contact angle of 52 ± 1°, and antioxidant activity of 0.055 µM Trolox equivalents g−1 (ABTS•+) and 60.19% (DPPH−). No heavy metals were detected in the multielement analyses. The optimized film was found to be suitable for use as edible hydrosoluble sachets, as it dissolved easily when the rice was cooked (10 ± 2 min) and in boiling water for infusion (5 min). The sensory analysis showed an acceptance and purchase intention of 85% and 81% for the rice seasoning sachets and 65% and 59% for the infusion sachets, respectively. Future studies should investigate the effects of olive leaf films on food preservation in different matrices.