Encapsulation of resveratrol on lecithin and β-glucans to enhance its action against Botrytis cinerea

Abstract

β-Glucans and soy lecithin were used as encapsulating materials for resveratrol and tebuconazole, in order to test their antifungal activity against Botrytis cinerea. First an oil-in-water emulsion was formed and afterwards the emulsion was dried by spray-drying or by particles from gas saturated solutions-drying (PGSS-drying). β-Glucans were precipitated also by supercritical anti-solvent (SAS), but it was not a suitable drying process for this material. Particles were characterized regarding particle size, morphology, crystallinity, encapsulation efficiency and in vitro activity against B. cinerea. Although the emulsions with β-glucans had bigger droplet size than the ones with lecithin, there was no difference on particle size for each encapsulating material, it was just dependent on the drying process. For all the materials and drying processes, completely amorphous particles were obtained, in spite of the crystalline form of the pure active compounds. Concerning the antifungal activity, the encapsulation of tebuconazole did not improve its action, because it was already very effective. Pristine resveratrol did not reduce fungal growth, but it was inhibited between 50% and 70% with encapsulated resveratrol, which implies the production of an effective fungicide against B. cinerea totally from natural origin substances.