antioxidants

Present of antioxidants in strawberry fruits and its possible relation to improved quality and extension of shelf-life

Botrytis cinerea, a major fruit pathogen, is limiting strawberry preservation. Grey mold causes extensive losses and alternative means to pesticides are requested. Fruit antioxydants protect tissues against stresses and participate to disease resistance. However, they cannot be used on their own as indicators of postharvest preservation: postharvest disease resistance can also be induced by specific antifungal molecules, e.g. phenolic compounds such as phytoalexins and proanthocyanidins. Strawberry proanthocyanidins (flavan-3-ol dimers and oligomers) may act both as antifungal chemicals to extend shelf-life, and as antioxidants to enhance quality preservation. The present study aims at determining whether proanthocyanidins may serve as biochemical markers of resistance to gray mold, and whether their contents correlate with maintenance of quality and extension of shelf life of strawberries. Proanthocyanidins (PA) were extracted from eight strawberry cultivars and assessed for their ability to control germination and growth of Botrytis. Mycelium growth was determined on Potato Dextrose Agar (PDA). Germination was evaluated in Potato Dextrose Broth (PDB) enriched with PA. A panel evaluated shelf-life (first mold appearance) and quality of the cultivars after 14 days of storage at 2°C. Strawberry proanthocyanidin extract inhibited Botrytis development. Radial growth of the mycelium on PDA enriched with PA was significantly reduced (as much as 75% inhibition) and showed significant correlation with preservation of the cultivars. Germination and germ tube elongation were reduced in PA enriched PDB and multiple branching of hypha was observed. This research will offer a screening test to predict fungistatic and preservation potential of strawberry cultivars. This research will add new selection criteria for strawberry selections toward improved quality and extension of shelf-life.