Coating based on gelatin and propolis for the control of anthracnose in postharvest of bell pepper

Bell pepper (Capsicum annuum L.) is one of the most produced fruits in Brazil, however phytosanitary problems are still an obstacle to productivity. Anthracnose is one of the most aggressive diseases in postharvest. Seeking products of natural origin, the aim of this study was to evaluate ethanolic extracts of brown propolis (BP) and green propolis (GP) and their homeopathic preparations against the pathogen Colletotrichum scovillei. Additionally, the products were tested for the control of anthracnose, and their effects on physicochemical characteristics were assessed. GP extract inhibited completely the mycelial growth at 2.5 mg mL- 1 and the spore germination at 5.0 mg mL- 1, while the BP extract inhibited 100% the mycelial growth and 50% the spore germination at 5.0 mg mL- 1. The homeopathic preparations from propolis and C. annuum (30 CH dynamizations) reduced the spore germination around 50%. When bell peppers inoculated with C. scovillei were immersed only in propolis extracts or homeopathic preparations, there was no effect on disease control. On the other hand, coating with these products combined with 10% gelatin reduced the disease incidence by around 50%. Bell peppers coated with propolis (ethanolic extract or homeopathic preprations) and gelatin showed 44% lower weight loss, 56% higher retention of titratable acidity, and 27% lower vitamin C content, indicative of a delay in the maturation process. This is the first report showing the potential of a homeopathic preparation of propolis combined with gelatin to control a post-harvest disease.