Impact of Solar Drying Techniques on Bioactive Composition and Antibacterial Activity of Chamomile (Chamaemelum nobile L.).

Abstract

Chamomile flowers (Chamaemelum nobile L.), widely known for their medicinal properties, were dried under different methods and conditions to preserve the plant and its health benefits. Sun drying with forced and natural convection was applied, and the effect of adding a mesh shading was evaluated to compare against controlled conditions (drying in an electric oven and a forced convective dryer). Bioactive compounds such as carotenoid content (3.15-7.95 mg/g), antioxidant activity (70.20-89.23%), and ascorbic acid (32.59-52.31 mg/100 g) were evaluated as response variables. Physical properties such as moisture content, water activity, and color parameters were also evaluated to ensure microbiological stability and visual acceptance. Chamomile flowers showed an excellent antibacterial capacity, finding the best results with solar drying with mesh shading and natural convection with minimum inhibitory concentrations of 0.375 mg/mL against E. coli and 0.300 mg/mL against S. aureus, while the minimum bactericidal concentrations were 0.750 mg/mL for E. coli and 0.600 mg/mL for S. aureus. The findings underscore solar drying's capacity to maintain both nutritional and medicinal integrity, positioning it as a promising approach for the food and herbal medicine industries seeking eco-friendly processing solutions. PRACTICAL APPLICATIONS: The findings of this research support the use of solar drying as a sustainable and cost-effective technique for preserving medicinal and nutritional value in chamomile. Potential applications include the production of high-quality chamomile tea, herbal infusions, and natural medicinal products, as well as the development of sustainable drying methods for other medicinal herbs. The optimized solar drying conditions can also contribute to the development of eco-friendly and energy-efficient drying technologies for the food and herbal medicine industries.