Production of polyphenol-rich Guava leaf (Psidium guajava L.) powder using spray-drying technology and evaluation of its antibacterial activity

Spray drying is a widely applied technique for converting liquid materials, including solutions, suspensions, emulsions, and pastes, into dry powder form through atomization in a hot-air environment. This study investigates the application of spray-drying technology in the production of guava leaf powder derived from fresh leaves of Psidium guajava cultivated in Vietnam. The research focuses on evaluating the technological parameters influencing the spray-drying process of concentrated guava leaf extract supplemented with maltodextrin. The findings demonstrate that the resulting guava leaf powder exhibited favorable physicochemical properties, particularly high solubility, with a water solubility index of 64.54 ± 0.46%. In addition, the reconstituted solution was clear and free from sedimentation, indicating good product stability and dispersibility. Notably, the spray-dried powder showed significant antibacterial activity against Staphylococcus aureus ATCC 25923, achieving a bactericidal efficacy of 99.96%. These results highlight the potential application of spray-dried guava leaf powder as a functional ingredient with promising antibacterial properties for food and pharmaceutical applications