Assessment of Conventional and Advanced Drying Methods on the Physicochemical Characteristics of Banana Peel

Banana peel, an abundant organic by-product, is a rich source of dietary fiber, protein, and antioxidant compounds. Effective drying methods are essential to preserve nutritional and functional properties for potential food applications. This study evaluated four drying techniques—sun drying, hot air oven drying, microwave heating, and ultrasound drying—to identify the method that best retains the nutritional quality of banana peel powder. The powders were analyzed for proximate composition, total phenolic content, antioxidant potential (DPPH and FRAP assays), texture, color, and microbial growth. Among the techniques assessed, ultrasound drying demonstrated superior results, yielding a powder with a moisture content of 13.56%, ash 11.74%, fat 7.11%, fiber 11.94%, and protein 10.42%. Ultrasound-dried powder also exhibited the highest antioxidant activity and retained desirable texture and color compared to other treatments. Microwave drying resulted in higher residual moisture, attributed to the protective peel surface, which in turn promoted microbial growth, particularly fungi. Minimal biomass formation in agar media further confirmed the stability of ultrasound-dried extracts. In conclusion, ultrasound drying proved to be the most effective method for dehydrating banana peel, ensuring lower microbial load and superior preservation of nutrients and antioxidant properties. These findings highlight its potential for sustainable utilization of banana peel in functional food applications.