Innovation in the processing of fermented purple sweet potato (

Abstract. Purple sweet potato ( Ipomoea batatas L.) is a valuable local crop with high anthocyanin and flavonoid contents, but its utilization remains limited to fresh consumption. This study aimed to develop an energy efficient and functional flour processing technique combining fermentation and air frying. The research contribution is to propose a simple green technology approach for preserving bioactive compounds in purple sweet potato flour. Four treatments were conducted: non fermented (Control), spontaneous fermentation, yeast fermentation, and yogurt fermentation, each incubated for 48 h before drying with an air fryer (70°C). Anthocyanin and flavonoid contents were analyzed spectrophotometrically. Results showed that fermentation significantly reduced both compounds, following the trend: Control > Yogurt > Spontaneous > Yeast. Yogurt fermentation retained higher levels due to acidic stability, while non fermented samples preserved the highest antioxidant profile. Therefore, air frying without fermentation is recommended as an efficient method to produce high antioxidant flour. This study contributes to understanding the degradation kinetics of anthocyanin and flavonoid compounds under mild drying and fermentation conditions.