The usage of enzyme in ultrasound-assisted enzymatic extraction method and its effect on yield extract from Keji Beling (Strobilanthes crispus.) leavesAngelina, Mauhibah Yumna, Abdullah, Rita Arbianti, Tania Surya Utami and Heri HermansyahE3S Web Conf., 67 (2018) 03002DOI: https://doi.org/10.1051/e3sconf/20186703002