Optimasi ekstraksi rimpang temulawak (curcuma xanthorrhiza roxb.) menggunakan pelarut ionic liquid 1-heksadesil-3-metilimidazolium klorida dengan ultrasound-assisted extraction = Optimization of temulawak rhizome extraction (curcuma xanthorrhiza roxb.) using ionic liquid solvent 1-hexadecyl-3-methylimidazolium chloride with ultrasound-assisted extraction