J. Eng. Technol. Sci., Vol. 53, No. 6, 2021, 210608 Received January 27 th , 2021, Revised February 2 nd , 2021, Accepted for publication August 13 th , 2021. Copyright ©2021 Published by ITB Institute for Research and Community Services, ISSN: 2337-5779, DOI: 10.5614/j.eng.technol.sci.2021.53.6.8 The Effect of Acids on Alkaloid Yield in Pressurized Water Extraction of Narcissus Pseudonarcissus Orchidea Rachmaniah 1,2,* , Jaap van Spronsen 2 , Robert Verpoorte 3 & Geert Jan Witkamp 2,4 1 Chemical Engineering Department, Institut Teknologi Sepuluh Nopember, Sukolilo, Surabaya 60111, Indonesia 2 Biotechnology Department, Faculty of Applied Science, Delft University of Technology, Julianalaan 67, 2628 BC, Delft, The Netherlands 3 Natural Products Laboratory, Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE, Leiden, The Netherlands 4 Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia *Email: orchidea@chem-eng.its.ac.id Highlights:  Pressurized water (PW) extraction is an alternative method for extracting galanthamine from the plant matrix at a high yield.  A high-pressure condition in PW extraction of galanthamine is not necessarily required.  A high yield of galanthamine as a major product (ca. 74%-w) was obtained.  Other Narcissus alkaloids, i.e. lycoramine, O-methyloduline, norgalanthamine, epi- norgalanthamine, narwedine, oduline, haemanthamine, O-methyllycorenine, and a haemanthamine derivate, were also extracted, at lower yield.  PW extraction of galanthamine followed by subsequent purification steps of alkaloids has good economic prospects for industrial application. Abstract. Pressurized water (PW) extraction of galanthamine from Narcissus pseudonarcissus bulbs was performed. The obtained yield was compared with the yield from conventional acidified water extraction and methanolic Soxhlet extraction. Both PW and conventional acidified water extraction were followed by a subsequent purification step for the alkaloids. The PW extraction (70 °C, 150 bar, 45 min) yielded as much galanthamine as methanolic-Soxhlet extraction (ca. 3.50 mg/g). Meanwhile, acid-base extraction with 1% of HBr (v/v) at 65 °C for 3 h gave a lower yield (ca. 2.65 mg/g). A higher PW temperature did not significantly increase the galanthamine yield. Pressure increase is not necessary since more water-soluble compounds such as proteins and polysaccharides are co- extracted, resulting in high viscosity of the water extract solution, which hampers the filtration process. Hence, the acidity of the solution is highly important both in the case of PW extraction and acidified water extraction. Besides galanthamine, the total alkaloid profile following Narcissus alkaloids was also obtained. Lycoramine, O-methyloduline, norgalanthamine, epi-norgalanthamine,