Purification of Anthocyanin Extract from Roselle by Progressive Freezing: Effect of coolant temperature and stirring rateAisyah Nur Hanis Azhar, Muhammad Athir Mohamed Anuar, Siti Nor Adibah Mustapha and Nurul Aini AmranE3S Web Conf., 287 (2021) 04009DOI: https://doi.org/10.1051/e3sconf/202128704009