Extraction, isolation of some active compounds from Hibiscus sabdariffa calyx – study on processing Hibiscus sabdariffa calyx instant tea
Nguyen Kim Khanh1, Le Thanh Hai1, Le Nguyen Tuong Vi2,3
1 Faculty of Food Technology, Binh Duong University, Binh Duong Province, Viet Nam
2Graduate University of Science and Technology, Vietnam Academy of Science and Technology, Ha Noi, Viet Nam
3Institute of Applied Materials Science, Vietnam Academy of Science and Technology, Ho Chi Minh City, Viet Nam Corresponding author: Nguyen Kim Khanh, E-mail: nkkhanh@bdu.edu.vn
Abstract:
Two compounds, including hydroxymethyl furfural (HS6) and quercitrin (HS2), were isolated from calyces extracts of Hibiscus sabdariffa. Their structures were confirmed by 1H-NMR, 13C-NMR, DEPT, HMBC, and HSQC spectral methods and compared with those reported in the literature. Test results of Hibiscus sabdariffa instant tea have identified some basic parameterss follows: moisture content (91.78%), ash content (1.38%), protein content (0.36 mg/ g of sample), reducing sugar content (2.87 mg/ g of sample). To achieve the highest extraction efficiency, the following parameters should be ensured: material ratio: solvent of 1:25, extraction temperature of 80°C, extraction time of 15 minutes. It is necessary to conduct a vacuum concentrate so that the extract after concentration is 5%. Proceeding with further preparation of additives with the following ratio: sugar ratio: 50%, maltodextrin ratio: 25%. The results of the study have partly proved that Hibiscus sabdariffa has beneficial activities for human health. Alcohol and water extracts from hibiscus calyx have antioxidant activity 1.4 times and 1.3 times higher than vitamin C, respectively. At the concentration of 800 mg/ mL, alcohol extract and water extract are α-glucosidase resistance of 1.23 times and 1.31 times higher than acarbose.
Keywords: Hibiscus sabdariffa; instant tea; antioxidant ability; α-glucosidase resistance.
BDU Journal of Science & Technology, ISBN 978-604-73-9259-9