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Hibiscus sabdariffa, commonly known as Roselle, is a native plant in Malaysia that is rich with bioactive compounds. In the present study, supercritical carbon dioxide (SC-CO2) extraction of Roselle was investigated. The optimum particle size (212µm, 300µm, 425µm, 600µm, and 710µm) to obtain highest yield was pre-determined. The effects of two operating parameters, pressure (20MPa, 25MPa, and 30MPa) and temperature (40 ºC, 60 ºC, and 80 ºC) on extraction yield were studied using response surface methodology (RSM). From the experimental data, the optimum conditions were achieved using particle size 300µm, pressure 27.5MPa, and temperature 50.8 ºC. Using the optimized parameters, the highest extraction yield was predicted to be 163.26 mg-extract/g-dried sample. The validation experimental results were consistent with the predicted values.

Application of water-in-oil emulsion in the formulation of color cosmetic is very common. However using natural water-soluble pigments as cosmetic colorant is not general in the cosmetic industry although we knew the side effect from using synthetic colorant. This study concerns one of the most important problems in using natural pigment which was to obtain the lip moisturizer formulation and to determine emulsion stability. Roselle is a local potential pigment source which is added into castor oil as the oil phase with the aid of Span 80 and Tween 85 as emulsifier. Several emulsions were prepared using different proportions of emulsifiers and the most suitable hydrophilic lipophilic balance (HLB) value for color emulsions was determined to continue with the finding of stable formulation. In addition, stable formulation was determined and emulsions stability were studied during the observation period. Emulsions were analyzed by using viscosity measurement, in order to determine a suitable formulation of emulsion. The formulation of emulsion was stabilized under HLB value of 5.3 which is 75% of Span 80 and 25 % of Tween 85.