MANNAN PRECIPITATION FROM ALOE VERA LEAF PULP JUICE USING METHANOL AND ISOPROPYL ALCOHOL AS ANTI-SOLVENT: EXPERIMENTAL AND EMPIRICAL MODELLING APPROACH

Abstract

Precipitation of mannan from Aloe vera leaf pulp ju ice was investigated using anti-solvent precipitation process under room temperature condit ion. The aims of this work were to study the effects of types (methanol and isopropyl alcohol) a nd amount of anti-solvent on the precipitation phenomena and to propose a simple mathematics model for evaluating the precipitation rate of mannan (Rβ). The experiments were carried out using a semi ba tch system; where continuous drop wise addition of anti-solvent to the Aloe vera leaf pulp juice was kept constant at 50.4 mL/min, while the speed of stirring was maintained at 675 rpm. At every run of the experiments, the time at which th e precipitation began was recorded and the experiment was terminated when no further precipitation occurred. The samples were withdrawn from the syste m at every 25 min after the first precipitation for mannan analysis. The results of this work showed th at isopropyl alcohol acted as a more effective anti solvent to precipitate mannan from Aloe vera leaf p ulp juice than methanol. The mathematics model represented the precipitation phenomena fairly well with average relative deviation only 11.73%, and finally suggested that the precipitation rate obeye d the zero order.