Characterization of powdered rhizophora mucronata bark tannins extractives using different drying methods

Abstract

The effect of different drying methods using spray dryer and rotary evaporator towards the physico-chemical properties and thermal stability of powdered tannin extractives from Rhizophora Mucronata bark was investigated. Prior to spray drying at 130°C and rotary evaporating at 80°C, tannin was extracted using water-based boiling extraction at temperature ranging from 80 to 90°C. Powdered tannin extractives obtained by spray dryer decomposed at higher temperature (at 270°C) than those using rotary evaporator (at 210°C). The powdered tannin extractives from spray dryer was higher in thermal stability due to the high crystallinity peak appeared from X-ray Powder Diffraction (XRD) analysis. Condensed and hydrolysable tannins were also quantified using Reverse-phase High Performance Liquid Chromatography (RP-HPLC) for both methods. Powdered tannins extractives using spray dryer contained 27.8% condensed tannins and 0.001% hydrolysable tannins, in which the condensed tannins are slightly higher in concentration than those formed using rotary evaporator which was 26.5%. The findings revealed that the used of spray dryer is more beneficial to obtain a stronger thermal stability and a higher concentration of powdered Rhizophora Mucronata bark tannins extractives.