Abstract—Lemongrass oleoresin was successfully extracted from lemongrass (Cymbopogon citratus) using Pressurised
Liquid Extraction. The biological active constituent in lemongrass oleoresin is citral or its isomers; geranial and neral
is more than 75% by weight of essential oil. Geranial was used as marker compound for this study. The solubility of geranial increased with the addition β-cyclodextrin until it reached the solubility limit at 7 mM β-cyclodextrin, with no further improvement after that. The phase solubility diagram obtained was characterised as BS. Inclusion complex of geranial was prepared by using co-precipitation (CP) and kneading method (KM). Based on phase solubility study, the stability constant, K1:1, it indicated that molar ratio obtained was 1:1 β-cyclodextrin (β-CD):geranial for complexation. The complexes formed were characterised by using Fourier transform infrared spectrometry (FTIR) and differential scanning
calorimeter (DSC). The shift of C-H stretching to higher wavenumber and the reduction of intensity of band C=O and
C-H band indicated the formation of new solid phase; β-CD-lemongrass oleoresin. The DSC thermogram showed the new
solid phase formed using co-precipitation and kneading methods. The peak intensity of co-precipitation shows the
highest compared to kneading. The results obtained from FTIR analysis showed that co-precipitation and kneading
methods were able to produce inclusion complex. However, DSC indicates that co-precipitation method able to produce
inclusion complex. Therefore, co-precipitation was the chosen method for the formation of inclusion complex between lemongrass oleoresin and β-cyclodextrin.