The Influence of Extraction Method on the Composition of Essential Oils from Lemon Peels Analysed with FTIR

Abstract

The extraction method selected for extracting essential oils from lemon peels has a marked impact on both the yield and the chemical composition of the resulting product. In this study, the chemical profiles of the oils extracted with solvent extraction using hexane and steam distillation were analysed via Fourier Transform Infrared Spectroscopy (FTIR). The findings demonstrate that hexane extraction preferentially recovers non-polar constituents, such as alcohols, phenols, and aromatic compounds. In contrast, steam distillation is more effective at isolating volatile and aliphatic hydrocarbons, particularly limonene and related terpenes, which are significant for their characteristic citrus aroma. The FTIR spectra showed the characteristic existence of certain functional groups such as alkanes, alkenes, carbonyls, and aromatics that enabled distinction between the compositions of the essential oils from the two extraction processes. The results emphasise the importance of selecting the extraction process, particularly when designing essential oil compositions for targeted purposes in the food, pharmaceutical, or cosmetic industries. In general, these results provide useful information regarding how methods for extraction could potentially be modified to more closely match the intended results.