Implementación de un sistema de Espectroscopia Fotoacústica para la caracterización termo-óptica de aceites esenciales cítricos

Abstract

Essential oils are complex mixtures of chemical substances which give their characteristic flavours and fragrances to plants and fruits. The most used in industry are obtained as byproduct of citrus juice processing. Although in natural way are used for flavours and fragrances their use is not restricted to this applications since several studies have proved their potential for medical applications as anti-microbial and anti-plasmid substances. The importance of these substances and the variety of methods for obtention and purification, together with their complex structure, make necessary the use of analytic techniques to determine their composition. The most used techniques for these purposes are spectroscopies (IR and UV) and gas chromatography (GC). The use of the thermal properties (in particular thermal diffusivity) has not been exploited in a systematic way for these purposes. To prove this feasibility in this work we used a photoacoustic methodology for the thermal diffusivity measurement in various essential oils obtained from Mexican citrus fruits [5]. The samples consisted on essential oils obtained by centrifugation of orange (Citrus sinensis), pink grapefruit (Citrus paradisi), mandarin (Citrus reticulata blanco var. mandarin), and lime (Citrus aurantifolia) the last one also obtained by steam distillation. Even though the results don’t show meaningful differences between thermal diffusivity values for the diverse essential oils obtained by centrifugation they do it between the samples obtained by two different obtention mechanisms (centrifugation and steam distillation) which demonstrate the feasibility to define the quality in terms of extraction method of this substances using thermal diffusivity as a parameter.