RESUMEN
Yerba mate (YM) is massively produced and consumed as an infusion in South America and spreading all over the world. This product is obtained from dried leaves of Ilex paraguariensis Saint Hilaire, mixed with fragments of dried branches (sticks). For its commercialization, YM must have a minimum percentage of leaves because its presence determines YM quality and price. Till today, a mechanical methodology to determine the relative amount of components (sticks, leaves, and powder) is used. There is not any modern analytical method that provides information for quick characterization of the YM components. Typical saponin fingerprints for leaves and sticks were found by using ultraviolet matrix-assisted laser desorption ionization and ultraviolet laser desorption ionization mass spectrometry. Then, their possible application as useful tools for quick characterization of components of commercial YM (leaves and sticks) is presented. Furthermore, fingerprints obtained from authentic samples of Ilex paraguariensis and Ilex dumosa are also included and discussed. Each Ilex show typical saponin fingerprints for leaves and sticks.
Asunto(s)
Ilex paraguariensis/química , Extractos Vegetales/análisis , Hojas de la Planta/química , Tallos de la Planta/química , Saponinas/análisis , Isomerismo , Análisis de Componente Principal/métodos , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción/métodos , Agua/químicaRESUMEN
The main goal of the present work was to clarify physiological strategies in plants whose chloroplasts were developed under different light environments. The specific objective was to elucidate the influence of the spectral distribution of light on the chlorophyll fluorescence ratio and on photosynthetic parameters. To achieve this purpose, three species of eggplant fruit (black, purple and white striped and white) were used as a case study and their chlorophyll fluorescence was analyzed in detail. Spectra of the non-variable fluorescence in each part of the fruit were corrected for distortions by light reabsorption processes using a physical model. The main conclusion of this work was that the corrected fluorescence ratio was dependent on the contribution of each photosystem to the fluorescence and consequently on the environmental lighting conditions, becoming higher when illumination was rich in long wavelengths. Variable chlorophyll fluorescence, similar to that observed from plant leaves, was detected for the pulp of the black eggplant, for the pulp of the purple and white striped eggplant and for the intact fruit of the black eggplant. The maximum quantum efficiency of photosystem II in the light-adapted state (F'v/F'm), the quantum efficiency of photosystem II (ΦPSII), and the photochemical and non-photochemical quenching coefficients (qP and qNP/NPQ respectively) were determined in each case. The results could be explained very interestingly, in relation with the proportion of exciting light reaching each photosystem (I and II). The photochemical parameters obtained from variable chlorophyll fluorescence, allowed us to monitor non-destructively the physiological state of the black fruit during storage under both chilled or room-temperature conditions.
RESUMEN
Yerba mate (YM) is massively produced and consumed as an infusion in South America and is gaining popularity all over the world. This product is obtained from the dried leaves of Ilex paraguariensis Saint Hilaire, mixed with fragments of its dried branches. For its commercialization YM must have a minimum percentage of leaves according to a standard classification. Until now, composition quantification has been mechanically performed, thus development of new methods is still pending. In this work a quantification method using solid-phase molecular fluorescence, alternately diffuse reflectance spectroscopy and an imaging technique using a scanner have been proposed. Strong differences between the spectroscopic properties of leaves and sticks were observed and in all the cases linear correlations between the processed signals and composition were observed. Interesting differences in chemical composition of YM leaves and sticks were additionally obtained in this work by means of total phenol content quantification, ultraviolet matrix assisted laser-desorption ionization mass spectrometry and ultraviolet laser-desorption ionization mass spectrometry.