Solid-to-liquid extraction and HPLC/UV determination of amygdalin of seeds of apple (Malus pumila Mill): Comparison between traditional-solvent and microwave methodologies

摘要

This work evaluates the efficiency in the extraction of the cyanogenic glycoside amygdalin [D-mandelonitrile- p-D-gentiobioside] from seeds of apples (Malus pumila Mill) by using the two most conventional solid-to-liquid methodologies (reflux and Soxhlet) in relation to the more contemporary microwave technique. The extraction efficiencies are determined by an optimized and standardized high-performance liquid chromatography (HPLC) method that requires retention times of about 1 min only. The best chromatographic separation of amygdalin is found in extracts obtained using the reflux method; however, the highest total separation efficiency, requiring only 10% of total time and the solvents inverted in reflux or Soxhlet extraction, is reached by employing microwave radiation. In contrast, the higher extraction amounts of amygdalin from the seeds are obtained using the Soxhlet solid-to-liquid technique. With the Soxhlet methodology, quantities of amygdalin from apple seeds are obtained in excess of three times and twice those obtained with reflux and microwave methodologies, respectively. The purity and structural identification of the extracted amygdalin were verified spectroscopically using UV-vis, NMR and FTIR techniques.