Microwave-assisted extraction (MAE) and pressurized liquid extraction (PLE) using food-grade solvents were applied to Stevia rebaudiana Bertoni leaves in order to obtain phenolic compound-rich extracts. The influence of various extraction parameters (i.e. solvent composition, temperature, time) on the total phenolic content was evaluated, reaching the highest phenol content (79 ± 9 mg gallic acid equivalents/g dried leaves) with PLE using 50% aqueous ethanol at 200 °C. In addition, high-performance liquid chromatography coupled to electrospray ionization quadrupole-time of flight mass spectrometry was used to characterize the bioactive compounds in the richest extracts. A variety of phenolic compounds was identified, mainly phenolic acids and flavonoids, along with the diterpene glycosides responsible for the sweet taste. This study indicates that PLE represent a powerful tool to obtain Stevia extracts suitable for human consumption which can be used as source of antioxidant compounds and non caloric sweeteners.
Evaluation of new extraction approaches to obtain phenolic compound-rich extracts from Stevia rebaudiana Bertoni leaves / Ciulu, Marco; Quirantes Piné, Rosa; Spano, Nadia; Sanna, Gavino; Borrás Linares, Isabel; Segura Carretero, Antonio. - In: INDUSTRIAL CROPS AND PRODUCTS. - ISSN 0926-6690. - 108:(2017), pp. 106-112. [10.1016/j.indcrop.2017.06.024]
Evaluation of new extraction approaches to obtain phenolic compound-rich extracts from Stevia rebaudiana Bertoni leaves
CIULU, Marco;SPANO, Nadia;SANNA, Gavino;
2017-01-01
Abstract
Microwave-assisted extraction (MAE) and pressurized liquid extraction (PLE) using food-grade solvents were applied to Stevia rebaudiana Bertoni leaves in order to obtain phenolic compound-rich extracts. The influence of various extraction parameters (i.e. solvent composition, temperature, time) on the total phenolic content was evaluated, reaching the highest phenol content (79 ± 9 mg gallic acid equivalents/g dried leaves) with PLE using 50% aqueous ethanol at 200 °C. In addition, high-performance liquid chromatography coupled to electrospray ionization quadrupole-time of flight mass spectrometry was used to characterize the bioactive compounds in the richest extracts. A variety of phenolic compounds was identified, mainly phenolic acids and flavonoids, along with the diterpene glycosides responsible for the sweet taste. This study indicates that PLE represent a powerful tool to obtain Stevia extracts suitable for human consumption which can be used as source of antioxidant compounds and non caloric sweeteners.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
