Efecto de dos métodos de secado en los compuestos fenólicos totales, L-DOPA y la actividad antioxidante de Vicia faba L.

L-DOPA is one of the secondary metabolites present in legumes, such as Mucuna pruriens and Vicia faba L., its content can be affected by the method of drying, variety and stage of development of the plant. The objective of this study was to analyze the effect of drying method by stove and lyophilization on the content of total phenolic compounds (TPC), L-DOPA and antioxidant activity in seedling and flower of two varieties of broad bean. Two varieties of broad bean, Diamante and Zac-22, were used as plant material, which were sown under field conditions. Seedlings were obtained at 10, 15 and 20 days after the emergence (DAE), and flowers during the flowering period. The tissues were subjected to two drying methods, by forced air oven at 38 °C and by lyophilization (-80 °C). The content of total phenolic compounds (TPC) was determined by the Folin-Ciocalteu method, and L-DOPA was analyzed by HPLC. The antioxidant activity was determined against the DPPH radical (IC50). The results showed that the drying method affected the concentration of TPC, L-DOPA and antioxidant activity. The highest concentrations of TPC (110.12 mg·g-1 DM) and L-DOPA (61.08 mg·g-1 DM) were detected in the samples processed by oven drying. Flowers had the highest content of TPC (142.19 mg·g-1 DM) and L-DOPA (82.02 mg·g-1 DM) compared to seedlings. While in the seedlings at 10 DAE had on average the highest concentration of TPC (110.12 mg·g-1 DM) and L-DOPA (61.08 mg·g-1 DM). The antioxidant activity was particularly affected by the drying method in the seedlings, but in the flowers, they did not show variation. The drying by stove favored the preservation of the antioxidant activity of the seedlings (IC50, 119.93 µg·mL-1), with respect to the drying method by lyophilization (IC50, 144.29 µg·mL-1). [ABSTRACT FROM AUTHOR]