Processing effect assessment in contents phenolic total and antioxidant capacity of the bean mangalô (Lablab Purpureus (L.) Sweet) and Bean Guandu (Cajanus Cajan (L.) Mll Sp)

Abstract

Antioxidant actions are attributed to bioactive compounds, such as total phenolics and tannins present in grains. However, the use of high temperatures and germination before of the consumption can alter these characteristics. The objective of this paper was to evaluate the effect of processing (TT-heat treatment and germination) on total phenolics (FT), tannins and antioxidant activity (AA) of mangalô bean and guandu bean. Two TT (100 °C/10' and 100 °C/30') and germination of the grains were carried out for 3 days. The FT contents were determined by the Folin-Denis method and AA the DPPH adial aptue ethod i the i atua gais ad suitted to the poessig. Fo the guadu ad agal i atua, the leels g/g foud ee: FT-197.01 and 57.73 and Tannins-267.8 and 57.73, respectively; After TT (100°C/10'): Guandu FT-141.64 and Tannins-168.4; Mangalô: FT-29.16 and Tannins-32.25; TT (100°C/30'): Guandu FT-124.31 and Tannins-169.3; Mangalô: FT-40.29 and Tannins-46.23. The germinated grains presented (mg/100g) 519.53 FT and 476.47 Tannins (Guandu) and 326.75 FT and 303.26 Tannins (Mangalô). The antioxidant activity (IC 50) for guandu and mangalô before and after germination was respectively: guandu (10.28; 20.47) and mangalô (82.64; 87.56). Concluded that there was variation of the contents of FT and tannins after the processing and an inverse correlation between the bioactive compounds and AA after the thermal treatments in the studied grains.