Anais do Simpósio Latino Americano de Ciências de Alimentos
Anais do 14 SLACA - Simpósio Latino Americano de Ciência de Alimentos

Agroindustrial activity results in a wide variety of food products but also generates expressive amounts of solid residues along processing chains. The extraction of oils from Brazilian native fruits, such as açaí (Euterpe oleracea), generates large amounts of a by-product named “cake” after mechanical pressing of the fruit, which is discarded in the environment as a residue. However, plant by-products may conserve bioactive compounds, mainly polyphenols, that have potential as sources of natural antioxidants. Therefore, the objective of this work was to optimize the extraction of polyphenols from açaí cake and to evaluate it regarding biological activities and phenolic profile. A central composite rotatable design (CCRD) was developed to assess the best condition of extraction, considering temperature (ºC) and ethanol:water (%, v/v) as the independent variables. Afterwards, the optimized extract was freeze-dried and evaluated for reducing power (FRAP and ABTS radical scavenging assays), peroxyl radical scavenging (ORAC assay), inhibition of NF-κB activation, and antimicrobial activity. The CCRD showed the optimal extraction condition at 70°C and ethanol:water (50%, v/v). The optimized extract showed a reducing power of 986.0 ± 22.0 µmol of ferrous sulfate equivalentes/g and 820.0 ± 36.4 µmol Trolox equivalentes/g for FRAP and ABTS assays, respectively. The extract also showed high scavenge capacity of peroxyl radical and an activity against NF-κB activation around 80%. It also demonstrated antibacterial effect against important pathogens. Phenolic profile determined using high-resolution mass spectrometry indicated the presence of anthocyanins, flavonoids and phenolic acids, among other groups. All biological activities can be related to the diverse phenolic profile that included the presence of anthocyanins and flavones. Therefore, the CCRD was effective to obtain the extraction condition with a higher yield in polyphenols. Furthermore, the extract obtained under optimized conditions showed to be rich in phenolic compounds with important biological activities.