The present study was performed to identify the effects of ultrasound assisted extraction (UAE) conditions over total phenolic content, total flavonoid content, and antioxidant activity of pecan nutshell extracts of Western, Wichita, and Mahan cultivars. The analyzed UAE conditions were extraction time, amplitude, and sample-solvent ratio. Antioxidant activity was evaluated through ABTS, DPPH, and FRAP assays. Optimal extraction conditions were used to obtain an extract for the determination of medium inhibitory concentration (IC 50 ) and FTIR analysis. Results indicate that extraction time of 25 min favored the extraction of phenolic compounds and flavonoids; in addition, extract with an extraction time of 1 min exhibits antioxidant activity by ABTS, while extraction time of 5 min presents higher DPPH and FRAP activity. The highest concentration of phenolic compounds and flavonoids was obtained with a 50% amplitude. Antioxidant activity by ABTS was higher for an extract with 80% amplitude, while extract with 30% amplitude had higher antioxidant activity by DPPH and FRAP. Sample-solvent ratio of 1/50 had the highest content of phenolic compounds while flavonoid content was higher in the extract with a 1/30 sample-solvent ratio. Sample-solvent ratio using UAE did not have an effect over antioxidant activity by ABTS and DPPH; however, antioxidant activity by FRAP was increased by UAE were a 1/30 sample-solvent ratio exhibited the highest value. FTIR spectra suggests the presence of phenolic compounds, proteins, and polysaccharides; therefore, bioactive compounds can be recovered from pecan nutshell through ultrasound assisted extraction.

El bagazo, es uno de los residuos que se obtienen del procesamiento del café, es una fuente importante de metabolitos, como polisacáridos y compuestos fenólicos, con propiedades funcionales derivadas de su actividad antioxidante y antimicrobiana. El objetivo de este estudio fue evaluar el efecto del solvente de extracción sobre el contenido de metabolitos, así como sobre la actividad antioxidante y antibacteriana del extracto acuoso (T1), etanólico (T2) y acuoso-etanólico (T3) del bagazo del café. Los resultados demostraron que T1 presentó el mayor contenido total de carbohidratos, flavanonas y dihidroflavonoles, T2 presentó el mayor contenido total de flavonoides y ácido cafeoilquínico mientras que T3 presentó el mayor contenido de fenoles totales, flavonas y flavonoles (p < 0.05). Además, la mayor inhibición de radicales libres y poder de reducción antioxidante del ión férrico se detectaron en T1 y T3, mientras que T2 mostró mayor capacidad de poder reductor dependiendo de la concentración (p < 0.05). Se observaron mayores efectos inhibidores en T3 frente a las bacterias Gram-positivas (Staphylococcus aureus y Listeria monocytogenes), T2 frente a Echerichia coli, T2 y T3 frente a Pseudomonas aeruginosa según la concentración (p < 0.05). En conclusión, estos resultados indican que la composición y propiedades del extracto de bagazo del café dependen del solvente utilizado durante la extracción.