Green Extraction of Oleoresin from Pink Pepper Fruits: Effect of Experimental Conditions and Characterization

Abstract

This work evaluated the green extraction of oleoresin from pink pepper fruits (ORPPF) using ultrasound-assisted extraction (UAE) and ethanol as a solvent. The effects of temperature, ultrasound power intensity, sample to solvent ratio and time on the global extraction yield (YGE) and phenolic compounds yield (YPC) were evaluated. The oleoresin samples were characterized and its antimicrobial activity determined, and the obtained results were compared to conventional extraction in Soxhlet. From the results it was found that the application of the highest levels of the independent variables favored the extraction process. The maximum values of YGE and YPC were 28.60 wt% and 6.37 mg GAE per g fruit, respectively, obtained at 60 °C, 100% of ultrasound power (165 W), 1:20 g mL−1 (sample:solvent) and 45 min. Under maximized conditions, the ORPPF obtained by UAE showed a content of phenolic compounds and antioxidant activity inferior to soxhlet–ethanol extraction. However, the time and solvent consumption were reduced. Oleic and linoleic acids predominated in the fatty acid composition of ORPPF, in addition to sesquiterpenes and gallic and syringic acids. The ORPPF presented weak antibacterial activity, with minimum inhibitory concentration ranging from 31.25 to 125 mg mL−1.