Supercritical fluid extraction from dried banana peel (Musa spp., genomic group AAB): Extraction yield, mathematical modeling, economical analysis and phase equilibria

Supercritical fluid extraction from dried banana peel (Musa spp., subgroup Prata, genomic group AAB, popularly known in Brazil as Enxerto) was studied. The aspects investigated were: overall extraction curve (OEC), mass transfer modeling of the yield curves, economical analysis of the process and phase equilibrium data for the pseudo-ternary system of banana peel extract, carbon dioxide and ethanol. The extraction operating conditions evaluated were: pressure ranging from 100 bar to 300 bar, temperature from 40 to 50 °C and constant solvent flow rate of 5.0 gCO2/min. Experimental extraction data were correlated using three kinetic models based on mass transfer equations (logistic, diffusion and Esquível models). Phase equilibrium measurements were performed using pressure from 64.9 bar to 239.9 bar and mass fraction of supercritical extract from 0.52 to 3.55 wt%. Yield results ranged from 0.6 to 6.9% d.b. (dry basis). The lowest deviation between experimental and correlated data was obtained by the Logistic model, except for the curve at 300 bar and 40 °C which was best represented by the Esquível model. The economical analysis identified the possibility to apply the supercritical fluids to obtain extracts from banana peel in an industrial scale. Phase equilibrium for the supercritical extract from banana peel with carbon dioxide modified by ethanol exhibited liquid–liquid, vapor–liquid (bubble point) and vapor–liquid–liquid phase transitions. A crossover phenomenon for the systems evaluated was observed for pressures between 200 bar and 240 bar, for both groups of assays, i.e., supercritical extraction and phase equilibrium.