Process optimization for the supercritical carbondioxide extraction of lycopene from ripe grapefruit (Citrus paradisi) endocarp

Abstract

In this study, an underutilized citrus family fruit named grapefruit was explored for the extraction of lycopene using supercritical carbon dioxide (CO₂) extraction technique. An experimental design was developed using response surface methodology to investigate the effect of supercritical carbon dioxide (CO₂) operating parameter viz., pressure, temperature, CO₂ flow rate, and extraction time on the extraction yield of lycopene yield from grapefruit. A total of 30 sets of experiments were conducted with six central points. The statistical model indicated that extraction pressure and extraction time individually, and their interaction, significantly affected the lycopene yield. The central composite design showed that the polynomial regression models developed were in agreement with the experimental results, with R² of 0.9885. The optimum conditions for extraction of lycopene from grapefruit were 305 bar pressure, 35 g/min CO₂ flow rate, 135 min of extraction time, and 70 °C temperature.

Figure 1

Schematic of the supercritical carbon dioxide extraction and characterization of lycopene from grapefruit.

Figure 2

Chromatograms for blank (hexane) and hexane spiked with 40 ppm lycopene standard at using BEH 2 EP 2.1 × 150 mm, 5 µm column at optimized experimental conditions.

Figure 3

Response surface plot showing effects of two independent variables on lycopene yield from grapefruit while the remaining were kept at the central point (Pressure—300 bar; Flow rate—35 g/min; Time—135 min; and Temperature—70 °C). [SAS (r) Proprietary Software 9.4 (TS1M1), Copyright (c) 2002–2012 by SAS Institute Inc., Cary, NC, USA].