Pressurized liquid extraction and low-pressure solvent extraction of carotenoids from pressed palm fiber: Experimental and economical evaluation

In this work, a comparison of Soxhlet extraction (LPSE-SOX), percolation (LPSE-PE) and pressurized liquid extraction (PLE) for the recovery of carotenoid-rich extracts from pressed palm fiber (PPF) was carried out in terms of yield, carotenoid profile and economic viability to evaluate the methods' industrial applicability. An optimization study was performed for each extraction technique with ethanol at a solvent/feed ratio of 20. The independent variables were temperature (35-55 °C), pressure (0.1-8 MPa) and flow rate (1.6, 2.4 g/min). The results showed that the global extraction yield obtained using LPSE-SOX (96 ± 4 mg extract/g PPF d.b.) after 6 h was higher than that obtained using LPSE-PE (74 ± 5 mg extract/g PPF d.b., 35 °C, 2.4 g/min) or PLE (44 ± 3 mg extract/g PPF d.b., 55 °C, 4 MPa, 2.4 g/min) after dynamic extraction time of 17 min under optimized conditions. On the other hand, the carotenoid yield obtained using PLE (305 ± 18 μg α-carotene/g extract and 713 ± 46 μg β-carotene/g extract) was higher than the obtained by LPSE-SOX (142 ± 13 μg α-carotene/g extract and 317 ± 46 μg β-carotene/g extract). PLE technique showed the highest selectivity for carotenoids than LPSE techniques. The lowest cost of manufacturing (COM) were obtained for LPSE-PE and PLE with values of US$13.4 and US$29.2/kg extract for a 0.5 m³ vessel capacity.