Membrane separation of bioactive lycopene from tomato juice

This thesis is a study of the concentration and purification of lycopene from tomatoes and tomato juice using membrane technology and solvent extraction. In the first part of the study, three polymeric ultrafiltration (UF) membranes (PCI?s FP 200, FP 100, and ES 404) were screened for lycopene concentration in a cross-flow pilot plant-scale membrane unit with tomato juice containing 10-11 mg lycopene/100g of tomato juice. PCI?s FP 200 membrane was the best in terms of flux with average of 155 LMH at 60?C and 50 psi TMP for a 4.5 X concentration process. The tomato concentrate obtained as retentate, contained 51.7 mg lycopene/100g sample. In the solvent extraction study, five solvents (ethanol, ethyl acetate, tetrahydrofuran, acetone, and isopropanol) were tested at ambient temperature as cosolvents with hexane for extraction of lycopene from the tomato concentrate obtained by UF. Ethanol:hexane (4:3) resulted in the highest recovery. Multiple extractions of the same tomato paste with fresh ethanol:hexane resulted in an all-trans-lycopene yield of 91% after 3 extractions at a solvent-to-solids ratio of 45 ml per g. Total recovery of carotenoids from the tomato concentrate was 58.8 mg carotenoids/100g tomato concentrate where all-trans-lycopene counted for 87.9%, ?-carotene for 4.9%, 13-cis-lycopene for 3.2%, 7-cis-lycopene for 2.2%, and unidentified lycopene cis-isomers for 1.7%. In the nanofiltration study, five polymeric membranes were screened with lycopene-hexane extracts. The DS 7 manufactured by Osmonics-Desal was the best in terms of flux, rejection and stability. The DS 7 membrane resulted in an average flux and rejection of 152 LMH and 72% respectively at 26.7oC and 400 psi when concentrating lycopene in hexane from 17.1 ?g/ml to VCR 5. Preliminary design calculations indicate a 5-stage nanofiltration system can recover 90.2% of the lycopene and could result in a final retentate stream with 157 mg/l lycopene or more and a permeate stream with as low as 3.6 mg/l lycopene that can be recycled to the extraction stage. Economic calculations show that the industrial application of membrane technology for recovering lycopene is promising and profitable