Concentration and purification of lycopene from watermelon juice by integrated microfiltration-based processes

International audienceThe aim of the study was to evaluate a new process based on crossflow microfiltration forconcentration and partial purification of lycopene from watermelon. The process includedsequentially juice extraction, enzymatic liquefaction, crossflow microfiltration andcentrifugation. Different technological schemes were compared including or not adiafiltration step in order to remove soluble solids and increase lycopene purity.Microfiltration was performed at 50-60 °C using alumina tubular membranes with averagepore diameter from 0.2 to 1.4 m and varying the transmembrane pressure from 0.5 to 2.0bar. Using the best operating conditions at the crossflow microfiltration step, permeate fluxwas close to 110 L.h-1.m-2 and lycopene concentration was increased 11 times in theretentate. Centrifugation at 10,000 g for 10 min, enabled to enhance lycopene concentrationup to 4 times. Diafiltration allowed to decrease total soluble solids from 100 to 20 g.kg-1and so to purify lycopene further. No cis-isomerization was highlighted that proved that theprocess maintained carotenoid integrity. Finally, the optimal processing scheme allowed toobtain a natural extract of lycopene 42 times more concentrated and 34 times purer than the initial juice. The results looked very promising for industrial application even if economicviability has still to be assessed