Optimization of Lycopene Extraction from Tomato Cell Culture

For biomedical research, radioisotope‐labeled lycopene is important but not commercially available. A tomato cell suspension culture system for the production of radioisotope‐labeled lycopene was previously developed in our laboratory. In this study, our aim was to improve the lycopene extraction efficiency from the tomato cell culture. We employed the response surface methodology (RSM) which combines fractional factorial design and a second‐degree polynomial model. Tomato cells were homogenized with ethanol, saponified by KOH, extracted by hexane, and the lycopene content was analyzed by HPLC. We varied five factors with five levels: ethanol volume (4–12 mL); homogenization period (0–120 second); saturated KOH solution volume (0–2 mL); hexane volume (5–9 mL); and vortex period (15–75 second). RIDGE analysis by SAS suggested that the optimal extraction procedure employed 9.5 mL ethanol, 75 seconds homogenization, 0.94 mL KOH, 6.4 mL hexane, and 36 seconds vortex to yield lycopene 13.9 nmol lycopene /g from 3 g tomato cells. By repeating this predicted condition, the improvement of extraction yield was confirmed. The production of radioisotope‐labeled lycopene was more efficient and economical with improvement of the extraction procedure by RSM.