Lu, Chi-Hua, Nancy J. Engelmann, Mary Ann Lila and John W. Erdman, Jr. 2008. Optimization of lycopene extraction from tomato cell suspension culture by response surface methodology. Journal of Agricultural and Food Chemistry 56: 7710-7714.
Radioisotope-labeled lycopene is an important tool for biomedical research but currently is not commercially available. A tomato cell suspension culture system for the production of radioisotope-labeled lycopene was previously developed in our laboratory. In the current study, the goal was to optimize the lycopene extraction efficiency from tomato cell cultures for preparatory high-performance liquid chromatography (HPLC) separation. We employed response surface methodology (RSM), which combines fractional factorial design and a second-degree polynomial model. Tomato cells were homogenized with ethanol, saponified by KOH, and extracted with hexane, and the lycopene content was analyzed by HPLC-PDA. We varied five factors at five levels: ethanol volume (1.33-4 mL/g); homogenization period (0-40 s/g); saturated KOH solution volume (0-0.67 mL/g); hexane volume (1.67-3 mL/g); and vortex period (5-25 s/g). Ridge analysis by SAS suggested that the optimal extraction procedure to extract 1 g of tomato cells was at 1.56 mL of ethanol, 28 s homogenization, 0.29 mL of KOH, 2.49 mL of hexane, and 17.5 s vortex. These optimal conditions predicted by RSM were confirmed to enhance lycopene yield from standardized tomato cell cultures by more than 3-fold.