Extraction of Lycopenes from Tomato By-Products Using Supercritical Fluids

Importance of the Topic

Tomato by-products are a rich source of lycopene, a potent antioxidant associated with protection against cardiovascular diseases and other chronic conditions. Efficiently recovering lycopene from agricultural waste supports sustainable processing, reduces reliance on toxic solvents, and meets analytical and industrial demands for high-purity natural carotenoids.

Study Objectives and Overview

This work evaluates a supercritical carbon dioxide extraction protocol for isolating lycopene from tomato skins. The goals include comparing extraction efficiency, time, and solvent usage against the conventional Soxhlet method and demonstrating a rapid, green alternative suitable for both analytical laboratories and industrial applications.

Methodology and Instrumentation

Sample Preparation

• Weigh 12 lb of ripe tomatoes, quarter and crush to separate solids from juice
• Dry solids in a vacuum oven at 40 °C for 24 hours and grind in a laboratory mill

Supercritical CO2 Extraction

• Load 30 g of dried tomato solids into a 50 mL extraction vessel, with plugs of porous wool at top and bottom
• Pack surrounding void volume with inert matrix material to promote uniform flow
• Set extraction parameters: 680 bar pressure, 80 °C vessel temperature, 120 °C valve temperature, 4 L/min CO2 flow, 30 min dynamic extraction time
• Collect extracts in a pre-weighed amber vial fitted with wool filter

Instrumentation

• Supercritical extractor Spe-ed SFE-NP system
• Spe-ed matrix packing material (Cat. number 7950)
• Spe-ed wool sample support (Cat. number 7953)
• Industrial grade carbon dioxide supply with dip tube

Main Results and Discussion

Compared with a 10-hour Soxhlet extraction using an acetone-hexane mixture, the supercritical CO2 method achieved 96.1 percent relative recovery in under one hour with no organic solvents. The yield was statistically comparable to the conventional procedure, while reducing processing time by more than 90 percent and eliminating solvent exposure and disposal concerns.

Benefits and Practical Applications

The supercritical CO2 approach offers multiple advantages:

• Eliminates hazardous organic solvents and associated handling risks
• Shortens extraction time from hours to minutes
• Delivers high-purity lycopene suitable for food, pharmaceutical, and analytical uses
• Facilitates scalable, environmentally friendly processing of tomato by-products

Future Trends and Opportunities

Emerging developments may include coupling supercritical extraction with inline spectroscopic monitoring to optimize yield in real time, integrating enzymatic or mechanical pretreatments to improve matrix accessibility, scaling up to continuous flow systems for industrial throughput, and extending the methodology to other high-value bioactives present in agro-industrial residues.

Conclusion

Supercritical CO2 extraction represents a viable, green alternative to solvent-based recovery of lycopene from tomato skins. The method matches traditional yields and precision while significantly reducing extraction time and eliminating toxic solvents, aligning with sustainability goals in analytical and production environments.

References

• Kaziunas A. The Supercritical Carbon Dioxide Extraction of Lycopenes from Tomato Byproducts. Pittcon 2003.
• Khachik F. Journal of Agricultural and Food Chemistry 1992, 40, 390–398.
• Favati F. Fourth Italian Conference on Supercritical Fluids and Their Applications, 1997, 121–128.