Development of a Cloud Point Extraction Technique Based on Lecithin for the Recovery of Carotenoids from Liquid Tomato Wastewater

The traditional extraction methods used to recover natural antioxidants from food industry wastes involve significant amounts of hazardous solvents. A viable alternative is the use of non-toxic surfactants to remove organic compounds from wastes at temperatures above the cloud point. Cloud point extraction has only recently begun to be used to recover high-value added compounds from food industry wastes. In the current work, a method for the isolation of high-value added components from liquid tomato wastewater using a cloud point extraction method was developed and optimized. Food-grade lecithin was examined for its potential to be used as a surfactant in the developed procedure. Moreover, parameters affecting the extraction (ionic strength, sample pH, temperature of extraction, and surfactant concentration) were examined and optimized. According to the results, the maximum recovery of carotenoids from the sample could be achieved with the developed procedure, by simply adjusting the pH to 3.5, adding 35.6% (w/v) sodium chloride, and setting the temperature at 45 °C. Moreover, the amount of lecithin used was examined. In order to extract the total amount of carotenoids from a sample, it was found that either three extractions with 1% lecithin are needed, or two extractions with 2% lecithin. In addition, the antioxidant activity of the extract was examined and it was found to scavenge 36.3% of DPPH free radicals. This percentage was 10% lower compared to the initial sample, which suggests that the extracted compounds retain their activity. Overall, the developed procedure can be used to recover carotenoids in a cost-efficient and easy way.