Optimization of a green process for the extraction of lutein and chlorophyll from spinach by-products using response surface methodology (RSM)

Industrial vegetables wastes contain valuable phytochemicals that can be used as a source of biomolecules. Spinach production yields about 25% of waste material that is high in lutein and in chlorophyll. A green extraction method, using ethanol and water as extraction solvents was developed in order to extract these phyto-compounds from spinach by-products. Response Surface Methodology was used to optimize the extraction parameters of lutein and chlorophyll. The model predicted that a high yield of lutein and chlorophyll could be obtained with ecological extraction, close to the conventional methods. The optimum extraction parameters predicted were 93% ethanol concentration, for 4.3 h at 43 °C and a solvent to raw material ratio of 1/66. These parameters were validated with an experiment carried out under the optimal conditions determinated, given a recovery of these molecules close to those predicted (96% for chlorophyll and 70% for lutein). These results confirmed that the model was adequate to optimize extraction of lutein and chlorophyll from spinach by-products using green solvents.