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

•An efficient extraction procedure of lutein and chlorophyll from spinach is proposed using green ethanolic solvent.•The optimization was performed using box behnken design.•Effects of extraction parameters on the extraction efficiency were tested.

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.