A sustainable valorization of industrial tomato seeds (cv Rio Grande): Sequential recovery of a valuable oil and optimized extraction of antioxidants by microwaves

Abstract

Tomato seeds are a major waste of tomato paste manufacturing. In this study, an in- teresting yield of oil was obtained (21.69%) from the seeds of an industrial tomato by- product (Rio Grande variety), after a Soxhlet extraction. The fatty acid profile of the extracted oil was established by gas chromatography and the tomato seed oil (TSO) was rich in unsaturated fatty acids (79.83%). After that, microwave- assisted extrac- tion (MAE) was used to recover phenolic compounds from the defatted tomato seeds (DTS). The effect of three independent variables (microwave power, irradiation time, and solvent fraction) on the total phenolic content (TPC) and the antioxidant activity (AA) was estimated by using response surface methodology (RSM). The approach of desirability was applied to define the best operative conditions for the simultaneous extraction of TPC and AA which resulted in 700 W for microwave, 70 s for irradiation time, and water as extracting solvent. Practical applications By adopting a sustainable development approach, agro- industrial manufactories could earn the challenge of turning their waste into a source of additional income while also saving on disposal costs. In this study, a process by exhaustion following a smart and green approach was designed to recover added- value nutrients from an industrial tomato byproduct. First, tomato seeds were used as a feedstock to extract a multi- useful oil (edible, biofuel, cosmetic, etc.). Then, the residue was extracted again with hydro- ethanol as a safe and green solvent, by using microwaves as a green and cheap technology to optimize the extraction of antioxidants. In addition, com- putational tools (RSM and desirability approach) were applied for optimization and modeling of the operative conditions.