Enhanced Mineral Recovery from Tiger Nut By-products Using PEF and ASE Technologies

This study investigates the efficiency of various green extraction technologies on the recovery of mineral elements from tiger nut (Cyperus esculentus L.) by-products using water as a solvent. A conventional maceration method served as the control, while two advanced extraction approaches were applied: Pulsed Electric Fields (PEF) and Accelerated Solvent Extraction (ASE). Maceration and PEF extraction were carried out using 20 g of a sample and 200 mL of water, while ASE extraction was performed using 3 g of a sample and 65 mL of water. PEF was conducted under four different energy and electric field conditions: 2 kV/cm at 100 and 200 kJ/kg and 3 kV/cm at 100 and 200 kJ/kg. ASE extractions were carried out at 40 °C and 120 °C, both at 1500 psi. The results revealed substantial differences in mineral extraction efficiencies across the methods. Notably, PEF at 3 kV/cm and 200 kJ/kg and ASE at 120 °C resulted in the highest concentrations of key minerals such as phosphorus (P), potassium (K), magnesium (Mg), and iron (Fe) compared to the control. ASE at 120 °C showed a marked increase in iron content (2.02 mg/100 g), nearly ten times higher than the control (0.216 mg/100 g). Additionally, zinc (Zn) and copper (Cu) also exhibited significant enhancement under high-intensity extraction conditions. This study uniquely demonstrates the transformative potential of PEF and ASE over conventional methods for sustainably recovering critical bioavailable minerals (P, K, Mg, Fe, Zn, and Cu) from tiger nut by-products. The application of these technologies could contribute to the valorization of tiger nut by-products, promoting a circular economy and improving the mineral content of food applications.

Acknowledgements: This work is part of the project CIGE/2023/108 "Recuperación de nutrientes y compuestos bioactivos de coproductos de chufa y trufa y evaluación de sus propiedades saludables", funded by the Generalitat Valenciana.