Use of biphasic NADES to evaluate the extraction of biocompounds in hydrophilic phase from okara

Soybean seeds (Glycine max L.) are used in a wide variety of food products. Soybean is recognized as an extremely nutritious food due to its high protein and beneficial compound content. Soybeans processing is related to okara production, soymilk production byproduct. Despite it is considered waste, okara retains a significant amount of biocompounds. Also, green solvents, such as Natural Deep Eutectic Solvents (NADES), are relevant for extracting biocompounds. In a world with growing interest in sustainability, NADES offer environmentally friendly and safer alternatives. They provide numerous advantages, including lower toxicity, recyclability, and biodegradability. This study aims to evaluate the extraction of hydrophilic biocompounds from okara using a combination of hydrophilic and hydrophobic NADES. Isoflavone solubility prediction was performed by using the conductorlike model for real solvents (COSMORS) to screen three hydrophobic and three hydrophilic NADES combinations. The extraction was performed using heatingorbital shaker for 45 minutes at 45°C. After, the extraction of biocompounds was evaluated as Total Phenolic Content (TPC) and Total Antioxidant Capacity (TAC) in hydrophilic phase. COSMORS screening has simplified the identification of the most interesting combination of NADES formulations, reducing the need for extensive experimental assays. The biphasic NADES composed of Camphor:Thymol 3:2 and Citric Acid: Glucose 1:1 was the best option for the extraction of biocompounds in the hydrophilic phase (TPC=24,8139 mg GAE/g; DPPH=0,039726 mg TE/g; TEAC= 47,80434 μmol TE/g). Funded by MCIN/AEI/10.13039/501100011033 and by European Union NextGenerationEU/PRTR/CPP202008937. Agritech National Research Center and by European Union NextGenerationEU (PIANO NAZIONALE DI RIPRESA E RESILIENZA (PNRR) – MISSIONE 4 COMPONENTE 2, INVESTIMENTO 1.4 – D.D. 1032 17/06/2022, CN00000022).