Application of Multi-Stage Countercurrent of Low-temperature-and-alkali-assisted Aqueous Extraction Processing in the Extraction of Oil and Protein from Rapeseed

Optimizing the extraction efficiency of rapeseed oil and protein, which is crucial for achieving sustainability, necessitates overcoming challenges such as low protein extraction rates and high solvent usage in aqueous extraction processes. Therefore, innovative approaches are required to simultaneously achieve high-yield extraction with minimal solvent consumption to advance industrial utilization. This study explores an economically viable approach for extracting oil and protein from rapeseed using multi-stage countercurrent extraction with low-temperature-and-alkali-assisted aqueous extraction processing (LA-AEP). Optimal LA-AEP conditions were identified at a material-to-solvent ratio of 1:4 (w/v), pH 11.0, and 40 C, yielding a residual oil rate of just 5.00%. Subsequently, four-stage countercurrent LA-AEP (FC-LA-AEP) was conducted, resulting in a reduced residual oil rate of less than 3.42% and an increased protein concentration in the water phase to 5.90% (w/w). Notably, only 2.00 L/kg of rapeseed was required as the extracting agent. Rapeseed oil obtained through FC-LA-AEP exhibited tocopherol and sterol contents of 42.78 mg/100 g and 378.25 mg/100 g, respectively. FC-LA-AEP emerges as a promising method for rapeseed oil extraction, offering mild operating conditions, simultaneous high-quality oil and protein extraction, and minimal aqueous usage.