Extraction of an emulsifying agent from the cellulose-based filtration aid of cold-pressed rapeseed oil

This study aimed to extract an emulsifying agent from the cellulose-based filtration aid of cold-pressed rapeseed oil. This material is currently a low-value stream but contains phospholipids retained during filtration and proteins from residual seed peel and pulp particles. A range of two-step extraction methods were assessed, with oil removal using diethyl ether (DE) or petroleum ether followed by chloroform-methanol (CM) extraction (2:1, 3:2 or 5:4 ratios) or the reversed order. Emulsions prepared with the DE/CM3:2 extract displayed the highest emulsifying activity and stability indexes (35.52 m2/g and 2,045.18 min) and similar small mean oil droplet sizes (3 μm) to those of whey protein concentrate emulsions. A range of extracted compounds contributed to the DE/CM3:2 functionality, including napins, cruciferins and phospholipids. This study demonstrated for the first time the potential to upcycle this co-product by recovering emulsifying agents. Future studies will focus on optimising the extraction process and yield.