Green solvents for deoiling pumpkin and sunflower press cakes: impact on composition and technofunctional properties

Abstract

SummaryThe applicability of protein‐rich press cake from mechanical seed oil production is limited because of its relatively high residual oil content. To overcome this drawback, pumpkin and sunflower press cakes were deoiled at room temperature by using two green solvents, namely ethanol and isopropyl alcohol. Hexane, which is mostly used in the plant oil industry, was used as a reference. The derived meals were analysed regarding composition as well as with respect to technofunctional properties such as water‐binding capacity, water solubility, nitrogen solubility and colour. Extraction efficiencies of more than 94% were achieved once the solvents were refreshed during extraction. In contrast to pumpkin meal, solvent‐specific differences in the residual oil content of sunflower press cake were discovered, which was lowest for hexane and highest for ethanol. The water‐binding capacity and nitrogen solubility of the meals were improved after solvent extraction. The results indicate that it is possible to replace hexane with more sustainable green solvents such as ethanol or isopropyl alcohol to extract residual oil from sunflower and pumpkin press cake.