A twin-screw extruder for oil extraction: II. Alcohol extraction of oleic sunflower seeds

Our work is about the extraction of sunflower seed oil in a twin-screw extruder with or without the injection of 2-ethylhexanol and acidified 2-ethylhexanol. 2-Ethylhexanol is mixed with phosphoric acid. The oil recovery is increased to 90% by the co-injection of acidified alcohol. Mixing phosphoric acid with the alcohol enhances the lability of the oily spherosomes. Its addition increases the destruction of the membranes enveloping the lipid-containing organelles to release the oil more easily. Phosphoric acid exhibits an extracting and a degumming role. The best oil-quality was obtained at a low extraction temperature (80 degrees C), when 88% of the oil was removed. Alter alcoholic distillation, the oil exhibited a total acid value (mineral acidity plus organic acidity) of 4 mg KOH/g of oil and an organic phosphorus content below 30 ppm.