Lupinus mutabilis oil obtained by expeller press: Yield, physicochemical characterization, antioxidant capacity, fatty acids and oxidative stability analyses

Abstract

The oil of debittered and dehulled grains from two Andean lupins (Lupinus mutabilis) from Peru, Andenes and Común, was extracted by expellerpress. The extraction yield and the proximal composition of both varieties were assessed. The oil and the cake, as well as the defatted flour from thevariety with the highest extraction yield, werecharacterised for physico-chemical properties, total polyphenol content andantioxidant capacity. Theoil shelf-life at 25 °C was extrapolated by Rancimat test. Andenes presented an oil yield of 22.1% (vs. 18.4% of Común), CIELAB colour coordinates ofL* = 36.5, a* = 2.2, b* = 20, refractive index and density at 25 ºC of 1.469 and 0.903 g/mL, acid number of 3.2 mg KOH/g, free fatty acids content of1.6%, peroxide number of 2.7 meqO2/kg, p-anisidine number of 1.3, unsaponificable content of 58%, total antioxidant capacity 21.4 μmol TE/g and total polyphenol content of 7.0 mg AGE/100 g. The predominant fatty acid, tocopherol and phytosterol in the oil were oleic acid (56.2%), γ-tocopherol (555 mg/kg) and β-sitosterol (41900 mg/100 g), respectively. The oil shelf-life at 25 ºC was 2.7 years. The Lupinus mutabilis oil extracted by expeller presented an acceptable quality with a lower environmental negative impact than the oils obtained by solvent extraction.