Influence of Extraction Techniques on Almond Oil Quality: A Comparative Study of Solvent-Extracted and Commercial Products

The aim of the study was to compare the quality of almond oils obtained using different extraction methods, including cold solvent extraction, Soxhlet extraction, and the Folch method. Oils were extracted from four commercially available almond-based products-unpeeled almonds, blanched almonds, almond flakes, and almond protein concentrate-and compared with a commercially refined almond oil. The extracted oils were analyzed for their fatty acid (FA) composition and selected quality parameters, including acid value, peroxide value, <i>p</i>-anisidine value, the TOTOX index, and specific extinction coefficients (K₂₃₂ and K₂₆₈). Based on the FA profiles, health-related indices such as atherogenic index, thrombogenic index, and hypocholesterolemic/hypercholesterolemic ratio were also calculated. Additionally, the oxidative stability of the oils was assessed using an accelerated method-pressure differential scanning calorimetry. The obtained results demonstrated that the extraction method had a stronger influence on almond oil quality than the type of raw material. Oil extracted from unpeeled almonds using Soxhlet and cold solvent techniques showed better oxidative stability and more favorable FA profiles, while oils obtained using the Folch method and commercial refined oils exhibited higher levels of primary and secondary oxidation products. These findings were further supported by statistical analyses, which revealed distinct groupings based on oxidation indices and lipid composition.