Extraction and Purification of Squalene from Virgin Olive Oil via Catalytic Transesterification and Molecular Distillation

Abstract

Squalene, a highly valuable compound abundant in various natural sources, shows great potential in pharmaceutical, cosmetic, and nutraceutical applications. This research article outlines a comprehensive methodology for extracting and purifying squalene from virgin olive oil, a rich source of the compound. The extraction process begins with degumming, which involves heating the olive oil to 60-70°C to reduce viscosity, followed by the addition of 2-3% warm water to hydrate phospholipids. Food-grade phosphoric acid is then added to react with the phospholipids, forming precipitates. The mixture is stirred for 20-30 minutes and allowed to rest for an additional 20-30 minutes, enabling impurities to settle. The upper layer of degummed oil is separated via decantation or centrifugation and washed with warm water for pH adjustment. Next, transesterification is performed by mixing 100 ml of virgin olive oil with 25% methanol (w/w) and a catalyst (0.5% sodium methoxide or PTSA), and heating the mixture to 80-90°C under reflux for 1-2 hours. Following transesterification, the solvent and acetone are distilled out, and acetone precipitation is repeated 2-3 times to remove unsaponified matter, which is then filtered and evaporated. The concentrated oil undergoes molecular distillation at 180°C and 0.0033 bar pressure for 1 hour, yielding the distillate and residue for further analysis. Qualitative analysis using Thin Layer Chromatography (TLC) involves Merck TLC plates with silica gel 60 F254 and a hexane: chloroform (9:1) mobile phase. Spots are developed with a 10% HCl solution, confirming the presence of squalene with an RF value of 0.93. Quantitative analysis via High-Performance Thin-Layer Chromatography (HPTLC) employs Merck TLC plates with cyclohexane as the mobile phase and CAMAG at 254 nm and 366 nm wavelengths, revealing a squalene purity of 67% and a recovery rate of 69.8%. The initial purification through transesterification facilitated the conversion of ester groups, yielding squalene-rich fractions, while acetone precipitation effectively removed saponified matter. Molecular distillation further enhanced squalene purity. TLC analysis confirmed the qualitative presence of squalene, and HPTLC provided precise quantitative measurements. The obtained squalene purity of 67% significantly enriches the initial content in virgin olive oil, though further optimization could enhance purity and yield. Complementary techniques like GC-MS or HPLC could validate the purification process. This study presents an efficient, replicable procedure for extracting and purifying squalene from virgin olive oil, with significant implications for pharmaceutical, cosmetic, and nutraceutical industries. The findings support a sustainable and ethical shift towards vegetable-derived squalene, meeting market demands while ensuring high-quality production.