A rapid in-house validated GC-FID method for simultaneous determination of lipophilic bioactives in olive oil: Squalene, α-tocopherol, and β-sitosterol

Supercritical CO2 Extraction of Phytocompounds from Olive Pomace Subjected to Different Drying Methods

Olive pomace is a semisolid by-product of olive oil production and represents a valuable source of functional phytocompounds. The valorization of agro-food chain by-products represents a key factor in reducing production costs, providing benefits related to their reuse. On this ground, we herein investigate extraction methods with supercritical carbon dioxide (SC-CO₂) of functional phytocompounds from olive pomace samples subjected to two different drying methods, i.e., freeze drying and hot-air drying. Olive pomace was produced using the two most common industrial olive oil production processes, one based on the two-phase (2P) decanter and one based on the three-phase (3P) decanter. Our results show that freeze drying more efficiently preserves phytocompounds such as α-tocopherol, carotenoids, chlorophylls, and polyphenols, whereas hot-air drying does not compromise the β-sitosterol content and the extraction of squalene is not dependent on the drying method used. Moreover, higher amounts of α-tocopherol and polyphenols were extracted from 2P olive pomace, while β-sitosterol, chlorophylls, and carotenoids were more concentrated in 3P olive pomace. Finally, tocopherol and pigment/polyphenol fractions exerted antioxidant activity in vitro and in accelerated oxidative conditions. These results highlight the potential of olive pomace to be upcycled by extracting from it, with green methods, functional phytocompounds for reuse in food and pharmaceutical industries.

Determination of squalene in edible oils by transmethylation and GC analysis

Squalene is a triterpenoid with medicinal, therapeutic and cosmetic applications. There is interest in identifying novel sources of squalene, creating a need for a rapid and accurate method of squalene determination. Here, we describe such an approach that involves first transmethylating the oil base containing squalene using a basic catalyst, followed by addition of internal standard and quantification by gas chromatography flame ionization detection (GCIFD).

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The method uses a single reference standard for quantification.

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Validation showed it to be both repeatable and accurate.

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It was successfully applied to nutraceutical and edible oils containing squalene.

Effect of subcritical water and steam explosion pretreatments on the recovery of sterols, phenols and oil from olive pomace

Hydrothermal pretreatments including steam explosion and subcritical water (SCW) facilitate hydrolyses of plant cell wall materials and supply environmentally friendly extraction solvents to recover value added compounds. In this study, effect of steam and SCW and temperature (160, 180 and 200 °C, 5 min) on yield and β-sitosterol content of pomace oil and phenolics were compared for value added utilization of olive pomace. Compared to acid hydrolysis, hydrothermal pretreatments yielded similar oil recovery. 54-76% of the bound oil and 18-32% of the bound β-sitosterol of the pomace were recovered by hydrothermal pretreatments. Steam pretreatment was more effective than SCW pretreatment at lower temperatures, however SCW showed increasing trend on oil yield related to steam pretreatment. As further research on process development, use of sequential temperature might be investigated, starting with steam explosion (<180 °C), followed by SCW pretreatment (>200 °C) to obtain multiple, aqueous and meal, fractions for total valorization of olive pomace.