Solid carbon dioxide to promote the extraction of extra-virgin olive oil

Abstract

The use of solid carbon dioxide (dry ice) as a cryogen is widespread in the food industry to produce high quality wines, rich in color and perfumes. The direct addition of carbon dioxide to olives in the solid state before milling represents a fundamental step which characterizes this innovative extraction system.\ud At room temperature conditions solid carbon dioxide evolves directly into the air phase (sublimation), and the direct contact between the cryogen and the olives induces a partial solidification of the cellular water inside the fruits. Since the volume occupied by water in the solid state is higher than that in the liquid state, the ice crystals formed are incompatible with the cellular structure and induce the collapse of the cells, besides promoting the diffusion of the cellular substances in the extracted oil, which is thus enriched with cellular metabolites characterized by a high nutraceutical value. Furthermore, a layer of CO2 remains over the olive paste to preserve it from oxidative degradation. The addition of solid carbon dioxide to processed olives induced a statistically significant increase in oil yield and promoted the accumulation of tocopherols in the lipid phase, whereas a not significant increase in the phenolic fraction of the oil occurred

Potato Peels as a Source of Novel Green Extracts Suitable as Antioxidant Additives for Fresh-Cut Fruits

“…To maximize the recovery of the bioactive compounds from potato waste, the peels stored as described were maintained in direct contact with solid CO 2 (ratio peels/CO 2 , s = 1/1 w/w) over a period of 24 h. The addition of a cryogen to vegetal matrix induces, indeed, intracellular water freezing, and as a consequence of the greater volume occupied by the same amount of water in solid state than in the liquid phase, the consequent laceration of cellular membranes (cellular break) occurs permitting the immediate diffusion of many cellular compounds in the liquid phase [20]. The bioactive compounds present in potato peels (P) were then protected by oxidation due to the sublimation of solid CO 2 that at room temperature and 1 atm of pressure passes to the gaseous phase, thus forming an inert gas layer in storage atmosphere [19].…”

“…According to the literature [20][21][22]35], cryomaceration of vegetal byproducts by means of solid carbon dioxide can be profitably applied to improve the green extraction of bioactive compounds, favouring the next mass transfer processes in solid/liquid extraction. Furthermore, the concentration of phenolic compounds in both of the proposed extracts appears comparable with data obtained by our group when Sc-CO 2 was utilized in combination with ethanol to promote the supercritical fluid extraction (SFE) of phenolic compounds from potato byproducts [36].…”

“…In this context the objective of this research was twofold: (i) to verify the effectiveness of an innovative multi-step green extraction process to recover some high-added-value antioxidant compounds from organic potato byproducts; (ii) to evaluate the preservation during postharvest storage of the main quality physicochemical parameters of MP fruits. In order to improve the extraction yield, as well as to avoid the oxidation of extracted compounds [19][20][21][22], the potato peels were cryomacerated with the use of solid CO 2 before their utilization as substrate in solid/liquid extraction with different solutions. Finally, the obtained extracts were utilized alone or in combination with citric acid in the pretreatment of cubes of fresh-cut apples, and the results obtained in terms of shelf life extension were compared with those collected in the same experimental conditions when traditional preserving solutions (i.e., ascorbic acid, citric acid, and BHT) were utilized.…”

Preliminary Results About the Use of Argon and Carbon Dioxide in the Extra Virgin Olive Oil (EVOO) Storage to Extend Oil Shelf Life: Chemical and Sensorial Point of View

“…The quality of an olive oil depends on many factors such as cultivar, climate conditions, agronomic techniques, harvesting time, and olive crushing method . Furthermore, the storage and packaging conditions are decisive for the commercial life of several foods and beverages as well as olive oil .…”

Development of Phenol-Enriched Olive Oil with Phenolic Compounds Extracted from Wastewater Produced by Physical Refining

“…As widely reported in the literature, oil manufacturers aim at producing foods that maintain their shelf life and nutritional quality over a defined period [ 11 , 12 , 13 ]. Thus, the use of antioxidants to minimize the oxidation of lipids in food materials is extensively accepted [ 14 ].…”