Effect of Clarification System on the Conservation of Virgin Olive Oil during Its Storage

Abstract

The results obtained in this work explain how clarification systems can affect the conservation of virgin olive oils (VOOs) during the storage step. The evolution of the quality and sensory properties during the storage of VOOs clarified by different systems, vertical centrifugal separator (VCS) with minimal water addition and conical bottom settling tank (CBST), is studied at industrial scale for two different crop years. In general, VCS oils show a slight higher moisture and solid impurities content at the end of the storage step due to a higher emulsion grade (because of the emulsion generated) caused by the rotating movement of this clarification system. For the studied clarification systems, no remarkable differences are observed between the oils during their storage for quality indexes. However, these systems show differences regarding oil sensory properties. The VOOs clarified by VCS are characterized by a higher presence of phenol components, higher positive sensory attributes intensity, and higher lipoxygenase (LOX) aldehydes content during their storage. VOOs from CBST show lower phenol content, a higher “non‐LOX” volatiles content, and the presence of sensory defects during storage. Practical Applications: The results obtained in this work are very important in order to provide specific recommendations and scientific support based on objective data to improve VOO quality. As described in this study, the VCS with a minimal water addition can be a better option to produce VOO of improved quality. This clarification system is an efficient and quick operation that reduces the contact between oil and the remaining water and impurities during the storage step. The minimal water addition used in this clarification system allows obtaining VOOs with higher phenol content and positive sensory notes. This leads to prolong VOO shelf‐life and conservation during the storage stage, due to preservation of the quality indexes and minor components with antioxidant activity. Besides, this clarification system reduces the water consumption during oil clarification and generates a lower wastewater volume regarding conventional vertical centrifugation, and therefore can be considered more environmentally friendly.

Composition and Physical Stability of the Colloidal Dispersion in Veiled Virgin Olive Oil

“…They showed an effect of the oil extraction technique on the water droplets size; the three-phase decanter extraction formed larger and more polydispersed droplets than the two-phase decanter extraction. Gila et al [13] observed a better performance of gravity sedimentation than centrifugation in reducing the content of moisture and solid organic impurities during VOO storage; the above results were explained by a highest emulsification degree in the centrifuged VOO as a result of the rotating movement imposed by the centrifuge.…”

“…The effect of the above operations on VOO was studied and some innovative plant solutions were proposed. [13][14][15][16] Many effects on oil quality were observed after filtration, in relation with its high efficacy to remove water and solids. [9] According to "Best Practice Guideline for the Storage" document (IOC/BPS/Doc.…”

“…An overall improvement of oil shelf-life was also related to removal of water and solids by means of gravity sedimentation and centrifugation, even though to a lesser extent in comparison with filtration. [13][14][15] Recently, Cayuela-Sanchez and Caballero-Guerrero [2] suggested a more extended characterization of the cloudy appearance, which is also based on methods to estimate the so-called colloidal stability. Microdroplets of vegetation water, solid particles from fruit pulp, and stone fragments are the main components of the dispersed phase.…”

“…An overall improvement of oil shelf‐life was also related to removal of water and solids by means of gravity sedimentation and centrifugation, even though to a lesser extent in comparison with filtration. [ 13–15 ]…”

“…Gila et al. [ 13 ] observed a better performance of gravity sedimentation than centrifugation in reducing the content of moisture and solid organic impurities during VOO storage; the above results were explained by a highest emulsification degree in the centrifuged VOO as a result of the rotating movement imposed by the centrifuge.…”