The freezing process helps to preserve the quality of extra virgin olive oil over time: A case study up to 18months

Markers of sensory dynamics in phenols-rich virgin olive oils under optimal storage conditions

Early changes in sensory quality of phenols-rich virgin olive oil (VOO) and their relationship with the chemical changes are less studied in the literature. Therefore, the objective of this study was to propose a predictive model of dynamics of sensory changes based on specific chemical markers. The evolution of the sensory quality of phenol-rich VOOs from Tuscan cultivars stored under optimal storage conditions (i.e., absence of light, no O2 exposure, low temperature) was investigated using a multi-step methodological approach combining sensory (official sensory analysis (so-called Panel Test), Descriptive Analysis and Temporal Dominance of Sensation) and chemical measurements. The sensory map from descriptive data was related to the phenolic and volatile profiles, measured using HPLC-DAD and HS-SPME-GC-MS, respectively. A predictive model of the sensory changes over storage based on chemical compounds was developed. Results showed that very early changes involving phenolic and volatile compounds profiles occur in VOOs stored under optimal storage conditions, which turn in changes in sensory properties evaluated by the official panel test, the descriptive analysis and the temporal dominance of sensation. Furthermore, a chemical marker of sensory dynamics of oils during storage was identified as the ratio between two groups of secoiridoids. The proposed model, supported by the mentioned chemical marker, has the potential of improving the control of sensory changes in phenols-rich virgin olive oils during storage in optimal conditions.

Stability of monovarietal Sicilian olive oils under different storage condition: Chemical composition, sensory characteristics, and consumer preference

Monovarietal olive oils, known for their distinct aromatic profiles, face challenges in preserving their initial quality due to variations in stability and susceptibility to oxidative deterioration. This study focused on the storage stability of two Italian cultivars, 'Biancolilla' and 'Cerasuola', from Sicily, chosen for their aromatic complexity and divergent storage stability. Oils, whether filtered or unfiltered, underwent storage at two thermal regimes (18 °C and - 20 °C) over a year. The combination of filtration and low-temperature storage was employed to mitigate oxidative deterioration and hydrolytic processes, as filtration removes suspended particles and emulsified water, while low temperatures slow down enzymatic activities and oxidative reactions, thereby enhancing the overall stability and shelf life of the olive oils. Unfiltered samples at room temperature showed a significant increase in secoiridoid aglycone derivatives (Hydroxytyrosol and Tyrosol) due to hydrolytic processes, along with a decrease in secoiridoid aglycone. Filtration delayed these processes, with a more pronounced effect observed when combined with -20 °C storage. Sensory analysis identified the emergence of the "fusty" defect in the less resilient 'Biancolilla' cultivar after six months, a phenomenon mitigated by filtration and freezing. Consumer tests validated these findings. In summary, the synergistic approach of combining filtration with low-temperature storage emerges as a promising strategy for maintaining high-quality standards, especially for less stable monovarietal extra virgin olive oils. This strategy ensures compliance with EU regulations beyond the conventional 12-month shelf life, offering a practical solution for preserving the nutritional and sensory quality of olive oil.

Effect of freezing, fast-freezing by liquid nitrogen or refrigeration to preserve premium extra virgin olive oil during storage

During storage, premium extra virgin olive oils (PEVOO), which are oils of exceptional sensory quality, may lose the organoleptic characteristics that define them. This study assessed the effect of applying modified atmospheres and low temperatures (refrigeration and freezing) on the quality of 4 PEVOO for 24 months. Also, the effect of two freezing methods was studied (in the freezer at − 20 °C and in a bath of liquid nitrogen), along with the impact of freezing on the quality of the oils after thawing and storing at room temperature. Official quality parameters, organoleptic assessment, phenolic compounds, volatile compounds and oxidative stability index were measured periodically. While no significant effect of headspace composition was found, the oils stored at − 20 °C maintained their initial quality better than the oils stored at room temperature. Physicochemical quality parameters remained unchanged throughout the 24 months at − 20 °C. Polar phenolic and volatile compounds associated with green and fruity aromas were better preserved at − 20 °C, which translated into a minimum change in the sensory profile of the oils. While no significant difference was observed regarding oxidative parameters, freezing at − 20 °C maintained the initial volatile and sensory profile of the oils better than freezing with liquid nitrogen. Lastly, quality of thawed oils showed no significant differences compared to control oils during storage at room temperature. In conclusion, storage at − 20 °C maintains the quality of PEVOO, especially their sensory profile, and does not compromise their quality after thawing.

Evolution of Extra Virgin Olive Oil Quality under Different Storage Conditions

The extent and conditions of storage may affect the stability and quality of extra virgin olive oil (EVOO). This study aimed at evaluating the effects of different storage conditions (ambient, 4 °C and −18 °C temperatures, and argon headspace) on three EVOOs (low, medium, and high phenols) over 18 and 36 months, analyzing the main metabolites at six time points. The results showed that low temperatures are able to maintain all three EVOOs within the legal limits established by the current EU regulations for most compounds up to 36 months. Oleocanthal, squalene, and total phenols were affected by storage temperatures more than other compounds and degradation of squalene and α-tocopherol was inhibited only by low temperatures. The best temperature for 3-year conservation was 4 °C, but −18 °C represented the optimum temperature to preserve the organoleptic properties. The present study provided new insights that should guide EVOO manufacturers and traders to apply the most efficient storage methods to maintain the characteristics of the freshly extracted oils for a long conservation time.

Olive oil consumption can prevent non-communicable diseases and COVID-19 : Review

The Mediterranean diet is appraised as the premier dietary regimen and its espousal is correlated with the prevention of degenerative diseases and extended longevity. The consumption of olive oil stands out as the most peculiar feature of the Mediterranean diet. Olive oil rich in various bioactive compounds like oleanolic acid, oleuropein, oleocanthal, and hydroxytyrosol is known for its anti-inflammatory as well as cardioprotective property. Recently in silico studies have indicated that phytochemicals present in olive oil are a potential candidate to act against SARS-CoV-2. Although extensive studies on olive oil and its phytochemical composition; still, some lacunas persist in understanding how the phytochemical composition of olive oil is dependent on upstream processing. The signaling pathways regulated by olive oil in the restriction of various diseases is also not clear. To answer these queries, a detailed search of research and review articles published between 1990 to 2019 were reviewed in this effect. Olive oil consumption was found to be advantageous for various chronic non-communicable diseases. Olive oil's constituents are having potent anti-inflammatory activities and thus restrict the progression of various inflammation-linked diseases ranging from arthritis to cancer. But it is also notable that the amount and nature of phytochemical composition of household olive oil are regulated by its upstream processing and the physicochemical properties of this oil can give a hint regarding the manufacturing method as well as its therapeutic. Moreover, daily uptake of olive oil should be monitored as excessive intake can cause body weight gain and change in the basal metabolic index. So, it can be concluded that olive oil consumption is beneficial for human health, and particularly for the prevention of cardiovascular diseases, breast cancer, and inflammation. The simple way of processing olive oil maintains the polyphenol constituents and provides more protection against non-communicable diseases and SARS-CoV-2.

Virgin Olive Oil Volatile Compounds: Composition, Sensory Characteristics, Analytical Approaches, Quality Control, and Authentication

Volatile organic compounds strongly contribute to both the positive and negative sensory attributes of virgin olive oil, and more and more studies have been published in recent years focusing on several aspects regarding these molecules. This Review is aimed at giving an overview on the state of the art about the virgin olive oil volatile compounds. Particular emphasis was given to the composition of the volatile fraction, the analytical issues and approaches for analysis, the sensory characteristics and interaction with phenolic compounds, and the approaches for supporting the Panel Test in virgin olive oil classification and in authentication of the botanical and geographic origin based on volatile compounds. A pair of detailed tables with a total of approximately 700 volatiles identified or tentatively identified to date and tables dealing with analytical procedures, sensory characteristics of volatiles, and specific chemometric approaches for quality assessment are also provided.

EFFECTS OF FİLTRATİON PROCESS AND STORAGE TİME ON THE CHEMİCAL CHANGES AND SENSORY PROPERTİES OF OLİVE OİL EXTRACTED FROM TURKİSH USLU CULTİVAR

Upper Mesopotamia is a part of Turkish territory is the homeland of the olive tree with a wide range genetic resource. This is the first report on chemical composition and oxidative stability of olive oil extracted from Uslu cultivar grown locally in a small amount.  In this research, a Turkish olive cultivar named as “Uslu” locally grown in Akhisar was used for production of monocultivar extra virgin olive oil by using Mobile Olive Oil Processing Unit”. Olive oil samples were bottled before and after filtration and stored up to 24 months. Some chemical properties such as free fatty acid content, peroxide value, moisture content, UV absorbance value, minor and major components (fatty acid composition, tocopherols, total phenol compounds and phenolic composition), were determined during storage for 24 months. Chemical parameters such as free fatty acid, peroxide value except UV absorption values of both filtered and unfiltered “Uslu” olive oil samples were in agreement with the trade standards of International Olive Council (IOC). Color values of EVOO changed from green to yellow while UV absorbance values altered during storage. Very low free fatty acidy (0.2%) values which are unusual for commercial olive oils in Turkey were obtained for filtered and unfiltered samples. A slight increase was seen for unfiltered sample at the end of storage.  Filtration had no detectable effect on fatty acid profile. Filtered sample had higher total phenols (407.64±4.051 ppm) and α-tocopherol (237 and 123.31 ppm) contents than unfiltered ones and their contents decreased approximately 50% at the end of storage. Luteolin was the most abundant phenolic compound and its concentration decreased from 268.65±5.428 to 93.57±0.541ppm during storage. It seemed effect of filtration was more obvious on total phenolic contents. This study was good practice for producing premium extra virgin olive oil by using Mobile Olive Oil Processing Unit. The results obtained in this study showed that Uslu olive oils has a unique chemical composition and a good oxidative stability with high tocopherols and phenolics contents that are uncommon in most of the commercial olive oils.

Determination of some chemical and quality parameters of changes in turkish Sari Ulak monocultivar extra virgin olive oil during 12 months of storage

In this study Turkish monocultivar extra virgin olive oil (EVOO) “Sarı Ulak” was extracted by using the Mobile Olive Oil Processing Unit (TEM Oliomio 500-2GV, Italy). Changes in minor and major components and quality characteristics, free fatty acid content, peroxide value and UV absorbance value, were surveyed during a year’s storage period. “Sarı Ulak” olive oil samples were classified as EVOO according to the trade standards of the International Olive Council (IOC) based on free fatty acid, peroxide value, K232 and ΔK values up to the eighth month of the storage period. The results have shown that color values of EVOO changed from green to yellow slowly while UV absorbance values changed during storing. Total polyphenol content of extra virgin olive oil decreased from 205.17 ppm to 144.29 ppm during a year’s storage. Luteolin was the most abundant phenolic compound, and its concentration changed from 184.33 ppm to 115.06 ppm. Apigenin concentration was differed from 2.67 to 1.06 ppm during storing. The initial level of α-tocopherol contents was 184.51 ppm, it decreased to 147 ppm at the end of storage time. After 12 months of storing, about 20 % of α-tocopherol content was destroyed. The amounts of phenolic and tocopherol isomers decreased during storage as expected.

Modulating the bitterness of Empeltre olive oil by partitioning polyphenols between oil and water phases: Effect on quality and shelf life

Bitterness is a positive sensorial attribute of olive oil that mainly depends on phenol concentration. However, excessive bitterness may be unpleasant for consumers. The aim of this investigation was to evaluate if partitioning polyphenols between oil and water phases could modulate the bitterness of an Empeltre olive oil containing a phenolic concentration higher than the typical content for this olive oil variety. The linear relationship observed between the percentage of oil in the extraction system and the percentage of phenols removed from the oil permitted estimating the olive oil-to-water ratio required to reduce the concentration of phenols for a given value in order to modulate Empeltre olive oil bitterness. Olive oils after liquid-liquid extraction did not develop any negative sensory attributes, and their physicochemical parameters were not substantially affected. Liquid-liquid extraction using water as a solvent is a procedure capable of effectively reducing the total phenol compounds of Empeltre extra virgin olive oil and, as a consequence, of reducing its bitterness intensity without affecting the highest commercial category determined by the parameters legally established by European Community regulations just after extraction and during nine months of storage.

Influence of Extreme Storage Conditions on Extra Virgin Olive Oil Parameters: Traceability Study

This study reflects the effect of extreme storage conditions on several extra virgin olive oil (EVOO) varieties (arbequina, hojiblanca, and picual). The conditions were simulated in the laboratory, by means of heating treatments in stove at different temperatures (40 and 60°C) and times (two and three weeks). The aim is the evaluation of the deterioration of the quality parameters and minority components, which are responsible for the nutritional and therapeutic properties (fatty acids, polyphenols, pigments, and tocopherols), and organoleptic qualities. The quality criteria and limits used in this work are according to International Olive Council. The results contribute to the control of the traSceability for the commercialization of the EVOO.

Variability of 4-Monomethylsterols and 4,4'-Dimethylsterols in Olive Oil and Their Use as Indicators of Olive Variety, Ripening Degree, and Oil Storage Temperature

To investigate the variability of 4-monomethylsterols and 4,4'-dimethylsterols in olive oil as a result of variety, ripening, and storage temperature, 36 samples were subjected to gas chromatography with flame ionization detection (GC-FID) and with mass spectrometric detection (GC-MS), and results were processed by univariate and multivariate statistics. Relative amounts (percent) of β-amyrin, cycloartenol, and 24-methylenecycloartanol accounted for the most variation due to variety, while citrostadienol (percent) and 24-methylenecycloartanol (milligrams per 100 g) were strongly affected by ripening. Multivariate statistics differentiated olive oils regardless of storage conditions, which implied the possibility to use 4-monomethyl- and 4,4'-dimethylsterols as indicators of variety and ripening degree for fresh and stored oils. Absolute changes in 4-monomethyl- and 4,4'-dimethylsterols after storage were of a much smaller magnitude, meaning the investigated olive oils essentially retained health-beneficial features that derive from these compounds. Relative changes caused by storage were specific for each storage temperature and were useful in discriminating oils by linear discriminant analysis.

Assessment of carbon footprint and energy performance of the extra virgin olive oil chain in Umbria, Italy

The cradle to grave carbon footprint (CF) and energy footprint (EF) analysis of extra virgin olive oil (EVOO) produced in the Province of Perugia (Umbria, Italy) is assessed. In this study, olive orchard cultivation, EVOO extraction, bottling, packaging, storage at -18°C and distribution in the main importing countries were studied from a life cycle assessment perspective, with the main objective of identifying the processes with the largest environmental impacts. The selected functional unit was 1L of EVOO, packaged for distribution. Inventory data was gathered mainly through both direct communication using questionnaires and direct measurements. To determine the CF the ISO/TS 14067:2013 was followed while the EF was evaluated according to ISO standards 14040 and 14044. Results showed that the most impacting process is the distribution, mainly due to the choice of employing air transport. The main other hot spots identified were the olive orchard fertilization, EVOO freezing during its storage at the olive mill factory and the manufacture of glass bottles. Suggested improvement opportunities included shifts in the EVOO transportation policy, the introduction of lighter glass bottles in the bottling process, the use of cooling agent with lower global warming potential and the employment of biodiesel in the farming machineries.