Virgin olive oil sensory properties: Comparing trained panel evaluation and consumer preferences

Activation of specific bitter taste receptors by olive oil phenolics and secoiridoids

Extra-virgin olive oil (EVOO) is a critical component of the Mediterranean diet, which has been found beneficial to human health. Bitterness is often positively associated with the presence of phenolic compounds in EVOO. There are twenty-five bitter taste receptors (TAS2Rs) in humans, each of which responds to specific bitter tastants. The identity of phenolic compounds and the bitter taste receptors they stimulate remain unknown. In this study, we isolated 12 phenolic and secoiridoid compounds from the olive fruit and the oil extracted from it, and tested their ability to stimulate bitter taste receptor activity, using a calcium mobilization functional assay. Our results showed that seven out of twelve studied compounds activated TAS2R8, and five of them activated TAS2R1, TAS2R8, and TAS2R14. The phenolic compounds oleuropein aglycon and ligstroside aglycon were the most potent bitter tastants in olive oil. TAS2R1 and TAS2R8 were the major bitter taste receptors activated most potently by these phenolic compounds. The results obtained here could be utilized to predict and control the bitterness of olive oil based on the concentration of specific bitter phenolics produced during the milling process of olives.

Check-All-That-Apply (CATA) Test to Investigate the Consumers' Perception of Olive Oil Sensory Properties: Effect of Storage Time and Packaging Material

Sensory changes during shelf-life of oils have been mostly studied by descriptive methods, while consumer-based approaches have been poorly explored. This study assessed the variations in consumers’ liking and sensory perception of extra virgin olive oil (EVOO) and olive oil (OO) packaged in glass, polyethylene terephthalate and tinplate. After 2, 10 and 19 months of storage, oil perception was investigated with consumers (n = 50) performing both a liking test and a check-all-that-apply (CATA) test. No significant effect of the packaging material on consumers’ response was found, whereas storage time negatively affected the sensory properties of and acceptability of OOs and EVOOs from the 10th month of storage. The CATA test results revealed the sensory changes in oils over 19 months, mainly described as a decrease in pungency for EVOO and a decrease in herbaceous and ripe fruitiness in OO. The CATA technique combined with the liking test allowed the drivers of liking (“olive” for OO and “green fruitiness” for EVOO) and disliking (“bitter” and “pungent” for EVOO) to be identified. In conclusion, the sensory approach based both on CATA technique and liking test seems promising as a rapid tool to evaluate the changes in sensory properties perceivable during the shelf-life of oils.

Alignment and Proficiency of Virgin Olive Oil Sensory Panels: The OLEUM Approach

A set of 334 commercial virgin olive oil (VOO) samples were evaluated by six sensory panels during the H2020 OLEUM project. Sensory data were elaborated with two main objectives: (i) to classify and characterize samples in order to use them for possible correlations with physical–chemical data and (ii) to monitor and improve the performance of panels. After revision of the IOC guidelines in 2018, this work represents the first published attempt to verify some of the recommended quality control tools to increase harmonization among panels. Specifically, a new “decision tree” scheme was developed, and some IOC quality control procedures were applied. The adoption of these tools allowed for reliable classification of 289 of 334 VOOs; for the remaining 45, misalignments between panels of first (on the category, 21 cases) or second type (on the main perceived defect, 24 cases) occurred. In these cases, a “formative reassessment” was necessary. At the end, 329 of 334 VOOs (98.5%) were classified, thus confirming the effectiveness of this approach to achieve a better proficiency. The panels showed good performance, but the need to adopt new reference materials that are stable and reproducible to improve the panel’s skills and agreement also emerged.

Consumers' Perceptions and Preferences for Bitterness in Vegetable Foods: The Case of Extra-Virgin Olive Oil and Brassicaceae-A Narrative Review

The presence of some healthy phytochemicals in food can be paired with high bitterness, and consumers have a widespread avoidance toward bitter-tasting food. This causes a gap between preferences and healthy needs of consumers. Therefore, this review collected insights from literature belonging to different discipline domains in order to have a broad view of the current state-of-the-art about biochemical aspects and consumers’ perceptions and preferences toward foods with an enhanced bitter taste. In detail, we focused on two core products of the Mediterranean diet: Extra-virgin olive oil (EVOO) and Brassicaceae, both characterized by specific phytochemicals having strong healthy properties and bitter-pungent taste. Results suggested that, although bitter taste is a general driver of dislike, some exceptions can be represented by: niches of consumers (e.g., innovators and organic buyers), foods consumed with specific purposes (e.g., coffee, chocolate, and alcoholic beverages). The level of bitterness perceived by the consumers can be modulated through exposure, information on benefits, and elements within the environment (e.g., music). Thus, these insights can be used to develop specific campaigns aimed at promoting bitter (healthy) food, considering also the key role that could be played by food pairings.

Chemical and Sensorial Characteristics of Olive Oil Produced from the Lebanese Olive Variety ‘Baladi’

The olive oil quality, nutritional and sensorial characteristics are associated with the chemical composition, which is the result of a complex interaction between several environmental, agronomical and technological factors. The aim of the present study is to investigate the impact of the geographical origin, harvesting time and processing system on the chemical composition and sensorial characteristics of olive oils produced from the Lebanese olive ‘Baladi’. Samples (n = 108) were collected from North and South Lebanon, at three different harvesting times and from four processing systems. Results showed a strong effect of origin, processing system and harvest time on oil quality, fatty acid composition, total phenols and OSI. The early harvest showed higher total phenols content (220.02 mg GAE/Kg) and higher OSI (9.19 h). Moreover, samples obtained from sinolea and 3-phases recorded the lowest free acidity (0.36% and 0.64%), and the highest OSI (9.87 and 9.84 h). Consumers were not unanimous regarding the studied factors, although samples recording high ranks were mostly from South using sinolea, 3-phases and press systems at early and intermediate harvest. The overall findings suggest that the selection of the harvesting time and of the processing system could have significant influence on the characteristics of the olive oil.

Influence of olive ripening degree and crusher typology on chemical and sensory characteristics of Correggiolo virgin olive oil

BACKGROUND

In this study, two types of crusher, hammer and blade, were used to produce olive oils from cv. Correggiolo olives at four stages of ripeness, to analyse the effect of these two factors on oil quality indices (free acidity, peroxide value, UV absorption), on phenolic compounds content and sensory profiles. Differences in chemical and sensory data were analysed by two-way ANOVA.

RESULTS

Ripeness exerted a stronger influence than the crushing equipment on quality indices, phenolic content and sensory evaluation; moreover the statistical significance of interaction between the factors considered suggests that they are intertwined. Differences in the texture of olive pastes obtained by squashing and crushing were clearly evident at the first stage of ripeness via observation with a scanning electron microscope. The stronger mechanical action of the hammer crusher also produced smaller pit fragments compared to the blade crusher, as shown by particle size analysis of the kernels fragments.

CONCLUSION

Knowledge about the interaction between ripening and crushing will allow olive oil producers to pursue a product of the quality most suitable for a particular type of consumer. For example, bitterness and pungency, characters recently connected with health effects because sensory markers of extra virgin olive oil (EVOO) polyphenols, do not have a great sensory appeal for most consumers; however, there is a niche of gourmet estimators interested in these peculiar flavours and ready to pay a premium price for them. The producer will be able to customise the EVOO by modulating its chemical and sensory characteristics, especially the phenolic fraction, thus addressing the needs of consumers with different tastes. © 2016 Society of Chemical Industry.

Autochthonous cultivars of Emilia Romagna region and their clones: Comparison of the chemical and sensory properties of olive oils

The olive species (Olea europaea L.) is characterized by significant phenotypic and genetic variability the genetic matrix has a strong influence on several important extra virgin olive oil (EVOO) chemical components. Four clones from cultivars autochthonous of the Emilia Romagna region were selected for their notable performance in terms of agronomical characteristics, and the quality of the olive oil produced was studied in detail. In particular, we analyzed the fatty acid composition, the phenolic profile and the sensory analysis of the oils from these clones and compared them with the oils from the respective cultivars. Most of the new clones, all already provided with a genetic and sanitary certification, exhibited overall higher qualitative standards than the cultivars, producing monovarietal oils interesting both nutritionally and from a sensory point of view, and furthermore with a beneficial effect on health.