Bitterness enhancement induced by cut grass odorant (cis-3-hexen-1-ol) in a model olive oil

Characterization and Comparison of Extra Virgin Olive Oils of Turkish Olive Cultivars

Extra virgin olive oils (EVOOs) obtained from five Turkish olive cultivars widely produced in the Aegean and Marmara regions were investigated based on their total antioxidant capacity (TAC), total phenolic content (TPC), pigment contents, fatty acid (FA) profiles, phenolic compounds (PC), volatile compounds (VC), and sensory properties. The results showed that all properties of EVOO samples were significantly affected by the olive cultivar used. The pigment contents in Ayvalık (9.90 mg·kg^-1) and Uslu (9.00 mg·kg^-1) oils were higher than the others (p < 0.05). The greatest values for oleic acid (74.13%) and TPC (350.6 mg·kg^-1) were observed in Gemlik and Domat oils, respectively (p < 0.05). Edincik oil showed the maximum hydroxytyrosol content (48.022 mg·kg^-1) and TAC value (515.36 mg TE·kg^-1) (p < 0.05). The Edincik, Domat, and Uslu oils were significantly not different for the total content of C6 compounds derived by lipoxygenase, which are the main volatiles responsible for the typical aroma of EVOOs (p > 0.05). Domat oil also exhibited the highest scores for bitterness and pungency perceptions (p < 0.05). The fruitiness scores of the oil samples (except for Ayvalık oil) were close to each other, even if they were statistically different (p < 0.05). Principal component analysis (PCA) indicated that the Ayvalık oil was separated from the others due to its poor-quality characteristics. As a result, it can be stated that Domat olive oil has better quality than the others.

Fruit quality parameters and volatile compounds from 'Palmer' mangoes with internal breakdown

The internal breakdown (IB) is a premature and uneven mango pulp ripening physiological disorder that is noticed only when the fruit is sliced for consumption. Thus, there is a demand for analytical methods to detect IB in mangoes to avoid consumer dissatisfaction and reduce postharvest waste. In this work, physicochemical and volatile compounds were determined to evaluate the ability to predict pulp IB. Principal components analysis (PCA) and partial least squares discriminant analysis (PLS-DA) of the data show that color, firmness, and volatiles compounds are important to give some information about the physiological changes caused by IB. The volatile compounds methacrylic acid, ethyl ester, isopentyl ethanoate, limonene oxide, (E)-2-pentenal, tetradecane, and γ-elemene were identified as chemical markers of IB. Therefore, mango physical and chemical characteristics combined with PCA and PLS-DA were successfully employed for the identification of IB in mangoes, showing significant differences between healthy and IB fruits.

Comparative Study of Volatile Compounds and Sensory Characteristics of Dalmatian Monovarietal Virgin Olive Oils

Volatile compounds are chemical species responsible for the distinctive aroma of virgin olive oil. Monovarietal olive oils have a peculiar composition of volatiles, some of which are varietal descriptors. In this paper, the total phenolic content (TPC), fatty acid composition, volatile compounds, and sensory profile of monovarietal olive oils from four Dalmatian most common olive cultivars-Oblica, Lastovka, Levantinka, and Krvavica-were studied. The volatile composition of olive oils was analyzed using headspace solid-phase microextraction with gas chromatography/mass spectrometry. The highest mean TPC value was measured in Oblica and Krvavica oils (around 438 mg/kg). The difference among cultivars for fatty acids composition was detected for C16:1, C17:0, C18:1, C18:2, and the ratio C18:1/C18:2. Krvavica oils showed clear differences in fatty acid composition compared to oils from other cultivars. The most prevalent volatile compound in all oils was C6 aldehyde E-2-hexenal, with the highest value detected in Levantinka oils (75.89%), followed by Lastovka (55.27%) and Oblica (54.86%). Oblica oils had the highest value of Z-3-hexen-1-ol, which influenced its characteristic banana fruitiness, detected only in this oil. Lastovka oils had the highest amount of several volatiles (heptanal, Z-2-heptenal, hexanal, hexyl acetate), with a unique woody sensation and the highest astringency among all studied cultivars. Levantinka oils had the highest level of almond fruitiness, while Krvavica oils had the highest level of grass fruitiness.

Characterization of virgin olive oils obtained from minor Tunisian varieties for their valorization

Several compositional parameters (fatty acids, tocopherols, polar phenols and volatiles) in virgin olive oils from varieties located at the center of Tunisia, namely Baldi, Chemchali, Neb Jmel, Tounsi and Besbessi from Gafsa and Chemchali and Sehli cultivated in Sidi Bouzid, were studied. To the best of our knowledge, this is the first study focusing on the chemical composition of virgin olive oils (VOO) from Sidi Bouzid. Significant differences were found between varieties from Sidi Bouzid and Gafsa in monounsaturated saturated fatty acid levels, some volatile compounds and γ-tocopherol amounts. Notably, Tounsi and Baldi VOOs showed the highest six carbon atoms alcohol contents, whereas Neb Jmel VOO revealed the highest aldehyde six carbon atoms content. Fatty acid composition, as well as tocopherol content, showed differences among different VOO. Principal component analysis and hierarchical component analysis on polar phenols, fatty acids, tocopherols and volatiles data evidenced a good discrimination among oils from the different investigated varieties.

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.

Flavor Chemistry of Virgin Olive Oil: An Overview

Virgin olive oil (VOO) has unique chemical characteristics among all other vegetable oils which are of paramount importance for human health. VOO constituents are also responsible of its peculiar flavor, a complex sensation due to a combination of aroma, taste, texture, and mouthfeel or trigeminal sensations. VOO flavor depends primarily on the concentration and nature of volatile and phenolic compounds present in olive oil which can change dramatically depending on agronomical and technological factors. Another aspect that can change the flavor perception is linked to the oral process during olive oil tasting. In fact, in this case, some human physiological and matrix effects modulate the flavor release in the mouth. The present review aims to give an overview on VOO flavor, with particular emphasis on the mechanisms affecting its production and release during a tasting.

Tree Planting Density and Canopy Position Affect ‘Cerasuola’ and ‘Koroneiki’ Olive Oil Quality

To maximize orchard production and tree crop efficiency, optimization of both maximum orchard light interception and radiation distribution within the tree canopy are important strategies. To study the influence of planting density and fruit position within the canopy on oil quality from ‘Cerasuola’ and ‘Koroneiki’ olive (Olea europaea L.), fruits were harvested from the upper and lower canopy layers of trees in hedgerow planting systems at two densities: High at 1000 trees ha−1 (HD) and Medium at 500 trees ha−1 (MD). Tree crop efficiency and fruit weight, water and fat content were measured together with olive oil standard quality parameters, phenolic and volatile composition. Fruits in the upper layers of the canopy always showed a higher maturity index, 6% more fat content, and 4% less water content than lower layers. Upper layers of HD trees showed the highest phenol content, whereas lower layers of MD trees showed the lowest phenol content (36% less than the upper layers of HD). HD trees showed the largest differences in fruit maturation, water and fat content between upper and lower canopy positions, increasing quality and oil yield variability at harvest. ‘Koroneiki’ showed more stable oils with a 28% higher MUFA/PUFA ratio and 12% higher phenol content than ‘Cerasuola’ oils. This study provides further evidence of the fact that cultivar, planting density, and canopy architecture may be strong determinants of olive oil yield and composition in hedgerow planting systems.

Exploring Olfactory-Oral Cross-Modal Interactions through Sensory and Chemical Characteristics of Italian Red Wines

This work aimed at investigating red wine olfactory–oral cross-modal interactions, and at testing their impact on the correlations between sensory and chemical variables. Seventy-four Italian red whole wines (WWs) from 10 varieties, and corresponding deodorized wines (DWs), were evaluated by sensory descriptive assessment. Total phenols, proanthocyanidins, ethanol, reducing sugars, pH, titratable and volatile acidity were determined. PCA results highlighted different sensory features of the 10 wine types. ANOVAs (p < 0.05) showed that olfactory cues might play modulation effects on the perception of in-mouth sensations with 7 (harsh, unripe, dynamic, complex, surface smoothness, sweet, and bitter) out of 10 oral descriptors significantly affected by odours. Three weak but significant positive correlations (Pearson, p < 0.0001) were statistically found and supported in a cognitive dimension: spicy and complex; dehydrated fruits and drying; vegetal and unripe. In the absence of volatiles, correlation coefficients between sensory and chemical parameters mostly increased. Proanthocyanidins correlated well with drying and dynamic astringency, showing highest coefficients (r > 0.7) in absence of olfactory–oral interactions. Unripe astringency did not correlate with polyphenols supporting the idea that this sub-quality is a multisensory feeling greatly impacted by odorants. Results support the significance of cross-modal interactions during red wine tasting, confirming previous findings and adding new insights on astringency sub-qualities and their predictive parameters.

Multivariate Statistical Analysis and Odor-Taste Network To Reveal Odor-Taste Associations

Odor-taste association has been successfully applied to enhance taste perception in foods with low sugar or low salt content. Nevertheless, selecting odor descriptors with a given associated taste remains a challenge. In the aim to look for odors able to enhance some specific taste, we tested different multivariate analyses to find links between taste descriptors and odor descriptors, starting from a set of data previously obtained using gas chromatography/olfactometry-associated taste: 68 odorant zones described with 41 odor descriptors and 4 taste-associated descriptors (sweetness, saltiness, bitterness, and sourness). A partial least square analysis allowed for identification of odors associated with a specific taste. For instance, odors described as either fruity, sweet, strawberry, candy, floral, or orange are associated with sweetness, while odors described as either toasted, potato, sulfur, or mushroom are associated with saltiness. A network representation allowed for visualization of the links between odor and taste descriptors. As an example, a positive association was found between butter odor and both saltiness and sweetness. Our approach provided a visualization tool of the links between odor and taste description and could be used to select odor-active molecules with a potential taste enhancement effect based on their odor descriptors.

Seeking for sensory differentiated olive oils? The urge to preserve old autochthonous olive cultivars

Mediterranean olive heritage richness is poorly characterized. Olive oils from minor cultivars of Northeast-Portugal (Lentisca, Madural, Rebolã, Redondal, Verdeal and Verdeal Transmontana) from centenarian trees were chemical and sensory characterized, aiming to identify autochthonous cultivars capable of producing differentiated olive oils. All oils, produced during two campaigns, were classified as extra virgin. Cv. Redondal showed the highest oxidative stability (OS), total phenols, vitamin E and C_18:1/C_18:2. Contrary, cv. Madural presented the lowest OS and C_18:1/C_18:2 ratios, supporting the importance of fatty acids on OS, while cv. Verdeal had the lowest total phenols and vitamin E contents. Sensory notes of tomato, apple, dry fruits, fresh herbs, tomato leaves and cabbage were predominant on the oils of most cultivars, whilst some attributes were more specific, such as banana and kiwi (Madural), cherry and apricot (cvs. Lentisca and Madural). The chemical and sensory diversity enabled the statistical discrimination of all cultivars and harvesting years.

Sensory Profiling and Consumer Acceptance of Pasta, Bread, and Granola Bar Fortified with Dried Olive Pomace (Pâté): A Byproduct from Virgin Olive Oil Production

An olive pomace (pâté) obtained from virgin olive oil production, was used for the fortification of pasta, bread, and granola bar. For each food, a control (without pâté) and a fortified sample (with pâté, 7% in pasta and 5% in bread and granola bar) were manufactured. Descriptive analysis showed that pâté strongly affected the appearance of pasta and bread and increased the bitterness of bread and granola bar but not pasta. Granola bar was less affected in general, likely because of its higher ingredient complexity. In a central location test with 175 Californian consumers, both the control and the fortified samples of all three foods were well accepted overall, with only the mean liking of the appearance of the fortified pasta falling below the "neither like nor dislike" mark. Approximately 30% of consumers preferred the fortified sample over the control for each food and 50% were willing to pay more for the fortified products. The percentage of phenols from pâté recovered in the prepared samples was such that 63 g of pasta, 18 g of bread, and 12 g of granola bar would be sufficient to meet the EFSA health claim for olive oil phenols. This study demonstrates that pâté can be used for fortification of foods for human consumption, thus adding potential economic value to the virgin olive oil production chain and allowing for a higher daily intake of phenols from Olea europaea L., whose beneficial health properties are well recognized. PRACTICAL APPLICATION: The dried olive oil pomace (pâté) that we developed and tested in this research can be used to fortify pasta, bread, and granola bars with health-beneficial phenols with only slight alterations of their sensory profiles and slight reduction in consumer acceptance. Virgin olive oil producers can use this byproduct and gain further economic value from olive oil production.

Gas Chromatography-Mass Spectrometry-Olfactometry To Control the Aroma Fingerprint of Extra Virgin Olive Oil from Three Tunisian Cultivars at Three Harvest Times

Gas chromatography-mass spectrometry-olfactometry was used for the analysis of volatile compounds and key odorants of three less studied Tunisian olive oil cultivars for the first time. A total of 42 aroma compounds were identified and quantified in extra virgin olive oils. The present study revealed that the most dominant volatiles in olive oil samples qualitatively and quantitatively were aldehydes and alcohols, followed by terpenes and esters. Indeed, chemometric analysis has shown a correlation between chemical compounds and sensory properties. The determination of aroma-active compounds of olive oil samples was carried out using aroma extract dilution analysis. A total of 15 aroma-active compounds were detected in the aromatic extract of extra virgin olive oil, of which 14 were identified. On the basis of the flavor dilution (FD) factor, the most potent aromatic active compound was hexanal (FD = 512) in Fakhari olive oil, (FD = 256) in Touffehi oils, and (FD = 128) in Jemri olive oil.

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.

Phenolic compounds of 'Galega Vulgar' and 'Cobrançosa' olive oils along early ripening stages

In this study, the lipophilic and hydrophilic phenol composition of virgin olive oils (VOO) obtained from olives from two of the most important Portuguese cultivars ('Galega Vulgar' and 'Cobrançosa'), harvested at different ripening stages and under two irrigation schemes (rain fed and irrigated), was evaluated. Phenolic alcohols (hydroxytyrosol and tyrosol), phenolic acids and derivatives and flavonoids (luteolin and apigenin), as well as tocopherols were quantified. Lipophilic (>300mgkg(-1)) and hydrophilic phenols (>600mgkg(-1)) were present in high contents in both VOO, for early ripening stages. Gamma-tocopherol content is higher in 'Galega Vulgar' VOO. Total phenols showed a decrease between ripening index 2.5 and 3.5. The dialdehydic form of elenolic acid linked to hydroxytyrosol (3,4-DHPEA-EDA), also known as oleacein, was the major phenolic compound identified in both oils. The concentration of free hydroxytyrosol and tyrosol in both VOO is very low while their esterified derivatives, like 3,4-DHPEA-EDA and p-HPEA-EDA, are much more abundant.

Healthy virgin olive oil: a matter of bitterness

Virgin olive oil (VOO) is the pillar fat of Mediterranean diet. It is made from olive fruits and obtained by squeezing olives without any solvent extraction. Respect to the seed oils, an unique polar polyphenol-rich fraction gives VOO a bitter and pungent taste. The recent substantiation by European Food Safety Authority (EFSA) of a health claim for VOO polyphenols may represent an efficient stimulus to get the maximum health benefit from one of the most valuable traditional product of Mediterranean countries educating consumers to the relationship between the VOO bitterness and its health effect. Agronomical practices and new processing technology to avoid phenolic oxidation and hydrolysis and to enhance the aromatic components of the VOO have been developed and they can be used to modulate taste and flavor to diversify the products on the market. VOOs having high concentration of phenol compounds are bitter and pungent therefore many people do not consume them, thus loosing the health benefits related to their intake. In this paper, the chemist's and nutritionist's point of view has been considered to address possible strategies to overcome the existing gap between the quality perceived by consumer and that established by expert tasters. Educational campaigns emphasizing the bitter-health link for olive oils should be developed.

Sensory Threshold Studies of Picrocrocin, the Major Bitter Compound of Saffron

This study is part of a wider project on the bitter taste of saffron and its preparations. A deeper knowledge on the taste perception of picrocrocin is necessary in order to develop products that satisfy consumer senses and provide them with adequate amounts of saffron major constituents, also appreciated for bioactivity. A systematic approach on the bitterness of picrocrocin, the major responsible compound, was conducted. A panel was trained specifically for the determination of taste detection and recognition thresholds of picrocrocin, which were found to be 5.34 and 7.26 mg/L, respectively, using the Ascending Forced Choice of Limits methodology. The threshold values were examined in water in absence and presence of other saffron constituents and ethanol and were found to decrease when served hot (61 ± 4 °C). Bitterness was enhanced in 40% (v/v) aqueous ethanol. In both aqueous and ethanol extracts, the presence of saffron volatiles improved bitterness perception. The usefulness of the study was tested in the case of commercial saffron based infusions.

Combined heterogeneous distribution of salt and aroma in food enhances salt perception

Combining salt and aroma heterogeneous distribution in hot snacks improves saltiness perception and helps to maintain consumer liking. This approach is relevant for lowering salt content in food.

Sensory analysis and consumer acceptance of 140 high-quality extra virgin olive oils

BACKGROUND

Sensory analysis is a crucial tool for evaluating the quality of extra virgin olive oils. One aim of such an investigation is to verify if the sensory attributes themselves - which are strictly related to volatile and phenolic compounds - may permit the discrimination of high-quality products obtained by olives of different cultivars and/or grown in various regions. Moreover, a crucial topic is to investigate the interdependency between relevant parameters determining consumer acceptance and objective sensory characteristics evaluated by the panel test.

RESULTS

By statistically analysing the sensory results, a grouping - but not discriminatory - effect was shown for some cultivars and some producing areas. The preference map shows that the most appreciated samples by consumers were situated in the direction of the 'ripe fruity' and 'sweet' axis and opposite to the 'bitter' and 'other attributes' (pungent, green fruity, freshly cut grass, green tomato, harmony, persistency) axis.

CONCLUSION

Extra virgin olive oils produced from olives of the same cultivars and grown in the same areas shared similar sensorial attributes. Some differences in terms of expectation and interpretation of sensory characteristics of extra virgin olive oils might be present for consumers and panellists: most of the consumers appear unfamiliar with positive sensorial attributes, such as bitterness and pungency.

Extra virgin olive oil bitterness evaluation by sensory and chemical analyses

An experimental investigation was performed on blend extra virgin olive oils (EVOOs) from different cultivars and EVOO from different olive monovarieties (Coratina, Leccino, Maiatica, Ogliarola) with the aim to evaluate the possibility of estimating the perceived bitterness intensity by using chemical indices, such as the total phenol content and the compounds responsible for oil bitterness measured spectrophotometrically at 225 nm (K225 value), as bitterness predictors in different EVOO. Therefore, a bitterness predictive model, based on the relationship between the perceived bitterness intensity of the selected stimuli and the chosen chemicals parameters has been built and validated. The results indicated that the oil bitterness intensity could be satisfactorily predicted by using the K225 values of oil samples.

Sensory properties of Californian and imported extra virgin olive oils

Production and consumption of extra-virgin olive has been increasing in the United States, particularly in California. The objective of this study was to compare the sensory characteristics of 22 extra virgin olive oils (EVOO) from California, Italy, Spain, Chile, and Australia using a generic descriptive analysis. A total of 22 sensory attributes were identified and defined by the descriptive panel. With the exception of thick and citrus, all sensory attributes were significantly different among the oils. Canonical Variate Analysis (CVA) showed that California oils differed from some imported EVOOs, mainly by their absence of defects. A second analysis, of only those attributes included in the International Olive Council (IOC) official scorecard, provided a less detailed description of the samples and did not allow for a full characterization of the oils. While the IOC attributes allowed for faster classification in terms of clean versus defective EVOOs, the more comprehensive descriptive analysis provided both more information and a more refined classification of the samples. Variety and region of origin were important factors in the classification of both Californian and imported EVOOs.

PRACTICAL APPLICATION

  Measuring olive oil sensory quality using the IOC method-positive attributes of fruitiness, bitterness, and pungency, and defects including fusty, musty, winey, and rancid-allows for the certification of oils as extra virgin but it provides limited information on the sensory characteristics of the oils. A full descriptive profile, on the other hand, provides information that can be used by producers in the processing and marketing of their oils, and is a useful tool in the education of consumers about the wide range of (positive) sensory attributes in EVOO and the various sensory styles of EVOO.

Using phytochemicals to enhance health benefits of milk: impact of polyphenols on flavor profile

The focus of new product development of functional foods is not only on the associated health benefits but also on the sensory properties of the finished product. A trained panel (n=13) assessed 5 milk-based beverages fortified with added apple or grape seed polyphenols and a control using descriptive analysis techniques. The resulting vocabulary consisted of 16 odor, taste, flavor, and mouthfeel attributes, complete with reference standards and scale intensities. Panelists differentiated between samples using all 16 attributes in the vocabulary (P<0.001). Samples fortified with polyphenols, sourced from grape seed and apple extracts, differed significantly. Bitterness and UHT (ultra-high temperature) odor and flavor were the key drivers of product difference. Relatively small (but still significant) differences were identified between those containing polyphenols from the same plant source but different suppliers. We concluded that both grape seed and apple polyphenols suppress the flavor characteristics of the milk, with apple polyphenols having more of an impact than grape seed polyphenols. In particular, the high level of bitterness in apple extracts has large flavor profile implications for product development.