•GC × GC-TOF-MS and 1D-GC–MS to differentiate olive oil variety and geographical origin.•256 identified volatiles, 131 significant for variety, 60 for geographical origin.•Both lipoxygenase and ...non-lipoxygenase-generated volatiles were significant.•Multivariate statistics extracted 21 varietal markers with the highest discriminant power.•The most detailed profiling of volatile aroma compounds in olive oil up to date.
Comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (GC × GC-TOF-MS) was combined with conventional mono-dimensional GC–MS to differentiate Croatian virgin olive oils (VOO) according to variety and geographical origin, based on the profile of volatile aroma compounds isolated by HS-SPME. More than 1000 compounds were detected after untargeted profiling and 256 were identified or tentatively identified, providing one of the most detailed profiles of volatile aroma compounds in VOO up to date. Among them, 131 volatile compounds were significantly different across monovarietal VOOs, while 60 were found useful for the discrimination according to geographical origin. Many major lipoxygenase and minor non-lipoxygenase-generated compounds were shown to have discriminating ability with respect to both factors. Multivariate statistical analysis extracted twenty-one volatile markers with the highest discriminant power for varietal differentiation. The approach reported may have practical application in better understanding, defining, managing, and communicating the varietal or geographical typicity of monovarietal VOOs.
•Two crop levels were combined with leaf removal or untreated control.•Leaf removal had larger effect than crop level on wine aromas and phenolic acids.•Crop level showed limited impact on aroma ...compounds in wine.•Leaf removal increased the concentration of several monoterpenes and esters.•Hydroxycinnamic acids in wine were enhanced only by leaf removal.
The impact of crop level and leaf removal on Istrian Malvasia (Vitis vinifera L.) white wine aroma and phenolic acids composition was studied over two vine-growing seasons. Two crop levels were combined with leaf removal or untreated control in two-factorial design. Crop level showed limited impact on aroma compounds in wine and the concentration of some esters was increased by higher crop level. In contrast, leaf removal increased the concentration of several aroma compounds and especially monoterpenes and esters. The concentration of hydroxycinnamic acids in wine was enhanced only by leaf removal, while no consistent impact of the investigated factors on hydroxybenzoic acids was observed. The obtained results suggest that in cases where environmental conditions are not limiting, increasing the crop level under adequate microclimate in fruit zone has no detrimental effects on white wine aroma and hydroxycinnamic acids composition, potentially leading to economically more sustainable grape production.
Olive oil is considered one of the most valuable vegetable oils and is highly appreciated by consumers for its specific and distinguishable taste and aroma, as well as its nutritional value. Sterols ...and triterpene diols are important carriers of bioactive properties of olive oil and are responsible for some of the beneficial effects of its consumption on human health, such as lowering serum LDL-cholesterol levels and significantly reducing the risk of cardiovascular diseases. The concentration of total sterols and the proportions of particular sterols and triterpene diols are among the parameters used to verify and prove the authenticity of olive oil in accordance with the EU and other countries’ regulations. Finally, their composition has been shown to have high discrimination potential for ensuring traceability with respect to variety, geographical origin, harvest date, and other factors. For these reasons, the research on sterols and triterpene diols in olive oil is an ever-growing field of scientific interest with great practical importance. This review focuses on all the important aspects of sterols and triterpene diols in olive oil, from their chemical structure, biosynthesis, occurrence and role in plants, health benefits, and their use in official controls of olive oil purity and authenticity, to a conclusive survey on the recent findings about the effects of different factors of influence on their content and composition, with a detailed comparative analysis of studies that investigated the effects of the two most important factors, variety and ripening degree.
► The aim: sterols and triterp, diols as indicators of variety and ripening in olive oil. ► GC–FID data were processed by MANOVA, PCA and SLDA. ► Sterols and triterp. diols can be indicators of ...variety regardless ripening degree. ► Sterols and triterp. diols can be indicators of ripening degree regardless variety. ► The majority of indicators are stable after a 12-month storage.
Sterols and triterpene diols in olive oil as indicators of variety and degree of ripening derived from three olive varieties and produced at three different harvesting periods were studied. In order to test the stability of the proposed indicators, oils obtained were stored for 12months at three different temperatures. Thirty-six samples in total were subjected to GC analysis and results were processed by multivariate chemometric methods (MANOVA, PCA, and SLDA). Campesterol, β-sitosterol, Δ7-campesterol/Δ5,24-stigmastadienol, clerosterol, uvaol, and campestanol/Δ7-avenasterol were established as the indicators of variety of fresh oils, while when stored oils were included in the model, the final three compounds were substituted by 24-methylene-cholesterol/stigmasterol. The most important variables for differentiating fresh oils according to degree of ripening were Δ7-campesterol/β-sitosterol, uvaol/stigmasterol, clerosterol/Δ5-avenasterol and sitostanol/uvaol, while stored oils were differentiated by campestanol/stigmasterol, erythrodiol, stigmasterol/Δ7-campesterol, Δ5-avenasterol, 24-methylene-cholesterol/β-sitosterol and 24-methylene-cholesterol. Results demonstrated that sterols and triterpene diols can be used as indicators of variety and degree of ripening among virgin olive oils.
•Aromas and phenols during fermentation with and without skins were studied.•Monoterpenols increased the first 3days with skins, then some glycosides decreased.•Skin fermentation reduced ho-trienol, ...β-damascenone and particular esters.•Phenols increased constantly with skins, especially flavonoids after the third day.•Skin fermentation wine had more varietal aromas and phenols, and less esters.
Recently, various technologies which utilise fermentation with skins have been developed for obtaining distinct white wines. This study first reports the dynamic changes of volatiles and phenols that occur during skin fermentation in white winemaking. Volatiles were analysed by solid-phase extraction (SPE), solid-phase microextraction (SPME) and gas chromatography (GC), and phenols by ultra-performance liquid chromatography (UPLC), both with mass spectrometric detection. Monoterpenols increased during the first 3days of skin fermentation, after which certain glycosides decreased, but were higher than in control. The presence of skins reduced ho-trienol, β-damascenone, acids and esters. After a 1–3days lag phase, skin fermentation caused a constant increase of most phenols. It was estimated that skin fermentation up to 1–3days might be beneficial for monoterpenol varietal aroma, which should be re-evaluated through further studies. Longer durations promoted phenol extraction more strongly, which is possibly suitable for obtaining more distinct wines or blending components.
To differentiate monovarietal wines made from native and introduced varieties in Istria (Croatia), samples of Malvazija istarska, Chardonnay and Muscat yellow from two harvest years (2013 and 2014) ...were subjected to headspace solid-phase microextraction and gas chromatographic/mass spectrometric analysis (HS-SPME-GC/MS) of volatile aroma compounds. Significant effects of variety and harvest year were determined, but their interaction complicated the differentiation. Particular compounds were consistent as markers of variety in both years: nerol for Malvazija, ethyl cinnamate and a tentatively identified isomer of dimethylbenzaldehyde for Chardonnay, and terpenes for Muscat yellow. Wines from 2013 contained higher concentrations of the majority of important volatiles. A 100% correct differentiation of Malvazija istarska and Chardonnay wines according to both variety and harvest year was achieved by stepwise linear discriminant analysis.
•Bentonite fining during fermentation reduced the required dose up to 21%.•The most effective was fining in the middle and at the end of fermentation.•Wines fermented with bentonite had more ...hydroxycinnamoyltartaric acids than control.•The effect on varietal aromas was weak to moderate.•Bentonite in fermentation preserved key esters and enhanced wine sensory quality.
To test the effects of bentonite addition at various stages of fermentation, five Malvazija istarska white grape must vinification treatments were performed with 100 g/hL of bentonite added in clear juice, at the beginning, in the middle, and at the end of fermentation, while control was fermented without bentonite. Phenols and free and bound volatile aromas were determined by HPLC-DAD and SPE-GC-MS. Wines were evaluated sensorially. Fining during fermentation reduced the total bentonite dose required, and was most effective near the end of fermentation with the reduction of 16% and 21%, depending on the protein stability test. All treated wines preserved more hydroxycinnamoyltartaric acids with respect to control. The side-effect of these treatments on varietal aromas was moderate, but enhanced the preservation of key fermentation volatiles in relation to control, and exhibited positive sensory effects. It was concluded that bentonite added during fermentation may positively affect wine quantity and quality.
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•Fertilisation combined with AMF affected the composition and quality of tomato fruits.•AMF increased nitrogen, manganese, and hydrophilic phenol content in tomato fruits.•Interaction ...between fertilisation and AMF application modified tomato fruit volatiles.•The effect of AMF inoculation might depend on native AMF and environmental conditions.
The effects of different fertilisation treatments with arbuscular mycorrhizal fungi (AMF) inoculation on AMF root colonisation, fruit yield, nutrient and total phenol contents, volatile compound composition, and sensory attributes of tomato (Solanum lycopersicum L.) were investigated. Mineral, organic, and mineral + organic fertiliser application positively affected tomato yield (35%–50%) and phosphorus concentration (24%–29%) compared with controls. AMF application had a significant impact on the total nitrogen (+9%), manganese (+12%), and hydrophilic phenol (+8%) contents in the fruit. Volatile compounds were affected by the interactive effects of fertilisation and AMF application. The response of tomato fruit sensory quality indicators was relatively modest, with only a few sensory characteristics affected to a lesser extent. Although tomato showed susceptibility to field-native AMF, particular combinations of fertilisation and AMF inoculation were more effective at improving the quality parameters of tomatoes under field conditions applied in this study.
•Changes in aroma of Gewürztraminer wine after late and ice harvest were studied.•Late harvest wine had higher amounts of the majority of aromas than control.•Icewine had complex aroma (terpenes, ...furans, acetals, etc.) and reduced esters.•Main odorants in ice wine: cis-rose oxide, β-damascenone, 1,1-diethoxyethane.•Ice wine had increased terpenic, floral, pungent and ripe fruit aroma series.
To investigate the changes in physico-chemical and aroma composition after late and ice harvest, Gewürztraminer wines were subjected to standard, enzymatic and GC/MS analysis. Late harvest (LHGW) and ice wines (IHGW) contained more sugars, extract and volatile acidity than standard wines (SGW). IHGW had elevated glycerol and gluconic acid amounts. LHGW was richer in monoterpenol oxides, β-damascenone, 1-octen-3-ol, acetates, ethyl cinnamate and 4-vinylguaiacol than SGW. IHGW contained even higher amounts, with increased citronellol, acetaldehyde, ethyl acetate, dicarboxylic acids esters, benzenoids, furans and acetals, and reduced fermentation aroma compounds. Based on odour activity values, the strongest odorants in SGW were fruity esters. In LHGW the impact of esters increased, while in IHGW cis-rose oxide, β-damascenone and 1,1-diethoxyethane emerged as the most potent. Fruity and sweet were the dominant aroma compound series in SGW and LHGW, but in IHGW declined, while terpenic, floral, chemical, pungent and ripe fruit aroma compound series increased.
•Interactive effects of ripening and malaxation on olive oil quality were studied.•Ripening degree exhibited the strongest effect, and malaxation duration the weakest.•Ripening degree and malaxation ...temperature interacted most strongly.•The effect of malaxation temperature was the strongest for ripe olives.
The interactive effects of ripening degree, malaxation duration and temperature on Oblica cv. (Olea europaea L.) virgin olive oil phenols, volatiles, and sensory quality were investigated. Olives were picked at three ripening degrees with International Olive Council indices of 0.68, 2.48 and 4.10, and processed by malaxation at 22 and 30°C, and at both temperatures for 30 and 60min. Ripening exhibited the strongest effect, and malaxation duration the weakest. Phenols were generally found to decrease during ripening; however 3,4-DHPEA-EDA and p-HPEA-EDA increased. Similar behaviour was observed for (E)-2-hexenal. Higher malaxation temperature induced an increase in particular important phenols and C6 alcohols, while C6 aldehydes mostly decreased. Interactions between the factors were established, mostly between ripening degree and malaxation temperature: the effect of the latter was most pronounced for ripe olives, especially for 3,4-DHPEA-EDA, p-HPEA-EDA and C6 volatiles. Sensory attributes were generally in agreement with the chemical composition.
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