Plant, pest and predator interplay: tomato trichomes effects on Tetranychus urticae (Koch) and the predatory mite Typhlodromus (Anthoseius) recki Wainstein.

Trichomes are well-known efficient plant defense mechanisms to limit arthropod herbivory, especially in Solanaceae. The present study aims to evaluate the impact of trichome types on the development, survival and dispersal of Tetranychus urticae, and the phytoseiid predatory mite Typhlodromus (Anthoseius) recki. Six Solanum lycopersicum cultivars and two wild Solanum species, S. cheesmaniae and S. peruvianum, presenting contrasting densities and types of trichomes, were considered. Cultivars and species were characterized by counting each trichome type on leaves, petioles and stems. Mites stuck on petiole and stem and alive mites on the leaflet used for mite release and in the whole plant were counted three weeks after T. urticae plant infestation. Tetranychus urticae settlement and dispersal were differently affected by trichomes. Trichome types V and VI did not affect settlement and dispersal, whereas trichome types I and IV on the petiole had the highest impacton mites. Trichomes on leaves slightly affected mite establishment, there appears to be a repellent effect of trichome types I and IV. The low densities of both T. urticae and its predator detected for the cv. Lancaster could not be clearly associated to the trichome types here considered. The predator did not seem to be affected by plant characteristics, but rather by T. urticae numbers on the plant. The trichome traits unfavorable to T. urticae, did not affect the predator which showed high efficiency to control this pest on all the plant genotypes considered, but at a favorable predator:prey ratio (1:1). Altogether, these results are encouraging for the use of T. (A.) recki as a biological control agent of T. urticae regardless of the trichome structure of the tomato cultivars, but other conditions should be tested to conclude on practical implementations.

Attitudes towards natural wines among Spanish winemakers: Relationship with environmental awareness.

There is an important movement in the wine industry towards the production of alternative and more sustainable wines. Natural wine (NW) is a controversial category of alternative wines, which needs to be further explored. Given the role of technical experts as opinion leaders, the present work aims to explore the attitudes of Spanish winemakers towards NW and their relationship with their overall environmental awareness. Therefore, 307 Spanish winemakers completed a questionnaire to evaluate: (1) their attitudes towards NW by scoring their agreement with 31 statements, (2) their ecological awareness by evaluating 11 items, (3) their frequency of consumption and interest towards NW, and (4) their sociodemographic profile and general information about wine production. PCA with varimax rotation calculated on 28 of the 31 statements related to their attitudes showed six independent dimensions. Further hierarchical cluster analysis calculated with the six dimensions showed five clusters of wine experts with different attitudes towards NW. Results show that there is a major negative attitude towards the flavour of NW, their ageing capacity and their quality-price ratio, but a positive one in terms of economic impact for the wine industry. Aspects related to the role of NW in tradition, social identity, ecology, health, artisanal production and economic feasibility mark differential attitudes. Interestingly, the dimension related to winemakers attitude towards tradition, social identity, and ecology of NW was positively correlated with their overall ecological awareness and thus their life style. This paper sheds light in the understanding of the behaviour of Spanish winemakers regarding ecological transition and provides tools for policymaking regarding NW certification.

Host adaptation and specialization in Tetranychidae mites.

Composite generalist herbivores are comprised of host-adapted populations that retain the ability to shift hosts. The degree and overlap of mechanisms used by host-adapted generalist and specialist herbivores to overcome the same host plant defenses are largely unknown. Tetranychidae mites are exceptionally suited to address the relationship between host adaptation and specialization in herbivores as this group harbors closely related species with remarkably different host ranges-an extreme generalist the two-spotted spider mite (Tetranychus urticae Koch [Tu]) and the Solanaceous specialist Tetranychus evansi (Te). Here, we used tomato-adapted two-spotted spider mite (Tu-A) and Te populations to compare mechanisms underlying their host adaptation and specialization. We show that both mites attenuate induced tomato defenses, including protease inhibitors (PIs) that target mite cathepsin L digestive proteases. While Te solely relies on transcriptional attenuation of PI induction, Tu and Tu-A have elevated constitutive activity of cathepsin L proteases, making them less susceptible to plant anti-digestive proteins. Tu-A and Te also rely on detoxification of tomato constitutive defenses. Te uses esterase and P450 activities, while Tu-A depends on the activity of all major detoxification enzymatic classes to disarm tomato defensive compounds to a lesser extent. Thus, even though both Tu-A and Te use similar mechanisms to counteract tomato defenses, Te can better cope with them. This finding is congruent with the ecological and evolutionary times required to establish mite adaptation and specialization states, respectively.

Natural versus conventional production of Spanish white wines: an exploratory study.

BACKGROUND: Natural wine (NW) lacks an official or agreed definition, but it can be generally described as a wine produced with organic or biodynamic grapes with minimal intervention in the cellar, and with minimal or no use of oenological additives. The present study aimed to test the hypotheses that self-defined NWs differ from conventional wines (CW) in their chemical composition and main sensory characteristics. The levels of conventional oenological parameters, turbidity, biogenic amines, ochratoxin A, ethyl carbamate, sulphites, chlorides, some metals, major, trace and Strecker aldehyde volatile compounds were determined in 28 wines, including natural and conventional Spanish commercial white wines. Wines were also sensory described following a labelled free sorting task. RESULTS: NWs presented higher pH, volatile acidity (VA) and turbidity values, and a more intense yellow colour, whereas they have a lower malic acid content compared to theor conventional counterparts. NWs presented lower levels of total sulphur dioxide but significantly higher levels of biogenic amine putrescine, although both compounds are within the legal limits in all cases. None of the dimensions of the similarity space discriminated NWs from CWs. However, 70% of the NWs were grouped on the basis of various aromatic defects related to their higher content in 4-ethylphenols and VA. The remaining 30% were not differentiated from their conventional counterparts. CONCLUSION: It could be confirmed that NW can be globally differentiated from CW with respect to to their chemical and their sensory profiles, whereas the content in toxicants was not significantly different, with the exception of total sulphur dioxide and putrescine levels. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Modeling grape taste and mouthfeel from chemical composition.

This research aims at predicting sensory properties generated by the phenolic fraction (PF) of grapes from chemical composition. Thirty-one grape extracts of different grape lots were obtained by maceration of grapes in hydroalcoholic solution; afterward they were submitted to solid phase extraction. The recovered PFs were reconstituted in a wine model. Subsequently the wine models, containing the PFs, were sensory (taste, mouthfeel) and chemically characterized. Significant sensory differences among the 31 PFs were identified. Sensory variables were predicted from chemical parameters by PLS-regression. Tannin activity and concentration along with mean degree of polymerization were found to be good predictors of dryness, while the concentration of large polymeric pigments seems to be involved in the "sticky" percept and flavonols in the "bitter" taste. Four fully validated PLS-models predicting sensory properties from chemical variables were obtained. Two out of the three sensory dimensions could be satisfactorily modeled. These results increase knowledge about grape properties and proposes the measurement of chemical variables to infer grape quality.

How has COVID-19, lockdown and social distancing changed alcohol drinking patterns? A cross-cultural perspective between britons and spaniards.

During the early months of 2020, the world experienced a novel, violent, and relentless pandemic era. By the end of the year more than seventy-seven million cases of COVID-19 had been reported around the globe. Due to it being a highly contagious disease, the recommended measures adopted by most nations to prevent infection include social distancing and quarantine. How did these measures affect people's relationship with alcohol consumption in cultures where alcohol plays an important social role? A questionnaire-based study, designed to follow the drinking behaviour of people before and during lockdown was applied to two different cultural groups impacted by the pandemic during the strict phase of lockdown. These are the British and Spanish populations (179 participants from each country were interviewed). Considering the frequency of consumption of the alcoholic beverages evaluated (wine, beer, cider, whisky and spirits), the results showed that a significant lockdown*country interaction was observed. Overall, Spanish participants consumed alcoholic beverages less frequently during lockdown than before, while British participants reported no change in their consumption habits. Spaniards' decrease in alcohol consumption is related to the absence of a social contexts while Britons seems to have adapted their consumption to the modified context. Results suggest that, alcohol consumption is a central core of the British culture, while for the Spanish, socialization is more a cultural characteristic than the alcohol itself.

To fear the unknown: Covid-19 confinement, fear, and food choice.

The coronavirus outbreak in December 2019 completely changed the dynamic of consumption in different sectors of industry. The food and beverage industries have been profoundly affected, from production, to modifications in consumers' choices. Among the different reasons behind those modifications is confinement, which forces consumers to stay at home for an extended period and just go out to perform essential tasks, such as going to the supermarket. We hypothesized that this new dynamic of consumption could create a situation of fear that changes food choice. To test this hypothesis, two studies were conducted in three countries with a different degree of confinement: Mexico (flexible), Spain (strict), and Peru (hard). Study one consisted of a free association task with 60 participants in each country with the inductor word "coronavirus and food". The different associations served as the basis to build a structured questionnaire, which was used in the second study focused on fear and food choice. The second study was applied to 450 participants in the same three countries. Results showed that fear can be separated into nine dimensions: social, emotional, food supply, government, basic needs, food-delivery, overeating, immunity, and family conflicts. The participants could also be clustered into four different groups that differ in their country of origin and sex, but also in their food choice. Overall, the results showed that fear influenced consumer's food choices during a confinement period.

A New Classification of Perceptual Interactions between Odorants to Interpret Complex Aroma Systems. Application to Model Wine Aroma.

Although perceptual interactions are usually mentioned and blamed for the difficulties in understanding the relationship between odorant composition and aromatic sensory properties, they are poorly defined and categorised. Furthermore, old classifications refer mainly to effects on the odour intensity of the mixture of dissimilar non-blending odours and do not consider odour blending, which is one of the most relevant and influential perceptual interactions. Beginning with the results from classical studies about odour interaction, a new and simple systematic is proposed in which odour interactions are classified into four categories: competitive, cooperative, destructive and creative. The first categories are most frequent and display a mild level of interaction, being characterised mostly by analytical processing. The last two are less frequent and activate (or deactivate) configurational processes of object recognition with deep effects on the quality and intensity of the perception. These interactions can be systematically applied to interpret the formation of sensory descriptors from the odorant composition, suggesting that qualitatively the system works. However, there is a lack of quantitative data to work with odour intensities reliably, and a pressing need to systematise the effects of creative interactions.

Sensory Relevance of Strecker Aldehydes in Wines. Preliminary Studies of Its Removal with Different Type of Resins.

The orthonasal quality of two synthetic contexts of wine (young wine and oaked wine) spiked with six different levels of the Strecker aldehydes (isobutyraldehyde, 2-methylbutanal, 3-methylbutanal, methional and phenylacetaldehyde) was evaluated by a panel of wine experts. The aldehyde levels simulated the concentrations present in wines protected from oxidation during production and storage and after severe oxidation. Significant quality detriments were observed at concentrations of 13 µg/L of methional, 49 µg/L of phenylacetaldehyde, 17 µg/L of isobutyraldehyde, 12 µg/L of 2-methylbutanal and 24 µg/L of 3-methylbutanal. The presence of these levels of aldehyde concentrations induced the reduction of fruitiness in young wines and of woody notes in oaked wines as well as the appearance of the typical attributes that define wine oxidation. More than 75% of recently opened commercial wines contain total levels of Strecker aldehydes higher than those, however their effect is not always noticeable as they are forming inodorous adducts with SO2. Nevertheless, this content is a potential risk for the shelf life of the wine, as once SO2 is depleted, these aldehydes could release back into their odour-active forms. Thus, in order to reduce the presence of Strecker aldehydes, eight different resins were studied (two scavengers, four mixed-mode anion exchange and two pure anion exchange) in white wine at two levels of SO2. After 24-h contact, the mixed mode Strata X-A resin was able to significantly reduce aldehydes' percentages: between 11% for isobutyraldehyde and 86% for phenylacetaldehyde. On the other hand, wine colour was affected and therefore the applicability of the treatment should be further studied. However, this work can be considered a starting point to solve the technological challenge involved in the elimination of aldehydes from wine.

An assessment of voltammetry on disposable screen printed electrodes to predict wine chemical composition and oxygen consumption rates.

The present work aimed at determining the applicability of linear sweep voltammetry coupled to disposable carbon paste electrodes to predict chemical composition and wine oxygen consumption rates (OCR) by PLS-modeling of the voltammetric signal. Voltammetric signals were acquired in a set of 16 red commercial wines. Samples were extensively characterized including SO2, antioxidant indexes, metals and polyphenols measured by HPLC. Wine OCRs were calculated by measuring oxygen consumption under controlled oxidation conditions. PLS-Regression models were calculated to predict chemical variables and wine OCRs from first order difference voltammogram curves. A significant number of fully validated models predicting chemical variables from voltammetric signals were obtained. Interestingly, monomeric and polymerized anthocyanins can be differently predicted from the first and second wave of the first derivative of voltammograms, respectively. This fast, cheap and easy-to-use approach presents an important potential to be used in wineries for rapid wine chemical characterization.

Wine quality and berry size: a case study with Tempranillo Tinto progenies.

BACKGROUND: Small berry size is normally associated with quality wine production. However, the contribution of grapevine variety and environment to sensory quality has not been well established. In this study, genotypes from two intra-specific hybrid populations were categorized by size according to berry diameter and weight: small (< 13.5 mm, <1.5 g), and large (>16 mm, >2 g). Chemical and sensory attributes of wines produced in two consecutive vintages (2017 and 2018) from each size category were characterized. Perceived intrinsic wine quality was judged by 20 wine professionals. RESULTS: Wines obtained from small berry genotypes consistently displayed higher proportions of phenolic compounds and deeper color and were judged higher in quality regardless of genetic background and vintage. Perceived quality was positively correlated with anthocyanin and phenolic content. Wines presented high sensory variability in both vintages. Small berry size genotypes produced sweeter, fruitier wines with greater astringency; whereas wines from larger berries were perceived as more alcoholic and with lower positive aroma intensities. Berry size influenced color and phenolic compounds more than genotype or environment. CONCLUSION: Small berry-size genotypes were related to high quality judgements in both years, thus providing a predictor of wine categories, which could be used to meet different market demands. © 2020 Society of Chemical Industry.

How the country-of-origin impacts wine traders' mental representation about wines: A study in a world wine trade fair.

Using data collected at a world wine trade fair, we study how the country-of-origin impacts wine traders' mental representation about wines. In the analysis we use traditional exporters in Old (France) and New (Argentina) world wine countries in comparison to non-traditional exporters in Old (Switzerland) and New (Brazil) world wine countries. Three main findings are reported. First, the country-of-origin of wines was more important on guiding participants' representations, than the category of countries the traders came from. Second, participants' evocations were more precise and specific for traditional wine-exporting countries than for less traditional wine exporting countries. Finally, the lack of traders' knowledge of wines from non-traditional wine-exporting countries produced associations and beliefs related to the image of the country itself. Our findings have important implications for the marketing and export activities of the wine industry.

Sensory variability associated with anthocyanic and tannic fractions isolated from red wines.

Tannins and anthocyanins are important modulators of the intrinsic quality of red wines, playing a major role in consumer preference and appreciation. Tannins are chiefly responsible for the astringency in wines although their role in eliciting different astringent subqualities is still relatively unknown. On the other hand, the sensory contribution of anthocyanic fractions is even less clear. The main aim of the present study was to assess whether anthocyanic fractions from red wine elicit specific mouthfeel and taste attributes that differ from their tannin counterparts, and to evaluate the contribution of anthocyanic and tannic fractions to taste and mouthfeel of red wines. Isolation of tannin (Ftannin) and anthocyanin (Fantho) fractions from 20 wines involved reversed-phase semipreparative liquid chromatography followed by solid phase extraction. The 40 derived fractions subsequently underwent sensory characterisation using a labelled sorting task and a rate-K attributes method. Bitterness and dryness were the salient attributes differing among the sensory spaces of both Fantho and Ftannin. Likewise, other independent and non-correlated mouthfeel dimensions differed for both Fantho ("grainy" and mouthcoating") and Ftannin ("gummy"). A significant linear model predicting wine dryness from the "dry" intensity of Fantho and Ftannin was obtained, with tannic fractions presenting a higher contribution than anthocyanic fractions. These results not only confirmed that tannins have a major implication in red wine dryness but also unequivocally demonstrated a relevant implication of certain anthocyanins in this attribute. In contrast, bitterness of the original wines could not be directly related to the bitterness perceived in any of the two groups of fractions. The addition of an extremely bitter anthocyanic fraction to wines only increased bitterness in certain wines, suggesting that bitterness in wines may result from perceptual interactions and that some wines contain strong bitterness suppressors.

Sensory, olfactometric and chemical characterization of the aroma potential of Garnacha and Tempranillo winemaking grapes.

Reconstituted polyphenolic and aromatic fractions (PAFs) from 33 different Garnacha and Tempranillo grapes were incubated in strict anoxia (75 °C × 24 h). Obtained hydrolyzates were characterized by sensory analysis, gas chromatography-olfactometry (GC-O) and gas chromatography-mass spectrometry (GC-MS). Five different aroma categories emerged. Garnacha may develop specific tropical/citrus fruit, kerosene and floral and Tempranillo toasty-woody and red-fruit characteristics. Those notes seem to mask alcoholic and fruit-in-syrup descriptors and the common vegetal background. Twenty-seven odorants were detected by GC-O. GC-MS data showed a clustering closely matching the one found by sensory analysis, suggesting the existence of five specific metabolomic profiles behind the five specific sensory profiles. Overall results suggest that 3-mercaptohexanol is responsible for tropical/citrus fruit, TDN for kerosene, volatile phenols for woody/toasty, ß-damascenone and massoia lactone, likely with Z-1,5-octadien-3-one for fruit-in-syrup and alcoholic notes. Nine lipid-derived unsaturated aldehydes and ketones may be responsible for the vegetal background.

Effect of aroma perception on taste and mouthfeel dimensions of red wines: Correlation of sensory and chemical measurements.

The present study was aimed at increasing the understanding of red wine mouthfeel by investigating the potential cross-modal effect of aroma and establishing relationships between sensory dimensions and chemical measurements. Investigations involved a set of 42 non-wooded red wines that were described with a novel application of a variant of the rate-all-that-apply sensory methodology ("rate-K attributes") by a group of Spanish wine experts under two conditions: (1) with no aroma perception (using nose clips) and (2) with aroma perception. In parallel, ethanol content, pH, titratable acidity, tannin activity, concentration of tannins, and spectroscopic measures of wines were determined. Results suggest that aroma does not play a main effect on taste or mouthfeel perception of red wines, except for oily mouthfeel, which was hypothesised to be masked by earthy aromas and enhanced by alcoholic nuances attributed to cognitive interactions. Independent and non-correlated mouthfeel dimensions such as dry/silky and sticky, grainy, prickly or oily were also identified. Tannin activity was shown to be highly positively correlated to dry on the palate, and tannin concentration with both overall dry and dry on the palate. A significant partial least squares regression model showed that tannin concentration and activity (positive contribution) as well as pH values (negative) were good predictors of the mouthfeel dimension mainly related to dry and sticky terms.

Some clues about the changes in wine aroma composition associated to the maturation of "neutral" grapes.

This paper presents a study of the influence of the harvesting date on concentrations of odorants in Moristel wines of two vintages. The wine made from grapes harvested early facilitated the accumulation of acetaldehyde (associated with low polyphenols concentrations) and higher concentrations of branched acids. A reason for these greater levels could be the lack of reduction factors (NADH or NADPH). Other changes with potential sensory consequences are the decrease of the branched acid/branched alcohol, branched ester/branched acid and branched ester/branched alcohol ratios that occurs as the grapes ripen. Besides, the variations of varietal or typical maturation markers did not have sensory importance. These results suggest that the characteristics of wines associated to the degree of maturity of grapes are mostly related to the changes in the profiles of fermentative compounds (especially acetaldehyde) induced by changes in the polyphenolic content and in the medium in which the yeast develops.

Fourteen ethyl esters of wine can be replaced by simpler ester vectors without compromising quality but at the expense of increasing aroma concentration.

Aroma contribution of individual esters has been studied in complex mixtures mimicking red wine models. A mixture containing 14 ethyl esters at concentrations found in wine (V1) was prepared and kept as reference. Isointense and qualitatively similar aroma vectors with a reduced number of esters (V2-V7) were prepared. Those vectors were introduced in two reconstituted wines to assess whether simpler vectors could replace V1 without compromising wine quality. In the simpler young wine model, V1 could be replaced by a vector containing just 3 odorants (ethyl 2-methylbutyrate, ethyl butyrate and hexanoate). In the oaky model, a vector containing just ethyl 2-methylbutyrate (V7) could replace V1 without any discernible sensory change. Results also reveal that sub- or perithreshold odorants play outstanding roles on the overall odour intensity of the mixture and that aroma simplification concomitantly implies an increase in the amount of odorant required to keep the intensity of the aroma vector.

Chemo-sensory approach for the identification of chemical compounds driving green character in red wines.

The present work seeks to define the "green character" of red wines and characterise the groups of molecules potentially involved in that perception. Fifty-four wines were screened by wine experts for different levels of green character. Six different phenolic fractions were obtained by liquid chromatography (LC) and further submitted to sensory and chemical characterisation. The volatile fraction was screened by semipreparative LC, Gas Chromatography-Olfactometry (GC-O) and quantitative analysis. The green character was linked to vegetal aroma, astringency, green and dry tannins according to experts of the Somontano region. Non-volatile fractions containing tannins with mean degree of polymerisation of ten and smaller anthocyanin-derivative pigments (