New insights into Viticulture, Enology and Vitivinicultural Economy: Ciência e Técnica Vitivinícola 2021

New insights into Viticulture, Enology and Vitivinicultural Economy arise from the fourteen articles published by the Ciência e Técnica Vitivinícola in 2021. Research carried out by several international teams covered a wide range of topics that seek to respond to current main challenges: chemical, morphological and anatomical features of the grapevine cultivars explored to withstand biotic and abiotic stresses; seaweed foliar application to grapevines as an innovative and integrated vineyard management technique; nutritional management of grapevine cultivars under cold climate conditions and under water constraint scenarios; viability and cost-effectiveness of photovoltaic solar energy for wineries; viticultural technologies and the food safety of wine; characterization of grapes and methods for juice production; chemical composition of grape seeds; development of analytical and sensory methodologies; portrait of the wine spirits sector in Portugal and its recent evolution.

Comparison of the chemical diversity of Vitis rotundifolia and Vitis vinifera cv. ‘Cabernet Sauvignon’

Grapevine is one of the most important fruit plants in the world, mainly due to its grapes and related products, with a highly economic and cultural importance. Every year, vineyards are affected by several pathogen outbreaks and the only way to control them is through preventive applications of agrochemicals every 12 to 15 days. This approach is not sustainable and not always effective. The Vitis genus comprise different species that exhibit varying levels of resistance to pathogens, thus the understanding of the innate resistance/susceptibility mechanisms of these different Vitis species is crucial to cope with these threats. In this work, an untargeted metabolomics approach was followed, using Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR-MS), to analyse the metabolic chemical diversity of two Vitis species: Vitis rotundifolia (resistant to pathogens) and V. vinifera cv. ‘Cabernet Sauvignon’ (susceptible to pathogens). Chemical formulas from both Vitis were used to build Van Krevelen diagrams and compositional space plots, which do not require full metabolite identification and provide an easy comparison method. Based only on these visualization tools, it was shown that the V. rotundifolia metabolome is more complex than the metabolome of V. vinifera cv. ‘Cabernet Sauvignon’. Moreover, the regions that present a higher density are associated to lipids, polyketides and carbohydrates. Also, V. rotundifolia metabolome presented a higher ratio O/C compounds.

Seaweeds in viticulture: a review focused on grape quality

Cell walls of seaweeds contain a wide number of organic and inorganic constituents, of which polysaccharides have important biological activity. Some researchers suggest that polysaccharides from seaweeds can behave as biotic elicitors in viticulture, triggering the synthesis of phenolic compounds in leaves and grape berries. The mechanism of action of seaweeds after a foliar application to grapevines is not fully understood but it is discussed in this review. An overview of the recent research focused on the effects of seaweeds foliar applications on grapevine productivity, on grape and wine quality is included as well as a short-term future perspective for the research in this field.

Influence of water scarcity on macronutrients contents in young leaves of wine grape cultivars

This study aimed to determine the variability of plant nutrition content in two-year old local and well-known wine grape cultivars under different water constraint scenarios. Own rooted and potted eight grapevine cultivars (cv. ‘Adakarası’, ‘Papazkarası’, ‘Karasakız’, ‘Karalahana’, ‘Yapıncak’, ‘Vasilaki’, ‘Cabernet Sauvignon’ and ‘Sauvignon Blanc’) were subjected to five irrigation treatments (100% daily irrigation of available water capacity (AWC), 75% irrigation of AWC, 50% irrigation of AWC, 25% irrigation of AWC, and no irrigation for 0% treatment) for two consecutive years during vegetative growth (May – late September). An increase in nitrogen, potassium and magnesium contents in leaf tissues with decreasing water amount was observed. Similar effect was found for phosphorus and calcium contents. The sulfur concentration in leaf tissues remained almost unchanged. In addition, the variability of genetic potential influenced the nutrient intake of the studied cultivars. The ability of grapevine cultivars to cope with the water deficit of the cultivars should definitely be assessed in adaptation strategies developed to make viticulture sustainable under the effects of the climate crisis.

The role of grapevine leaf morphoanatomical traits in determining capacity for coping with abiotic stresses: a review

Worldwide, there are thousands of Vitis vinifera grape cultivars used for wine production, creating a large morphological, anatomical, physiological and molecular diversity that needs to be further characterised and explored, with a focus on their capacity to withstand biotic and abiotic stresses. This knowledge can then be used to select better adapted genotypes in order to help face the challenges of the expected climate changes in the near future. It will also assist grape growers in choosing the most suitable cultivar(s) for each terroir; with adaptation to drought and heat stresses being a fundamental characteristic. The leaf blade of grapevines is the most exposed organ to abiotic stresses, therefore its study regarding the tolerance to water and heat stress is becoming particularly important, mainly in Mediterranean viticulture. This review focuses on grapevine leaf morphoanatomy - leaf blade form, leaf epidermis characteristics (cuticle, indumentum, pavement cells and stomata) and anatomy of mesophyll - and their adaptation to abiotic stresses. V. vinifera xylem architecture and its adaptation capacity when the grapevine is subjected to water stress is also highlighted since grapevines have been observed to exhibit a large variability in responses to water availability. The hydraulic properties of the petiole, shoot and trunk are also reviewed. Summarising, this paper reviews recent advances related to the adaptation of grapevine leaf morphoanatomical features and hydraulic architecture to abiotic stresses, mainly water and heat stress, induced primarily by an ever-changing global climate.

Impact of trellis systems and rootstocks on global phenolic composition and antioxidant activity of ‘Isabel Precoce’ grapes produced during rainy seasons in semi-arid region of Brazil

Crop components, such as trellis systems, might affect solar radiation uptake by grapevines while others, such as rootstocks, influence the vigor of the scion. Proper management provides a suitable reproductive and vegetative balance that could influence the chemical composition of grapes. This study aimed to characterize the global phenolic composition and antioxidant activity of ‘Isabel Precoce’ grapes raised for juice, growing under different trellis systems and rootstocks, in rainy seasons, in semi-Arid conditions in Brazil. With a randomized block experimental design and split-split plots over time, the overhead trellis, lyre, and vertical shoot positioning systems and two rootstocks (‘IAC 572’ and ‘IAC 766’) in the harvest seasons of January-May, 2017 and January-May, 2018 were studied. Trellis systems, rootstocks, harvest seasons and their interactions affected the characteristics of the grapes. The treatments with equivalent responses in the seasons defined the specific characteristics of the grapes. The rootstock ‘IAC 766’ provided greater bunch weight and lower acidity to the ‘Isabel Precoce’ grapes, while ‘IAC 572’ induced higher soluble solids contents. In both seasons, there was lower variation in berry resistance to compression and polyphenol and anthocyanin contents in grapes from grapevines grown on an overhead trellis. In turn, the use of lyre provided high antioxidant activity by the ABTS●+ method in 2018. The highest antioxidant activity by the DPPH● method was due to the association of overhead trellis and ‘IAC 766’. With the use of the overhead trellis, equivalent phenolic compounds and antioxidant activity during the seasons resulted in a uniform quality.

Fatty acids, phenolic compounds and antioxidant capacity of the seeds from nine grape cultivars (Vitis vinifera L.)

Seeds are one of the main parts of the grapes, and they contain important constituents such as polyphenols, lipids, proteins and carbohydrates. In this study, oil contents, fatty acid composition, total phenolic content, total flavonoid content, monomeric flavan-3-ols and antioxidant capacities of nine grape seeds from nine cultivars were investigated. The correlations between the analyzed parameters were also examined. The oil contents of seeds ranged from 4.96 to 13.35%. Linoleic acid was the predominant fatty acid in the seeds, and it was followed by oleic acid, palmitic acid, stearic acid, linolenic acid, 11-eicosenoic acid and arachidic acid. Total phenolic and total flavonoid contents were 646.50-1120.78 mg GAE/g and 336.69-589.85 mg CE/g, respectively. ‘Italia’ seeds had the highest antioxidant capacity for DPPH and CUPRAC assays while ‘Cabernet Sauvignon’ seeds had the lowest one. The (-)-epigallocatechin, (+)-catechin, (-)-epigallocatechin gallate, (-)-epicatechin and (-)-epicatechin gallate contents in the seeds varied from 1.23 to 6.53 mg/g, 11.61 to 80.20 mg/g, 0.21 to 0.51 mg/g, 2.78 to 48.26 mg/g and 0.08 to 1.50 mg/g, respectively. The (+)-catechin and (-)-epicatechin were the major flavan-3-ol compounds in the grape seeds. Significant correlations were found between total phenolic content, total flavonoid, RSA (DPPH Radical scavenging activity), CUPRAC (Cupric reducing antioxidant capacity) and flavan-3-ols. Consequently, the current study findings support previous information that grape seeds are an important source of antioxidants as well as unsaturated fatty acids, which have positive effects on human health.

Evaluating uncertainty in sensory analysis. A case study of the panel of tasters of the Dão Regional Wine Commission

Metrological reliability in the sensory evaluation of products is of fundamental importance in ensuring the comparability of results. The issue of uncertainties regarding measured data in such contexts has led to new scientific approaches in the field of sensory analysis, which have become fundamental to studies that seek to compare results of sensory measurement and analysis, including studies regarding wine. The new normative framework, ISO/IEC 17025:2017, which replaces the previous version ISO/IEC 17025, published in 2005, draws attention to the concept of measurement uncertainty, stating that it should be considered by laboratories when assessing conformity and quantifying risks arising in decision-making processes. The present work examines the evaluation of uncertainty and its importance for the interpretation of results from sensory analyses, examining sensory analysis tests related to the certification of the Designation of Origin “Dão”, the Designation of Origin “Lafões” and the Geographical Indication “Terras do Dão”, carried out by a panel composed of 20 tasters of the Dão Regional Wine Commission, trained and accredited by the standard NP ISO/IEC 17025:2018. The results achieved led to a conclusion that the panel presented different values of uncertainty regarding the tests to determine sensory attributes. The results and respective values of uncertainty made it possible to assess the performance of the panel of tasters and to establish a level of risk (false accept, false reject and statistical assumptions) for decision rules used when issuing statements of conformity. In this study, a new methodology was presented to determine an estimate of uncertainty to be applied in the interpretation of results related to sensory analysis tests of wines for the certification of Designation of Controlled Origin “Dão”, Designation of Origin “Lafões” and Geographical Indication “Terras do Dão. This progress led to an evolution in the day-to-day work of the Dão Regional Wine Commission tasting chamber enabling greater solidity in the opinions issued, in line with the requirements of the reference standard NP ISO/IEC 17025: 2018.

Nutritional status differentially affect yield and must composition of hybrids and V. vinifera varieties established under cold climate conditions

Nova Scotia is characterized by cold climate and acidic soils and high organic matter for viticultural development. There is little scientific information available about the nutritional management of grapevine varieties cultivated under cold climate conditions even in Nova Scotia. This study carried out in three seasons aimed to find correlations between tissue nutrients with yield and must composition in order to provide better nutritional management for a given variety. The yield of “L’Acadie” variety was correlated with B, K and Mg. In this variety, Ca to Mg ratio could be an interesting indicator of yield. The yield of “New York Muscat” variety was correlated with Zn, while N, P and K was related to bunch weight and weight of berries. Interspecific hybrids presented lower accumulation of B in their tissues than V. vinifera varieties. Zn and Fe were found as determinant micronutrients in “Chardonnay” variety. “Riesling” variety accumulated high levels of K in their tissues even over the optimal values recommended for grapevines. K to Ca ratio could be an important indicator of yield in “Pinot Noir” variety. A strong correlation between the petiole and blade analysis was found in macro and micro-nutrients. These results may contribute to improve the nutritional management of grapevines grown under cold climate conditions, mostly in Nova Scotia.

Aguardentes vínicas envelhecidas portuguesas: caracterização da produção, da comercialização e do estado de desenvolvimento do sector

As aguardentes vínicas envelhecidas são percepcionadas como produtos de status e elevada qualidade, com longa história e tradição em Portugal. Apesar de a nível mundial este sector ter registado um aumento no volume e valor das vendas nos últimos anos, a nível nacional não existe informação disponível. O objectivo principal deste trabalho consiste assim na caracterização do sector das aguardentes vínicas em Portugal. A metodologia seguida incluiu a recolha de dados oficiais, a realização de entrevistas exploratórias a entidades do sector e o inquérito a produtores. Os resultados obtidos revelaram que a tecnologia de produção de aguardentes vínicas envelhecidas segue, em Portugal, os procedimentos estabelecidos como boas práticas a nível internacional. No entanto, uma fracção importante dos produtores não realiza sub-processos relevantes, como a destilação, o que poderá constituir um constrangimento à diversidade, tipicidade e qualidade das aguardentes vínicas envelhecidas portuguesas. Entre 2014 e 2018, os dados disponíveis apontam para uma estagnação do sector, com volumes anuais de vendas próximos dos 850.000 litros e um peso muito reduzido das Denominações de Origem. Os produtores consideram que o sector apresenta fraco dinamismo e que os volumes comercializados são reduzidos, faltando inovação, interesse e investimento. O peso excessivo da burocracia associada às numerosas questões legais que regulam a actividade, a elevada carga fiscal, a reduzida dimensão e a falta de procura (condicionada pelo desconhecimento dos consumidores sobre estes produtos), são as questões apontadas como principais entraves ao crescimento do sector. Em conclusão propõem-se algumas medidas de incentivo ao seu desenvolvimento.