Background and Aims
The grape ripening disorder called berry shrivel is characterised by cessation of sugar accumulation, low pH, impaired anthocyanin biosynthesis in dark‐skinned cultivars and water ...loss. We tested whether damage to the bunch peduncle vasculature can induce berry shrivel and whether cell death in the rachis precedes cell death in the berries.
Methods and Results
Peduncle phloem removal, but not xylem removal, resulted in symptoms resembling berry shrivel. Fluorescein diacetate staining, however, and microscopic observations of non‐manipulated bunches showed that cell death in the berries often preceded that in the rachis. Mesocarp cell death started around the central vasculature proximal to the seeds and spread outward as symptoms worsened. Berries near the bunch tip were the earliest to be affected and developed the most severe symptoms, but ripening of all berries on symptomatic bunches was impaired.
Conclusions
Loss of functionality of the rachis phloem may not be the primary cause of berry shrivel. The disorder may originate in the distal berries of a bunch and spread towards the proximal berries as they soften at the onset of ripening.
Significance of the Study
This study contributes towards an eventual understanding of the causes and consequences of an important grape ripening disorder.
Two separate artificial sensors, an electronic eye (EE) and an electronic tongue (ET), were recently developed to monitor grape ripening based on the analysis of must. The aim of this research is to ...exploit the complementary information obtained by means of EE and ET sensing systems using different data fusion strategies, in order to develop an integrated device able to quickly and easily quantify the physico-chemical parameters that are used to assess phenolic ripeness. To this purpose, both low-level and mid-level data fusion approaches were investigated. Partial Least Squares (PLS) regression was applied to the fused data, with the aim of relating the information brought by the two sensors with twelve physico-chemical parameters measured on the must samples by standard analytical methods. The results achieved with mid-level data fusion outperformed those obtained using EE and ET separately, and highlighted that both the artificial sensors have made a significant contribution to the prediction of each one of the considered physico-chemical parameters.
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•Data fusion was used to improve the performance of a device to monitor grape ripening.•Data from an electronic tongue (ET) and an electronic eye (EE) were combined.•Low-level and mid-level data fusion were used to build PLS calibration models.•The use of data fusion allowed to increase significantly the prediction performances.•Mid-level data fusion of PLS latent variables gave generally the best results.
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•A device has been developed for fast determination of anthocyanins in red grapes.•It is based on multivariate image analysis of grape berries taken by a smartphone.•Device hardware ...is a 3D-printed case to guarantee controlled lighting.•Device software is a user-friendly smartphone app coupled to a web interface.•It allows measuring anthocyanins in field and real-time data sharing with wineries.
The choice of the proper moment for harvesting is a crucial aspect in winemaking process, since the chemical attributes of grape berries strongly influence red wine quality. In particular, phenolic composition of red grapes plays a significant role in many sensory properties of wine related to color and taste. Anthocyanins are the most important phenolic compounds for red grapes: they accumulate in the grape skin during ripening, and they are responsible for the purple color of ripe berries. Routine analysis for the determination of grapes phenolic maturity includes chromatographic and spectroscopic techniques, that are time-consuming and expensive. In this work, we propose an innovative device conceived for the determination of grape phenolic maturity based on RGB images of grape berries acquired with a smartphone. The device has been designed to be used directly in the vineyard thanks to its small size and to the possibility of acquiring geolocated images of the berries under controlled lighting conditions. In this study, grape samples of three different varieties (Ancellotta, Lambrusco Salamino and Sangiovese) were collected at different harvest times from veraison to maturity and imaged by means of a common smartphone using the device. The RGB images were then converted into one-dimensional signals, named colourgrams, which codify the color properties of the images. The dataset of colourgrams was then used to calculate calibration models using Partial Least Squares (PLS) regression in order to relate color information with chemical parameters generally employed to evaluate grape phenolic maturity, such as total anthocyanins content and extractable anthocyanins content. The calibration models were implemented in a software interface that allows to acquire geolocated images of the grape samples, visualize the outcomes of the analysis, visualize maps and plots related to phenolic maturity, store data and share relevant information.
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•Wine flavonoids and aromas were strongly affected by cluster thinning.•Green/aroma compounds in wine had the strongest negative correlation to grape sugar content.•Cluster thinning ...led to yield loss compensation through bigger berry sizes.•Defoliation reduced berry size even one season after treatments were applied.
Sugar levels in grape berries are necessary for wine production but also, they are the main driver of most ripening processes. Sugar levels are very responsive to canopy and crop load adjustments. The aim of this study is to test the effect of different levels of defoliation and cluster thinning on grape ripening and wine composition. ‘Cabernet sauvignon’ grapevines (Vitis vinifera L.) were subjected to defoliation (keeping 100 %, 66 % and 33 % of the leaves) and fruit thinning treatments (keeping 100 %, 66 % and 33 % of the clusters) combined in a factorial design. The experiment was repeated for 2 consecutive seasons (2017 and 2018) and the plants were left untreated for a third season (2019) to observe the carry-over effects of the treatments. The treatments implied precise adjustments of leaf and cluster numbers. However, the proportion of leaf area to fruit mass tended to compensate each other and interact resulting in smaller differences in leaf area or fruit mass by harvest. Berry mass was strongly reduced by defoliation even in the subsequent season where no defoliation was applied. Berry ripening indicators (soluble solids, acidity and anthocyanin levels) were also more affected by defoliation than fruit thinning. Anthocyanin profile was shifted to a higher proportion of Malvidin-derived anthocyanins for defoliated vines and lower proportion of Malvidin-derived anthocyanins in the case of thinned vines. However, when it came down to wine, the physicochemical parameters as well as the aroma profile were more affected by cluster thinning. There was a clear relationship between sugar levels of the unfermented must and many wine-aroma compounds. Green aromas (2-isobutyl-3-methoxypyrazine, hexanol and cis-3-Hexen-1-ol) were among those presenting a negative correlation to must sugar whereas other compounds like Isobutyric acid, Benzyl alcohol, 1-Octen-3-ol and γ-Nonalactone had a positive correlation. This study reveals a higher level of complexity of source sink relations where leaves and clusters do not only act as a source and a sink of carbon, respectively. Therefore, the results of this study should be considered before making comparisons of leaf area to fruit mass ratios across different vine-growing systems.
Devido à viticultura ser uma atividade em processo de consolidação na região do Planalto Norte Catarinense, os produtores não realizam um acompanhamento da qualidade físico-química dos seus produtos, ...com o objetivo de comparar e atender a legislação brasileira vigente e os padrões de qualidade. Neste contexto, o objetivo deste trabalho foi realizar a caracterização físico-química de sucos de uva elaborados na região do Planalto Norte Catarinense na safra 2021. O presente estudo foi realizado no Instituto Federal de Santa Catarina – IFSC Câmpus Canoinhas, abrangendo a região do Planalto Norte Catarinense - Santa Catarina. As avaliações foram realizadas em triplicata, sendo avaliados as variáveis: densidade relativa (g mL-1), sólidos solúveis (°Brix), Grau Glucométrico (°Babo), acidez titulável total (meq L-1) e pH. Observou-se para as dez amostras avaliadas, valores médios de densidade relativa de 1,0476 g mL-1. Para o teor de sólidos solúveis (°Brix) observou-se valor médio de 11,79° Brix. O grau glucométrico, expresso em °Babo, apresentou entre as amostras avaliadas valor médio de 9,82 °Babo, com valores variando de 7,0 a 15,0 °Babo. O valor médio para a variável acidez total titulável foi de 75,6 meq L-1, com valores entre 63,0 a 89,2 meq L-1. Observou-se valor médio de 3,32 para o pH das amostras, com valores variando de 3,2 a 3,62. O Planalto Norte Catarinense possui potencial para a elaboração de sucos de uva de qualidade, contudo, é importante atentar-se ao ponto de maturação das uvas colhidas, com intuito de obter produtos com maiores teores de sólidos solúveis, grau glucométrico e densidade relativa, além da necessidade de refinar o processo de elaboração.
Wine made from grapes subjected to accelerated ripening, an increasingly frequent phenomenon occurring in many wine regions due to peaks of heat and water stress, displays higher alcohol levels and ...lacks balance with color and flavor compounds. Herein, the rate of sugar accumulation of grapes was manipulated by varying the crop load and irrigation regime and the development of secondary metabolites was monitored by gas chromatography–mass spectrometry (GC–MS) and high-performance liquid chromatography (HPLC). A 3-week delay in ripening correlated to an increase in the concentration of some monoterpenes and norisoprenoids and a greater decrease of green aroma compounds. Delayed ripening had a positive impact on the phenolic composition of grapes, displaying higher contents of total anthocyanins, total phenolics, quercetin glycosides, and polymeric pigments. A map of the chemical composition of grapes close to harvest allowed discrimination of compounds mainly responsive to delayed ripening from those driven by crop load or irrigation.
Vitis vinifera berries are sensitive towards infection by the necrotrophic pathogen Botrytis cinerea, leading to important economic losses worldwide. The combined analysis of the transcriptome and ...metabolome associated with fungal infection has not been performed previously in grapes or in another fleshy fruit. In an attempt to identify the molecular and metabolic mechanisms associated with the infection, peppercorn-sized fruits were infected in the field. Green and veraison berries were collected following infection for microarray analysis complemented with metabolic profiling of primary and other soluble metabolites and of volatile emissions. The results provided evidence of a reprogramming of carbohydrate and lipid metabolisms towards increased synthesis of secondary metabolites involved in plant defence, such as trans-resveratrol and gallic acid. This response was already activated in infected green berries with the putative involvement of jasmonic acid, ethylene, polyamines, and auxins, whereas salicylic acid did not seem to be involved. Genes encoding WRKY transcription factors, pathogenesis-related proteins, glutathione S-transferase, stilbene synthase, and phenylalanine ammonia-lyase were upregulated in infected berries. However, salicylic acid signalling was activated in healthy ripening berries along with the expression of proteins of the NBS-LRR superfamily and protein kinases, suggesting that the pathogen is able to shut down defences existing in healthy ripening berries. Furthermore, this study provided metabolic biomarkers of infection such as azelaic acid, a substance known to prime plant defence responses, arabitol, ribitol, 4-amino butanoic acid, 1-O-methyl- glucopyranoside, and several fatty acids that alone or in combination can be used to monitor Botrytis infection early in the vineyard.
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•An IoT spectral sensing system for monitoring the grape berry ripening process through reflectance signals was developed.•The system was evaluated in both lab and field environments ...for red and white grapes.•The PCA analysis of the reflectance data collected showed a trend related to the grape berry ripening process.•A Partial Least Squares model for predicting the Total Soluble Solids content in red and white grapes was applied.
The present work proposes a novel autonomous Internet of Things (IoT) spectral sensing system for in-situ optical monitoring of grape ripening through reflectance signals. To this end, tailor-made hardware for this IoT end node was developed, characterized, and operated in both lab and field conditions. It included three complementary modules: the optical module, the host module, and the controller module. The optical module included four photodetectors and four LEDs with maximum emission wavelength centered at 530, 630, 690, and 730 nm that was placed in direct contact with the grape berry. The host module included the LED driver and the analog front-end for signal acquisition. Finally, the controller module provided full control of the system and ensured data storage, power management, and connectivity. The system was capable of measuring reflectance in the range of 4 – 100 % with a linear response (r2 > 998) and with a high reproducibility among different optical units. This design made it possible to collect reflectance signals from red (cv. Touriga Nacional) and white (cv. Loureiro) grape varieties in both lab and field environments. The relationship between this optical fingerprint (comprised of the different reflectance intensities recorded) and the evolution of grape berry quality parameters throughout the ripening period (for approximately two months), was analyzed and discussed. Lab data was used to establish a multivariate model based on Partial Least Squares for the prediction of the Total Soluble Solids (TSS) content in both varieties. The model error (Root Mean Square Error in Cross Validation) was 2.31 and 0.73 °Brix for Touriga Nacional and Loureiro, respectively. This model was applied to data acquired in the field in an illustrative example of the potential of the system to predict TSS in real time. The field observations collected during the monitoring period also provided relevant information about the potential issues that may occur during the unattended operation of the optical sensors. Additionally, the modular architecture of the optical module proposed makes it possible to use different LEDs and photodetectors, as well as the assembly of optical filters. This creates the possibility of using the same principles for measuring reflectance in different spectral ranges (e.g. IR) or even fluorescence. The results herein described paved the work for future developments of this technology that will include the development of prediction models for the most relevant grape ripening parameters based on reflectance data, as well as its operation as part of a Wireless Sensor Network.
An electronic tongue (ET) consisting of two voltammetric sensors, namely a poly-ethylendioxythiophene modified Pt electrode and a sonogel carbon electrode, has been developed aiming at monitoring ...grape ripening. To test the effectiveness of device and measurement procedures developed, samples of three varieties of grapes have been collected from veraison to harvest of the mature grape bunches. The derived musts have been then submitted to electrochemical investigation using Differential Pulse Voltammetry technique. At the same time, quantitative determination of specific analytical parameters for the evaluation of technological and phenolic maturity of each sample has been performed by means of conventional analytical techniques. After a preliminary inspection by principal component analysis, calibration models were calculated both by partial least squares (PLS) on the whole signals and by the interval partial least squares (iPLS) variable selection algorithm, in order to estimate physico-chemical parameters. Calibration models have been obtained both considering separately the signals of each sensor of the ET, and by proper fusion of the voltammetric data selected from the two sensors by iPLS. The latter procedure allowed us to check the possible complementarity of the information brought by the different electrodes. Good predictive models have been obtained for estimation of pH, total acidity, sugar content, and anthocyanins content. The application of the ET for fast evaluation of grape ripening and of most suitable harvesting time is proposed.
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•An electronic tongue has been developed aiming at monitoring grape ripening.•Electrochemical signals on grapes at different ripening stages have been collected.•Calibration models have been built for estimation of physicochemical parameters.•Good predictive models have been obtained for pH, acidity, sugars and anthocyanins.
It is widely accepted that prevéraison application of naphthaleneacetic acid (NAA) can delay the ripening of grapes and improve their quality. However, how NAA impacts grape aroma compound ...concentrations remains unclear. This study incorporated the analyses of aroma metabolome, phytohormones, and transcriptome of Vitis vinifera L. cv. Cabernet Sauvignon grapes cultivated in continental arid/semiarid regions of western China. The analyses demonstrated that NAA application increased β-damascenone and 1,1,6-trimethyl-1,2-dihydronaphthalene (TDN) in the harvested grapes by delaying véraison and upregulating VvPSY1 and VvCCD4b expressions. Additionally, NAA treatment decreased 2-isobutyl-3-methoxypyrazine (IBMP) at the same phenological stage. Notably, abscisic acid (ABA) levels increased in NAA-treated grapes during véraison, which triggered further changes in norisoprenoid metabolisms. The ABA-responsive factor VvABF2 was potentially involved in VvPSY1 positive modulation, while the auxin response factor VvARF10 may play a role in VvCCD4b upregulation and VvOMT2 downregulation during NAA induction. VvARF10 possibly acts as a crosstalk node between the ABA and auxin signaling pathways following NAA treatment in regulating aroma biosynthesis.
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