Improving Cuticle Thickness and Quality Traits in Table Grape cv. 'Italia' Using Pre-Harvest Treatments.

Table grape viticulture, due to the impact of climate change, will have to face many challenges in the coming decades, including resistance to pathogens and physiological disorders. Our attention was focused on fruit cracking due to its ubiquitous presence in several species. This study explores the effects of three different treatments on the epidermis and cuticle of table grape berries by evaluating the impact of the girdling technique on various fruit quality parameters, including cuticle thickness, sugar content, acidity, color, bunch weight, and rheological properties. The treatments were (1) calcium chloride (CaCl2), (2) calcium chloride + salicylic acid (CaCl2 + SA), and (3) calcium chloride + Ascophyllum nodosum (CaCl2 + AN), with and without girdling, plus an untreated control. This research was conducted over the 2021-2022 growing season in a commercial vineyard in Licodia Eubea, Sicily, Italy. The results indicate significant variations in cuticle thickness and other qualitative traits throughout the growth and ripening phases, with notable differences depending on the treatment used. This study's findings suggest that specific treatments can influence the structural integrity of the grape cuticle, potentially impacting the fruit's susceptibility to cracking and overall marketability. The findings provide valuable insights into the role of chemical treatments and cultural techniques in enhancing fruit quality and resistance to environmental stresses in table grape cultivation.

Aromatic Profiling of New Table Grape Varieties Using Gas Chromatography/Mass Spectrometry and Olfactometry.

The aim of this study is the aromatic characterization of new table grape varieties, namely Guzun (V. vinifera), Melona (V. vinifera), Cotton Candy (V. vinifera), IVC SA3 (V. labrusca), and IVC SB1 (V. labrusca). The qualitative and quantitative analysis of odorant molecules present in the berries allows for the definition of the aroma profile of the grape. This analysis benefits from the progress of analytical techniques and sensory methodologies. Gas chromatography/mass detection enable the efficient detection of the substances present and their concentrations. Through the coupling of gas chromatography with sensory detection (gas chromatography-olfactometry), it is possible to correlate the compounds detected by gas chromatography with olfactory stimuli, exploiting the human olfactory system. Aroma, a significant flavor component, is an important attribute of table grape that contributes to defining their quality. This characteristic is highly valued by consumers, and consequently, the market asks for table grapes with a particular or new aroma. Aromatic characterization is a crucial step in the study of the table grape varieties to evaluate their potential at the commercial level or, for instance, in breeding programs focusing on organoleptic properties.

Pre- and postharvest chitosan coatings extend the physicochemical and bioactive qualities of minimally processed 'Crimson Seedless' grapes during cold storage.

BACKGROUND: Food marketers desire residue-free fresh grapes although grapes have a short postharvest life. This study was performed to determine the influences of pre- and/or postharvest chitosan (Ch) coatings on postharvest quality of minimally processed (stem-detached) organic 'Crimson Seedless' berries. Berries were sorted as: (a) control (untreated berries); (b) preharvest Ch (dipping the clusters on the vine into 1% Ch 10 days before harvest at 20% soluble solid content (SSC)); (c) postharvest Ch (dipping the stem-detached berries into 1% Ch); and (d) pre + postharvest Ch. Berries were stored in 12 × 15 cm rigid polypropylene cups for up to 42 days at 1.0 ± 0.5 °C. RESULTS: Pre- and/or postharvest Ch coating reduced weight loss during storage. Pre- + postharvest Ch was the best treatment for restricting polygalacturonase (PG) activity, extending the visual quality, color features (L*, C and h°), skin rupture force, biochemical (SSC, titratable acidity, maturity index and pH) and bioactive (total phenol content, antioxidant activity) features. Pre- or postharvest Ch was also significantly effective in maintaining many quality features. CONCLUSION: Pre- and/or postharvest 1% Ch coatings effectively maintained the quality of minimally processed grape berries of organically produced 'Crimson Seedless' grapes by delaying weight loss and PG activity and keeping the postharvest physical, biochemical and bioactive features for 42-day cold storage at 1.0 ± 0.5 °C. The combined use of pre- and postharvest Ch found to be more effective than single treatment. Thus, pre- + postharvest 1% Ch coating could be recommended as an ecofriendly sustainable methodology for extending the postharvest quality of minimally processed fresh grapes. © 2024 The Author(s). Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Breeding new seedless table grapevines for a more sustainable viticulture in Mediterranean climate.

The growing demand for sustainable and environmentally friendly viticulture is leading to a multiplication of breeding programs aimed at obtaining vines that are resistant to powdery mildew (PM) and downy mildew (DM), the two most damaging vine diseases. In Puglia, the most important Italian region for the production of table grapes, an extensive crossing program was launched in 2015 with 113 crosses, including elite table varieties, seedless varieties, and resistant varieties. The main seedling production parameters were measured for each cross. In particular, berries harvested as well as the number of seeds and seedlings obtained were considered. Approximately 103,119 seedlings were obtained and subjected to marker-assisted selection for seedlessness using the marker VvAGL11 and for resistance to PM and DM with appropriate markers. Approximately one third (32,638) of the progenies were selected as putative seedless and seventeen thousand five hundred-nine (17,509) were transferred to the field for phenotypic evaluation, including 527 seedless individuals putatively resistant, of which 208 confirmed to be resistant to DM, 22 resistant to PM, and 20 individuals that combined resistance and seedlessness traits. The work discusses the effects of parental combinations and other variables in obtaining surviving progeny and pyramiding genes in table grapes and provides useful information for selecting genotypes and increasing the efficiency of breeding programs for seedless disease-resistant grapes.

Comparison of the sugar and organic acid components of seventeen table grape varieties produced in Ankara (Türkiye): a study over two consecutive seasons.

Sugars and organic acids not only have a significant impact on taste balance and sensory acceptance by consumers but also play a crucial role in the chemical equilibrium of grape juices and wines. Therefore, this study aimed to quantify the content and composition of sugars and organic acids in 17 grape varieties over two consecutive years using high-performance liquid chromatography. The variability in all the parameters studied was strongly influenced by both the grape cultivars and specific years (p ≤ 0.05). In grape berries, the primary sugars identified were fructose and glucose, which ranged from 6.50 to 11.10 g/L and from 5.83 to 12.12 g/L, respectively, over the two years. However, sucrose was not detected in any of the grape varieties examined. For the two respective years, the highest titratable acidity (TA) was found in Tekirdag Çekirdeksizi (TeCe) (0.89 and 0.90 g/L), while the lowest was detected in Victoria (Vi) (0.48 and 0.51 g/L). Total soluble solids (TSS) peaked in Horoz Karasi (HoKA) (21.90 °Brix), whereas it reached its lowest point in Big Perlon (BiPe) (14.1 °Brix). The tartaric acid content in the grape berries, ranging from 1.48 to 10.33 g/L for the two years, exhibited similar characteristics to malic acid, which ranged from 1.09 to 9.62 g/L and from 1.03 to 9.68 g/L for the two respective years. The succinic, malic, tartaric, citric, and oxalic acid contents were notably higher in the Kyoho (Ky) variety than in the other varieties. When examining the dendrogram of the contents of organic acid and sugar for similarities, it was evident that 16 out of the 17 grape varieties had a high degree of similarity, except for Alphonse Lavallée (AlLa) and HoKa. The similarity levels among the varieties ranged from 99.49% to 72.36%. The highest similarity (99.49%) was observed between the AlLa and Baris (Ba) varieties. The lowest similarity was observed among the AlLa, HoKa, and Ky varieties. In summary, this study underscores that certain table grape varieties grown in Ankara exhibit significant variations in valuable organic acids and sugars, which are associated with potential health benefits when considering human consumption.

On the Way to the Technological Development of Newly Selected Non-Saccharomyces Yeasts Selected as Innovative Biocontrol Agents in Table Grapes.

Post-harvest decay of fresh table grapes causes considerable annual production losses. The main fungal agents of decay both in pre- and post-harvest are B. cinerea, Penicillium spp., Aspergillus spp., Alternaria spp., and Cladosporium spp. To date, the use of agrochemicals and SO2 are the main methods to control grape molds in pre- and postharvest, respectively. Significant improvements, however, have already been made in to apply innovative and more environmentally sustainable control strategies, such as Biological Control Agents (BCAs), which can reduce disease severity in both pre- and post-harvest. In this study, 31 new non-Saccharomyces yeast strains, isolated from berries of native Apulian table grape genotypes, were tested for their in vivo effectiveness against grey mold of table grapes, resulting in two St. bacillaris ('N22_I1' and 'S13_I3'), one S. diversa ('N22_I3'), one A. pullulans ('OLB_9.1_VL') and one H. uvarum ('OLB_9.1_BR') yeast strains that were marked as efficient and good BCAs. Their mechanisms of action were characterized through in vitro assays, and additional characteristics were evaluated to assess the economic feasibility and viability for future technological employment. Their effectiveness was tested by reducing the working concentration, their antagonistic effect on a wide range of fungal pathogens, their ability to survive in formulations with long shelf life, and their safety to human health.

The roles of brassinosteroids and methyl jasmonate on postharvest grape by regulating the interaction between VvDWF4 and VvTIFY 5 A.

Brassinosteroids (BRs) and methyl jasmonate (MeJA) are known for the regulation of plant development, and the crosstalk between them is important for plant growth. However, the interaction between them in the development of postharvest fruit is unresolved. We found that BR treatment enhanced the accumulation of sugar composition and aroma content, reduced the content of organic acids (such as tartaric acid) and promoted the coloring of grape callus. After the application of MeJA, the acidity increased and the sugar content decreased. The physiological data showed that exogenous BR also attenuated the JA inhibition of postharvest ripening in grape. DWF4 is a key enzyme in the BR biosynthetic pathway, and it can effectively regulate the content of endogenous BRs. TIFY 5 A, which belongs to the Jasmonate ZIM-domain (JAZ) family, can be baited by DWF4 through the Y2H experiment. TIFY 5 A represses the expression of dihydroflavonol-4-reductase (DFR) which plays a key role in the synthesis of anthocyanins, while this will be alleviated by VvDWF4. The interaction between TIFY 5 A and DWF4 contributes to the cross talk between JA and BR signalling pathways. This is also verified by the transgenic experimental results. The results in this paper provides a new insight into the relationship between BR and JA signalling pathways, which is important to the regulation of the postharvest ripening of grape.

Quality Assessment and Ripeness Prediction of Table Grapes Using Visible-Near-Infrared Spectroscopy.

Ripeness significantly affects the commercial values and sales of fruits. In order to monitor the change of grapes' quality parameters during ripening, a rapid and nondestructive method of visible-near-infrared spectral (Vis-NIR) technology was utilized in this study. Firstly, the physicochemical properties of grapes at four different ripening stages were explored. Data evidenced increasing color in redness/greenness (a*) and Chroma (C*) and soluble solids (SSC) content and decreasing values in color of lightness (L*), yellowness/blueness (b*) and Hue angle (h*), hardness, and total acid (TA) content as ripening advanced. Based on these results, spectral prediction models for SSC and TA in grapes were established. Effective wavelengths were selected by the competitive adaptive weighting algorithm (CARS), and six common preprocessing methods were applied to pretreat the spectra data. Partial least squares regression (PLSR) was applied to establish models on the basis of effective wavelengths and full spectra. The predictive PLSR models built with full spectra data and 1st derivative preprocessing provided the best values of performance parameters for both SSC and TA. For SSC, the model showed the coefficients of determination for calibration (RCal2) and prediction (RPre2) set of 0.97 and 0.93, respectively, the root mean square error for calibration set (RMSEC) and prediction set (RMSEP) of 0.62 and 1.27, respectively; and the RPD equal to 4.09. As for TA, the optimum values of RCal2, RPre2, RMSEC, RMSEP and RPD were 0.97, 0.94, 0.88, 1.96 and 4.55, respectively. The results indicated that Vis-NIR spectroscopy is an effective tool for the rapid and non-destructive detection of SSC and TA in grapes.

Screening of antagonistic yeast strains for postharvest control of Penicillium expansum causing blue mold decay in table grape.

Blue mold decay caused by Penicillium expansum is one of the most important postharvest diseases of grapes, leading to considerable economic losses. Regarding the increasing demand for pesticide-free foods, this study aimed to find potential yeast strains for biological control of blue mold on table grapes. A total of 50 yeast strains were screened for antagonistic activity against P. expansum using the dual culture method and six strains significantly inhibited the fungal growth. All six yeast strains (Coniochaeta euphorbiae, Auerobasidium mangrovei, Tranzscheliella sp., Geotrichum candidum, Basidioascus persicus, and Cryptococcus podzolicus) reduced the fungal growth (29.6-85.0%) and the decay degree of wounded grape berries inoculated with P. expansum while G. candidum was found to be the most efficient biocontrol agent. On the basis of antagonistic activity, the strains were further characterized by in vitro assays involving inhibition of conidial germination, production of volatile compounds, iron competition, production of hydrolytic enzymes, biofilm-forming capacity, and exhibited three or more putative mechanisms. To our knowledge, the yeasts are reported for the first time as potential biocontrol agents against the blue mold of grapes but more study is required to evaluate their efficiency related to field application.

Vineyard light manipulation and silicon enhance ethylene-induced anthocyanin accumulation in red table grapes.

Red color resulted from anthocyanin pigment, is an essential trait for premium table grape production. Anthocyanin biosynthesis occurs through the flavonoid pathway which includes several enzymatic reactions coded by different genes. The expression of these genes is regulated by different cultural practices, cultivars, environmental conditions, and plant hormones. Recently, we reported that the anthocyanin pathway is regulated by several factors such as light and antioxidant activity. Despite the advances in cultural practices, it is still challenging to produce table grapes with high coloration, especially under the current and expected global climate change in warmer areas such as California. In the current study, we deployed two approaches to improve the accumulation of red pigment in table grapes. The first approach involves improving the expression of critical genes involved in the anthocyanin pathway through hormonal treatments and light manipulation using a reflective ground cover (RGC). The second approach was to reduce the negative effect of heat stress through stimulation of the antioxidant pathway to help remove free radicals. Treatments included ethephon (ET) at 600 mg/L, silicon (Si) at 175 mg/L, and a commercial light-reflective white ground cover (RGC) alone and in various combinations. Treatments were conducted either with or without a combination of cluster-zone leaf removal at veraison (LR) on Flame seedless (Vitis vinifera L.). Data collected in 2019 and 2020 showed that the best treatment to improve berry coloration was using ET in combination with Si and RGC, applied at veraison. Adding the LR to this combination did not improve berry color any further, but rather caused a reduction in color development. RGC without conducting LR at veraison significantly increased the quantity of reflected blue and red lights as well as the red (R) to far-red (FR) ratio (R: FR) around clusters. Results were in accordance with the increase in gene expression of flavonoid-3-O-glucosyltransferase (UFGT), a key gene in the anthocyanin biosynthesis pathway, as well as Peroxidase dismutase (POD). Manipulating the light spectrum and application of silicon in combination with the ethephon treatment could be used in table grape vineyards to improve the ethylene-induced anthocyanin accumulation and coloration.

Antimicrobial Properties, Functional Characterisation and Application of Fructobacillus fructosus and Lactiplantibacillus plantarum Isolated from Artisanal Honey.

Honey is a valuable reservoir of lactic acid bacteria (LAB) and, particularly, of fructophilic LAB (FLAB), a relatively novel subgroup of LAB whose functional potential for human and food application has yet to be explored. In this study, FLAB and LAB strains have been isolated from honeys of different floral origins and selected for their broad antimicrobial activity against typical foodborne pathogenic bacteria and spoilage filamentous fungi. The best candidates, two strains belonging to the species Lactiplantibacillus plantarum and Fructobacillus fructosus, were submitted to partial characterisation of their cell free supernatants (CFS) in order to identify the secreted metabolites with antimicrobial activity. Besides, these strains were examined to assess some major functional features, including in vitro tolerance to the oro-gastrointestinal conditions, potential cytotoxicity against HT-29 cells, adhesion to human enterocyte-like cells and capability to stimulate macrophages. Moreover, when the tested strains were applied on table grapes artificially contaminated with pathogenic bacteria or filamentous fungi, they showed a good ability to antagonise the growth of undesired microbes, as well as to survive on the fruit surface at a concentration that is recommended to develop a probiotic effect. In conclusion, both LAB and FLAB honey-isolated strains characterised in this work exhibit functional properties that validate their potential use as biocontrol agents and for the design of novel functional foods. We reported antimicrobial activity, cytotoxic evaluation, probiotic properties and direct food application of a F. fructosus strain, improving the knowledge of this species, in particular, and on FLAB, more generally.

Sulfur dioxide maintains storage quality of table grape (Vitis vinifera cv 'Kyoho') by altering cuticular wax composition after simulated transportation.

The cuticular wax layer as a natural defensive barrier plays a key role in postharvest fruit quality maintenance. This study investigated the effects of simulated transport vibration (STV) on the berry quality and cuticular wax, and the ability of sulfur dioxide (SO2) to ameliorate STV damage in table grapes during cold storage. Results showed that STV damage accelerated the deterioration in grapes quality, and resulted in degradation and melting of cuticular wax, accompanied by a decrease in load of total wax, triterpenoids, fatty acids, alcohols, and olefins while an increase in alkanes and esters content during subsequent storage. However, SO2 effectively reversed the adverse impact of STV damage by increasing most wax fraction levels and corresponding genes expression, especially triterpenoids, although it had no apparent effect on wax structure. Overall, SO2 delayed the quality deterioration caused by vibration damage that occurs during transportation and storage by altering cuticular wax composition.

Beneficial Effects of Table Grape Use on Serum Levels of Omega-3 Index and Liver Function: A Randomized Controlled Clinical Trial.

This clinical trial was aimed to investigate the effects of fresh table grape intake on the serum levels of the Omega-3 index, defined as the sum of eicosapentaenoic acid (EPA) + docosahexaenoic acid (DHA) levels. Forty consecutive healthy subjects were randomly assigned to the control group, receiving only dietary recommendations, and the grape group receiving a daily dose of 5 g of fresh table grape per kg of body weight, for 21 days. Compared with baseline, the grape treatment produced no significant difference in the serum levels of glucose, liver transaminase, and triglycerides, with the exception of cholesterol value, which was significantly reduced in both control and grape group (180.5 ± 20.32 vs. 196.1 ± 30.0 and 181.4 ± 21.9 vs. 194.3 ± 37.5, respectively). After 4 weeks from the end of grape treatment, the analysis of single fatty acids showed a significant increase in oleic acid content (14.15 ± 1.8 vs. 12.85 ± 1.6, p < 0.05) and a significant induction of the Omega-3 index (8.23 ± 1.9 vs. 6.09 ± 1.2, p < 0.05), associated with increased serum levels of adiponectin (24.09 ± 1.08 vs. 8.8 ± 0.7, p < 0.001). In contrast, the expression of fibroblast growth factor 21 (FGF21), a molecule associated with metabolic syndrome and liver disease, was significantly reduced (37.9 ± 6.8 vs. 107.8 ± 10.1, p < 0.001). The data suggest that the intake of fresh grape improves the Omega-3 index in the serum and exerts beneficial effects on liver function through the overexpression of adiponectin and the reduction in FGF21 levels.

Effect of Gaseous Citral on Table Grapes Contaminated by Rhizopus oryzae ITEM 18876.

Rhizopus oryzae is responsible for rapidly producing a deliquescent appearance in grape berries, generally favoured by cold chain interruptions. To counteract fruit spoilage and to meet consumer acceptance, innovative strategies based on the application of natural compounds are ongoing. Due to their biological activities, including antimicrobial ones, natural flavour compounds extend the shelf life and improve the nutritional value as well as the organoleptic properties of foods. Thus, in this work, the application of the antimicrobial citral, a flavor component of monoterpenes identified in plant and fruit essential oils, was developed and validated against one spoiler of R. oryzae. Citral, as pure compound, was first investigated in vitro against R. oryzae ITEM 18876; then, concentrations equal to the minimal inhibitory concentration (MIC) and 4-fold MIC (4MIC) value were applied on the table grape cv Italia infected with this strain and stored. The MIC value was equal to 0.0125 µL/cm3; both citral concentrations (0.0125 and 0.05 µL/cm3) were effective in counteracting the microbial decay of infected table grapes over the storage period. The HS-SPME/GC-MS method showed citral persistence in the head space of plastic trays with the infected samples; as expected, a higher content of citral isomers was found in the sample treated with 4MIC value. In conclusion, citral revealed its efficacy to counteract the onset of soft rot by R. oryzae ITEM 18876 under storage conditions. Thus, it could be successfully exploited to develop an active packaging or natural preservatives to extend table grape shelf life without affecting its quality and sensory characteristics, whilst also satisfying the consumer demand for natural preservative agents.

Detection of Pesticide Residue Level in Grape Using Hyperspectral Imaging with Machine Learning.

Rapid and accurate detection of pesticide residue levels can help to prevent the harm of pesticide residue. This study used visible/near-infrared (Vis-NIR) (376-1044 nm) and near-infrared (NIR) (915-1699 nm) hyperspectral imaging systems (HISs) to detect the level of pesticide residues. Three different varieties of grapes were sprayed with four levels of pesticides. Logistic regression (LR), support vector machine (SVM), random forest (RF), convolutional neural network (CNN), and residual neural network (ResNet) models were used to build classification models for pesticide residue levels. The saliency maps of CNN and ResNet were conducted to visualize the contribution of wavelengths. Overall, the results of NIR spectra performed better than those of Vis-NIR spectra. For Vis-NIR spectra, the best model was ResNet, with the accuracy of over 93%. For NIR spectra, LR was the best, with the accuracy of over 97%, but SVM, CNN, and ResNet also showed closed and fine results. The saliency map of CNN and ResNet presented similar and closed ranges of crucial wavelengths. Overall results indicated deep learning performed better than conventional machine learning. The study showed that the use of hyperspectral imaging technology combined with machine learning can effectively detect the level of pesticide residues in grapes.

Use of Artificial Neural Networks and NIR Spectroscopy for Non-Destructive Grape Texture Prediction.

In this article, a combination of non-destructive NIR spectroscopy and machine learning techniques was applied to predict the texture parameters and the total soluble solids content (TSS) in intact berries. The multivariate models obtained by building artificial neural networks (ANNs) and applying partial least squares (PLS) regressions showed a better prediction ability after the elimination of uninformative spectral ranges. A very good prediction was obtained for TSS and springiness (R2 0.82 and 0.72). Qualitative models were obtained for hardness and chewiness (R2 0.50 and 0.53). No satisfactory calibration model could be established between the NIR spectra and cohesiveness. Textural parameters of grape are strictly related to the berry size. Before any grape textural measurement, a time-consuming berry-sorting step is compulsory. This is the first time a complete textural analysis of intact grape berries has been performed by NIR spectroscopy without any a priori knowledge of the berry density class.

Vitis vinifera Turkish novel table grape 'Karaerik'. Part II: Non-anthocyanin phenolic composition and antioxidant capacity.

BACKGROUND: 'Karaerik' is a novel table grape (Vitis vinifera L.) native to Turkey and widely cultivated in areas bordering the city of Erzincan. Because of the demonstrated beneficial effects on human health of the grape phenolic composition, the aim of this work was to conduct a detailed profiling of non-anthocyanin phenolic fractions from different grape tissues of the 'Karaerik' table grape. Both qualitative and quantitative characterization of phenolic compounds were achieved using high-performance liquid chromatography-diode array detection-electrospray ionization-tandem mass spectrometry. Total phenolic content and oxygen radical absorbance capacity were also determined to evaluate the antioxidant properties of this table grape. RESULTS: A high number of non-anthocyanin phenolic compounds was identified in 'Karaerik' table grape skins and seeds, including 11 flavonols, six hydroxycinnamic acid derivatives, two stilbenes, several monomeric and dimeric flavan-3-ols and proanthocyanidins. Quercetin-type derivatives dominated the flavonol profile of grape skins, followed by myricetin type. Tartaric acid esters of three acids (caffeic, coumaric and ferulic acids) were the main hydroxycinnamic acid derivatives in this cultivar. Qualitative and quantitative differences were observed in flavan-3-ol composition among the grape tissues. Proanthocyanidins were the most abundant class of phenolic compounds in 'Karaerik' grapes, being mainly located in seeds. Higher antioxidant capacity values were determined in grape seeds, in correlation with the total phenolic content. CONCLUSION: These results provide useful information for a better understanding of phenolic antioxidants from the 'Karaerik' table grape and will contribute to promoting the varietal identity and health-related properties of this fruit. © 2021 Society of Chemical Industry.

Ozone and Bioactive Compounds in Grapes and Wine.

Ozone is widely used in the agri-food and food processing industries mainly as a sanitizing agent. However, it has recently become clear that ozone exposition leads to another important benefit: in living tissues, the induced-oxidative stress triggers the antioxidant response, and, therefore, it enhances the production of antioxidant and stress-related secondary metabolites. As such, ozone can be considered an abiotic elicitor. The goal of the present review was to critically summarize knowledge about the possibility of improving bioactive compounds and, consequently, the health-related properties of grapes and wine, by using ozone. The greatest interest has been given not only to the pre- and post-harvest treatment of table and wine grapes, but also to the explanation of the mechanisms involved in the ozone-related response and the main secondary metabolites biosynthetic pathways. From the literature available, it is clear that the effect of ozone treatment on health-related properties and secondary metabolites accumulation depends on many factors, such as the cultivar, but also the form (water or gaseous), doses, and application method of ozone. Most of the published papers report an increase in antioxidant compounds (e.g., polyphenols) and stress-related volatiles, confirming the hypothesis that ozone could be used to improve berry and wine compositional and sensory quality.

Classification of Browning on Intact Table Grape Bunches Using Near-Infrared Spectroscopy Coupled With Partial Least Squares-Discriminant Analysis and Artificial Neural Networks.

Table grape browning is a complex physiological disorder that occurs during cold storage. There is a need to investigate novel and innovative ways to manage the problem that hampers the progressive and sustainable growth of table grape industries. Given the complex nature of the browning phenomenon, techniques such as near-infrared (NIR) spectroscopy can be utilized for the non-destructive classification of different browning phenotypes. In this study, NIR coupled with partial least squares discriminant analysis (PLS-DA) and artificial neural networks (ANN) were used to classify bunches as either clear or as having chocolate browning and friction browning based on the spectra obtained from intact 'Regal Seedless' table grape bunches that were cold-stored over different periods. Friction browning appears as circular spots close to the pedicel area that are formed when table grape berries move against each other, and chocolate browning appears as discoloration, which originates mostly from the stylar-end of the berry, although the whole berry may appear brown in severe instances. The evaluation of the models constructed using PLS-DA was done using the classification error rate (CER), specificity, and sensitivity and for the models constructed using ANN, the kappa score was used. The CER for chocolate browning (25%) was better than that of friction browning (46%) for weeks 3 and 4 for both class 0 (absence of browning) and class 1 (presence of browning). Both the specificity and sensitivity of class 0 and class 1 for friction browning were not as good as that of chocolate browning. With ANN, the kappa score was tested to classify table grape bunches as clear or having chocolate browning or friction browning and showed that chocolate browning could be classified with a strong agreement during weeks 3 and 4 and weeks 5 and 6 and that friction browning could be classified with a moderate agreement during weeks 3 and 4. These results open up new possibilities for the development of quality checks of packed table grape bunches before export. This has a significant impact on the table grape industry for it will now be possible to evaluate bunches non-destructively during packaging to determine the possibility of these browning types being present when reaching the export market.

[Characteristics of water requirement of table grape in the growing season]. / è‘¡è„ç”Ÿé•¿å­£å† éœ€æ°´ç‰¹å¾.

To quantitatively assess the satisfaction degree of precipitation on water requirement of table grape in the main producing areas in China, we analyzed the temporal and spatial variations of precipitation, water requirement and water deficit in different growth stages of table grape based on the 1981-2016 daily meteorological data from 429 meteorological stations in the study region (Jinlin and Liaoning of Northeast China; Shanxi and Hebei of North China; Xinjiang, Gansu, Ningxia and Shaanxi of Northwest China; Sichuan, Guizhou and Yunnan of Southwest China; Jiangsu, Shandong, Zhejiang, Anhui, Fujian, Henan, Hubei, Hunan and Guangxi of Southeast China). Results showed that precipitation in each growth stage showed an increasing trend from north to south and from west to east in the study period. The precipitation in germination-flowering stage was the lowest and showed a decreasing trend. The precipitation in maturation-defoliation stage showed a decreasing trend, while that in flowering-veraison and veraison-maturation stage exhibited an increasing trend. Water requirement of grape exhibited an increasing trend in each growth stage in the study region. Water requirement of grape in Xinjiang and the northern of Gansu Province was the highest. The precipitation could not meet water requirement of grape in Xinjiang, northern Gansu, Ningxia, northern Shaanxi, northern Shanxi, northern Hebei, western Liaoning and western Jilin in each growth stage, as well as northern Yunnan and southern Sichuan during germination-flowering stage. In constrast, water surplus was obvious in the other areas, especially in the southeast and southwest of China. The water deficit of grape showed an increasing trend during the germination-flowering and maturation-defoliation stage, while that during flowering-veraison and veraison-maturation stage showed a decreasing trend.