Control Grapes Research Articles

Effect of chitosan and alginate beads incorporated with lavender, clove essential oils, and vanillin against Botrytis cinerea and their application in fresh table grapes packaging system

Encapsulation of clove, lavender essential oils (EOs)m and vanillin into chitosan (CH) and alginate (AL) beads was prepared using a simple oil‐entrapped emulsion to inhibit Botrytis cinerea in table grapes. The overall encapsulation efficiency of AL beads was observed to be higher than that of CH beads. The release of EO from beads depended mostly on surrounding relative humidity. The inhibition efficiency of the beads was investigated with grapes packed in a clamshell by placing a permeable sachet containing beads inside and storing at 5°C for 28 days. Visible mould growth on the control grapes and grapes packed with CH beads containing clove EO was observed on Days 21 and 28, respectively. The grapes packed with AL beads containing clove EO were free from mould until Day 28. The qualities of the grapes during storage, including the CO2 and O2 concentration in the packaging, firmness, total soluble solids, titratable acidity, ascorbic acid content, and acceptability of grapes, were evaluated. The use of CH or AL beads releasing clove EO maintained the freshness, firmness, flavour, odour, and overall acceptability of the grapes better than the control.

Harpin Proteins Improve Bioactive Compounds Content in Crimson Seedless Table Grape

Background:Frequently, in warm climates such as Mediterranean areas, a red-pink table grape ‘Crimson Seedless’ does not reach a good berry skin color; and an acceptable anthocyanin bioactive compounds content, responsible for the red color of berries. Harpin proteins are biotechnologically developed bio-activators that, if applied on plants during the growing period, trigger the expression of hundreds of genes among which those associated with the biosynthesis of bioactive compounds (such as anthocyanins).Aim:This research aimed at using harpin proteins to test their suitability in improving the grape skin color.Methods and Materials:Beta-harpin protein 1% p.a. (400 g/Ha) was applied to ‘Crimson Seedless’ vines three times at the beginning of veraison. Six samplings were carried out for both the treated and control grapes until commercial harvest. In the skin extracts, total and individual anthocyanins content was determined by UV-Vis and RP-HPLC-DAD analyses, respectively.Results:The collected results confirmed that the application of harpin proteins effectively stimulated the anthocyanin biosynthesis leading to make peonidin-3O-glucoside, cyanidin-3O-glucoside, and malvidin-3O-glucoside values from 2 to almost 10 folds higher in treated grapes than in control grapes (P< 0.05).Conclusion:Actually, harpin proteins improved the color of the berry skin, leading to a significantly higher concentration of anthocyanins in treated than in control grapes.

Changes in global aroma profiles of Cabernet Sauvignon in response to cluster thinning.

Cluster thinning (CT) is a common practice to prevent overcropping in viticulture. CT affects vine balance between vegetative and productive growth and further modifies grape composition. This study investigated the effects of cluster thinning treatments applied at pea-size stage (CT-AF) and the onset of veraison (CT-V), respectively, on volatile compounds of Cabernet Sauvignon in two seasons (2013-2014). The experimental vineyard was located in the north-west of China with semi-arid and monsoon climate. CT exhibited limited effects on the evolutions of volatile compounds. CT-AF exhibited an inhibition on 6-methyl-5-heptene-2-one accumulation. There were no differences in terpene concentrations between CT-treated and control grapes regardless of CT time. Regarding C6/C9 compounds and their derivatives, CT-AF decreased nonanal concentration whilst CT-V increased (Z)-3-hexen-1-ol concentration. Additionally, there were increases in nonanal, (E)-2-hexen-1-ol, (Z)-2-hexen-1-ol and (Z)-3-hexen-1-ol concentrations in grapes with delayed CT. Among benzene derivatives, earlier CT resulted in lower phenol concentrations.

Characterization of Saccharomyces bayanus CN1 for Fermenting Partially Dehydrated Grapes Grown in Cool Climate Winemaking Regions

This project aims to characterize and define an autochthonous yeast, Saccharomyces bayanus CN1, for wine production from partially dehydrated grapes. The yeast was identified via PCR and Basic Local Alignment Search Tool (BLAST) analysis as Saccharomyces bayanus, and then subsequently used in fermentations using partially dehydrated or control grapes. Wine grapes were dried to 28.0°Brix from the control grapes at a regular harvest of 23.0°Brix. Both the partially dehydrated and control grapes were then vinified with each of two yeast strains, S. bayanus CN1 and S. cerevisiae EC1118, which is a common yeast used for making wine from partially dehydrated grapes. Chemical analysis gas chromatography-flame ionization detector (GC-FID) and enzymatic) of wines at each starting sugar level showed that CN1 produced comparable ethanol levels to EC1118, while producing higher levels of glycerol, but lower levels of oxidative compounds (acetic acid, ethyl acetate, and acetaldehyde) compared to EC1118. Yeast choice impacted the wine hue; the degree of red pigment coloration and total red pigment concentration differed between yeasts. A sensory triangle test (n = 40) showed that wines made from different starting sugar concentrations and yeast strains both differed significantly. This newly identified S. bayanus strain appears to be well-suited for this style of wine production from partially dehydrated grapes by reducing the oxidative compounds in the wine, with potential commercial application for cool climate wine regions.

Effects of IPT or NDGA Application on ABA Metabolism and Maturation in Grape Berries

The effects of isoprothiolane (IPT: a fungicide used to control rice blast) and nordihydroguaiaretic acid (NDGA: an inhibitor of the phytohormone abscisic acid (ABA) biosynthesis) on the maturation of “Shine Muscat” grape berries were investigated. The results showed that IPT and NDGA retarded chlorophyll degradation in the berry skin. Transcriptional profiling revealed that 2218 genes in the grapes treated with IPT and 2270 genes in those treated with NDGA were differentially expressed compared to the untreated control grapes at 70 days after full bloom (DAFB). IPT or NDGA application regulated the expression of genes involved in ABA, auxin, and ethylene metabolism. MapMan analysis and qRT-PCR validation showed that the expression levels of VvNCED1, VvCYP707A1, VvAAO4, and VvGEM-like genes in the ABA metabolic pathway were negatively regulated by IPT and NDGA treatment at 70 DAFB. Moreover, IPT and NDGA treatment inhibited glucose accumulation via the VvSUS, VvAI, VvHT genes in the sugar metabolic pathway. In addition, IPT and NDGA treatment delayed (E)-2-hexenal and hexanol productions, and down-regulated aroma metabolic pathway genes such as VvLOX, VvADH, VvGPPS, and VvTPS. These results suggest that IPT and NDGA influence chlorophyll degradation, ABA accumulation, and sugar and aroma volatile syntheses in the maturation process.

Influence of air flow and dehydration technique on respiration and VOCs of ‘Pecorino’ grapes

Some special wines are usually obtained from dried grapes by using traditional techniques without control of temperature, relative humidity (RH) and airflow. A new technology (tunnel) for grape dehydration based on controlled air speed, temperature and RH has been tested on 'Pecorino' grape and compared with traditional practice of grape dehydration. The grapes were harvested at 21 °Brix of solid soluble content (SSC). The tunnels (2) dried the grapes at 15°C, 60% of RH, and air flow of 1.2 or 2.5 m s-1. Control grapes were kept in a room with open windows but without controlled environment of dehydration. Vapour pressure deficit (VPD) in the two tunnels was always between 7.5 and 8.0 mbar while, in the control, VPD fluctuated between 0.7 and 6.4 mbar with temperature between 25 and 7°C, depending on the outside temperature conditions. The dehydration lasted until the time of reaching 45% mass loss (m.l.). SSC reached 32 °Brix in tunnel samples and 26 °Brix in control one. CO2 production of grapes showed a peak in all 3 samples at 10% m.l. then it declined and rose again in control sample, reaching the highest value at 17% m.l. while, in the tunnel samples, it reached a peak at 30 and 40% m.l. for 1.2 and 2.5 m s-1 tunnels, respectively. Significant difference in volatile organic compounds (VOCs) was observed between the samples at the last sampling, where the concentration of alcohols was much higher than esters and aldehydes in control sample and it was much higher than the same compounds in the tunnel sample.

Control of environmental parameters in postharvest partial dehydration of wine grapes reduces water stress

The hypothesis that a controlled environmental condition of postharvest partial dehydration of wine grapes may reduce berry water stress keeping a better grape quality, was verified on white wine grapes, var. ‘Pecorino’. Grapes were harvested at 21.5% solid soluble content (SSC) and kept at 15°C, 60% relative humidity (RH), and 2.5ms−1 or 1.2ms−1 air speed (tunnel), with a vapor pressure deficit (VPD) of 7.5–8mbar; control bunches were kept in an uncontrolled condition (VPD=0.7–6.4mbar). Samplings for chemical and biochemical analyses were performed on grapes with 10, 25, 35, and 45% mass loss (m.l.). Tunnel and control samples reached 31.5% (in 24-26days) and 28.5% (in 28days) SSC, respectively. Control grapes had higher CO2 production, alcohol dehydrogenase (ADH) and lipooxygenase (LOX) activities and proline content. Ethanol and acetaldehyde contents reflected ADH activity patterns. Control grape had higher percentage of branched alcohols than control ones. An activation of aerobic fermentation in control grapes is discussed with comment on related generation of specific volatile organic compounds (VOCs).

Postharvest putrescine and ultrasound treatments to improve quality and postharvest life of table grapes (Vitis vinifera L.) cv. Michele Palieri

The main objective of this study was to assess the effectiveness of putrescine (Put) (1 and 2 mM for 10 min) and ultrasound treatments (32 kHz for 10 min) alone or in combination on changing biochemical compounds and extending postharvest life of grape. After treatments, clusters were packed in boxes with modified atmosphere packaging and stored at 1-2 °C with 90-95% relative humidity for 60 days. The weight loss, total soluble solids, titratable acidity, total anthocyanins, total phenolic content, antioxidant capacity, stem browning, decay rate and visual appearance at 0, 20, 40 and 60 days after harvest were recorded. Statistically significant differences were observed between different treatments in all measured parameters except for weight loss and total soluble solids. The data showed that individual Put or ultrasound treatment had a positive response in maintaining grape quality during storage, but conjugation of Put with ultrasound treatments showed better effects. Combination treatments maintained higher levels of anthocyanins, total phenolic content, antioxidant capacity and reduced the loss of sensory acceptability and decay incidence compared to control. At the end of the storage, control grapes markedly lost their quality, reaching below the critical marketable level while all the treatments preserved better the visual quality. These results demonstrated that the combined treatments of Put and ultrasound could be a promising approach to maintain postharvest storage quality of grapes.

Brassinosteroids Regulate Anthocyanin Biosynthesis in the Ripening of Grape Berries

Anthocyanins are important components in the skins of grapes and in the development of wine colour. Various environmental factors cause poor coloration in some areas, even for the same cultivars planted in different production areas. The objective of this study was to evaluate the effect of exogenous brassinosteroids (BR) on the accumulation of anthocyanins and gene expression of anthocyanin biosynthesis in wine grape berry skins. The results show that total anthocyanin content in BR-treated grapes was higher than that in the control (CT) grapes, and that 0.4 mg/L was the most effective treatment concentration. The effect of BR on downstream genes was more effective than that on upstream genes. Full coloration of BR-treated grapes was achieved seven days earlier than in the case of CT. Moreover, BR enhanced the transcript level of the downstream genes of anthocyanin biosynthesis, which caused the total anthocyanin content to increase. The induction of structural and regulatory genes of the flavonoid pathway suggests that the interrelationships between developmental and environmental signalling pathways were magnified by BR treatment, which actively promoted fruit coloration, namely anthocyanin biosynthesis.

Impact of preharvest and postharvest alginate treatments enriched with vanillin on postharvest decay, biochemical properties, quality and sensory attributes of table grapes

Alginate solution enriched with vanillin as a bioactive compound was investigated for improving preharvest and postharvest quality and safety of table grapes. Alginate treatments with or without vanillin as preharvest spray and postharvest coating were implemented on table grapes of Alphonse Lavalleé and Razaki cultivars. Fungal decay, biochemical properties, quality and sensory attributes were evaluated at day of preharvest treatment, at harvesting and during 35days of storage at 4±2°C. Alginate treatments with or without vanillin were effective in preventing weight and firmness losses. Total soluble solids, titratable acidity, and color of grapes coated with alginate coatings with or without vanillin showed minor changes compared to control grapes. Alginate coating incorporating vanillin provided significant reduction (1.73log CFU/g) in yeast-mold growth. Moreover, the coatings maintained greater total phenolic content and antioxidant activity compared to others during postharvest storage. In terms of sensory attributes, appearance was ranked as the highest for alginate coating without vanillin due to glossiness of alginate.

The significance of postharvest disinfection for prevention of internal decay of table grapes after storage

Table grapes can accumulate significant amount of dust carrying potential inoculum and this can be a significant problem for late season grapes or in regions with high dust content. Internal decay of table grapes during storage under SO2 atmosphere is expressed as visually intact berries but extensive internal decomposition. One hypothesis is that these symptoms are caused by latent infections of Botrytis cinerea or by another pathogen. Alternatively, SO2 restricts external fungal growth but its initial level is not sufficient to prevent penetration of external natural inoculum into the berry. To test these hypotheses clusters of ‘Scarlotta Seedless' grapes were externally disinfected by dipping in ethanol after harvest and cold-stored in the presence of one or two SO2 sheets for 6, 10, or 14 weeks followed by 3 days at shelf life. After 6 weeks of storage the untreated control grapes contained 60% decay – mainly typical gray mold symptoms – whereas SO2-treated berries displayed internal decay without external symptoms. Ethanol reduced decay to 4.1% and the combination of ethanol treatment and SO2 sheets eliminated the symptoms completely. The effect of the combined treatment was sustained after 10 and 14 weeks of cold storage. Only B. cinerea was recovered from berries that showed internal decay, ruling out potential involvement other pathogens. While the untreated clusters appeared dusty with dull red color, after external disinfection the original red color of the berries was apparent. It can be concluded that external disinfection of grapes after harvest can prevent internal decay under conditions which restrict external fungal growth.

Effect of cluster and berry thinning on Merlot and Cabernet Sauvignon wines composition

The manipulation of grape yield is widely practised to improve grape and wine quality. Merlot and Cabernet Sauvignon vines in the Zagreb vineyard hills, north-western Croatia, were subjected to three crop removal treatments [cluster thinning (CT), berry thinning (BT), CT+BT, and untreated control] in a randomised block design experiment. CT and CT+BT treatments reduced the grape yield but increased the mean cluster weight compared to control vines. BT alone had a little effect on the yield components. Control grapes generally had the lowest soluble solids (°Oe) and highest titratable acidity (g/l). In most cases, control wines had the lowest total phenols, flavan-3-ols, and anthocyanin concentrations, while CT+BT treatment had the highest ones followed by CT treatment. It was concluded that CT+BT produced wines with generally increased total phenols, flavan-3-ols, and anthocyanins, as well as many individual phenolic compounds. Thus, grape yield per vine seems to be strongly connected with the grape and wine compositions. The final cost-effectiveness of this canopy interventions still remains questionable.  

Effect of Two Different Treatments for Reducing Grape Yield in Vitis vinifera cv Syrah on Wine Composition and Quality: Berry Thinning versus Cluster Thinning

The influence of two treatments for reducing grape yield, cluster thinning and berry thinning, on red wine composition and quality were studied in a Vitis vinifera cv Syrah vineyard in AOC Penedès (Spain). Cluster thinning reduced grape yield per vine by around 40% whereas berry thinning only reduced it by around 20%. Cluster thinning grapes had higher soluble solids content than control grapes, and their resultant wines have greater anthocyanin and polysaccharide concentrations than the control wine. Wine obtained from berry thinning grapes had a higher total phenolic index, greater flavonol, proanthocyanidin, and polysaccharide concentrations, and lower titratable acidity than the control wine. Wines obtained from both treatments were sufficiently different from the control wine to be significantly distinguished by a trained panel in a triangular test. Even though both treatments seem to be effective at improving the quality of wine, berry thinning has the advantage because it has less impact on crop yield reduction.

Increasing the Phenolic Compound Content of Grapes by Preharvest Application of Abcisic Acid and a Combination of Methyl Jasmonate and Benzothiadiazole

Benzothiadiazole (BTH) and methyl jasmonate (MeJ) have been described as exogenous elicitors of some plant defense compounds, polyphenols among them. Given that they activate different arrays of biochemical reactions to induce resistance, the objective of this study was to determine whether the joint application of BTH and MeJ to grape clusters affects the level of the main flavonoid compounds in grapes and in the resulting wines. The results are compared with those obtained when abscisic acid (ABA), a plant growth regulator involved in several physiological processes, was sprayed in the same vineyard. The results obtained indicated that, although the application of ABA increased the content of skin anthocyanins and tannins, these positive effects were not reflected in the wines made from these grapes. BTH+MeJ-treated grapes also presented higher anthocyanin and flavonol contents, and in this case, their wines presented better chromatic characteristics that the wine made from control grapes.

Quality response of table grapes (Vitis vinifera L.) during cold storage to postharvest cap stem excision and hot water treatments

SummaryBerry quality, total phenol, sensory characteristics and decay incidence of grapes (V. vinifera cvs. Müşküle and Red Globe) as affected by prestorage hot water immersion with or without cap stem excision treatments were investigated with 7‐day interval during storage at 1 °C for 21 days. Weight loss occurred mainly up to the second week and was more pronounced for the untreated control samples subjected to the stem excision. In Müşküle, the least weight loss value was obtained from hot water–treated grapes (0.62%), while the highest loss occurred in control grapes of stem‐excised berries (0.96%). Immersion of stem‐retained grapes in hot water was the best applications for maintenance of overall storage quality for both cultivars. According to panellist scores, it is evident that hot water has positive effect on maintaining the minimally processed table grapes without altering the flavour and taste of the commodity. Stem‐retained berries of hot water treatment had the highest score for both Müşküle and Red Globe, with their values 3.8 and 4.2, respectively, while the least values were obtained from stem‐excised berries of untreated control group of both the cultivars (1.9 and 3.0, respectively). At the end of three‐week storage, the least decay rates were determined in stem‐retained berries that received hot water treatment (5.3% for Müşküle and 1.1% for Red Globe). Attenuate influence of brief high temperature exposure on ripening parameters (SSC, TA, MI, pH) was also observed. Postharvest hot water treatment may be used as a nonchemical means to extent storage life of minimally processed grapes with its alleviating effect on physiological disorders. Cap stem retaining in minimal processing can be recommended to maintain the quality of grapes.

Effect of Benzothiadiazole and Methyl Jasmonate on the Volatile Compound Composition of Vitis vinifera L. Monastrell Grapes and Wines

Benzothiadiazole and methyl jasmonate have been described as exogenous elicitors of some plant defence compounds. The objective of this study was to determine whether the application of benzothiadiazole and methyl jasmonate to Vitis vinifera L. Monastrell grape clusters at the beginning of the ripening process affects the synthesis of volatile compounds in grapes (as has been observed in other fruits) and whether this effect has a technological significance in the resulting wines. Results indicated that both treatments increased the levels of volatile compounds in grapes, especially terpenes and norisoprenoids in benzothiadiazole-treated grapes. The wines obtained from the treated grapes also showed higher levels of terpene and norisoprenoids. Wines from methyl jasmonate-treated grapes had levels of these volatile compounds almost two times higher than the wines made from control grapes. These differences in the volatile compound levels could be sensorially detected.

Effect of X-ray irradiation on the physical and chemical quality of America red globe grape

The use of irradiation as a phytosanitary treatment has expanded in recent years. It plays important roles in developed and developing countries, facilitating international trade in irradiated fresh fruit. To evaluate the potential of X-ray irradiation as a quarantine treatment for America red globe grapes, we investigated the effect of X-ray irradiation by 0.2, 0.4, 0.6 and 1.0 kGy on the physical and chemical quality of fresh grape. Irradiation by 0.2 and 0.4 kGy could reduce the respiration rate of fresh grape and extend the shelf life of fruit. There was no significant effect of irradiation on other physical and chemical quality of grapes (weight loss, total soluble solids, titratable acidity, protein, mineral, sweet and taste). The irradiation treatments also had a better appearance than the control grapes after 14 days. Therefore, irradiation as a quarantine treatment for fresh grapes is possible. Keywords: X-ray irradiation, quarantine treatment, physical-chemical, grape

Improving Grape Phenolic Content and Wine Chromatic Characteristics through the Use of Two Different Elicitors: Methyl Jasmonate versus Benzothiadiazole

Benzothiadiazole (BTH) and methyl jasmonate (MeJ) have been described as exogenous elicitors of some plant defense compounds, polyphenols among them. The objective of this study was to determine whether the application of BTH or MeJ to grape clusters at the beginning of the ripening process had any effect on the accumulation of the main flavonoid compounds in grapes (anthocyanins, flavonols, and flavanols) and the technological significance of these treatments in the resulting wines. The results obtained after a 2 year experiment indicated that both treatments increased the anthocyanin, flavonol, and proanthocyanidin content of grapes. The wines obtained from the treated grapes showed higher color intensity and total phenolic content than the wines made from control grapes. The exogenous application of these elicitors, as a complement to fungicide treatments, could be an interesting strategy for vine protection, increasing, at the same time, the phenolic content of the grapes and the resulting wines.

Postharvest ethylene treatment affects berry dehydration, polyphenol and anthocyanin content by increasing the activity of cell wall enzymes in Aleatico wine grape

Ethylene is known to induce cell wall degradation by acting on cell wall enzymes. Thus, the objective of this experimental study was to evaluate the effect of ethylene on weight loss in Aleatico wine grape during dehydration and whether this effect was due to cell wall enzyme activation. Moreover, the effect on polyphenol, anthocyanin content, and volatile compounds was studied. Aleatico red grapes (Vitis vinifera L, cv Aleatico) were treated with 1,000 μL/L of ethylene in air for 48 h at 20 °C and high relative humidity (RH). Control grapes were untreated. After 48 h, grape clusters were placed at 45% RH, 20 °C, and 1 m/sec air flow (dehydration treatment) to dehydrate until reaching 40% of weight loss (wl). Pectin methylesterase (PME), polygalacturonase (PG), α galactosidase, and β glucosidase were analyzed during dehydration treatment. Weight loss in ethylene-treated berries was about 6% higher than in control grapes, and PME, PG, galactosidase, and glucosidase activities had increased. During dehydration, the concentration of polyphenols and anthocyanins in ethylene-treated grape was higher than in untreated grape. Geraniol and citronellol peak areas rose slightly in ethylene-treated grapes following the pattern of β glucosidase, but the total peak area of terpene alcohols decreased. Ethylene increased the concentration of anthocyanins and polyphenols during dehydration.

APPLICATION OF ETHEPHON AND ABA AT 40% VERAISON ADVANCED MATURITY AND QUALITY OF 'BEIDANEH GHERMEZ' GRAPE

The market value of grape ‘Beidaneh Ghermez’, which is one of the most popular cultivar of table grapes in Iran, is dependant upon its desirable appearance (red color). Its color is relatively poor in Zanjan province, Iran. The research was conducted to study the effects of of ethephon and abscisic acid (ABA) at four dosages (0, 100, 200, 300 ppm) at 20 to 30% verasion of berries on skin color quality of ‘Beidaneh Ghermez’ during two seasons (2007-2008). Application of ABA was more effective than ethephon for enhancing the color and maintaining quality of fruits. The ABA application significantly increased berry total anthocyanin content. Total berry skin smart anthocyanin (extracted and absorbance at 520 nm) was associated with skin color. ABA-treated grapes were characterized by superior appearance both in berries and clusters, compared to ethephon-treated and un-treated control grapes. Grape treated with ABA showed higher firmness and soluble solids concentrations than the control. Firmness decreased with increasing ethephon dosages (up to 200 ppm). Berry size (berry weight) increased by ethephon application. Ethephon application enhanced fruit ripening, which is very important to avoid rain cracking.