Winegrapes dehydration under ozone-enriched atmosphere: Influence on berry skin phenols release, cell wall composition and mechanical properties (original) (raw)
Related papers
Journal of Agricultural and Food Chemistry, 2020
In this study, the combined effect of partial postharvest dehydration and long-term ozone treatment was evaluated at 10 and 20% weight loss as a strategy to induce compositional changes in grape skin flavanols. Two separate trials were carried out in thermohygrometric-controlled chambers at 20°C and 70% relative humidity. The first trial was conducted under an ozone-enriched atmosphere at 30 μL/L, whereas the second trial was performed under an air atmosphere as a control. Two red wine grape varieties were studied, Barbera and Nebbiolo (Vitis vinifera L.), for their different phenolic composition. Berry skin flavanol composition was determined by high-performance liquid chromatography after phloroglucinolysis and size-exclusion chromatography. The results showed that dehydration and ozone effects were variety-dependent. In Barbera skins, being characterized by lower proanthocyanidin contents, the two effects were significant and their combination showed interesting advantages related to lower proanthocyanidin loss as well as higher prodelphinidin and lower galloylation percentages. In Nebbiolo, skin flavanol composition was barely affected.
Ozone fumigation for safety and quality of wine grapes in postharvest dehydration
This paper proposes postharvest ozone fumigation (as a method) to control microorganisms and evaluate the effect on polyphenols, anthocyanins, carotenoids and cell wall enzymes during the grape dehydration for wine production. Pignola grapes were ozone-treated (1.5 g/h) for 18 h (A = shock treatment), then dehydrated or ozone-treated (1.5 g/h) for 18 h and at 0.5 g/h for 4 h each day (B = long-term treatment) during dehydration. Treatment and dehydration were performed at 10 °C. No significant difference was found for total carotenoid, total phenolic and total anthocyanin contents after 18 h of O 3 treatment. A significant decrease in phenolic and anthocyanin contents occurred during treatment B. Also carotenoids were affected by B ozone treatment. Pectin methylesterase (PME) and polygalacturonase (PG) activities were higher in A-treated grapes during dehydration. Finally, ozone reduced fungi and yeasts by 50%. Shock ozone fumigation (A treatment) before dehydration can be used to reduce the microbial count during dehydration without affecting polyphenol and carotenoid contents.
Ozone and Bioactive Compounds in Grapes and Wine
Foods
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 proper...
Grape VOCs Response to Postharvest Short-Term Ozone Treatments
Frontiers in Plant Science
Ozone has been recently recognized as an efficient sanitizing agent in wine industry because of its powerful oxidizing properties. Furthermore, postharvest treatments of grapes with ozone can stimulate defense responses by synthetizing secondary metabolites against oxidative stress. In this study, the effect of postharvest short-term ozone treatments was assessed for the first time on free and glycosylated volatile organic compounds (VOCs) of winegrapes. Two different ozone concentrations (30 and 60 µL/L) and exposure times (24 and 48 h) were investigated just after treatment (fresh grapes) and after partial dehydration up to 20% weight loss (withered grapes). The study was carried out on Moscato bianco winegrapes (Vitis vinifera L.) due to the importance of terpenes in white aromatic cultivars to produce high quality wines. The results obtained showed that short-term ozone treatment caused a significant decrease in total contents of free VOCs in fresh grapes, mainly due to terpenes. Among them, linalool, geraniol, and nerol are the major aromatic markers of Moscato bianco grapes. Ozone entailed a significant decrease of free linalool contents in fresh grapes, the less stressful ozone treatment showing the smaller linalool degradation. However, the stronger and longer ozone treatment induced the synthesis of this compound probably in response to higher abiotic stress. Instead, significant changes were not observed in geraniol and nerol contents in fresh grapes. This last ozone treatment also reduced the loss of free linalool by water loss in withered grapes even though total VOCs and terpenes remained relatively stable. Furthermore, ozone seems to promote the synthesis of free (+)-4carene and 4-terpineol in withered grapes under certain treatment conditions. Regarding glycosylated compounds, total VOCs and terpenes were less sensitive to ozone. Our findings highlight that ozone can be used as sanitizing agent in aromatic grape varieties prior to winemaking without affecting sharply the aromatic profile of fresh grapes and even improving it in withered grapes.
Ozone Fumigation Postharvest Treatment for the Quality of Wine Grape
Acta Horticulturae, 2015
High quality wine requires high quality grape. High quality grape means good aromatic properties and texture, excellent phenols panorama, and salubrity. Ozone is known as a great sanitizing agent but little is known on its effect on grape metabolism. Grape bunches of 'Sauvignon Blanc' (Vitis vinifera L.) were hand harvested at the end of day in Castello de "La Sala" winery, placed in perforated boxes in one single layer and then stacked in a cold room at 10°C and 70% RH (relative humidity). Ozone treatment (1.5 g h-1) started immediately and bunches were sampled before and after treatment which lasted 4, 8, and 16 h. The control sample consisted in grape bunch treated in similar way, placed in another cold room without ozone treatment. Total phenols on dry weight (d.w.) basis increased of 10% after 8 and 16 h treatment compared to the control sample. Hydroxycinnamic acids increased 50-100% in ozone-treated sample. Even total carotenoids raised in ozonetreated sample after 16 h. Glycosilated volatiles organic compounds (VOCs) increased in ozone-treated samples while decreased in untreated one; in contrast the free VOCs, which means the perceptible aroma compounds, were higher in untreated grape. This is an important result because the grape for vinification must have many glycosilated VOCs before fermentation which are released during the process by yeasts.
Food Research International, 2016
Ozone represents a potent antimicrobial compound that is already proposed as a possible sanitizing agent, especially for surface decontamination of fruits and vegetables. The main objective of this study was to evaluate the effect of ozone, either in aqueous or gaseous form, on wine grape mycobiota and its impact during spontaneous and inoculated fermentations. Gaseous (32 ± 1 μL/L, 12 and 24 h) and aqueous (5 ± 0.25 mg/L, 6 and 12 min) ozone were tested as sanitizing treatments. A multiphasic approach was used employing culture-dependent (traditional plate counts) and-independent techniques, based on DNA and RNA amplification (PCR-denaturing gradient gel electrophoresis [DGGE] and reverse transcription PCR [RT-PCR]-DGGE), respectively. Microbiological analysis data highlighted a reduction of N 0.5 Log CFU/mL of the total yeasts present on grape berry surfaces after ozone treatments, mainly due to the reduction of apiculate yeasts. The chemical analysis of the wines, produced from the treated grapes, showed higher acetic acid content in the untreated spontaneous fermentations (0.52 g/L) compared to the treated (ranged from 0.16 to 0.38 g/L), while all fermentation-inoculated wines contained higher amounts of pleasant volatile compounds.
Journal of Applied Microbiology, 2018
Aim: Straw wine is an high-valuable oenological production, affected by relevant economical losses due to proliferation of spoilage microorganisms during drying grapes, after being harvested. In this work ozone was evaluated as tool to preserve grapes during drying, in terms of both qualitative and quantitative changes induced in the epiphytic microflora. In addition, the alteration exerted by ozone on grape's chemical composition was analyzed. Methods and Results: Grapes from four vine varieties were treated with ozone produced by a cold plasma generator during the entire drying period (6 weeks). The microflora was quantified weekly by plate counts and characterized by 454-pyrosequencing, and was compared with identical, untreated, grape samples. At the end of drying, an extensive chemical characterization was performed onto the whole mass of grapes by FT-IR and GC-MS. Ozone counteracted the growth of microflora, by reducing the microbial population up to 3 log units. From the qualitative point of view, ozone reduced the incidence of spoilage microorganisms, such as Acetobacter and Botrytis cinerea, among the microbiota of grapes.
Ozone Improves the Aromatic Fingerprint of White Grapes
Scientific Reports, 2017
Ozone, a powerful oxidative stressor, has been recently used in wine industry as sanitizing agent to reduce spoilage microflora on grapes. In this study, we evaluated ozone-induced metabolic and molecular responses during postharvest grape dehydration. Ozone increased the contents of total volatile organic compounds (VOCs), which have a great impact on the organoleptic properties of grapes and wines. Among terpenes, responsible for floral and fruity aroma, linalool, geraniol and nerol were the major aromatic markers of Moscato bianco grapes. They were significantly affected by the longterm ozone treatment, increasing their concentration in the last phases of dehydration (>20% weight loss). At molecular level, our results demonstrated that both postharvest dehydration and ozone exposure induce the biosynthesis of monoterpenes via methylerythritol phosphate (MEP) pathway and of aldehydes from lipoxygenase-hydroperoxide lyase (LOX-HPL) pathway. Therefore, transcriptional changes occurred and promoted the overproduction of many important volatile compounds for the quality of white grapes.
This study was performed to evaluate and compare the effects of different pre-treatments of whole grape berries (freezing with dry ice or in a cold room, steam blanching with different exposure times, and microwave heating with different exposure times and microwave power density) on total content of some phenolic compounds and the composition of individual anthocyanins released into the pulp during the treatment and those extracted during the maceration step. Two red winegrape varieties with different proportions of di-and trisubstituted anthocyanins were used (Nebbiolo and Barbera, respectively). Pulpextracted anthocyanins were more significantly influenced by the pre-treatment. The results highlighted that freezing with dry ice, followed by freezing in a cold room and steam blanching for 5 min, have a great potential from an industrial point of view. They facilitated the extraction of anthocyanins in the must prior to maceration, when compared with the control samples, increasing their total content (+37.8−83.6%), and modifying the anthocyanin profile through the enrichment in the most stable compounds (+2.8−6.6% malvidin derivatives) to the detriment of others more prone to oxidation (−0.8−11.0% cyanidin derivatives). In Nebbiolo winegrapes, an improved extraction of low-and high-molecular weight flavanols into the pulp was also observed (+60.4−73.4%). Significant relationships between the phenolic composition of treated berries and the corresponding skin mechanical properties were also studied, but they were variety dependent. Discriminant analysis permitted a correct classification of the samples according to the variety and pre-treatment.