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South African & Italian Wine Research Innovations

CURRENT STATUS FUTURE PROSPECTS

Winemaking: State-of-the-Art Winery –Innovations in winemaking technologies,

processes, products

Winemaking technologies, processes, products: present situation and prospects in Italy

Antonella Bosso

CREA-VE Asti

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The present communication deals with oenologicalpractices and products that match the main lines ofdevelopment (axes) established in the OIV Strategic plan2020-2024, in agreement with the objectives for theSustainable Development Goals (SDG) fixed by the Agenda2030 of the United Nations:

➢Mitigation of CC

➢Adaptation to CC

➢Environmental sustainability

➢Quality

Preface

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Improvement of environmental performances in oenology:

a) Implementation of new winemaking processes aimedat reducing the use of inputs (additives, adjuvants)

b) Promotion of circular economy through the re-use ofwastes and the management of by-products

Protection of natural resources:

a) Reduction of the use of non-renewable resources andwater

b) Protection of biodiversity in the vineyard (increasingtypologies of wines from different cultivars)

Mitigation of CC

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A. Reduction of the use of sulphites

- At present, a safe product with all the oenological features of sulphurdioxide (SO2) has not yet been identified

- Therefore, the reduction of the use of SO2 is achievable through thecombination of different practices and/or oenological products

- A collection of guidelines is in preparation at OIV

A1. Aims of the research:

- Identification of a new product as effective as SO2 and without its sideeffects

- Deepening knowledge on the oenological practices for the control ofmicrobial development (antimicrobial effect of SO2)

- Deepening knowledge on the factors involved in the wines oxidationprocess and on the oenological products able to slowdown/stop thisprocess (antioxidant and antioxidase effect of SO2)

Reduction of inputs

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Factors involved in the oxidation process

tannins

SO2

metalsmetals

metalsGSH

SO2

Fenton’s reaction

These factors can influence thewine oxygen consumption rate.Normally they speed up the oxygenconsumption rate.Nevertheless, it does not necessarymean that they protect the winesagainst oxidation, as SO2 does.

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Oxygen consumption rate

➢ Oxygen consumption related to the presence and amount of SO2 and copper

➢ higher SO2, faster O2

consumption

➢ Copper (catalyzer) increased the rate of oxygen consumption, particularly during the first days

Model solution

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Wine oxygen consumption rate

➢ The higher the SO2 content, the faster the oxygen consumption➢ The oxygen consumption rate increased in the presence of GSH➢ High content of SO2 + GSH = faster oxygen consumption➢ The higher the oxygen content at bottling, the faster its consumption →

wine aging is influenced by bottling conditions.

Sample Free SO2

(mg/L)

GSH

(mg/L)

O2 (ppm)

o 20 0 3.3

so 60 0 3.3

(1) 20 0 1.3

s 60 0 1.3

og 20 20 3.3

sog 60 20 3.3

g 20 20 1.3

sg 60 20 1.3

The studied factors:

Wine

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Effect on color

Model solutions

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A. Study on some factors involved in the oxidation process

Aim• Studying the protective effect of GSH and tannins

compared to SO2 on the oxidative evolution ofmodel solutions and bottled wines in the presenceof different levels of oxygen (different bottlingconditions)

• Studying the effect of SO2 and transition metals onthe oxidative kinetics and the role of GSH in theFenton reaction in order to reduce the dose of SO2

in wines

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Influence on wines sensory descriptors

+SO2 samples = less colored, with more intense notes related to freshness and less intense notes related to oxidation

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Results

A significant effect of GSH was observed only for the descriptors pineapple(more intense for –GSH sample) and licorice (more intense for +GSH sample).

No significant effect of tannins was observed on any descriptor.

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Literature reports antioxidant activity of tannins in wine, related to different properties:

➢ presence of -OH groups in orto position which are oxidized to quinonescausing the consumption of dissolved oxygen (Pascual et al., 2017; Vignault etal., 2018);

➢ ability to scavenge peroxyl radicals (Magalhães et al.,2014);➢ chelating effect on iron (II) and consequent prevention of oxidative evolution

mediated by Fenton-based reactions (Perez,Wei, & Guo, 2009).

B. Study of the antioxidant properties of oenological tannins

OIV Research Grant 2016 - Silvia MottaComparison between tannins of different types and botanical origin:

evaluation of antioxidant and anti-radical properties

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Total polyphenols

content (GAE)

Ferric Reducing

Capacity (FRAP)

Antiradical power

(DPPH)

Redox properties

Total polyphenols (LSV1200 mV)

Redox properties

Easily oxidizable polyphenols

(LSV600 mV)

Oxygen

Consumption Rate

Ellagitannins Gallotannins Condensed tannins

OIV Research Grant 2016 Silvia Motta

Comparison between tannins of different botanical origin

➢ Differences between tannins for the O2 consumption trend

➢ Tannins with different botanicalorigin had different antioxydantproperties

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Dis

solv

ed o

xyge

n (m

g/L)

Days

Control Ellagic tannins Gallic tannins Condensed tannins

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2A. Evaluation of the possibility to reduce the use of SO2 insome winemaking processes through the combination ofsome oenological practices and products.Assessment of the impact of these winemaking protocolson wine quality.

• A divulgation program on the reduction of the SO2 contentin wines was recently started in our Research Centre(INNOWINE Project)

• 5 private wineries are involved

• The project includes theoretical lessons on oenologicalpractices and products to reduce the SO2 use duringwinemaking

Transfer of knowledge in the cellars

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The 5 wineries chose a winemaking process, or a single phase of it, toreduce the doses of SO2 on large scale;

a) White winemaking, for the Cortese cultivar (still wine)

b) Red winemaking, for the Barbera cultivar (still wine)

c) Complete production cycle of Asti secco (sparkling dry wine fromMoscato bianco cultivar)

d) Storage phase of the Moscato bianco must for the production ofAsti spumante (sparkling sweet wine from Moscato biancocultivar)

e) Shelf-life of Asti secco wines with different storage conditions andadditives

INNOWINE Project

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The winemaking protocols consist in a combination of recentlyauthorized technologies, older techniques, and oenologicalproducts aimed at verifying on large scale the feasibility toobtain quality wines without or with very low content ofsulphur dioxide

The products obtained during these experiments will becompared with the wines produced according to thetraditional protocols of the wineries, and containing sulphites.The comparisons will concern the chemical and sensorycharacteristics and the evaluation of the shelf-life of the wines

INNOWINE Project

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Protection from oxidation

• Storage on lees (exploitation of the property of lees to consume oxygen during the first months after the end of the AF)

• Addition of inactive yeasts to protect wine from oxidation

• Batonnages with limited exposure to air and rackings under inert gases

• Use of membrane contactors before bottling to reduce the dissolved oxygen

• Bottling under inert gases

Prevention of ML fermentation

• Addition of products (chitosan..) to control ML bacteria development in white wines

• Filtration before bottling

Practices to reduce the concentration of compounds that combine SO2 (for instance acetaldehyde)

• No addition of SO2 to musts (with healthy grapes)

• Addition of thiamine

• Use of yeast strains selected for being low SO2 producers

Oenological practices and products employed

INNOWINE Project

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B. Application of physical means, in particular membrane techniques, for:

• Tartaric stabilisation (instead of additives),

• Adjustment of acidity and pH (instead of adjuvants),

• Reduction of the concentration of certain organic acids (instead of adjuvants, only fortartaric acid).

Membrane techniques:

• Tartaric stabilization by electrodialysis (OENO 1/93). A physical method for the

extraction of ions under the action of an electric field, with membranes permeable only toanions on one side, and membranes permeable only to cations on the other side.

• Acidification by electromembrane treatment (bipolar membrane: electrodialysis)(OENO 361/2010). A physical method for ionic extraction under the action of an electricfield with membranes permeable only to cations on one side, and bipolar membranes onthe other side.

• De-acidification using an electromembrane process (OENO 484-2012). A physicalmethod of ionic extraction under the action of an electric field with membranespermeable only to anions on one side and bipolar membranes on the other.

Reduction of inputs (authorized processes)

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Resolution OIV-OENO 594A-2019 adopted in 2019 by the 17th General Assemblyof OIV: Reduction of indigenous microorganisms in grapes and musts bydiscontinuous high pressure processes (high hydrostatic pressure – HHP).

The process consists in the reduction of indigenous organisms in grapes andmusts by discontinuous high pressure processes, with pressures higher than 150MPa (1500 bar).

The elimination of yeasts in grapes and musts requires pressure levels of 200-400MPa, while the elimination of bacterial cells requires pressure levels of 500-600MPa. The treatment time range is 2-10 minutes.

OBJECTIVES:

- Reducing the microbial load of indigenous microorganisms, especially yeasts.

- Reducing SO2 levels generally used in winemaking,

- Enhancing maceration in red winemaking.

Reduction of inputs (new practices)

• DT adiabatic compression 2-3°C/100 Mpa

• It does not affect the covalentbonds of molecules

Physical methods

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Resolution OENO 616-2019 adopted in 2019 by the 17th General Assembly of OIV:Treatment of crushed grapes with ultrasound to promote the extraction of theircomponents. The objective of this practice is notably to obtain musts with a higherconcentration of phenolic compounds and other grape components, while reducing themaceration time compared to a traditional process.

Objectives:

• reduction of winemaking costs

• < use of pectolytic enzymes

• < use of sulphur dioxide

• sustainable technology

Reduction of inputs (new practices)

High power (2500 W) and low frequency (28 kHz) with a power density of 8 W/cm2.

Physical methods

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A. Studies on the management and properties of some oenological by-products

Promote circular economy

a) Polyphenolic characterisationof extracts from skins andseeds from grapes andfermented pomace.

Skins Seeds

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Grapes pomacethe by-products

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b) Comparison betweendifferent extractionmethods of polyphenolsfrom skins and seedsderived from fermentedand unfermented pomace.

Promote circular economy

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NAT4More Project

c. Study of the possible use of polyphenolic extracts as antioxidants in foodindustry and for pharmaceutical and medical purposes.

The objective of NAT4MORE isthe devolopment of innovative bioactive surfaces(smart biomaterials) for bone contact applications(orthopaedic and dentalimplants), able to modulate the local host response to implantation for physiologicalhealing and recovery, withoutinfection.

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Protocol of extraction of polyphenols from by-products. NAT4More Project

Extraction:• w/v ratio 1:6• Solvent H2O/ethanol 50:50 • Extraction on rocked shaker

(2 hours)

Concentrated extract

Evaporationunder vacuum

Whole/skins/seedsflour

centrifuge

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Reducing of the use of non-renewable resources

A. Reduction of heating coststhrough the co-inoculation ofML bacteria during AF. Studieson the effect of co-inoculationon wines composition andquality.

Some resultsThe ML fermentation began within 5days in the co-inoculated trials and1 day after post-AF bacterialinoculation.MLF was completed after 15 days inthe co-inoculated wines (before theend of AF) and after 35 days in thetrials inoculated after AF.MLF was not completed in non-inoculated wines (10-15% of malicacid consumed at day 70).

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No significant interactions were noticed between the factors«inoculation time» and «yeast» for the acidic composition

The yeast did not interfere with MLF when presentsimultaneously with bacteria, nor compromised post-AF MLF

when colonizing the wine before bacteria

Influence of co-inoculation on wine composition

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0

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60

70

red-violet

violet-rose

licorice

cherry

berries-blackberries

herbaceousacidity

bitter

softness

body

balance

Effect of bacteria

SEQ Control COI

aa

b

a bb

bb

a

abb

a

baab

bb

a

Influence of co-inoculation on the sensory profile

• No differences were observedfor the colour.

• Regarding the olfactorydescriptors, COI thesis wasdifferent from SEQ and Control due to the statistically higherliquorice note and the averagly higher fruity notes.

• Regarding the taste descriptors, MLF caused a significant decrease of acidityand an increase of balance and softness. No differences wereobserved between COI and SEQ theses.

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Reduction of the cooling costs for the tartaric stabilization of wines andpreservation of the quality of red wines (preservation of color and polyphenols)by using stabilizing additives.

Studies on the oenological properties of potassium polyaspartate, and otheradditives (carboxymethylcellulose, mannoproteins and metatartaric acids).

Reduction of the use of non-renewable resources

STABIWINE Project: “USE OF BIOPOLYMERS FOR SUSTAINABLE STABILIZATION OF QUALITY WINES” Funded by UE - FP7-SME program. Duration: 3 years (2012 – 2015)

Polymer of aspartic acid salifiedwith potassium. Potassiumpolyaspartate (KPA) is synthesized by thermal polymerization of L-aspartic acid. The polymer is negativelycharged at wine pH.

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Potassium polyaspartate for wine stabilization

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Potassium polyaspartate for wine stabilization

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Results of the mini-contact test: Dc (mS/cm)

Results of the cold test: DH2T (g/L)

Potassium polyaspartate for wine stabilization

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Potassium polyaspartate for wine stabilization

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Results of the mini-contact test: Dc (mS/cm)

Results of the cold test: DH2T (g/L)

Potassium polyaspartate for wine stabilization

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• KPA has a good stabilizingeffect against tartaricprecipitation in wines

• KPA is easy to use, and stableover time (aging for 1 year)

• No interaction with colour of white and red wines wasobserved. After the additionand during aging no differencein anthocyanins and polyphenols content wasobserved compared to the wines without the additive

0

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0,9

Control PASP3 PASP-K PASP5 PASP10 MTA

DH

2T

(g/L

)

Asp 1.6 mg/L

Asp5.1 mg/L Asp

3.3 mg/L

Asp 3.9 mg/L

Asp4.3 mg/L

n.d.

Potassium polyaspartate for wine stabilization

Wines after 1 year of aging

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• The appearance of turbidity inred wines soon after theaddition was observed in rarecases

• A preliminary treatment withbentonite prevented theappearance of turbidity afterthe addition of KPA

• The filtration at bottling (0.45mm) did not cause any loss ofstabilizing properties

• No influence of KPA on winefilterability was observed

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Turb

idit

y (N

TU)

48 hours after the addition after 1 year of bottle aging

Cold test

Potassium polyaspartate for wine stabilization

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Adaptation of the winemaking process to the variation ofgrapes and musts composition caused by CC in order topreserve the characteristics of the wines due to the cultivar oforigin.

The main effects of CC on musts and wines compositionconcern:

• Sugar/alchol content, that increases with warming.

• Acidity/pH, that respectively decreases and increases withwarming.

• Varietal aromas and polyphenolic composition.

Adaptation to CC

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Reduction of sugar content

a) Reduction of the sugar content in musts through membrane coupling (OENO450B-2012).

Process that consists in extracting the sugar from musts with membrane coupling:microfiltration or ultrafiltration combined with nanofiltration or inverted osmosis.

Clarified mustUltrafiltration

Ultrafiltered must(Permeate)

Retentate from UF(Macromolecoles) Nanofiltration

Retentate from NFSugar concentrate

Permeate UF(with a low sugar content)

Must with a reducedsugar content

Some physical techniques have been authorized by EU:

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b) Dealcoholization of wines by partial vacuum evaporation, membranetechniques and distillation (OENO 394B-2012).

The alcohol content can be reduced by a maximum of 20%. The minimum alcoholicstrength by volume must comply with the definition of wine.

A study was performed at CREA-VE concerning the comparison between vacuumdistillation (D) and membrane contactor (MC). The aim was to verify the influence of thetwo techniques on wine composition.

Correction of the alcoholic content in wines

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Influence on wine physicochemical composition

Rosato

Pelaverga

Barbera

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45,0

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Teste CM DISV

Total extract (g/L)

The dealcoholized fractions areconcentrated. The 2 techniques aresignificantly different from one anotherfor the final concentration. According tothe extract values the concentration was:

• 9% for MC

• 54% (6 times higher) for D

The pH dropped after dealcoholization(-0.10 unities in Barbera and Rosato and-0.15 unities in Pelaverga).

The fractions dealcoholized with D andMC techniques had similar pH values forall the 3 wines.

Rosato

Pelaverga

Barbera

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pH

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0

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Eth

ano

l (m

L)

Sample number

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mg

sample number

Isoamyl acetate

To the first group of volatile compounds belong:isoamyl acetate, that was completely absent already in the fourth fraction, then also ethylesanoate, ethyloctanoate, hexylacetate.

Trend of the losses of ethanolduring vacuum distillation

Influence on volatile compounds

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0 5 10 15 20 25

mg

sample number

Etil lactate

The second group includes the moleculeswhose loss trends were perfectly linear:ethyl lactate (figure), diethyl succinate, benzylic alcohol, -phenylethanol, hexanoic, octanoic and decanoic acids, etc.

The third group includes the moleculeswhose losses showed a logarithmic trend:isobutanol, isoamyl alcohol, n-butanol, n-hexanol (figure), cis-3-hexenol, phenylethylacetate.

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n-hexanol

Influence on volatile compounds

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• Implementation of new practices, or modification of alreadyexisting ones, with particular attention to environmentalsustainability and consumers safety.

• Implementation of new oenological practices to improve winequality: improvement of the sensory characteristics andpleasantness, production of more identifiable wines, prolongationof shelf-life.

• Implementation of new enological practices to enhance in thewines the varietal characteristics of the grape cultivar of origin.

• Oenological practices to reduce the use of potentially allergenicadditives (SO2) or to remove contaminants (ochratoxin A, ethylphenols, ..).

Enrivonmental substainability, consumer safetyand wines quality

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Varietal enology

The effect of two different pressingconditions - under air or nitrogen - onthe composition of the pressed mustsof four white grape cultivars wasstudied:

• Moscato bianco, from 3 locations

• Manzoni bianco, from 3 locations

• Cortese, from 2 locations

• Arneis, from 1 location

The aim was to compare the twotechniques with grapes with differentchemical composition, in order toidentify the most suitable techniqueto the compositional characteristics ofeach cultivar (varietal enology).

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Some results

The GSH and HCTA concentration andHCTA/GSH ratio depend on the cultivars.The highest GSH concentrations were found inArneis and Manzoni bianco.Differences between vintages were alsoobserved, but the ranking order of the cultivarswas the same, regardless of the vintage.The hyperoxidation technique resulted moreinteresting for Moscato bianco cultivar.

HCTA/GSH ratios

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The future perspective of the research is to perform studies onoenological practices and products, on rapid and not destructiveanalytical methods and on the application of informatic tools toimprove the monitoring of the winemaking process.

Future perspectives. Precision Oenology

QUALSHELL Project was presented toPiedmont Region under the «EuropeanAgricultural Fund of Rural Development»programme (EAFRD 2014-2020 – Misure16: Cooperation – PSR 16.1.1: Costitution,management and functioning of EIP-AGRIOperational Groups (Action 1) and Supportto the action of EIP-AGRI OperationalGroups (Action 2).The QUALSHELL Project will start in 2020vintage.

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The QUALSHELL Project

QualShelL Quality and Shelf-Life of the wines.Implementation of procedures for the evaluation of grapes quality and for processmonitoring.Project leader: CREA-VE – AstiOther participants: UNITO, INRIM; a cooperative winery (Terre del Barolo), nine small-medium wineries, an Association of Agricultural producers (Confagricoltura), an IT company(ERInformatica) and a consulting firm (Vassallo-Delfino & P.).

Preface The improvement of wines quality depends on the rationalisation of the use ofresources (precision oenology), on the reduction of the use of inputs, on the improvementof technical traceability through easy process indicators and on the capacity to adaptwinemaking practices to the characteristics of the grapes (varietal enology).

Expected results1. Development of rapid non-destructive methods for measuring the polyphenolic

composition of grapes, capable of predicting their quality and directing winemakingtechniques;

2. Development of rapid non-destructive analytical methods for monitoring wine duringstorage in tanks or barrels.

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Thanks for the attention!

antonella.bosso@crea.gov.it