Thesis (MScAgric)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: The quality of wine is largely dependent on environmental conditions and recent studies
have therefore focused on agricultural practices in terms of water, soil and biodiversity
conservation. The industry aims to create sustainable practice and to protect the natural
resources available. Sources of potential grape contamination include: vehicle pollution,
pesticides, bushfires and wood preservatives used for trellising systems. The latter have
come to the attention of the South African wine industry (e.g. creosote and Copper
Chromium Arsenate (CCA) products) as they may have consequences for the environment
and wine quality. Creosote is a known pollutant of soil and ground water and the volatile
fraction has been monitored in air. Plants may also accumulate polycyclic aromatic
hydrocarbons (PAHs), which constitute up to 85% of the mass of creosote, and of which
some have been proven carcinogenic. Because of the health risks associated with it,
creosote has therefore been restricted for use in most applications in Europe, and also in
the United States, Canada and Australia. This study focussed on the sensorial and chemical analyses of environmental and wine
samples taken from the area around the creosote stockyard to determine accumulation of
creosote-derived compounds. Environmental samples were collected and analysed at
different distances from the affected area, over two vintages. Wines were made from
grapes grown in vineyard blocks adjacent to the stockyard, to determine the effect of
distance and skin contact during alcoholic fermentation treatments on wine taint. A
sensory panel was trained for descriptive analysis to determine the intensity of the taint.
Analytical methods were developed for the analysis of volatile organic compounds (VOCs)
by gas chromatography mass spectrometry (GC-MS) and polycyclic aromatic hydrocarbons
by high performance liquid chromatography with diode array detection (HPLC-DAD).
The sensory results obtained showed white and rosé wines were perceived as clean,
whilst the red wines were associated with burnt rubber/tar taint. The perceived taint
decreased as distance from the stockyard increased. Wines made from the Cabernet
Sauvignon blocks adjacent to the stockyard also showed an increase of taint with the
increase of skin contact. Chemical data obtained showed that the taint consisted of a
complex mixture of compounds, each with its own pattern of retention within the vineyard
and wine. Only m-cresol was found above odour threshold, and only in red wines. The
synergistic effect of some compounds may lead to an increase in the perceived taint.
Berries and leaves had higher concentrations of volatile compounds than wines. Leaf
contamination varied and followed the general trend in literature where the plants with high
lipid content and exposed leaf area were the most contaminated. There may be other compounds present in creosote emissions, aside from those investigated here, with
sensory attributes related to the taint found in wines. These compounds are styrene,
indene, benzene, toluene, isoquinoline and quinoline and should be included in further
investigations.
From the PAH analysis of environmental samples and wines, it is evident that the
samples closest to the stockyard were affected the most. The contamination varied with
the depth of the soil: some of the heavier compounds were found in the samples taken from
the deeper levels, whilst nearly all other target compounds were present in the top layer of
soil. The concentrations found in the environmental samples were lower than reported in
literature. Wines had few PAHs present, but at much higher concentrations than is allowed
by EU legislation.
From this study it is evident that the stockyard had negative effects on the surrounding
environment in terms of sensory and chemical contamination. Recommendations include
area rehabilitation by means of bioremediation to protect resources and ensure sustainable
and safe production of crops. Industrial emissions should also be regulated and restricted
in agricultural areas. Furthermore the use of creosote should be revised, and prohibited for
agricultural use. / AFRIKAANSE OPSOMMING: Die kwaliteit van wyn is grootliks afhanklik van die omgewingstoestande. Daarom fokus
verskeie onlangse studies op landbou aktiwiteite en die invloed daarvan op die omgewing
in terme van water, grond en biodiversiteit bewaring. The wyn industrie se doelwitte sluit
volhoubare praktyke in, wat die natuurlike hulpbronne bewaar en beskerm. Druiwe kan
deur middel van die volgende bronne besoedel word: brandstof uitlaatgasse, insekdoders,
veldbrande, gifstowwe wat gebruik word vir houtperservering wat dan verder aangewend
word vir opleistelsels. Houtperservering (Koper chroom arsenaat (CCA) en kreosoot) het
veral in die laaste paar jaar onder aandag gekom in die wynbedryf van Suid-Afrika as
gevolg van die invloed daarvan op die omgewing en die uiteindelike wynkwaliteit.
Kreosoot is ‘n gekende gifstof wat verantwoordelik is vir grond en grondwater besoedeling
en wat gemonitor word in die atmosfeer. Plante akkummuleer ook poli-sikliese aromatiese
hidro-koolstowwe (PAHs), wat to 85% uitmaak van die massa van kreosoot. PAHs is
karsinogenies en dus is daar baie navorsing op die molekules reeds gedoen. Die
gesondheidsrisikos gepaardgaande met kreosoot het gelei tot die streng geregulasies tans
ingestel in Europa, die Verenigde State, Kanada en Australië.
Hierdie studie het gefokus op die sensoriese en chemiese analises van omgewings- en
wyn-monsters geneem van die omliggende area van die kreosoot palewerf om die
akkumulasie van kreosoot-afgeleide-verbindings. Omgewingsmonsters was versamel en
geanaliseer om verskillende afstande vanaf die bron van besoedeling (palewerf) te
ondersoek oor ‘n twee jaar periode. Wyne is gemaak van die druiwe wat afkomstig is van
die blok aangeplant langs die palewerf. Die wyne is ondersoek in terme van afstand vanaf
die kreosoot bron asook oenologiese invloede, dopkontak gedurende alkoholiese
fermentasie, op die kontaminasie beskryf in wyn. Die wyne is ook oor ‘n twee jaar periode
voorberei en sluit die 2011 en 2012 seisoen in. ‘n Sensoriese paneel is opgelei om die
beskrywende analises op die wyn uit te voer met die doel om die intensiteit van
kontaminasie te identifiseer. Analitiese metodes is ook ontwikkel vir die analise van vlugtige organiese verbindings(VOCs) met gas chromatografie-massa spektrometrie (GCMS)
en poli-sikliese aromaties hidro-koolstowwe (PAHs) met hoë druk vloeistof
chromatografie.
Die sensoriese resultate bekom het wit en rosé wyne as skoon laat blyk, terwyl rooi
wyne meer geassosieer was met die gebrande rubber/ teer afgeur beskrywing. Die
waargeneemde afgeur het afgeneem soos wat die afstand vanaf die palewerf toegeneem
het. Wyne gemaak van die Cabernet Sauvignon blokke langsaan die palewerf het ook ‘n
toename in die afgeur gehad met ‘n toename in dopkontak. Chemiese data bekom beeld uit dat die afgeur uit ‘n komplekse mengsel van verbindings bestaan, elk met sy eie patroon
van verspreiding en verbinding in die wingerd as ook in die wyn. Net m-kresol was gevind
bo die reuk drumpel, dit het ook net in rooi wyne voorgekom. Die sinergistiese effek van
die verbindings mag egter bydra tot die waargeneemde afgeur.
Druiwekorrels en blare het hoër konsentrasies van die vlugtige verbindings gehad as
wat gemeet is in die wyne. Blaar kontaminasie het ook baie gewissel en het ooreengestem
met die algemene tendens wat in literatuur beskryf is, naamlik dat plante met ‘n hoër lipid
inhoud en grootter blaar oppervlak die meeste gekontamineer word. Daar mag egter nog
baie ander verbindings bydra tot die waargeneemde afgeur gevind in die wyn. Spesifieke
verbindings wat wel ‘n rol kan speel in kontaminasie en wat voorkom in die vlugtige
gedeelte van kreosoot is styreen, indeen, benzeen, tolueen, isoquinoleen die vlugtige
verbindings van kreosoot. Die verbindings moet ingesluit word vir verdere studies wat
gedoen word op die kreosoot geassosieerde afgeur.
Die PAHs analise op die omgewingsmonsters en wyne het gelei tot die bevestiging dat
die naasliggende omgewing die meeste geaffekteer is. Die kontaminasie wissel in terme
van die diepte in die grond wat die gifstowwe voorkom: die swaarder molekulêre
verbindings is tot in die dieper vlakke waargeneem terwyl al die gemete verbindings in die
boonste lae teenwoordig was. Die vlakke wat waargeneem is in dié studie is egter laer as
wat voorheen in literatuur gevind is in ‘n kreosoot geaffekteerde omgewing. Wyn het PAHs
teenwoordig gehad, alhoewel slegs twee verbindings gemeet is, het dit in hoër vlakke
voorgekom as wat sekere Europese regulasies as toelaatbaar spesifiseer. Vanaf die studie resultate blyk dit, dat die palewerf se negatiewe invloed op die
omliggende omgewing beide meetbaar was in sensories en chemiese kontaminasie.
Voorstelle sluit onder andere die rehabilitasie van die omliggende omgewing deur middel
van bioremediasie in. Om sodoende die natuurlike hulpbronne in die area te bewaar asook
om volhoubare en veilige verbouing van gewasse te verseker. Industriële besoedeling en
afval moet ook gereguleer word en beperk word in landbou areas. Verder moet die gebruik
van kreosoot heroorweeg word en strenger regulasies moet in plek gestel word om aan
internastionale standaarde te voldoen. / Financial support from Winetech, Trip and UFS
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/80273 |
| Date | 03 1900 |
| Creators | Van Zyl, Annette |
| Contributors | McKay, Marianne, Stellenbosch University. Faculty of AgriSciences. Dept. of Viticulture and Oenology. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | Unknown |
| Type | Thesis |
| Format | 114 p. : ill. |
| Rights | Stellenbosch University |
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