In-Line Monitoring of Red Wine Fermentation
| dc.contributor.advisor | Aleixandre-Tudo, Jose Luis | en_ZA |
| dc.contributor.advisor | Du Toit, Wessel J. | en_ZA |
| dc.contributor.advisor | Nieuwoudt, Helene | en_ZA |
| dc.contributor.author | Lambrecht, Kiera Nareece | en_ZA |
| dc.contributor.other | Stellenbosch University. Faculty of AgriSciences. Dept. of Viticulture and Oenology. Institute for Wine Biotechnology. | en_ZA |
| dc.date.accessioned | 2021-03-08T07:27:44Z | |
| dc.date.accessioned | 2021-04-21T14:40:27Z | |
| dc.date.available | 2021-03-08T07:27:44Z | |
| dc.date.available | 2021-04-21T14:40:27Z | |
| dc.date.issued | 2021-03 | |
| dc.description | Thesis (MScAgric)--Stellenbosch University, 2021. | en_ZA |
| dc.description.abstract | ENGLISH ABSTRACT: Phenolic compounds may only account for a small percentage of the final composition of a finished red wine but are vital to its sensory attributes. During red wine making, extraction of these phenolic compounds takes place, whereby there is mass transfer from the solids of the grape into the liquid phase. The rate and the extent to which this extraction occurs is dependent on many factors. There are many different methods employed in the wine industry which can influence the composition of the wine. These techniques are varied and can involve manipulating process conditions such as temperature or the addition of certain oenological products. As the final composition of the wine is a major contributing factor to the quality of the wine, it is vital to be able to monitor and control this process. It has been demonstrated through a variety of studies that the use of infrared spectroscopy along with chemometrics provides an avenue for implementation of monitoring and control systems in wineries. However, the limiting factors in these studies are the extensive sample pre-treatment to remove solids before scanning as well as their discrete and off-sight sampling. In the contents of the first research chapter (Chapter 3), a system was designed for the purpose of automatic sampling directly from vessels containing fermenting wines. This was an extensive design process which required separate sampling pumps and sampling lines which delivered samples to a single instrument. Another requirement was automation of different components and synchronisation of these in an individual system. The resulting design was put through a series of stress tests to ensure functionality and reliability. The results showed that the automated system was capable of full-time operation without experiencing component failures and, therefore, it was applied to actual fermentations. For this, 24 hours of real time monitoring was achieved. The turbidity remained a challenge as a perfectly clarified sample was not achievable. This led to the development of partial least squares (PLS) calibrations for three different spectroscopy techniques where the samples used incorporated differing degrees of sample pre-treatment to reduce turbidity. The results of this endeavour compiled in Chapters 4 and 5 showed favourable results for samples with different levels of turbidity as well as for contactless methods of conducting analysis. With further optimisation of the models using spectral pre-processing and wavenumber selection, it was possible to develop models suitable for application in an industrial setting. Finally, in Chapter 6, these models were deployed for use with a series of fermentations, where the ability to monitor phenolic extraction of fermentations receiving different treatments was explored. The results show that the system can be used to monitor trends in phenolic extraction in an industrial set-up. In addition to this, the system has the capacity for updated models and different methods of process control, thereby allowing it to be tailored to each unique scenario. | en_ZA |
| dc.description.abstract | AFRIKAANSE OPSOMMING: Fenolverbindings is slegs 'n klein persentasie van die finale samestelling van 'n voltooide rooiwyn, maar is van uiterste belang vir die sensoriese eienskappe daarvan. Tydens die vervaardiging van rooiwyn vind ekstraksie van hierdie fenoliese verbindings plaas, en daar word massa-oordrag vanaf die vaste stowwe in die druif in die vloeistoffase plaasgevind. Die tempo en die mate waarin hierdie ekstraksie plaasvind, hang van baie faktore af. Daar is baie verskillende metodes in die wynbedryf wat die samestelling van die wyn kan beïnvloed. Hierdie tegnieke is uiteenlopend en kan die prosestoestande soos temperatuur of die toevoeging van sekere wynkundige produkte insluit. Aangesien die finale samestelling van die wyn 'n belangrike bydraende faktor tot die kwaliteit van die wyn is, is dit noodsaaklik om hierdie proses te kan monitor en beheer. In verskillende studies is aangetoon dat die gebruik van infrarooi spektroskopie en chemometrie 'n baan bied vir die implementering van monitering- en beheerstelsels in wynkelders. Die beperkende faktore in hierdie studies is egter die uitgebreide voorbehandeling van monsters om vaste stowwe te verwyder voor skandering, sowel as die diskrete en buite sig-monsterneming daarvan. In die inhoud van die eerste hoofstuk vir navorsing (Hoofstuk 3) is 'n stelsel ontwerp vir die outomatiese monsterneming direk vanaf vate wat fermenterende wyne bevat. Dit was 'n uitgebreide ontwerpproses wat afsonderlike monsternemingspompe en monsternemingslyne vereis wat monsters aan 'n enkele instrument gelewer het. 'N Ander vereiste was die outomatisering van verskillende komponente en sinkronisering hiervan in 'n individuele stelsel. Die gevolglike ontwerp is deur 'n reeks spanningstoetse deurgesit om funksionaliteit en betroubaarheid te verseker. Die resultate het getoon dat die outomatiese stelsel in staat was om voltyds te werk sonder om komponente te mislukking, en daarom is dit op werklike fermentasies toegepas. Hiervoor is 24 uur real-time monitering bereik. Die troebelheid was 'n uitdaging omdat 'n volkome opgeklaar monster nie haalbaar was nie. Dit het gelei tot die ontwikkeling van kalibrasies vir gedeeltelike minste vierkante (PLS) vir drie verskillende spektroskopietegnieke, waar die monsters wat gebruik is, verskillende grade van voorbehandeling bevat om troebelheid te verminder. Die resultate van hierdie poging wat in hoofstuk 4 en 5 saamgestel is, het gunstige resultate getoon vir monsters met verskillende vlakke van troebelheid, sowel as vir kontaklose metodes om analise uit te voer. Met verdere optimalisering van die modelle met behulp van spektrale voorverwerking en seleksie van golwe, was dit moontlik om modelle te ontwikkel wat geskik is vir toepassing in 'n industriële omgewing. Laastens, in hoofstuk 6, is hierdie modelle gebruik vir 'n reeks fermentasies, waar die vermoë ondersoek is om fenoliese ekstraksie van fermentasies wat verskillende behandelings ontvang, te monitor. Die resultate toon dat die stelsel gebruik kan word om tendense in fenoliese ekstraksie in 'n industriële opset te monitor. Daarbenewens het die stelsel die vermoë om opgedateerde modelle en verskillende metodes van prosesbeheer te bewerkstellig, waardeur dit op elke unieke scenario aangepas kan word. | af_ZA |
| dc.description.version | Masters | en_ZA |
| dc.format.extent | xvii, 181 pages : illustrations | en_ZA |
| dc.identifier.uri | http://hdl.handle.net/10019.1/110102 | |
| dc.language.iso | en_ZA | en_ZA |
| dc.publisher | Stellenbosch : Stellenbosch University | en_ZA |
| dc.rights.holder | Stellenbosch University | en_ZA |
| dc.subject | Red wines | en_ZA |
| dc.subject | Phenols -- Physiological effect | en_ZA |
| dc.subject | Partial Least Squares Calibration | en_ZA |
| dc.subject | Wine and wine making -- Chemistry | en_ZA |
| dc.subject | Fermentation | en_ZA |
| dc.subject | Grapes -- Biotechnology | en_ZA |
| dc.subject | UCTD | en_ZA |
| dc.title | In-Line Monitoring of Red Wine Fermentation | en_ZA |
| dc.type | Thesis | en_ZA |