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Sensory and consumer insights on low alcohol wines and MCC

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Project leader: Dr Hélène Nieuwoudt
Aim industry relevance: The lower-to-zero-alcohol wine market in South Africa is still very young and little to no information about the chemical and sensory profiles of the commercial products are available, and South African consumers’ perceptions about the category are unknown. This project aims to generate new knowledge about the sensory quality, chemical profiles and consumer perception of the lower-alcohol wines. A better knowledge base will make a contribution to support the development of the lower alcohol wine category.
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Investigation into the mystery of delayed winemaking strategies on white wine sensory and chemical characteristics

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Project leader: Dr Francois van Jaarsveld
Aim and industry relevance: The aim of this study is to compare the effect of different winemaking treatments prior to fermentation on the final volatile thiol content in white wines. These treatments include chilling and freezing of grapes and grape juice for different time periods before fermentation. Various research publications indicate these practices can enhance volatile thiol content in white wines. Anecdotal evidence from the South African wine industry indicates the same. The exact practice that will promote the biggest possible effect is not yet known and this research hopes to provide the answer.

A novel method that turns wine industry effluent into valuable product streams

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Project leader: Prof BJ Bladergroen

Aim and industry relevance: In this project, an unconventional, unprecedented, inventive, ground-breaking and robust technology will be tested on winery effluent. Previous research has shown it is a promising alternative to current available technology. Costs associated with both water consumption and waste water treatment form an ever increasing portion of the operational budget of many wineries, exacerbated by reduced rainfall and more stringent municipal regulations around effluent discharge. Re-use of winery wastewater for irrigation purposes without treatment is often not recommended as the Chemical Oxygen Demand (COD) and Total Dissolved Solids (TDS) levels cause the water to be an unfit source. The potential for water re-use in the wine industry is great but currently the cost of water treatment plants is too high, specifically for many small to medium scale wineries.
This new technology aims to address major shortcomings of current treatment sy…

Biotic and abiotic stress protection in grapevine: a proof-of-concept study

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Project leader: Prof Melané Vivier

Aim and industry relevance:  It is widely accepted that innovative new solutions are necessary to move away from our dependence on chemical control mechanisms against pests and diseases. Moreover, as the impacts of climate change are manifesting throughout the different grapevine producing areas, it is clear that potential solutions that can protect plants against extreme climatic and environmental conditions are equally important. Through the study of the natural responses that grapevines have when they are under stress (from pathogens or abiotic stress such as drought), intrinsic mechanisms that the plant uses for stress protection have been identified in previous local research. This includes compounds naturally produced by grapevines in response to stress.
This project intends to confirm the ability of these natural compounds that form part of the innate defence system of plants, to protect grapevines against stresses when directly applied to grapevi…

Expression of virus proteins for Elisa kit development

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Project leader: Ms Inge Pietersen, Pathosolutions

Aim and industry relevance: The ultimate aim of this project is to provide affordable and reliable Grapevine virus A and B, and Grapevine fleck ELISA kits for detection within the One-Vitis certification scheme. No locally-produced ELISA kits currently exist and due to the high costs associated with importing commercial kits, only select nurseries and suppliers test for these viruses. The development of ELISA kits locally, should significantly reduce the costs to the wine and table grape industries associated with monitoring for these viruses, and will improve the availability of reagents for viral detection. This should increase the number of nurseries and producers monitoring for diseases as well as the number of tests performed per lab.
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Commercial trials with Candida zemplinina as active dried yeast

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Researcher: Dr Neil Jolly, ARC Infruitec Nietvoorbij

Aim and industry relevance:
ARC and Winetech funded research identified a fructophilic Candida zemplinina (Starmerella bacillaris) yeast strain with the potential for lowering alcohol content in wine when used as a co-inoculant with a S. cerevisiae wine yeast. The same yeast was previously found to be suitable for improvement of fermentation efficiency in a grape must with an initial glucose-fructose imbalance. However, before commercialisation can occur, the yeast needs to undergo further testing. This includes whether it can be produced in pilot-scale as an active dried yeast (ADY); the viability and shelf life of the yeast in the ADY form; whether it maintains the same characteristics as an ADY as it had in wet culture, and acceptance by the South African wine industry. A commercial company will attempt production on pilot scale in 2020 and if successful they will commence with winemaking trials.

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Developing commercial phenolic tests for the wine industry

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Researcher: Prof Wessel du Toit, South African Grape and Wine Research Institute (SAGWRI), Department of Viticulture and Oenology, Stellenbosch University

Aim and industry relevance:
The aim of this study is to improve upon existing phenolic measurement methods in grapes. Phenolic compound management is very important in red winemaking since it is directly linked with final wine quality. Currently, most commercial laboratories offer the Glories index protocol (developed in the 1980’s) for the measurement of phenolic compounds. It has been identified through research that the tannin measurement component of the Glories index can be improved upon in order to deliver more accurate values, as well as better correlations between grape and final wine tannins. Discussions with winemakers indicated their need for improved commercially available tannin testing methods. If successful, the new method(s) will be communicated to commercial laboratories.

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