WINETECH Technical Yearbook 2019

to the variety, geographical origin and vintage of the resulting wine. However, the accurate prediction of a grape must variety and origin based on a component of the grape juice matrix implies that the component is characteristic of that particular variety or origin. This information may aid the understanding of winemakers and viticulturists, and, subsequently, help them to make more informed decisions regarding practices and processes that could be employed to ensure the desired quality and style of the final wine. OVERVIEW OF AMINO ACID PROFILES A heat map of the relative average amino acid concentrations is shown in Figure 1. It presents how much in terms of standard dev i a t i ons t he ave rage ami no ac i d concentration per cultivar deviates from the overall average across all cultivars. This method of representing the data provides a comprehensive overview of how the cultivars may compare to one another based on their amino acid content. Furthermore, the associated dendrogram indicates how the cultivars may relate to one another based on their amino acid profiles. Horizontally, the heat map shows the amino acid profile per cultivar and vertically, the relative average concentrations across cultivars for a specific amino acid. Thus, the cultivars containing very high or very low concentrations in comparison to the mean can be easily identified. For example, the white cultivars,

This study aimed to investigate how well cultivars could be predicted based on their amino acid profile, regardless of origin or vintage. The amino acid results obtained from the survey of 738 grape must samples (2016 and 2017 harvests) were presented in Part 1, while Part 2 focuses on additional information that we could extract from the data. The amino acid profile of a particular grape must is a result of a variety of factors since an interaction of the grape variety with the climate, soil and various viticultural practices exists. This knowledge has prompted the investigation of various grape compositional elements in relation

AMINO ACIDS IN SOUTH AFRICAN GRAPE MUSTS (PART 2): CULTIVAR CLASSIFICATION

APRIL 2019

ASTRID BUICA, GABRIELLA PETROVIC & JOSE-LUIS ALEIXANDRE-TUDO: Department of Viticulture and Oenology, Stellenbosch University, Stellenbosch KEYWORDS: Amino acid profile, cultivar classification.