Role of DNA methylation in wine yeast : A Dissertation submitted in partial fulfilment of the requirements for the Degree of Master of Science in Food Innovation at Lincoln University

Abstract

We have shown for the first time that dietary epigenetic compound could alter the characteristics of the fermented food products using wine as an example. Chemical X, a dietary epigenetic compound has shown to impact chemical composition and sensory profile of wine. Altering organoleptic properties of fermented food products using this technology is economical compared to developing new plant varieties or isolating new yeast strains. This novel technique can be applied in the food products as it has the ability to alter the gene expression without altering the gene sequence. This area of research can be termed as ‘Nutrifermentics’ as it involves the study of effect of dietary epigenetic modifiers/nutrients on fermentation and differentiate it from ‘nutrigenomics’ which is study of effects of dietery compounds on gene expression especially on gut microbiota. Gene expression or silencing can be modulated using epigenetic modifiers by the interaction between DNA and histones. The modifications involve DNA methylation/demethylation or histone acetylation/deacetylation. Dietary phytochemicals have gained attention in human health and chemotherapy due to its Histone deacetylase (HDAC) inhibition activity. In this current study, we have experimentally tested for the first time HDAC activity of three potential dietery epigenetic compounds and selected Chemical X as the epigenetic modifier to alter the charecterstics of wine due to its solubility in water and its presence in many fruits. The modifications in wine can be achieved by culturing the wine yeast cells in presence of Chemical X and using these stressed strains to ferment Pinot Noir grape juice. Wine containing lower alcohol level was achieved using the stressed strain of yeast culture. The results of the aroma compounds showed variation and few compounds were detected in the wine samples fermented using stressed strain which were not detected in control. Hence, wine with low alcohol and certain aroma compounds were achieved by using epigenetic modifiers. The main focus of the study is to use simple eukaryotic model like yeast cells to understand the histone modification which alters the gene expression leading to the phenotypic changes due to compounds like Chemical X.