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Dr. Anita Oberholster
Cooperative Extension Specialist in Enology
Dr. Anita Oberholster joined the department April 2011 as a new Cooperative Extension Specialist in Enology. During her PhD studies she was involved in the development of the mouth-feel wheel for red wine and investigated the changes in polymeric pigment structure and composition with wine aging. Dr. Oberholster's research focuses on two main parts: firstly, the influence of both viticulture practices and environmental factors on grape ripening and composition and related wine quality. The emphasis is specifically on tannin and carotenoid biosynthesize. Both are important contributors to grape and wine quality; tannins contribute to mouth-feel (astringency) and bitterness, whereas carotenoids are the precursors to norisoprenoids which are important volatile compounds with a low olfactory threshold. The second core research focus is investigations to determine the influence of different vinification practices on wine composition and quality. This includes studies to determine the influences of different cap management techniques and the impact of oxygen (macro- and micro-oxygenation) and wood (barrel aging and oak alternatives) on wine aging and quality. Sustainability in both focus areas are important and alternative practices to enhance sustainability is investigated, including the use of new technologies and 'green' chemicals' in the winery and the re-use of winery waste water for the irrigation of vines.
Lerno, L. A., M. Reichwage, R. Ponangi, L. Hearne, D. E. Block, A. Oberholster (2015), The Effects of Cap Temperature and Overall Fermentation Temperature on Phenolic Extraction in Cabernet Sauvignon Fermentations. American Journal of Enology and Viticulture 66:4, 444-453. (doi: 10.5344/ajev.2015.14129).
Panprivech, S., L. A. Lerno, C. A. Brenneman, D. E. Block, A. Oberholster (2015), Investigating the Effect of Cold Soak Duration on Phenolic Extraction during Cabernet Sauvignon Extraction. Molecules, organized by UIV20, 7974-7989.
Oberholster, A., B.L. Elmendorf, L.A. Lerno, E.S. King, H. Heymann, C.E. Brenneman, R.B. Boulton (2015), Barrel maturation, oak alternatives and micro-oxygenation: Influence on red wine aging and quality. Food Chemistry 173, 1250-1258.
A. Oberholster, B.L. Elmendorf, L.A. Lerno, E.S. King, H. Heymann, C.E. Brenneman (2014) Barrel maturation, oak alternatives and micro-oxygenation: Influence on red wine aging and quality. Food Chemistry (DOI: 10.1016).
A. W. Chassy, C. Büschel, H-Y. Lee, L. A. Lerno, A. Oberholster, D. Barile, R. Schuhmacher, A. L. Waterhouse (2014) Probing in vivo anthocyanin degradation in grapes using stable isotope tracer guided LC-MS. Food Chemistry 166: 448-455 (doi: 10.1016).
W. J. Du Toit and A. Oberholster (2014) Chapter 7: Antioxidants in wine during fermentation. In: Processing and Impact on Antioxidants in Beverages. Ed., Victor R. Preedy, Academic Press, UK, ISBN 9780124047389, p. 59-68, 319pp.
A. Oberholster, L. M. Carstens, W.J. du Toit (2013), Investigation of the effect of gelatine, egg albumin and cross-flow microfiltration on the phenolic composition of Pinotage wine. Food Chemistry 138, 1275-1281
A. Oberholster (2012), Chapter 19: Extraction of Carotenoids From Plants: A Focus on Carotenoids with Vitamin A Activity. In: Food and Nutritional Components in Focus No. 1. Vitamin A and Carotenoids: Chemistry, Analysis, Function and Effects. Ed., Victor R. Preedy, Royal Society of Chemistry, p. 316-331, DOI: 10.1039/9781849735506-00316, www.rsc.org.
L. Geldenhuys, A. Oberholster, W. J. du Toit (2012), Monitoring the effect of microoxygenation before malolactic fermentation on South African Pinotage red wine with different colour and phenolic analyses. South African Journal of Enology and Viticulture 33 (2), 150-160.
K. A. Bindon, P. Myburgh, A. Oberholster, K. Roux, C. du Toit (2011), Response of Grape and Wine Phenolic Composition in Vitis vinifera L. cv. Merlot to Variation in Grapevine Water Status. South African Journal of Enology and Viticulture, 32, 71-88.
Z. Kamffer, K. A. Bindon, A. Oberholster (2010), Optimization of a Method for the Extraction and Quantification of Carotenoids and Chlorophylls during Ripening in Grape Berries (Vitis vinifera cv. Merlot). Journal of Agricultural and Food Chemistry 58, 6578-6586.
A. Oberholster, I. L. Francis, P. G. Iland, E. J. Waters (2009), Mouth-feel of white wines made with and without pomace contact and added anthocyanins. Australian Journal of Grape and Wine Research 15, 59-69.
K. L. Taylor, A. E. Brackenridge, M. A. Vivier, A. Oberholster (2006), High-performance liquid chromatography profiling of the major carotenoids in Arabidopsis thaliana leaf tissue. Journal of Chromatography A 1121, 83-91.
R. Gawel, A. Oberholster, I. L. Francis (2000), A 'Mouth-feel Wheel': terminology for communicating the mouth-feel characteristics of red wine. Australian Journal of Grape and Wine Research 6, 203-207.