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Researcher Studies Syrah’s Peppery Aroma

December 7, 2009

Hawke’s Bay’s growing reputation as a producer of quality Syrah is not lost on Gerard Logan, lecturer in viticulture at EIT Hawke’s Bay and inaugural winner of the Bragato Trust’s postgraduate scholarship.

The recently-formed trust manages a substantial bequest from the estate of the late Jan Colville, granddaughter of the legendary Italian viticulturist Romeo Bragato.  It also attracted a grant from the New Zealand Grape Growers Council.

The trust provides scholarships for New Zealand graduates and exceptional undergraduates seeking further qualifications or experience relevant to the viticulture and wine industry.

Logan’s postgraduate scholarship, providing him with $9000 for each of the next two years, allows him to continue working on his thesis:  “Rotundone:  the impact of viticulture on fruit and wine sensory components in Vitis vinifera L. Syrah”.

The Australian Wine Research Institute recently identified rotundone as the compound responsible for the peppery aroma in Shiraz (Syrah) grapes.

As an aroma compound, it’s the world’s most popular spice.  We associate it, of course, black and white pepper, but it also provides the pepper character in nut grass, marjoram, rosemary, salt bush, geranium, thyme, basil and oregano – to name a few.

Logan’s PhD research project, supervised by Associate Professor Paul Kilmartin at the University of Auckland’s Chemistry Department, involves collaboration with several prestigious international organisations and identities including the Australian Wine Research Institute, the Bioactive Natural Products Chemistry laboratory at Michigan State University, Mission Estate Winery, Lincoln University, world-renowned viticulture consultant Dr Richard Smart and Craggy Range Vineyards winemaker Rod Easthope.

The project focuses on determining the impact of viticulture on levels of rotundone in Syrah fruit and wines.  The concentration of rotundone varies significantly between vineyards and vintages, with levels influenced by such factors as temperature, light, soil crop load, canopy management, pest/disease/virus pressure and rainfall.

Logan is investigating these and other factors to determine the impacts each has on rotundone biosynthesis and degradation through the ripening phase of Syrah fruit.

One of his research goals is to provide vineyard managers and viticulturists with knowledge of how to manage vines to increase or decrease the peppery notes in the final wines.

Logan is also investigating the impact of rotundone in the wine to determine what other chemical compounds may interact to produce differing perceptions of the peppery level of the wine.

This involves analysing a large number of different aroma compounds in New Zealand Syrah wines.  The aim here is to provide evidence on the impact of rotundone chemistry on Syrah wines, further improving the understanding of how to manage vines and fermentations to produce desirable wines.

Another component of the research focuses on the extent to which rotundone and other nutraceuticals with biological activities enhance food safety and add value to red wines, and to evaluate what role these compounds may play as phytomedicines for treating cancer, neutodegenerative diseases such as Alzheimer’s disease and Parkinson’s disease, musculoskeletal disease, mental health problems, type-2 diabetes, obesity, inflammation and parasitic/microbial diseases.

Logan joined EIT in 2006 after graduating from Michigan State University with a Master of Science, majoring in oenology and viticulture.  His recent research work has focused on a variety of fruit ripening, colour and now aroma/flavour impacts of the fruit of red Bordeaux and Rhone cultivars.

As well as EIT Hawke’s Bay’s Faculty of Science and Technology, his research sponsors are Mission Estate, Craggy Range Vineyards, Australian Wine Research Institute, Michigan State University – Bioactive Natural Products Chemistry and the University of Auckland’s Wine Science Programme.