Glycosylation of Volatile Phenols in Grapes following Pre-Harvest (On-Vine) vs. Post-Harvest (Off-Vine) Exposure to Smoke

Taint in grapes and wine following vineyard exposure to bushfire smoke continues to challenge the financial viability of grape and wine producers worldwide. In response, researchers are studying the chemical, sensory and physiological consequences of grapevine smoke exposure. However, studies involving winemaking trials are often limited by the availability of suitable quantities of smoke-affected grapes, either from vineyards exposed to smoke or from field trials involving the application of smoke to grapevines. This study compared the accumulation of volatile phenol glycosides (as compositional markers of smoke taint) in Viognier and Cabernet Sauvignon grapes exposed to smoke pre- vs. post-harvest, and found post-harvest smoke exposure of fruit gave similar levels of volatile phenol glycosides to fruit exposed to smoke pre-harvest. Furthermore, wines made from smoke-affected fruit contained similar levels of smoke-derived volatile phenols and their glycosides, irrespective of whether smoke exposure occurred pre- vs. post-harvest. Post-harvest smoke exposure therefore provides a valid approach to generating smoke-affected grapes in the quantities needed for winemaking trials and/or trials that employ both chemical and sensory analysis of wine.Julie A. Culbert, WenWen Jiang, Renata Ristic, Carolyn J. Puglisi, Elizabeth C. Nixon, Hongmei Shi, and Kerry L. Wilkinso

NDMA attracting international attention: the latest news on nitrosamines

N-nitrosodimethylamine (NOMA), and nitrosamines in general, are attracting increasing worldwide attention. While Australia has now established a guideline for NOMA, other countries such as New Zealand, the US, Canada and the European Union, are still deciding the most appropriate concentration of this disinfection by-product to allow in drinking water, and whether to include other nitrosamines in any ruling. Such intense interest brings an increase in knowledge, so the authors considered it timely to publish an update on the situation regarding nitrosamines in Australia and overseas. This paper complements similar topic reviews published in 2006 (Nicholson, 2006) and 2009 (Newcombe et al., 2009).G Newcombe, J Morran, J Culber

Accumulation of volatile phenol glycoconjugates in grapes following grapevine exposure to smoke and potential mitigation of smoke taint by foliar application of kaolin

Main Conclusion: The accumulation of volatile phenol glycoconjugates in smoke-exposed grapes was monitored following grapevine exposure to smoke, with different glycoconjugate profiles observed for fruit sampled 1 and 7 days after smoke exposure, and at maturity. Foliar application of kaolin reduced the concentration of volatile phenol glycoconjugates in smoke-exposed fruit, but efficacy depended on the rate of application and extent of coverage. Smoke taint can be found in wines made from grapes exposed to smoke from bushfires or prescribed burns. It is characterized by objectionable smoky and ashy aromas and flavors, which have been attributed to the presence of smoke-derived volatile phenols, in free and glycoconjugate forms. This study investigated: (1) the accumulation of volatile phenol glycoconjugates in grapes following the application of smoke to Sauvignon Blanc, Chardonnay and Merlot grapevines at approximately 10 days post-veraison; and (2) the potential mitigation of smoke taint as a consequence of foliar applications of kaolin (a clay-based protective film) prior to grapevine smoke exposure. Varietal differences were observed in the glycoconjugate profiles of smoke-exposed grapes; the highest glycoconjugate levels were found in Merlot grapes, being pentose-glucosides of guaiacol, cresols, and phenol, and gentiobiosides of guaiacol and syringol. Changes in volatile phenol glycoconjugate profiles were also observed with time, i.e., between fruit sampled 1 day after smoke exposure and at maturity. The application of kaolin did not significantly affect the glycoconjugate profiles of Sauvignon Blanc and Chardonnay grapes, but significantly lower volatile phenol glycoconjugate levels were observed in Merlot fruit that was treated with kaolin prior to smoke exposure. The potential for control and smoke-exposed grapes to be differentiated by measurement of spectral reflectance was also demonstrated.Lieke van der Hulst, Pablo Munguia, Julie A. Culbert, Christopher M. Ford, Rachel A. Burton, Kerry L. Wilkinso

Influence of production method on the chemical composition, foaming properties, and quality of Australian carbonated and sparkling white wines

The chemical composition (protein, polysaccharide, amino acid, and fatty acid/ethyl ester content), foaming properties, and quality of 50 Australian sparkling white wines, representing the four key production methods, that is, Méthode Traditionelle (n = 20), transfer (n = 10), Charmat (n = 10), and carbonation (n = 10), were studied. Méthode Traditionelle wines were typically rated highest in quality and were higher in alcohol and protein contents, but lower in residual sugar and total phenolics, than other sparkling wines. They also exhibited higher foam volume and stability, which might be attributable to higher protein concentrations. Bottle-fermented Méthode Traditionelle and transfer wines contained greater proportions of yeast-derived mannoproteins, whereas Charmat and carbonated wines were higher in grape-derived rhamnogalacturonans; however, total polysaccharide concentrations were not significantly different between sparkling wine styles. Free amino acids were most abundant in carbonated wines, which likely reflects production via primary fermentation only and/or the inclusion of nontraditional grape varieties. Fatty acids and their esters were not correlated with foaming properties, but octanoic and decanoic acids and their ethyl esters were present in Charmat and carbonated wines at significantly higher concentrations than in bottle-fermented wines and were negatively correlated with quality ratings. Research findings provide industry with a better understanding of the compositional factors driving the style and quality of sparkling white wine.Julie A. Culbert, Jacqui M. McRae, Bruna C. Condé, Leigh M. Schmidtke, Emily L. Nicholson, Paul A. Smith, Kate S. Howell, Paul K. Boss and Kerry L. Wilkinso

Technological Innovation and Organisational Culture: An Exploratory Comparison of Larger and Smaller Firms

The relationship between organisation size, technology implementation, and organisational culture is examined. Thirty-five American and Canadian manufacturing organisations were surveyed concerning their approach to implementing statistical process control (SPC) technology. Organisations were classified as either large or small and hierarchic or non-hierarchic. Approaches to implementing SPC were measured and compared among the four groups (large hierarchic, small hierarchic, large non-hierarchic and small non-hierarchic). Results indicated that both the size of the organisation and its culture determine how that organisation goes about implementing technological change. Larger organisations use interdepartmental liaisons, temporary task forces, and permanent implementation teams more than smaller organisations in implementing new technology. Non-hierarchic organisations appear to use goal and direct contact mechanisms at higher levels than hierarchical organisations when it comes to innovation and change. Results also indicate that there is more in common in the area of technological implementation between large and small businesses, and hierarchical and non-hierarchical organisations than is often suggested

On the Collapse of Historical Civilizations

To explain the collapse of historical civilizations, scholars typically point to suboptimal behaviors including misunderstanding the natural environment, shortsightedness, or a lack of institutions. We examine the collapse of four historical societies with a model of endogenous population growth and renewable resources employing components of optimal resource management, economic growth theory, and the moral philosophy of social welfare function choice. We find that these collapses may have been socially optimal. Further, we show that the transient behavior of the system is more sensitive to assumptions than the equilibrium behavior and that focusing solely on equilibria may miss key insights. Copyright 2009, Oxford University Press.