In this work, an amperometric biosensor has been designed for the fast detection of sulphite in aqueous solutions. A sulphite oxidation peak at is observed using cyclic voltammetry and exhibits a linear peak increase with sulphite concentration. A calibration curve (current versus sulphite concentration) was produced to characterise the biosensors. However, the complex wine solutions revealed no observable signal indicating that the polyphenols and/or proteins present in wine inhibited the electron transfer. With the use of polymer films, control of pH, gold nanoparticles and/or enzymes and proteins, it was hoped that the design may be improved increasing the stability and signal. However, work to date has not been successful in getting the sensor to work in wine or other beverages.
Salt in irrigation water and soil is a concern in some Australian wine regions. Strategies for maintaining long term performance of grapevines in saline environments include use of salt excluding rootstocks to which wine varieties of choice are grafted. Performance of eight different rootstocks with a range in vine vigour was assessed in a salt affected region with Shiraz as scion. The rootstocks were 140 Ruggeri, 1103 Paulsen, 110 Richter, Ramsey, 101-14, Merbein 5489, Merbein 5512 and Merbein 6262 (hereafter referred to as M 5489, M 5512 and M 6262). Rootstock M 6262 was a relatively poor chloride (Cl‾) excluder. Wines of M 6262 contained 482 mg/L Cl‾ in 2012 and were characterised as having Salty taste and a perceived thickness of the wine on the palate (Viscosity), whereas wines of M 6262 contained 384 mg/L Cl‾ in 2013 and were not characterised as having Salty taste or Viscosity. Sodium (Na+) concentrations in wine from all rootstocks were relatively low (under 40 mg/L). Hence, Salty taste detection for red wines, based on the methods used in this study, occurred at wine Cl‾ concentrations of between 384 and 482 mg/L. The other seven rootstocks were similar in capacity for Cl‾ exclusion from grape juice, but there were differences between the rootstocks in final concentrations in wine (all under 175 mg/L Cl‾). A salt tolerance index (STI) for the various rootstocks was calculated based on yield, leaf area index, grape juice Cl‾ and Na+ concentrations and wine colour density. Best STI was obtained for M 5489, 110 Richter and 140 Ruggeri rootstocks and the lowest for M 6262.
This project was successful in using advanced genetic approaches for both strategic and applied grapevine research. The methods developed resulted in the creation of a mutagenized grapevine population for gene function studies and the discovery and linking of DNA markers to key agronomic and berry traits. Crucial to the success of the project was the use of microvine material that flowered quickly and had a short generation time. The DNA markers were further developed and used to determine if marker-assisted selection (MAS) was possible for speeding up the process of producing new grapevine varieties. Over 8,000 young grapevine seedlings in a glasshouse were screened with DNA markers for mildew resistance, flower sex and berry colour and over 1,200 that passed the DNA screen were planted in the field for evaluation. The DNA markers accurately predicted the phenotype of the plants in the field. This first generation of powdery and downy mildew resistant selections displayed no evidence of mildew in the field in a no-spray vineyard. To identify elite selections within the 1,200 vines, assessment of agronomic performance and berry and wine attributes was initiated with both white and red selections found to have variation in yield and diverse wine flavours.
The award of this travel grant permitted Dr Renata Ristic to attend SenseAsia 2014, The Asian Sensory and Consumer Research Symposium. The Symposium was held between 11th and 13th May 2014 in Singapore. The SenseAsia 2014 conference focused on sensory and consumer science and provided the latest updates by the world’s experts in these fields. Attendance to the Symposium permitted me to: i) promote our GWRDC funded research and newly developed tool for assessing consumers’ willingness/reluctance to purchase unfamiliar wines, ii) present two posters and iii) develop and enhance international collaborations, in particular with world renowned Herb Meiselman who is currently collaborating on our project. Furthermore, diversity of the scientific knowledge presented at the conference provided an excellent opportunity to broaden my knowledge of recent advances in sensory and consumer research, particularly in development of new sensory techniques and methods for measuring various aspects of consumers’ preferences and behaviour.
Understanding and leveraging the marketing opportunities of engaging wine buyers through virtual communities and other e-based sales channels
The report presents the findings of a three-year project investigating the use of on-line of live-streaming video technology as a consumer-engagement strategy. Demonstrated in the three on-line wine communities developed for this project, it was found that use of this technology and similar engagement strategies may exert an important positive influence on consumers’ engagement, brand attachment, word of mouth, and willingness to pay more for wines. However, and despite this opportunity, the research also indicates that the Australian wine industry currently lacks the critical foundations (including effective websites and expertise) to enable interaction, with consumers, through the on-line engagement strategies used in this project.
Abstract (description) The objectives of this project included the development of methodology for the preparation of tannins standards that can be used to investigate the function of tannin structure in wine quality. Isolated tannin standards of different structures were used to investigate the relationship of tannin polymer length and the effect of the wine matrix on tannin-protein interactions involved in astringency. The structures of different tannins were determined to investigate tannin conformation, tannin solubility and colloid formation in wine. The outcomes of this project include fundamental knowledge that contributes to our understanding of tannin interactions such as astringency, colloid formation and extractability.
Functional characterisation of transgenic winegrape varieties containing the MrRUN1 powdery mildew resistance gene and the MrRPV1 downy mildew gene from M. rotundifolia demonstrated that these genes confer strong resistance to mildew isolates from Australia, Europe and North America. However, a powdery mildew isolate from SE USA was identified which can break MrRUN1 resistance. New sources of genetic resistance to powdery and downy mildew from other North American and Chinese Vitis species were identified which could ultimately be combined with MrRUN1 and MrRPV1, in the same grapevine variety, to enhance the durability of this resistance in the vineyard.
The 10th Pangborn Sensory Science Symposium was held in Rio De Janeiro, Brazil from 11th – 15th August, 2013 and attracted more than 750 delegates from over 30 different countries. The conference discussed Sensory and Consumer Science, with an emphasis on the following themes: • Advances in sensory and consumer methodology • Sensory and instrumental relationships • Cross-cultural and income-related research • Food choice and consumer behavior • Fundamentals of sensory research • Sensory properties for health and wellness • Sensometrics • Sensory and consumer research of non-food products • Sensory evaluation in quality control and product development • Cross-modal interactions • Age-related sensory perception and behaviour This travel grant enabled participation in the conference via a poster presentation titled: “Do oak volatiles influence consumers’ emotions and acceptance of wine?”
This travel had three major objectives. The first was to participate at an international grapevine conference in La Serena Chile, where I gave a seminar outlining our current GWRDC-supported research progress. The second was to carry out a small research project in the lab of a collaborator in Dundee, Scotland, in order to advance an aspect of our current GWRDC-supported research programme through the use of a chromatography technique. The third was to interact with grapevine researchers at their host institutions in Chile, Spain and France, where I gave seminars and learned a new technique for grapevine leaf transformation.
Improving quality of wine maturation products through real-time analysis of oak wood volatiles using proton-transfer-reaction mass spectrometry
The author (Ross Farrell) travelled to Switzerland to undertake a research placement at Zurich University of Applied Science (ZHAW), from September-December 2013. A GWRDC travel grant was used to part fund the flight costs to Zurich. The balance of funding (accommodation and living expenses) was provided by ZHAW and UTAS. The research placement was conducted under the supervision of Professor Chahan Yeretzian (Head of Analytical and Physical Chemistry). Prof. Yeretzian is an expert in the application of real-time mass spectrometry, (primarily) in the coffee industry.