ORCID Profile
0000-0003-2623-0958
Current Organisation
The University of Auckland
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Publisher: CSIRO Publishing
Date: 2014
DOI: 10.1071/CH13452
Abstract: We report the multistep synthesis and polymerisation of a novel aniline derivative with a pendant α-d-mannose substituent. The α-D-mannose functionality was successfully introduced before polymerisation via copper-catalysed azide alkyne click chemistry and the resulting monomer was polymerised using general oxidative polymerisation conditions, producing a water soluble mannosylated polyaniline. The polymer was characterised by several techniques and compared with standard polyaniline. The selective binding of the polymer to Concanavalin A (ConA) was successfully demonstrated by the precipitation of polymer–ConA aggregates. Potential applications of these novel polyaniline glycopolymers could include the development of electroactive biomaterials with the ability to bind mannose receptors, or as sensors for proteins or microbes.
Publisher: American Chemical Society (ACS)
Date: 17-01-2022
DOI: 10.26434/CHEMRXIV-2022-Q6PFJ
Abstract: A new perspective is presented to investigate the sensorially relevant gas-phase concentrations of volatile compounds in wine. This is achieved by measuring the partition coefficients and matrix-phase concentrations of volatiles using static headspace-gas chromatography-ion mobility spectrometry (SHS-GC-IMS). Physicochemical properties that can contribute to the partition behaviors of ten volatile esters, such as hydrophobicity and matrix temperature, are also discussed. Partition coefficients are then linked to quantitative measurements to obtain partial pressures, which describes the availability of volatile compounds in the gas phase. The concept of partition coefficients and partial pressure have then been applied to a time series of aroma changes due to oxidation in commercial wines. As a follow-up study, a full factorial design was devised to inspect the impact of three common wine matrix components, namely, copper, polyphenols and ascorbic acid, on the partial pressure changes after 30-day oxidation treatment in either full-alcohol or low-alcohol simulated wine matrices. Interesting interactive effects between antioxidant behaviors and alcohol levels were elucidated, especially around the controversial use of ascorbic acid in winemaking. These results can guide winemakers who wish to minimize oxidative damage to wine aroma during wine storage or bulk transport, where ullage may be present or continual oxygen ingress may be occurring.
Publisher: Universite de Bordeaux
Date: 24-06-2022
Publisher: American Chemical Society (ACS)
Date: 04-03-2021
Publisher: American Chemical Society (ACS)
Date: 07-12-2021
Abstract: A new quantitative method based on static headspace-gas chromatography-ion mobility spectrometry (SHS-GC-IMS) is proposed, which enables the simultaneous quantitation of multiple aroma compounds in wine. The method was first evaluated for its stability and the necessity of using internal standards as a quality control measure. The two major hurdles in applying GC-IMS in quantitation studies, namely, nonlinearity and multiple ion species, were also investigated using the Boltzmann function and generalized additive model (GAM) as potential solutions. Metrics characterizing the model performance, including root mean squared error, bias, limit of detection, limit of quantitation, repeatability, reproducibility, and recovery, were investigated. Both nonlinear fitting methods, Boltzmann function and GAM, were able to return desirable analytical outcomes with an acceptable range of error. Potential pitfalls that would cause inaccurate quantitation, that is, effects of ethanol content and competitive ionization, were also discussed. The performance of the SHS-GC-IMS method was subsequently compared against that of a currently established method, namely, GC-MS, using commercial wine s les. These findings provide an initial validation of a GC-IMS-based quantitation method, as well as a starting point for further enhancing the analytical scope of GC-IMS.
Publisher: Wiley
Date: 05-07-2022
Abstract: Almost all processed food comes packaged in either plastic, glass, metal, or paper and paperboard materials, and many packaging materials are disposed of after a single use (linear economy). Based on the concept of a circular economy, the recycling of food packaging materials has become one of the main targets for industries and regulators around the world. However, recycling presents particular challenges, mainly related to the recycled material composition, which determines its reusability, application, functionality, and chemical safety. In this latter matter, it has been demonstrated that the use of recycled food packaging materials increases the number and possible sources of substances that could be present in the packaging material, which is of concern as substances that can migrate into food and cause health hazards upon consumption. This review compiles information regarding substances detected in non‐permanent food packaging materials, focusing mainly on plastics, paper, and paperboards. The compilation of literature studies (110 research articles) on the presence of intentionally added substances (IAS) and non‐intentionally added substances (NIAS) in food packaging materials, their migration, toxicity, and dietary exposure has been summarized, evaluated, and discussed. In addition, current sustainable food packaging trends have been mentioned. Finally, approaches to reduce the presence, migration, and potential exposure to substances that have migrated from packaging materials into food have been reviewed.
Publisher: Elsevier BV
Date: 10-2019
DOI: 10.1016/J.BIOCHI.2019.07.002
Abstract: Polyphenol oxidases (PPOs) are important enzymes that are widely found in both prokaryotes and eukaryotes including grapes. Studies of grape PPO to date have mostly relied on enzymes extracted and purified from plants. In this work, we describe the production of the mature form of Shine Muscat grape PPO by using an Escherichia coli expression system. We have optimised the purification procedure to obtain pure and active recombinant enzymes and characterised the catalytic efficiency of the recombinant grape PPO by using ultraviolet/visible (UV/Vis) spectrophotometry. Our work provides a simple protocol of obtaining pure and active recombinant grape PPO that will enable further studies about the catalytic mechanism and inhibition of this enzyme.
Publisher: American Chemical Society (ACS)
Date: 16-12-2020
DOI: 10.26434/CHEMRXIV.13347317.V2
Abstract: In this paper, we report on the application of the static headspace-gas chromatography-ion mobility spectrometry (SHS-GC-IMS) instrument in the field of wine aroma analysis and its potential in constructing a prediction model for the quality gradings of wines. The easy-to-operate, cost effective SHS-GC-IMS instrument was innovatively used for a non-targeted search for volatile compounds in Sauvignon Blanc wine, with the identification of volatiles seldom before reported. The wine aroma profile acquired by the instrument was organically and innovatively combined with advanced classification models, inspired by the computer science community, to produce high classification accuracy in terms of wine quality gradings. Useful insights were also extracted by using advanced interpretation methods on complex models to learn the important volatiles correlated with wine quality grading.
Publisher: Wiley
Date: 21-03-2015
DOI: 10.1002/PI.4881
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 05-2010
Publisher: Wiley
Date: 28-03-2008
Publisher: Elsevier BV
Date: 08-2021
Publisher: American Chemical Society (ACS)
Date: 13-05-2022
Abstract: A new perspective is presented to investigate the sensorially relevant gas-phase concentrations of volatile compounds in wine. This is achieved by measuring the partition coefficients and matrix-phase concentrations of volatiles using static headspace-gas chromatography-ion mobility spectrometry. Physicochemical properties that can contribute to the partition behaviors of 10 volatile esters, such as hydrophobicity and matrix temperature, are also discussed. Partition coefficients are then linked to quantitative measurements to obtain partial pressures, which describe the availability of volatile compounds in the gas phase. The concept of partition coefficients and partial pressure has then been applied to a time series of aroma changes due to oxidation in commercial wines. As a follow-up study, a full factorial design was devised to inspect the impact of three common wine matrix components, namely, copper, polyphenols, and ascorbic acid, on the partial pressure changes after 30-day oxidation treatment in either full-alcohol or low-alcohol simulated wine matrices. Interesting interactive effects between antioxidant behaviors and alcohol levels were elucidated, especially around the controversial use of ascorbic acid in winemaking. These results can guide winemakers who wish to minimize oxidative damage to wine aroma during wine storage or bulk transport, where ullage may be present or continual oxygen ingress may be occurring.
Publisher: Wiley
Date: 13-11-2017
No related grants have been discovered for Paul Kilmartin.