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Investigation of the effects of age, vintage and style on phenolic composition of Pinot Noir wines of a major New Zealand producer : A thesis submitted in partial fulfilment of the requirements for the Degree of Doctor of Philosophy at Lincoln University
No full textPinot Noir has become the most important red grape variety and built a solid reputation for the New Zealand wine industry. In terms of quality attributes, phenolic compounds are thought to be important for the colour, basic tastes, and mouthfeel of red wine. This thesis investigates the phenolic composition of Pinot Noir wines and the potential effects of age, vintage, and style on phenolic compounds as well as wine colour.
The first stage included a general exploration of phenolic compounds of Pinot Noir wine where colour properties, total phenolics, and tannin concentrations of 22 Pinot Noir wines produced by Pernod Ricard Winemakers (New Zealand) Ltd. were determined using spectrophotometric measurements including the modified Somers assay and the methylcellulose precipitable (MCP) tannin assay. Generally, strong age-related trends were observed concerning colour properties and total phenolics, whilst tannin concentration fluctuated between vintages and styles.
The second aim was to focus on separating polymeric phenolics from monomeric phenolics using three different methods including isoamyl alcohol extraction (F-iso), solid phase extraction (SPE), and size exclusive chromatography (SEC). Five polymeric fractions were examined using spectrophotometric measurements. The red colour of polymeric phenolic material in old wines tended to be more resistant to changes in pH as indicated by a reduction in the factor A520 pH1/pH3.4 from 2.6 to 1.1 during ageing, with the degree of ionisation of these bleachable polymeric components increasing during ageing. This result for Pinot Noir wines is the first report of this age-related trend in polymeric material. In addition, colour and phenolic properties and tannin concentrations in extracted polymeric fractions were significantly influenced by wine age and style (P < 0.05). Tannin fractionation to some extent contributed to the discrimination of style, for example, MCP tannin in SEC fraction and total phenolics in SEC fractions contributed to the discrimination of super premium wines.
The final aim was to characterise the composition of monomeric and polymeric materials using three chromatographic techniques. The monomeric material was analysed using RP-HPLC, while the phloroglucinol adducts of the total isolated polymeric material were determined by both HPLC and Orbitrap-UPLC-MS/MS to explore tannin composition as well as quantification markers of polymeric pigments.
Six monomeric phenolics, total monomeric red pigments and one type of polymeric pigment were significantly affected by vintage, age, and style (P < 0.05): i.e. protocatechuic acid, caftaric acid, trans-coutaric acid, grape reaction product (GRP), quercetin-3-glucoside, malvidin-3-glucoside, total red pigments, as well as the M3G-C/EC (A type)-F trimers and the corresponding T-A-F (A type)-F adducts (A, malvidin-3-glucoside; F, catechin/epicatechin; T, condensed tannin). General decreasing patterns with age were seen in p-hydroxybenzoic acid, caftaric acid, coutaric acid, flavan-3-ols, resveratrol, malvidin-3-glucoside, total red pigments, as well as yield of tannin, mDP (mean degree of polymerisation), average molecular weight, and catechin and epicatechin extension units, and coloured T-A and A-methlymethine-T adducts, whilst general increasing patterns were seen in p-coumaric acid, proportions of catechin and epicatechin terminal units, seed-derived epicatechin gallate subunits, and skin-derived epigallocatechin subunits, as well as proportions of A-type polymeric pigments.
Considering wine colour, the decreased proportion of malvidin-3-glucoside, T-A and A-methlymethine-T adducts, as well as the increased proportion of other red pigments measured by RP-HPLC contributed to the change of colour density and hue with age (3-19 years). In contrast, increased proportions of T-A-F (A type), A-F (A type)-T, T-F-A-F (A type) and T-A-F (A type)-F adducts resulted in colour reduction and compositional stability in old wines. The discrimination of one group of regionally distinct wines was driven by monomeric phenolics, whilst the discrimination of super premium wines was driven by the significantly higher colour density, SO2-resistant pigments, total phenolics, and tannin concentrations, as well as higher proportions of malvidin-3-glucoside-(epi) catechin dimers and the corresponding T-A-F adducts.
With respect to wine age, vintage and style, this study has established three main associations with wine attributes: the first between wine age and colour properties, the second between style and colour and phenolic parameters, and the third between wine age and style, and monomeric and polymeric phenolics. High-quality wines have been found to be positively correlated with higher colour and phenolic parameters, and tannin concentrations, as well as higher proportions of malvidin-3-glucoside-(epi) catechin dimers. Thus, any modifications in winemaking techniques that could improve wine colour, total phenolics and tannin concentration, and malvidin-3-glucoside-(epi) catechin dimers are important to improve the perceived quality of the wine
Should you add kiwifruit to your cereal? The effect of purified actinidin from green kiwifruit on oat bran proteins and the subsequent generation of bioactive oat peptides : A dissertation submitted in partial fulfilment of the requirements for the Degree of Master at Lincoln University
No full textPurified actinidin was added to Oat bran protein to investigate the bioactivity of peptides generated before and after in vitro gastrointestinal digestion. Actinidin purification was conducted using ion-exchange chromatography. Ferric antioxidant power (FRAP) and Total phenolic concentration (TPC) analysis was conducted post in vitro digestion. Dialysate prepared from commercial kiwifruit powder (External) had a 1.65 fold higher specific enzyme activity than freeze-dried fresh kiwifruit powder (In-house). Actinidin specific activity (External) increased from 2.61 ± 0.57 U/mg to 196.53 ± 36.45 U/mg due to purification. Purified actinidin showed a molecular weight of 25 kDa on NuPAGE. After in vitro digestion, a significant increase (p < 0.05) was observed in FRAP and TPC for Oat bran protein + Purified actinidin compared to Oat bran protein. These results suggest after in vitro digestion a greater amount of bioactive peptide were produced when expose Purified actinidin to Oat bran protein
Agroecology niche for New Zealand's native earthworms
No full textExotic lumbricid earthworms have had some limited success colonising productive agricultural pastures in New Zealand, in place of native megascolecid species that did not adapt to the conversion from native vegetation cover. Native earthworms in lowland intensively-farmed landscapes are now almost entirely restricted to small fragments of native vegetation on marginal land where they coexist with adventive lumbricids. In recent years, regular pasture replacement using cultivation has been largely replaced by herbicide spray-out followed by direct drilling; much less soil disturbance potentially creates a new opportunity for native earthworms to colonise pastures. Reclaiming native earthworm habitat is critical not only to protecting diversity, but also to sustaining New Zealand's unique soil ecosystem services strongly associated to role of native species; however, there have been no studies related to this. Using a mesocosm experiment, we investigated how native and exotic earthworms modify physicochemical properties of a sheep-grazed pasture soil. The pasture soil was found to be equally suitable for the growth and survival of native and exotic species. Most burrowing earthworms increased the more soluble forms of macronutrients (N, P, S, K and Mg), but differences between native and exotic species were found to be larger than between functional groups. Two species of native earthworms, Octochaetus multiporus and Maoridrilus transalpinus, modified some soil properties in similar way to exotic species, but had significantly different impacts on pH, mineralisation of nutrients, and plant availability of trace elements. Compared to control, plant available N (PAN) and S concentrations were higher by more than 100% and 40%, respectively, in soils with presence of burrowing activity of the two native earthworms. Future co-existence of communities of native and exotic earthworms in agricultural pastures appears realistic, and this would benefit conservation of native species as well as dairy production. Further research may also reveal additional and unique benefits to soil quality that could be attributable to this formerly unavailable niche for native earthworms
Effect of phosphogypsum application on aluminum speciation in acid pasture soils
No full textPurpose: Legume establishment and persistence in New Zealand hill and high-country soils are largely limited by high soil acidity and associated aluminum (Al) toxicity. The present study aimed to evaluate the effect of four rates of phosphogypsum (0, 1, 3, and 9 t ha¯¹) on Al speciation in the soil solution and to examine which species are mostly impacting total dry matter (TDM) yield of lucerne.
Methods: Glasshouse and incubation experiments were conducted using three acid soils with different exchangeable Al concentrations: Molesworth, Glenmore, and Lindis Peaks. The distribution of Al species was modeled using visual Minteq. Partial least square (PLS) regression was used to evaluate the relationships between Al³⁺ and other variables in the soil-soil solution system.
Results: In the planted and incubated Molesworth soils, Al³⁺ and hydroxylated Al (Al–OH) fractions decreased significantly at 1 and 3 t of phosphogypsum ha−1 compared to 0 t ha¯¹. However, in the planted Glenmore and incubated Lindis Peaks soils, these two fractions remained unchanged. The contribution of variables in Al³⁺ concentration depended on the soil type. However, the loading plot of the whole soil data set (n = 62) showed that Al–OH, base saturation, soil/soil solution pHw, and exchangeable Al were the main explanatory variables for the variation in Al³⁺ concentration. The TDM yield of lucerne was better explained by Al³⁺ , Al-F, and Al-DOM than exchangeable Al.
Conclusions: Reasonable amounts of phosphogypsum (1 to 3 t ha¯¹) can help to alleviate Al toxicity in acid soils (pH ≤ 5.3), but higher application rates should be avoided
Unquiet Women: Pimmy Takdhada on finding freedom
No full textAs part of the Unquiet Women series, Hafsa Ahmed reports from Christchurch with the latest profile: Pimmy Takdhada from Thailand, who moved to New Zealand almost 30 years ago
Spider biodiversity in crop orchard systems (Te kanorau koiora o te pūngāwerewere i roto i ngā pūnaha hauropi huanga kai)
No full textSpiders are the dominant, most abundant, and most diverse natural enemies in agroecosystems. They are generalist predators of insect pests, comprising many different functional groups. Spiders contribute economically to crop protection by reducing pest invertebrate numbers both by direct consumption, and non-consumptive effects. Despite this, very few studies on spider biodiversity in crop systems have been completed in New Zealand; moreover, there are no published data on spider biodiversity in New Zealand orchard systems. My master’s research aims to answer three questions: 1) What spiders are present in kiwifruit orchards? 2) How does the spider species composition change as native plantings are incorporated into the orchard? 3) What is the consumption rate of one to two spider species of key pest insects? I am addressing these questions through fieldwork and lab studies. During my fieldwork I am using a selection of spider sampling techniques including pitfall traps, active day sampling, active night sampling, and sweep netting. Samples are being collected along a transect that runs from inside a kiwifruit orchard into adjacent native plantings. Lab studies will include consumption bioassays of key spider species found in the orchard with key insect pests found in the orchard. I will measure how many pest insects the spider eats in a certain period to get a measure of consumption rate. This research aims to align with Te Ao Māori goals of Taiao, environmental wellbeing, and contributes to industry goals of spray-free production. Interim results will be presented
What does the tourism industry think about academic tourism research? Not a lot!
No full textThe academia-tourism industry research/collaboration gap continues with the tourism industry seeing academic research not fit-for-purpose. Earlier research also highlights this, and it is concerning that there has not been any change in recent years. If academics wish their research to have an impact, more meaningful relationships need to be built with the industry
Surface melting of snow-firn-ice structures and estimation of extended transient energy and mass balances using a liquid solid phase-change model
No full textParameterized energy and mass balance models are often applied to estimate energy fluxes at the surface that are available for melting and sublimation of snow and ice surfaces. In this study we evaluate the suitability of quantifying transient energy and mass fluxes on frozen surface using the finite volume method in comparison with the traditional glaciological energy balance approach. To assess the model application, we apply the methods to two datasets: a glacier in the semiarid Andes, and an Antarctic ice shelf, estimating the effect of time varying surface irradiation, wind velocity, air temperature and humidity on the history of temperature, liquid water and heat fluxes during 30 months. Results of energy and mass balances are validated with previously published results of global balances and meteorological datasets
Creating a design framework to diagnose and enhance grassland health under pastoral livestock production systems
Get PDFGrasslands and ecosystem services are under threat due to common practices adopted by modern livestock farming systems. Design theory has been an alternative to promote changes and develop more sustainable strategies that allow pastoral livestock production systems to evolve continually within grasslands by enhancing their health and enabling the continuous delivery of multiple ecosystem services. To create a design framework to design alternative and more sustainable pastoral livestock production systems, a better comprehension of grassland complexity and dynamism for a diagnostic assessment of its health is needed, from which the systems thinking theory could be an important approach. By using systems thinking theory, the key components of grasslands—soil, plant, ruminant—can be reviewed and better understood from a holistic perspective. The description of soil, plant and ruminant individually is already complex itself, so understanding these components, their interactions, their response to grazing management and herbivory and how they contribute to grassland health under different climatic and topographic conditions is paramount to designing more sustainable pastoral livestock production systems. Therefore, by taking a systems thinking approach, we aim to review the literature to better understand the role of soil, plant, and ruminant on grassland health to build a design framework to diagnose and enhance grassland health under pastoral livestock production systems
Landscape Review: Māori landscapes
No full textThis special issue of Landscape Review is a significant one in its focus on Māori landscapes, from a range of perspectives and through different lenses. Thinking of Māori landscapes brings reflection on place, identity and what it means to be here in Aotearoa New Zealand. And it also is a time for farewells and welcomes, as well as a pause for remembering ngā mate, those we have lost