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Showing posts from September, 2019

How to cure a hangover

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Alcohol consumption often leads to hangover, a condition characterised by several symptoms, characteristically headache, nausea, fatigue and drowsiness. Hangover may be alleviated by altering the rate of alcohol metabolism and facilitating elimination of acetaldehyde (a breakdown product of alcohol) by affecting the activity of alcohol dehydrogenase (ADH) and/or aldehyde dehydrogenase (ALDH) enzymes. Anti-hangover effect can be expected when there is an increase in the ADH and/or ALDH activities. Further, the rate of conversion of acetaldehyde to other metabolites must be higher than the rate of conversion of alcohol to acetaldehyde. In the present study, several food commodities were investigated for their effect on the in vitro activities of the enzymes and their antioxidant properties.
PROJECT LAYOUT The following food commodities were individually prepared according to various protocols to render them in a fluid / extract form in order to be tested against the activity of the two en…

Shiraz-Viognier co-fermentation or blending

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By Karien O'Kennedy
The aim of this study was to determine the chemical and sensory effects of co-fermentation and post malolactic fermentation (MLF) blending of Shiraz (Syrah) with selected Rhône white cultivars. Co-fermentation of Shiraz is a traditional practice and in the Côte Rôtie appellation of the Rhône for instance, co-fermentation of Shiraz with up to 20% of Viognier is permitted. One of the aims of co-fermentation is to promote long term colour stability through co-pigmentation. Co-pigmentation is the formation of an interaction (or stacking) between flavonols and anthocyanins to form polymeric pigments. Polymeric pigments are more stable than monomeric anthocyanins during bottle ageing. Some white cultivars, such as Viognier, is reportedly richer in flavonols and co-fermentation could therefore theoretically increase colour stability. This is not necessarily always the case as certain studies have proved.
Two additional aims of co-fermentation is to increase acidity and …

Seasonal vine nutrient dynamics and distribution of Shiraz grapevines

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The aim of this study was to assess the nutrient dynamics of a major wine grape variety grown in Australia to determine the key nutrient uptake periods and to understand the mobilization patterns throughout a season. The nutrient reserves in the grapevine perennial structure perform a critical role in supplying the grapevine with nutrients when demand cannot be sustained by root uptake. The seasonal changes in these reserves largely depend on the developmental stage and the associated growth requirements. These stored reserves are, in turn, influenced by environmental conditions and vineyard management practices, such as production levels and water availability.
METHODS:
The own-rooted 10-year-old Shiraz vines used for the trial were located in the Riverina, which is a hot inland grape-growing region in New South Wales, Australia. Uniformly sized vines, identified by trunk circumference, were selected for 11 excavation dates with four replicates, from a month before bud-burst to leaf-fa…

The significance of scion x rootstock interactions

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In this study, researchers wanted to determine how consistently rootstocks affect the growth and fruit composition of scion varieties and identify scion x rootstock interactions.
PROJECT LAYOUT: Drip-irrigated, spur-pruned Chardonnay, Cabernet-Sauvignon and Shiraz, grafted on seven rootstocks, in a hot-climate, was assessed over five seasons from 2013 to 2017.The study was conducted with mature vines, established in 2006, as a randomised block design with five replicates. Rootstocks included Ramsey, 1103 Paulsen and 140 Ruggeri and four promising selections from the CSIRO rootstock development programme.Vines were trained as quadrilateral cordons on a two-wire vertical trellis of height 1.8 m and 3.0 m row × 1.8 m vine spacing, and irrigated with 5.5–6.0 ML/ha of water each season. Each variety was harvested at 25.0 °Brix. Vine performance and fruit composition was evaluated.
RESULTS: Despite identical management practices, there were large differences between scion varieties in key g…