Evaluation of alternative wine grape varieties in Manjimup, Western Australia

Since 1998 the Department of Agriculture and Food, Western Australia (DAFWA) in conjunction with the Western Australian Vine Improvement Association (WAVIA) have imported over 60 new varieties and clones of wine grape material into Western Australia. These new varieties and clones were identified by the wine industry as having both domestic and international wine market potential to enhance the production and development of premium WA wine. The grapevine material is currently located in the Foundation Collection at the Manjimup Horticultural Research Institute (MHRI). In 2003 a trial of 18 of these varieties was established in order to gain an understanding of their grape production, winemaking characteristics and suitability to production in Manjimup, Western Australia.https://researchlibrary.agric.wa.gov.au/bulletins/1118/thumbnail.jp

Smoke derived taint in grapes and wine

Smoke derived taint in grapes and wine is an issue of increasing significance and severity for the wine industry internationally. On commencement of this research, insufficient knowledge existed as to the effects of smoke on grapevines and the development of smoke taint in wine, with no substantial published information. This research was undertaken to investigate the effect of smoke exposure to grapevines on the development of smoke aromas, flavours and compounds in final wines. As such, this study pioneers the purposeful application of smoke to grape bunches and field-grown grapevines to establish the direct link between smoke exposure and the development of smoke taint in wine.This research identified key periods of grapevine sensitivity to smoke uptake as: (1) from shoots 10 cm in length to full-bloom (low levels of smoke taint); (2) from berries pea size to the onset of veraison (variable levels of smoke taint); and (3) from 7 days post veraison to harvest (high levels of smoke taint). A novel smoke application methodology consisting of a smoke generator and greenhouse-grade tent was developed to facilitate the accurate application of smoke treatments to field-grown grapevines. Smoke treatments were applied to grapevines at key stages during the seasonal growth cycle, on repeated occasions and at a range of densities and durations.Elevated concentrations of guaiacol, 4-methylguaiacol, 4-ethylguaiacol, 4-ethylphenol, eugenol and furfural were detected, by gas chromatography-mass spectrometry analysis, in wines made from fruit exposed to smoke; whereas these compounds were either not detected or detected in trace concentrations in wines produced from unsmoked (control) fruit. Wine sensory analysis established a difference between smoked and unsmoked wines, with smoked wines exhibiting ‘smoky’, ‘dirty’, ‘earthy’, ‘burnt’ and ‘smoked meat’ aromas. The density and duration of smoke exposure to grapevines was found to affect the chemical composition and sensory properties of wine and repeated smoke applications demonstrated a cumulative effect

Evaluation of alternative wine grape varieties in Manjimup, Western Australia

Since 1998 the Department of Agriculture and Food, Western Australia (DAFWA) in conjunction with the Western Australian Vine Improvement Association (WAVIA) have imported over 60 new varieties and clones of wine grape material into Western Australia. These new varieties and clones were identified by the wine industry as having both domestic and international wine market potential to enhance the production and development of premium WA wine. The grapevine material is currently located in the Foundation Collection at the Manjimup Horticultural Research Institute (MHRI). In 2003 a trial of 18 of these varieties was established in order to gain an understanding of their grape production, winemaking characteristics and suitability to production in Manjimup, Western Australia.https://library.dpird.wa.gov.au/bulletins/1118/thumbnail.jp

Smoke-derived taint in wine: the release of smoke-derived volatile phenols during fermentation of Merlot juice following grapevine exposure to smoke." Journal of agricultural and food chemistry 56(16

The release of smoke-derived volatile phenols during the fermentation of Merlot grapes, following grapevine exposure to smoke, has been investigated. The concentrations of guaiacol, 4-methylguaiacol, 4-ethylguaiacol, 4-ethylphenol, and eugenol were determined by gas chromatography-mass spectrometry and found to increase throughout the winemaking process. Only trace levels (e1 µg/L) of guaiacol and 4-methylguaiacol could be detected in free run juice derived from the fruit of smoked vines; the highest levels, 388 µg/L and 93 µg/L, respectively, were observed in the finished wine. Control wine (derived from fruit of unsmoked vines) contained 4 µg/L guaiacol, with the volatile phenols either not detected or detected at only trace levels (e1 µg/L) throughout fermentation. The role of enzyme and acid catalyzed hydrolysis reactions in releasing smoke-derived volatile compounds was also investigated. The volatile phenols were released from smoked free run juice by strong acid hydrolysis (pH 1.0) and enzyme ( -glucosidase) hydrolysis, but not mild acid hydrolysis (juice pH 3.2-3.7). Guaiacol was again the most abundant smoke-derived phenol, present at 431 µg/L and 325 µg/L in strong acid and enzyme hydrolysates, respectively. Only trace levels of each phenol could be detected in each control hydrolysate. This study demonstrates the potential for underestimation of smoke taint in fruit and juice samples; the implications for the assessment of smoke taint and quantification of volatile phenols are discussed

Model Membrane Systems Used to Study Plasma Membrane Lipid Asymmetry

It is well known that the lipid distribution in the bilayer leaflets of mammalian plasma membranes (PMs) is not symmetric. Despite this, model membrane studies have largely relied on chemically symmetric model membranes for the study of lipid–lipid and lipid–protein interactions. This is primarily due to the difficulty in preparing stable, asymmetric model membranes that are amenable to biophysical studies. However, in the last 20 years, efforts have been made in producing more biologically faithful model membranes. Here, we review several recently developed experimental and computational techniques for the robust generation of asymmetric model membranes and highlight a new and particularly promising technique to study membrane asymmetry