Pigment development during ripening oi the grape

Using marked berries from a single Shiraz grape cluster in a vineyard at Magill, South Australia, the composition of extractible grape pigment was examined over a 50-day period from veraison to post-harvest. The analyses of total skin extract were made by gel column chromatography, from which measures of acylated anthocyanins, anthocyanins and tannin pigments were obtained.Acylated anthocyanins were present from the earliest stages, and the levels of both acylated and non-acylated anthocyanins became maximal at 20 to 30 days after veraison, when the Brix value was 21 to 24 degrees. There was a decline from a maximum of about 1.0 mg total extractible anthocyanins per berry around day 20 to about 0.7 mg per berry approaching day 50; this decrease was associated with shrinkage of the berries.The tannin fraction was initially yellow and averaged 0.7 mg/berry at day 1. In the first few days after veraison, there was sharp increase in the quantity of this fraction per berry (to 2.4 mg at day 4) with fluctuation thereafter between 2.1 and 4.3 mg!berry (mean 3.1 mg from day 4 to day 50). There was also progressive change in spectral characteristics up to about day 30, with increasing pigmentation in the samples isolated during this period.The grape tannin pigments are considered to be artefacts arising from the use of HCI in the extraction and measurement of extremely labile phenolic materials, but their facile formation in such conditions is relevant to interpretations of the normal course of ageing reactions in red wines.Die Pigmententwicklung während der TraubenreifungAn gekennzeichneten Beeren einer einzigen Traube der Sorte Shiraz wurde über einen Zeitraum von 50 Tagen vom Weichwerden bis nach der Ernte die Zusammensetzung der extrahierbaren Traubenpigmente untersucht. Die Analyse des Gesamtextraktes der Beeren erfolgte durch Säulenchromatographie an Sephadex G25, wobei Daten über die acylierten und nichtacylierten Anthocyane und die Tanninfarbstoffe gewonnen wurden.Die acylierten Anthocyane lagen schon in den frühesten Beerenstadien vor; acylierte und nichtacylierte Anthocyane erreichten ihre Maximalkonzentration 20-30 Tage nach dem Weichwerden der Beeren bei 21-24 °Brix. Von einem Maximum mit ca. 1,0 mg extrahierbaren Gesamtanthocyanen je Beere um den 20. Tag ging die Anthocyanmenge auf ca. 0,7 mg je Beere gegen den 50. Tag zurück; diese Abnahme war vom Schrumpfen der Beeren begleitet.Die Tanninfraktion war anfänglich gelb und betrug am 1. Tag durchschnittlich 0,7 mg je Beere. In den ersten Tagen nach dem Weichwerden nahm der Gehalt dieser Fraktion je Beere stark zu (bis auf 2,4 mg am 4. Tag); danach schwankte er zwischen 2,1 und 4,3 mg je Beere (Mittelwert in der Zeit vom 4. bis zum 50. Tag: 3,1 mg). Auch die spektralen Kenndaten veränderten sich bis zum 30. Tag fortlaufend, wobei die Pigmentierung in den während dieser Periode isolierten Proben zunahm. Die Tanninpigmente der Trauben werden als Artefakte angesehen, die durch die Verwendung von HCl bei der Extraktion und die Messung von extrem labilem phenolischem Material entstehen; aber ihre leichte Bildung unter diesen Bedingungen erlaubt Rückschlüsse auf den normalen Ablauf der Alterungsreaktionen von Rotweinen

Pigment profiles of grapes and of wines

Gel column analysis of pigment extracts has been automated, and the distribution of total coloured constituents in terms of tannin pigments, acylated anthocyanins and anthocyanins can now be measured routinely, enabling rapid evaluation of materials. Quantitative determinations of polymeric and monomeric pigments in grape extracts and in young wines have been made from the pigment elution curves. Wine grape varieties from the same viticultural area were found to have characteristieally different elution curves. Evidence Ls presented for one variety that some degree of selective extraction of pigments occurs during normal fermentation on skins, the anthocyanins being more efficently extracted than other fractions - thus the composition of pigments in the new wine differs from that in the grape. Other young varietal wines are also qualitatively different from one another in pigment compositions, which generally resemble those of the grape varieties.Regional differences between grapes and wines oi one variety have been demonstrated, which relate to colour extraction and to the ageing characteristics of the wines from these regions.The gross changes in pigment distribution which occur during ageing of red wines, with progressive loss of monomeric pigments and increase in the relative proportions of tannin pigments are described. The latter fraction is seen to be of primary importance to red wine technology.The elution curves obtained are regarded as pigment profiles of the grapes or wines, and the utility of this concept in viticultural and oenological research is demonstrated

Interpretations of colour composition in young red wines

Recent developments in research on pigment composition and anthocyanin equilibria in red wines have enabled more objective description, and some useful interpretation, of the various wine types and styles.Very large variations in recognised parameters of wine colour have been shown in varietal Australian wines by application of a new analytical method. While there are wide ranges in phenolic content, which normally arise from corresponding variation in the harvest composition, the wine pH and the evel of free S02 are also significant determinants of wine colour density and hue. Data on such influences together with measures of the anthocyanin and total phenolic content, are readily obtained from a set of 6 spectrophotometric observations. The method is proposed as providing a kind of "anatomical description" of a young red wine in terms which relate both to the harvest composition and the wine making method. The utility of this concept in oenology has been emphasized by the showing of correlations between several parameters of wine colour and independent assessments of wine quality.Interpretation der Färbungskomponenten bei jungen RotweinenNeuere Erkenntnisse der Forschung über die Farbstoffzusammensetzung und das Anthocyangleichgewicht von Rotweinen ermöglichen eine objektivere Beschreibung und eine zweckmäßige Interpretation der verschiedenen Weintypen und -nuancen.Durch die Anwendung einer neuen analytischen Methode konnte bei australischen Rotweinsorten eine beträchtliche Variabilität der Parameter, welche die Weinfärbung charakterisieren, aufgezeigt werden. Der Phenolgehalt kann über einen breiten Bereich variieren, wofür normalerweise entsprechende Schwankungen in der Zusammensetzung des Lesegutes verantwortlich sind; aber auch Wein-pH und Konzentration der freien schwefligen Säure stellen wesentliche Faktoren für die Ausprägung der Farbintensität und -tönung dar. Aus insgesamt 6 spektralphotometrischen Bestimmungen können leicht Daten über solche Einflüsse sowie Werte des Anthocyan- und Gesamtphenolgehaltes gewonnen werden.Es wird vorgeschlagen, diese Methode für eine Art „anatomischer Beschreibung" junger Rotweine zu benutzen, wobei Größen verwendet werden, die in Bezug sowohl zu der Zusammensetzung des Lesegutes wie zur Weintechnologie stehen. Die Brauchbarkeit dieser Vorstellungen wird dadurch erhärtet, daß Korrelationen zwischen einer Reihe von Parametern der Weinfärbung und den unabhängig davon gewonnenen Ergebnissen sensorischer Qualitätsprüfungen aufgezeigt werden konnten

Predictors of survival in a cohort of patients with polymyositis and dermatomyositis: effect of corticosteroids, methotrexate and azathioprine

Introduction: The idiopathic inflammatory myopathies are rare diseases for which data regarding the natural history, response to therapies and factors affecting mortality are needed. We performed this study to examine the effects of treatment and clinical features on survival in polymyositis and dermatomyositis patients. Methods: A total of 160 consecutive patients (77 with polymyositis and 83 with dermatomyositis) seen at the University of Michigan from 1997 to 2003 were included. Medical records were abstracted for clinical, laboratory and therapeutic data, including initial steroid regimen and immunosuppressive use. State vital records were utilized to derive mortality and cause of death data. Survival was modeled by left-truncated Kaplan-Meier estimation and Cox regression. Results: The 5- and 10-year survival estimates were 77% (95% CI = 66 to 85), and 62% (95% CI = 48 to 73), respectively, and the rates were similar for polymyositis and dermatomyositis. Survival between the sexes was similar through 5 years and significantly lower thereafter for males (10-year survival: 18% male, 73% female; P = 0.002 for 5- to 10-year interval). The sex disparity was restricted to the polymyositis group. Increased age at diagnosis and non-Caucasian race were associated with lower survival. Intravenous versus oral corticosteroid use was associated with a higher risk of death among Caucasians (HR = 10.6, 95% CI = 2.1 to 52.8). Early survival between patients treated with methotrexate versus azathioprine was similar, but survival at 10 years was higher for the methotrexate-treated group (76% vs 52%, P = 0.046 for 5- to 10-year interval). Conclusions: Patients treated initially with intravenous corticosteroids had higher mortality, which was likely related to disease severity. Both methotrexate and azathioprine showed similar early survival benefits as first-line immunosuppressive drugs. Survival was higher between 5 and 10 years in the methotrexate-treated group, but could not be confirmed in multivariable modeling for the full follow-up period. Other important predictors of longterm survival included younger age, female sex and Caucasian race.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90025/1/IIM_ART2012.pdf1611

IN-SYNC. VII. Evidence for a decreasing spectroscopic binary fraction from 1 to 100 Myr within the IN-SYNC sample

We study the occurrence of spectroscopic binaries in young star-forming regions using the INfrared Spectroscopy of Young Nebulous Clusters(IN-SYNC) survey, carried out in SDSS-III with the APOGEE spectrograph. Multi-epoch observations of thousands of low-mass stars in Orion A, NGC 2264, NGC 1333, IC 348, and the Pleiades have been carried out, yielding H-band spectra with a nominal resolution of R=22,500 for sources with H $\le$ 12 mag. Radial velocity precisions of $\sim$0.3 $km\:s^{-1}$ were achieved, which we use to identify radial velocity variations indicative of undetected companions. We use Monte Carlo simulations to assess the types of spectroscopic binaries to which we are sensitive, finding sensitivity to binaries with orbital periods $< 10^{4}$ d, for stars with $2500 {\rm K} \le T_\mathrm{eff} \le 6000 {\rm K}$ and $\it{v} \sin \it{i}$ $\le$ 100 $km\:s^{-1}$. Using Bayesian inference, we find evidence for a decline in the spectroscopic binary fraction, by a factor of 3-4 from the age of our pre-main-sequence sample to the Pleiades age . The significance of this decline is weakened if spot-induced radial-velocity jitter is strong in the sample, and is only marginally significant when comparing any one of the pre-main-sequence clusters against the Pleiades. However, the same decline in both sense and magnitude is found for each of the five pre-main-sequence clusters, and the decline reaches statistical significance of greater than 95% confidence when considering the pre-main-sequence clusters jointly. Our results suggest that dynamical processes disrupt the widest spectroscopic binaries ($P_{\rm orb} \approx 10^3 - 10^4$ d) as clusters age, indicating that this occurs early in the stars' evolution, while they still reside within their nascent clusters.Comment: 21 pages, 9 Figure

Flavonol haze in white wines

The formation of a yellow haze in commercial white wines, and of yellow sediments from both juices and wines, was due to precipitation of quercetin. The vine leaves were found to be the major source of soluble quercetin glycosides, leading to excessive levels of free quercetin after hydrolysis during juice or wine storage. Flavonols were analysed by reversed-phase HPLC. Widespread use of machine harvesting, with higher leaf contamination of the grape crush, is considered to be the primary cause of this new form of wine instability. An enzymatic procedure for detecting susceptibility to such deposition in juices and wines is described

Phenolic assessment of white musts: Varietal differences in free-run juices and pressings

Direct spectrophotometry over the range 250-400 nm enables rapid assessment of juice fractions from commercial juice preparation systems. Attention is focused on spectral estimates of the total flavonoids which increase during skin contact, with increasing must temperature, and particularly during recovery of heavy pressings.Spectral data from many sets of commercial juice fractions, concerning eight grape varieties in several districts, were collated over three seasons, 1987-88-89. Such observations have indicated the prime importance of grape variety in relation to phenolic extract in the juice fractions. The data have suggested the notion of 'spectral recognition profiles' arising from intrinsic varietal differences in the distribution of phenolic constituents within wine grapes.Thus the flavonoid concentration appears to be a significant variable of varietal dry white wine style. Qualitative differences in phenolic composition have also been demonstrated by differential spectrophotometry of model skin extracts at 250-300 nm.Fining treatments with various commercial fining agents had only minor effect on flavonoid levels in juice pressings and in press wines

Evolution of red wines III. Promotion of the maturation phase

Die Entwicklung von RotweinenIII. Beschleunigung der ReifungsphaseAusgehend von der Tatsache, daß die chemischen Reaktionen zu Beginn des Weinausbaus im wesentlichen anaerob sind und durch erhöhte Temperaturen beschleunigt werden können, wurde der Einfluß der anaeroben Lagerung bei 42-45 ° C über einen Zeitraum von 25-40 d verfolgt; als Kontrolle dienten bei normaler Kellertemperatur gelagerte Weine. Die Versuche wurden mit Gebinden junger Rotweine (Shiraz, Cabernet Sauvignon, Malbec) in isolierten Edelstahltanks (250, 1200, 5000 l) durchgeführt. Es wurden stetige Veränderungen bei Komponenten festgestellt, die für Farbe, Geruch und Geschmack wesentlich sind; sie entsprachen den Veränderungen, die sich bei normaler Kühllagerung während eines viel längeren Zeitraumes einstellten. Die spektralen Veränderungen der Farbintensität und -tönung waren von einer raschen logarithmischen Abnahme der Anthocyankonzentration bei Wärmebehandlung begleitet, während sich die Kontrollweine nur geringfügig veränderten. In den behandelten Weinen stabilisierte sich die Färbung, bedingt durch die Zunahme oligomerer Farbstoffe.Es gab keine analytischen oder sonstigen Hinweise auf den nachteiligen Einfluß einer derartigen, zeitlich begrenzten Weinlagerung. Bei Shiraz-Weinen wurde die Entwicklung eines zarten Beerenaromas und -geschmackes festgestellt; gleichzeitig wurde zu Beginn der Wärmebehandlung die vermehrte Bildung von Damascenon beobachtet

Evolution of red wines I. Ambient influences on colour composition during early maturation

Observations of changing colour composition and phenolic content of two new red wines were made during the 12-month -period after vintage. Spectral data were plotted with reference to two storage temperatures (3 and 25 °C), storage under nitrogen and under air headspace, pasteurised and non-pasteurised wines, cold-stabilised and non cold-stabilised wines. Progressive formation of polymeric pigments occurred under nitrogen headspace with much faster reaction rates at 25 °C. The presence of oxygen increased rate of change in colour composition, but data points were erratic. Pasteurisation had no influence on phenolic ageing reactions, nor did prior cold-stabilisation. Two types of phenolic condensation reactions during normal wine ageing are indicated. Interpretations suggest the feasibility of accelerating red wine maturation, while at the same time directing phenolic ageing reactions along controlled lines