Search results for "wine"
showing 10 items of 1468 documents
UJI AKTIVITAS ANTIBAKTERI DARI ESTRAK TUMBUHAN AKWAY (Drimys beccariana. Gibbs)
2010
<p><em>The plant Akway (Drimys beccariana.</em>Gibbs<em>) is endemic to Papua and is frequently used traditionally by the Arfak tribe as a medicinal plant. We extract the plant by maceration with ethanol. The antibacterial test is done by Agar diffusion method. As microba test we used Escheresia coli and Bacillus subtilis. Result obtained from fitochemistry skrinning of the leaf and bark contained alkaloid, flavonoid, steroid, tannin, glikosida, saponin, triterpenoid, steroid and fenolik. Concentration of active substances from the leaf are flavonoid (0,3680%) and tanin (10.33 %); while from the bark flavonoid 18.35% and tanin (27.65%). Antibacterial test showed…
UJI AKTIVITAS ANTIBAKTERI DAN SKRINING FITOKIMIA EKSTRAK HEKSANA, ETIL ASETAT DAN METANOL TUMBUHAN SURUHAN (Peperomia pellucida L. Kunth)
2020
Antibacterial activity test and screening of phytochemical of extract hexane, ethyl acetate and methanol have been carried out. The extraction of the P.pellucida plants was carried out by the maceration method in stages based on the polarity of the solvent. Analysis of chemical compounds done with phytochemical screening test. Based on the identification of chemical compounds by phytochemical screening, hexane and ethyl acetate extract has been detected only in the presence of flavonoid compounds with moderate categories. Methanol extract contains high-grade alkaloids and moderate flavonoid and tannin compounds. Antibacterial test using disffusion methods suggest that ethyl acetate and me…
Allelic variants of hexose transporter Hxt3p and hexokinases Hxk1p/Hxk2p in strains ofSaccharomyces cerevisiaeand interspecies hybrids
2015
The transport of sugars across the plasma membrane is a critical step in the utilization of glucose and fructose by Saccharomyces cerevisiae during must fermentations. Variations in the molecular structure of hexose transporters and kinases may affect the ability of wine yeast strains to finish sugar fermentation, even under stressful wine conditions. In this context, we sequenced and compared genes encoding the hexose transporter Hxt3p and the kinases Hxk1p/Hxk2p of Saccharomyces strains and interspecies hybrids with different industrial usages and regional backgrounds. The Hxt3p primary structure varied in a small set of amino acids, which characterized robust yeast strains used for the p…
Experimental design approach in the synthesis of molecularly imprinted polymers specific for iprodione fungicide
2015
International audience; An experimental design (ED) approach was applied to study the weight of three factors in the synthesis of a molecularly imprinted polymer (MIP) specific for iprodione fungicide. The objective was to obtain a high specific polymer with the best performance of iprodione binding. Thirteen iprodione-imprinted polymers and 13 non-imprinted polymers (NIP) were synthesized according to ED having 3 influencing factors: the polymerization method, the crosslinker nature and the functional monomer type. For each factor, two levels were studied: bulk and precipitation polymerization for the first factor, trimethylolpropane trimethacrylate (TRIM) and ethylene glycol dimethacrylat…
Yeast interaction on Chardonnay wine composition: Impact of strain and inoculation time.
2022
Abstract It is of great importance to understand the molecular characteristics and substantial chemical transformations due to yeast-yeast interaction. Non-targeted metabolomics was used to unravel must in fermentation composition, inoculated with non-Saccharomyces (NS) yeasts and Saccharomyces cerevisiae (S) for sequential fermentation. ultrahigh-resolution mass spectrometry was able to distinguish thousands of metabolites and provides deep insights into grape must composition allowing better understanding of the yeast-yeast interactome. The dominance of S, characterized by a metabolic richness not found with NS, is dependent on inoculation time and on the yeast species present. Co-inocula…
Analysis of resveratrol in Burgundy wines
1993
Recent studies have shown that resveratrol (3,5,4'‐trihydroxystilbene), a phytoalexin related to grape disease resistance, could occur in American and Bordeaux wines. It was also suggested that resveratrol might have cardioprotective activities in humans, as a result of drinking wine. We report here the presence of this compound in Burgundy wines. Analysis of resveratrol in wine was carried out using gas chromatography and gas chromatography—mass spectrometry.
Monoterpenes in grape juice and wines.
2000
The importance of monoterpenes on varietal flavour of wines has been reviewed. These compounds were mainly found linked to sugar moieties in the grape juice and wines, showing no olfactive characteristics. In this way, mechanisms to liberate terpenes were studied, making a comparative study between acidic and enzymic hydrolysis of terpene glycosides. Finally, analytical techniques developed to study these compounds, in both free or glycosidically forms, and also to fractionate glycosidic precursors, have been discussed.
Influence of Mannaproteins from Yeast on the Aroma Intensity of a Model Wine
1994
Abstract The influence of mannaproteins released from yeast cell walls during alcoholic fermentation on the volatility of aroma substances was investigated in a model wine. After the characterization of macromolecules (substrates), two techniques have been used to study the interactions with aroma compounds: headspace analysis and an equilibrium dialysis method. The assumed effects of these macromolecules from yeasts on the fixation of volatile compounds were demonstrated. The physico-chemical interactions between aroma substances and mannaproteins depended on the nature of volatile compounds. Protein concentration in substrates was an important factor in their binding capacity. The retenti…
Influence of polysaccharides on wine protein aggregation.
2016
Abstract Polysaccharides are the major high-molecular weight components of wines. In contrast, proteins occur only in small amounts in wine, but contribute to haze formation. The detailed mechanism of aggregation of these proteins, especially in combination with other wine components, remains unclear. This study demonstrates the different aggregation behavior between a buffer and a model wine system by dynamic light scattering. Arabinogalactan-protein, for example, shows an increased aggregation in the model wine system, while in the buffer system a reducing effect is observed. Thus, we could show the importance to examine the behavior of wine additives under conditions close to reality, in…
2-Oxoglutarate decarboxylase ofLeuconostoc oenos
1990
InLeuconostoc oenos, the typical organism of the malolactic fermentation of wine, a 2-oxoglutarate decarboxylase was detected. This inducible enzyme decarboxylates 2-oxoglutarate but not pyruvate. The resulting succinaldehydate is rapidly reduced to 4-hydroxybutyrate or oxidized to succinate in further reactions. 2-Oxoglutarate decarboxylase is thiamin-diphosphate-dependent; the pH optimum is at 5.3 and theK m value for 2-oxoglutarate is 1.8 mmol/L.