Enzym Methods in Wine Analysis67-70.Views:119
In our laboratory for special determinations BOERINGER-MANNHEIM's enzyme-test combinations have been used for 10 years. Our present work deals with the practical aspects of the enzymatic determination of so important wine components like L-malic, L-lactic and citric acid, glycerol, D-gluconic acid, D-sorbitol, acetic aldehyde and D-glucose to D-fructose (G/F) ratio. Whenever possible, the results arc compared to the results of other methods (spectrophotometry, gas chromatography, polarimetry) used at our department.
Change of Thiamine concentration and amino acid composition during sparkling wine base Production62-66.Views:138
It has been established, that thiamin content added in 3 mg/I concentration to musts before fermentation resulted in the enhanced storability of sparkling wine base at lower SO2 levels. Fermentation rate is not increased by this concentration and it causes no "thiamine taste" in organoleptic evaluation.
Investigation of the Antioxidant Effect of Hungarian White Wines and Tokaj Wine Specialities22-26.Views:223
Authors investigated the antioxidant effect of wine-phenolics, expressed as total antioxidant status (TAS-value). This property may play an important role in elimination of the harmful effects of free radicals in human body.
Independently of their polyphenol composition, special quality Tokaj wines did not show extremely high TAS-values. In Tokaj Aszu wines the total antioxidant status was independent of the "puttony" number but was influenced by the length of aging time.
Visualization of the Gas Chromatography/Mass Spectrometry Data of Muscat Ottonel Must and Wine Measurements16-21.Views:163
The lack of interpretation methods useful in evaluating the aroma-profiles of wines makes it necessary to thoroughly investigate alternative evaluation procedures. By adding three appropriate normal hydrocarbon standards to all sample extracts, measuring the Programmed Temperature Retention Indexes of the components and by normalizing the peak areas to that of the 1-alpha-Terpineol (in musts) or Benzeneethanol (in wines), the aroma features could be visualized. The relationship or identity of the aroma patterns could be deduced from the presence or absence of similar polygons in the -constellation-map" of the components.
Investigation of the Relationship between the SO2 Production of Different Yeast Strains and Thiamine Concentration57-62.Views:131
Our general conclusion was that the thiamine amounts of 0,6 and 3,0 mg/1 added prior to wine fermentation, resulted in higher free-S02 level in comparison to the control. Furthermore, among the yeast strains examined in our experiments, Uvaferm BC strain produced the highest free-S02 content under the conditions mentioned before. As regards the dynamics of reductone and SO, production, the concentration of the previous one was practically identical in the middle and at the end of the fermentation while the SO2 content — both free- and total — was lower at the end. Thiamine addition did not cause any difference in the organoleptic properties of wines as proved by sensory analysis.
Volatile constituents of Nepeta cataria L., N. glechoma Benth. and N. parviflora M. Bieb. from Hungary47-50.Views:116
In the temperate zone live about 150 species of the Nepeta genus. Our investigations covered the examinations of the volatile oil containing species of the genus endemic in Hungary, Nepeta cataria and Nepeta parviflora. Latter is a relict of the ancient steppe-flora and endemic in Hungary as well. Phytochemical examination of the volatile oil containing plant material has also been carried out. Catnip growing in the Botanical Garden of PTE Department of Botany contained 0,67% volatile oil in May and 0,14% in November. Chemical character of the volatile oils were measured by gas chromatography/mass spectrometry and citronellol, citral-A, citral-B and geraniol components were identified. The composition of the oil of November samples shifted towards citronellol (65%). In both samples insecticide and repellent activity bearing compounds (+)-cis-p-menthane-3,8-diol, and (—)-trans-p-menthane-3,8-diol in 2-2.5 and 4-4.5% amount have been found. The catnip sample deriving from Germany contained a small amount of anetol, citronellol, neral, geraniol and geranial (6-13%), and possibly two isomers of nepetalactone in 23-31%.
The Nepeta parviflora endemic in the Nagyvolgy valley near Nagykaracsony consisted of the same compounds in the investigated years (1998-2000). Its limonene, methyl chavicol, b-cariophyllene, b-selinene, b-cubebene, davanone, germacrene-D constituents have been identified. In the year 2000 different GC % of these compounds were detected in the different organs of the plants.
The closely related species Nepeta cataria var. citriodora contained 83% citral, and the N. glechoma (= Glechoma hederacea) contained 41% a-cubebene, 20% patchoulenol, 7,7% spathulenol respectively. These compounds were identified by gas chromatography and gas chromatography / mass spectrometry.