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Maceration affects mineral composition and pH of wines
25-29.Views:298Mineral composition of wines is affected by many ecological and technological factors. These variables are mostly discussed focusing on certification of origin and human health. This paper gives data on possible changes in mineral composition and pH of wines due to 4 hours skin maceration (1st trial) and fermentation sur marc (2nd trial). Experimental site is situated on acidic sandy soil in middle east Hungary. The variety collection was established in 2003 with own rooted planting material in 3x1 m spacing, trained for single curtain training
system. Mineral composition of wines was determined with ThermoFischer Scientific iCAP 6300 ICP-OES, pH was measured with pH10pen (VWR International) in field, and with SevenEasyTM pH meter (Mettler Toledo) in laboratory. 1st trial with 9 PIWI white wine grape varieties pointed to demonstrate effects of skin maceration, which is abundantly used to elevate aroma content. 2nd trial with the use of ‘Medina’ red PIWI grape variety aimed to demonstrate effects of double pasta skin maceration in rose and red wine technology. Data of 1st trial show, that K, Cu, Mn and P respective increase with skin maceration, despite Fe show considerable decrease. Data of 2nd trial show, that K, Mg, Mn, P, Sr and B increase with longer skin contact and higher fermentation temperature, despite Fe and Ba decrease with this technology. In regard to pH, data show, that skin maceration and fermentation sur marc increase K content with about 30-70% respectively, withstanding that pH also increase with a considerable 0,4-0,5 value. K content can be higher in the end product, despite to earlier higher level of tartrate formation. An attention should be driven to lower level of tartaric acid and consequently higher pH characteristic for wines produced with the application of skin maceration or fermentation sur marc. -
Analysis of amino nitrogen content affecting fermentation and wine quality
13-16.Views:185A suitable amount of nitrogen source is needed for the optimal process of alcoholic fermentation. The professional literature mentions the complexity of nitrogen compounds exploitable for yeast-plants as an assimilable or immediately assumable nitrogen source. Former experiments proved that in case of low nitrogen concentration , yeast-plants produced a bigger quantity of hydrogen sulphide. According to the findings above, it is not indifferent when and how we complement the nitrogen content of the must. The aim of our present work was to elaborate such a quick, easily applicable method that can be used for routinish measurements in the viticultural practice.
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Determination of biogenic amine content of Tokaj Wine Specialities
87-90.Views:158The knowledge of the finest composition of the Tokaj Wine Specialities is an indispensable task. The presence of the biogenic amines as an eventual combination of hygiene, technology and activity of Botrytis cinerea is a very important point of view in the future. The objective of this study was to measure the biogenic amine-content of Tokaj Wine Specialities.
According to our findings, the histamine-concentration remained lower than the prescribed end values, but ill the case of serotonine, there were significant measured values. During the fermentation period, in the first cycle there was a decrease in the concentration of biogenic amines, but with the advancement of fermentation, an increase was found.
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Investigation of the Relationship between the SO2 Production of Different Yeast Strains and Thiamine Concentration
57-62.Views:159Our 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.
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Change of Thiamine concentration and amino acid composition during sparkling wine base Production
62-66.Views:155It 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.
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Polyphenol- and anthocyanin content changes effected by different fermentation- pressing and aging technologies
65-67.Views:209Different grape processing, fermentation and aging technologies were compared in our study on the white wine-grape variety Grüner Veltliner between 2012 and 2014 in Hungary,Cserszegtomaj. The vines are grown on brown forest soil on dolomite bedrock, stocks were planted 3x1 m row and vine space, respectively in our experimental area. The soil has slightly alkaline pH, the orientation of the vine rows are East-West. The training system is modified Guyot cordon, with 1 m trunk height and cane pruning method. After the harvest half of the yield has been put into the de-stemmer crusher before pressing while the other half has been pressed immediately (whole bunches). From the filtered and bottled wine anthocyanin, and polyphenol content was measured in 2013 and 2014. Another enological technology testing experiment has been set on aging of Grüner Veltliner in 2013. The wine was fermented with addition of fine lees from juice sedimentation. Traditional (racking only), battonage and fast ready-made aging technologies have been set together, each treatment in three replicates were observed.
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Bioactive phenols in leaves of Forsythia species
57-59.Views:240Nowadays a number of lignans (arctigenin, matairesinol, pinoresinol and phillygenin) have come to the fore in research due to their various biological activities. In this paper the accumulation of these constituents in leaf extracts of Forsythia plants (F. intermedia, F. ovata 'Robusta’ and `Tetragold', F. suspensa, F. viridissima) was quantified using a new isolation method, supercritical CO2 fluid extraction. The total phenolic and flavonoid contents, the antioxidant capacity and the aglycone lignan profile were determined in leaf extracts of Forsythia species. Within the phenols, the flavonoids were only present in small quantities, but the amount of aglycone lignans was extremely high. F. ovata `Robusta' had the highest total lignan content (103.8 mg/g) of all the Forsythia species. The main lignan in this species is arctigenin, which normally makes up about 60% of the total lignan content, but in the case of F. ovata `Robusta' this value was 96.1%. Since this arctigenin content is outstanding compared to that of other Forsythia species, it could be promising to develop a fermentation technology for the production of this natural compound.