Influence of must racking and fining procedures on the composition of white wine

A study of the effects of two kinds of must clarification. settling or filtration by rotary vacuum filter and 5 juice fining treatments (bentonite, potassium caseinate, and combinations: bentonite + gelatin, and bentonite + caseinate + microcrystalline cellulose) on wine characteristics was carried out using must of the white cultivar Parellada. Although the general characteristics (ethanol, color, limpidity, residual sugars, pH and acidity) of Parerllada wines were not modified, some wine components (e.g. nitrogenous substances, phenolic compounds and aroma) were lowered according to the type of must racking and juice fining agent added. The percentage of decrease of wine characteristics due to the pre-fermentative fining agent depends on the type of must racking. Highest losses were recorded when rotary vacuum filters were used for must racking, and when bentonite (0.3-0.5 g/l) was added to the juice as a fining agent before fermentation

Solid-phase microextraction in the analysis of virgin olive oil volatile fraction: characterization of virgin olive oils from two distinct geographical areas of northern Italy

SPME was employed to characterize the volatile profile of virgin olive oils produced in two geographical areas of northern Italy: the region of the Gulf of Trieste and the area near Lake Garda. There are as yet no data on the headspace composition of virgin olive oils from these regions, characterized by particular conditions of growth for Olea europaea. Using the SPME technique coupled to GC-MS and GC-FID, the volatile components of 42 industrially produced virgin olive oil samples were identified and the principal compounds quantitatively analyzed. Significant differences in the proportion of volatile constituents from oils of different varieties and geographical origins were detected. The results suggest that besides the genetic factor, environmental conditions influence the volatile formation

Solid-phase microextraction in the analysis of virgin olive oil volatile fraction: modifications induced by oxidation and suitable markers of oxidative status

Modifications of virgin olive oil subjected to accelerated storage were evaluated by HS-SPME analysis. To find a suitable marker of oxidative degradation, the volatile compounds showing variable concentration during the oxidative process have been identified and quantified by SPME coupled to GC-MS and GC-FID, respectively. The SPME analysis results were then compared with the parameters usually applied to assess the oxidative status of lipids, such as peroxide value, spectrophotometric absorbance, and loss of unsaturated fatty acids. Finally, the assessment of nonanal has been suggested as a marker of oxidative degradation. This rapid, inexpensive, and reliable method may allow screening of oils prior to testing by a panel of assessors

Volatile and semi-volatile components of oak wood chips analysed by Accelereated Solvent Extraction (ASE) coupled to gas chromatography-mass spectrometry (GC-MS)

Volatile and semi-volatile compounds of French and American oak wood used in wine and spirits ageing were extarcted by an Accelerated Solvent Extractor (ASE) and analysed by gas chromatography-mass specrtrometry. More 90 compounds were isolated, characterised and quantified after being separeted on two chromatographyc columns with distinct polarity. The main oak wood components were determined by using standard reference compounds. In addition, a number of compounds, mainly guaiacol and syringol derivatives, were detected and characterised. in particular, 10 compounds were tentatively identified as lignin dimers derivatives, whose presence in oak wood chips or barrels for wine and spirits ageing had not been previously described. Several of the characterised compounds enabled a distinction to be drawn between medium and high toasted wood chips, indipendently of their geographical orogin

Structure of the putative VPg site.

<p>(A) Structural superimposition of the TaV polymerase N-terminus (gold) with the equivalent residues in the IBDV RdRP (green). The strictly conserved residues within the VPg signature are shown as sticks and labeled. (B) Autoradiograph of <i>in vitro</i> self-guanlylation activities of TaV_pol and TaV rORF1 analyzed 11% SDS-PAGE (top). Gels were also stained with Coomassie blue to assess protein loading (bottom). The position of molecular mass markers (M) is indicated (kDa) at the bottom gel.</p