Wine starter selection for adsorption activity to control colour of Slovakian wines

New approaches in food fermentation

P-551

Wine starter selection for adsorption

acti

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ity to control colour

of Slovakian

w

ines

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Rossana

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l:Department ofScienze e Tecnologie Agro-Forestali e Ambientali, Mediterranea University ofReggio Calabria, Reggio Calabria,ITALY

2:Institute ofMolecular Biology, Slovak Academy of Sciences, Bratislava, SLOV AKIA

Corresponding author: rossana.sidari@unirc.it

The aim of this work was to specifically select autochthonous strains of Saccharomyces

cerevisiae toimprove colour of winesproduced inthe area of Little Carpathians (Slovakia)

by: (a) preservation of the phenolic compounds, and (b) protection of colour, for red

winemaking, or removing of residual colour, for white winemaking. In 2008 and 2009, a totalof 50 Slovakian autochthonous yeaststrains werepre-selected. The strains were stored

inYPD agar and molecular identification was performed to select only the Saccharomyces

cerevisiae. After this, 44 strains were chosen andstored at -85°C using the Protect system.

To study their aptitude to adsorb grapepigrnents, the 44 strains, together with 6 Calabrian strains of Saccharomyces cerevisiae previously selected forwinemaking, were characterized

bymicro-winemaking trials, carried outusing pasteurized (110°C x lO min) mustfrom black grapes, pressed after 3 days of cryomaceration at4°C in contact withskins andseeds.At the end of fermentation, wines were centrifuged at 4,500 rpm for 5 rnin and analysed for: alcoholic content (by ebulliometer), absorbance at 420, 520, and 620 nm, colour intensity

and tint, Folin-Ciocalteu index. Yeasts characterization was performed by two PCR-based typing methods (pCR-RFLP andfluorescence ITSPCR) inorder to cIusterand preliminarily

identifythe isolated yeasts.AftercIustering some yeast members wereidentified throughITS

sequencing. Among the selected yeasts, strains M2VCHU7 and M2FCHU9 exhibit the

highest aptitude to adsorb grape pigrnents, so producing wines with the lowest colour

intensity andtotalphenolic content. These yeasts are ableto remo ve the residual colour from

white wines, so allowingrefiningthem. Onthe contrary.istrains M2VCHU6 and M2FVUP4

exhibit the lowest aptitude to adsorb grape pigrnents, soproducing wines with the highest

colour intensity and total phenolic content. These yeasts are able to express the chromatic

properties ofblack grapes, givinganimproved performance in theproduction ofred wines.