P6
Wine strain improvement
strategies
to enhance red wine safety
based on parietal
adsorption
activity.
1. Two-step
selection
of
Calabrian and Sicilian wine yeasts
Andrea Carldi, Rossana Sidari and Antonella Costantino
"Scienze e Tecnologie Agro-Forestali e Ambientali", "Mediterranea" University of
Reggio Calabria, Via Feo di Vito, Reggio Calabria 1-89122, ITALY. Phone: +39 0965
332642, FAX: +390965817794, e-mail nr.midi@unirc.it,
Web: http/lwww.distqfiglnirc.itldett sezione.php?sect=fl
Aim of this study was to perform a two-step selection of 283 wine yeasts. In the first
step, a phenotypic-based methodology was employed to identify a maximum of 100
strains of
S
a
ccharomyces
cerevis
i
ae
able to easily sporify, low H2S-producing, low
aceti c acid-producing, not foam producing and exhibiting high fermentation power
during red winemaking. In the second step, a Petri plate evaluation of wine colour
adsorption phenotype of yeasts and the result confirmation by microvinification trials
were carried out. Strains were split based on their ability to adsorb phenolic grape
pigments to identify a maximum of ten strains, the lowest adsorbing ones. The 283
strains of S.
cerevisia
e
have been isolated from Calabrian and Sicilian musts and
wines in a period of twenty years and are included in the Department STAFA
collection (over than 700 strains). The yeasts were studied in Petri plates for the
following biochemical characteristics: spore production on aeetate agar at 25°C for
10d, H2S production on BiGGY agar at 25°C for 48h, acetie acid production on
calcium carbonate agar al 25°C for 7d, adsorption of grape pigmenls on grape skin
agar at 28°C for 10d (Caridi el al., 2002; 2007). The microvinification trials were
performed using Calabrian black grapes from the cultivar
Gagli
o
ppo;
Ihe grapes were
deslemmed, crushed and soaked al DOC for 3 days, performing a punch down Iwice
per davo The musi oblained after pressing was divided in aliquots of 20 mi and
fermenled al 20°C wilh the 98 wine yeasts inoeulated at 5% in triplicate. Analyses
were performed on diluted wine and values were reported considering the dilution.
Significant differences for each parameter were observed. Biomass colour varied
from 55 to 153 (red component), from 27 to 124 (green componenl), and from 32 lo
111 (blue componenl). Wine parameters vary from 0.658 to 3.878 (420 nm), from
0.407 lo 2.262 (520 nm), from 0.095 lo 1.005 (620 nm), from 1.168 lo 7.145
(inlensily), from 1.478 lo 1.800 (tinI), from 7.883 to 33.967 (Folin-Ciocalleu index).
Based on these resulls, parielal adsorplion aclivily is notably different among yeasts
and justifies a programme of genelic improvement of the strains, References Caridi
A. et al., (2002),
J
Gen Appl Microbiol, 48, 261. Caridi A. et al., (2007),
J
Appl
Microbiol, 103, 735. This work was supported by PRIN 2007 "Wine strain
improvemenl slrategies lo enhance red wine safely based on parielal adsorplion
activity",
