40 research outputs found
Ascomycetous yeast species recovered from grapes damaged by honeydew and sour rot
Aims: To identify ascomycetous yeasts recovered from sound and damaged
grapes by the presence of honeydew or sour rot.
Methods and Results: In sound grapes, the mean yeast counts ranged from
3.20 ± 1.04 log CFU g-1 to 5.87 ± 0.64 log CFU g-1. In honeydew grapes, the
mean counts ranged from 3.88 ± 0.80 log CFU g-1 to 6.64 ± 0.77 log CFU g-1.
In sour rot grapes counts varied between 6.34 ± 1.03 and 7.68 ± 0.38 log
CFU g-1. Hanseniaspora uvarum was the most frequent species from sound
samples. In both types of damage, the most frequent species were Candida vanderwaltii,
H. uvarum and Zygoascus hellenicus. The latter species was recovered
in high frequency because of the utilization of the selective medium DBDM
(Dekkera ⁄ Brettanomyces differential medium). The scarce isolation frequency of
the wine spoilage species Zygosaccharomyces bailii (in sour rotten grapes) and
Zygosaccharomyces bisporus (in honeydew affected grapes) could only be
demonstrated by the use of the selective medium ZDM (Zygosaccharomyces
differential medium).
Conclusions: The isolation of several species only from damaged grapes indicates
that damage constituted the main factor determining yeast diversity. The
utilization of selective media is required for eliciting the recovery of potentially
wine spoilage species.
Significance and Impact of the Study: The impact of damaged grapes in the yeast ecology of grapes has been underestimate