Ascomycetous yeast species recovered from grapes damaged by honeydew and sour rot

• Author(s): Barata, A. ; Seborro, F. ; Malfeito-Ferreira, M. ; Loureiro, V.
• Date: 2008
• Persistent ID: http://hdl.handle.net/10400.5/5589
• Origin: Repositório da UTL
• Subject(s): damaged grapes; honeydew; selective culture media; sour rot; spoilage yeasts; Zygosaccharomyces bailii; Zygoascus hellenicus; Zygosaccharomyces bisporus
• Document Type: Article
• Language: English

Description

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 3Æ20 ± 1Æ04 log CFU g)1 to 5Æ87 ± 0Æ64 log CFU g)1. In honeydew grapes, the mean counts ranged from 3Æ88 ± 0Æ80 log CFU g)1 to 6Æ64 ± 0Æ77 log CFU g)1. In sour rot grapes counts varied between 6Æ34 ± 1Æ03 and 7Æ68 ± 0Æ38 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 underestimated.