title: Culture-dependent and independent techniques to monitor yeast species during cold soak carried out at different temperatures in winemaking.
abstract: Transformation of grape must into wine is a process that may vary according to the consumers' requirements. Application of cold soak prior to alcoholic fermentation is a common practice in cellars in order to enhance flavor complexity and extraction of phenolic compounds. However, the effect of this step on wine yeast microbiota is not well-known. The current study simultaneously analyzed the effect of different cold soak temperatures on the microbiological population throughout the process and the use of culture-dependent and independent techniques to study this yeast ecology. The temperatures assayed were those normally applied in wineries: 2.5, 8 and 12°C. PCR-DGGE allowed detection of the most representative species such as Hanseniaspora uvarum, Starmerella bacillaris and Saccharomyces cerevisiae. As could be expected, highest diversity indices were obtained at the beginning of each process, and survival of H. uvarum or S. bacillaris depended on the temperature. Our results are in agreement with those obtained with culture independent methods, but qPCR showed higher precision and a different behavior was observed for each yeast species and at each temperature assayed. Comparison of both culture-independent techniques can provide a general overview of the whole process, although DGGE does not reveal the diversity expected due to the reported problems with the sensitivity of this technique.
authors: Instituto de Biotecnología, Universidad Nacional de San Juan (UNSJ), Av. San Martín 1109 (O), San Juan 5400, Argentina; Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Av. Rivadavia 1917, Ciudad Autónoma de Buenos Aires C1033AAJ, Argentina. Electronic address: paolamaturano@yahoo.com.ar.
authors: Y Paola
authors: YP
authors: Maturano
authors: Instituto de Biotecnología, Universidad Nacional de San Juan (UNSJ), Av. San Martín 1109 (O), San Juan 5400, Argentina; Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Av. Rivadavia 1917, Ciudad Autónoma de Buenos Aires C1033AAJ, Argentina.
authors: M Victoria
authors: MV
authors: Mestre
authors: Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Av. Rivadavia 1917, Ciudad Autónoma de Buenos Aires C1033AAJ, Argentina; Estación Experimental Agropecuaria Mendoza, Instituto Nacional de Tecnología Agropecuaria (INTA), San Martin 3853, 5507 Luján de Cuyo Mendoza, Argentina.
authors: Mariana
authors: M
authors: Combina
authors: Instituto de Biotecnología, Universidad Nacional de San Juan (UNSJ), Av. San Martín 1109 (O), San Juan 5400, Argentina.
authors: María Eugenia
authors: ME
authors: Toro
authors: Instituto de Biotecnología, Universidad Nacional de San Juan (UNSJ), Av. San Martín 1109 (O), San Juan 5400, Argentina.
authors: Fabio
authors: F
authors: Vazquez
authors: Biotecnologia Enològica, Departament de Bioquímica i Biotecnologia, Facultat d' Enologia, Universitat Rovira i Virgili, Marcel.li Domingo 1, Tarragona 43007, Spain.
authors: Braulio
authors: B
authors: Esteve-Zarzoso
mesh_terms: D001203:Ascomycota / Q000235:genetics; D044822:Biodiversity; D003080:Cold Temperature; D004586:Electrophoresis; D005285:Fermentation; D019649:Food Industry / Q000379:methods*; D055321:Hanseniaspora / Q000235:genetics; D016133:Polymerase Chain Reaction; D012441:Saccharomyces cerevisiae / Q000235:genetics; D027843:Vitis / Q000382:microbiology*; D014920:Wine / Q000382:microbiology*; D015003:Yeasts / Q000235:genetics*
keywords: Non-Saccharomyces yeasts; PCR- DGGE; Plate count; Pre-fermentative cold soak; Quantitative PCR (qPCR); Saccharomyces cerevisiae