title: Influence of freezing temperatures prior to freeze-drying on viability of yeasts and lactic acid bacteria isolated from wine.
abstract: OBJECTIVE
  To determine the effect of three different freezing temperatures on post-freeze-drying survival rates of wine yeasts and lactic acid bacteria (LAB). To know if a similar freeze-drying protocol can be used for both micro-organisms.
  
  
  RESULTS
  Cells from liquid culture media were recovered and concentrated in appropriate lyoprotectants. Aliquots of each strain were frozen at -20, -80 and -196°C before vacuum drying. Viable cell counts were done before freezing and after freeze-drying. Survival rates were calculated. Freezing temperatures differently affected yeast and bacteria survival. The highest survival rates were obtained at -20 and -80°C for yeasts, but at -196°C for LAB. Major differences in survival rates were recorded among freeze-dried yeasts, but were less drastic for LAB. Yeasts Pichia membranifaciens, Starmerella bacillaris and Metschnikowia pulcherrima, and LAB Lactobacillus paracasei, Pediococcus parvulus and Lactobacillus mali, were the most tolerant species to freeze-drying, regardless of freezing temperature.
  
  
  CONCLUSIONS
  Yeast and LAB survival rates differed for each tested freezing temperature. For yeasts, -20°C ensured the highest post-freeze-drying viability and -196°C for LAB.
  
  
  CONCLUSIONS
  Freezing temperature to freeze-dry cells is a crucial factor for ensuring good wine yeast and LAB survival. These results are important for appropriately preserving micro-organisms and for improving starter production processes.
authors.affiliation: ENOLAB, Estructura de Recerca Interdisciplinar (ERI) BioTecMed, University of Valencia, Dr. Moliner 50, Burjassot, Valencia, 46100, Spain.
authors.forename: L
authors.initials: L
authors.lastname: Polo
authors.affiliation: ENOLAB, Estructura de Recerca Interdisciplinar (ERI) BioTecMed, University of Valencia, Dr. Moliner 50, Burjassot, Valencia, 46100, Spain.
authors.forename: R
authors.initials: R
authors.lastname: Mañes-Lázaro
authors.affiliation: ENOLAB, Estructura de Recerca Interdisciplinar (ERI) BioTecMed, University of Valencia, Dr. Moliner 50, Burjassot, Valencia, 46100, Spain.
authors.forename: I
authors.initials: I
authors.lastname: Olmeda
authors.affiliation: ENOLAB, Estructura de Recerca Interdisciplinar (ERI) BioTecMed, University of Valencia, Dr. Moliner 50, Burjassot, Valencia, 46100, Spain.
authors.forename: L E
authors.initials: LE
authors.lastname: Cruz-Pio
authors.affiliation: Department of Microbiology and Ecology, University of Valencia, Dr. Moliner 50, Burjassot, Valencia, 46100, Spain.
authors.forename: Á
authors.initials: Á
authors.lastname: Medina
authors.affiliation: ENOLAB, Estructura de Recerca Interdisciplinar (ERI) BioTecMed, University of Valencia, Dr. Moliner 50, Burjassot, Valencia, 46100, Spain.
authors.forename: S
authors.initials: S
authors.lastname: Ferrer
authors.affiliation: ENOLAB, Estructura de Recerca Interdisciplinar (ERI) BioTecMed, University of Valencia, Dr. Moliner 50, Burjassot, Valencia, 46100, Spain.
authors.forename: I
authors.initials: I
authors.lastname: Pardo
mesh_terms: D003080:Cold Temperature; D005612:Freeze Drying / Q000379:methods; D019344:Lactic Acid / Q000378:metabolism; D013045:Species Specificity; D013312:Stress, Physiological; D014920:Wine / Q000382:microbiology*; D015003:Yeasts / Q000302:isolation & purification / Q000502:physiology*
chemical_list: D019344:Lactic Acid
keywords: freeze-drying; freezing; lactic acid bacteria; survival; wine; yeasts