INVESTIGADORES
SCHEBOR Carolina Claudia
artículos
Título:
Commercial baker´s yeast stability as affected by intracellular content of trehalose, dehydration procedure and the physical properties of external matrices.
Autor/es:
PATRICIA CERRUTTI; MARTA SEGOVIA DE HUERGO; MIGUEL GALVAGNO; CAROLINA SCHEBOR; MARÍA DEL PILAR BUERA
Revista:
APPLIED MICROBIOLOGY AND BIOTECHNOLOGY
Editorial:
Springer
Referencias:
Año: 2000 vol. 54 p. 575 - 580
ISSN:
0175-7598
Resumen:
<!--
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{mso-style-parent:"";
margin:0cm;
margin-bottom:.0001pt;
mso-pagination:widow-orphan;
font-size:12.0pt;
font-family:"Times New Roman";
mso-fareast-font-family:"Times New Roman";}
@page Section1
{size:612.0pt 792.0pt;
margin:70.85pt 3.0cm 70.85pt 3.0cm;
mso-header-margin:35.4pt;
mso-footer-margin:35.4pt;
mso-paper-source:0;}
div.Section1
{page:Section1;}
-->
The effects
of vacuum drying and freeze drying on the cell viability of a comercial baker´s
yeast, Saccharomyces cerevisiae,
strain with different endogenous content of trehalose were analyzed. An osmotolerant
Zygosaccharomyces rouxii strain was
used for comparative purposes. Higher viability values were observed in cells
after vacuum drying than after freeze drying. Internal concentrations of
trehalose in the range 10-20% protected cells in both dehydration processes.
Endogenous trehalose concentrations did not affect the water sorption isotherm
nor the Tg values. The effect of external matrices of trehalose and maltodextrina
was also studied. The addition of external trehalose improved the survival of S. cerevisiae cells containing 5%
internal trehalose during dehydration. Maltodextrin (1.8 kDa) failed to protect
vacuum dried samples at 40ºC. The major reduction in the viability during the
freeze drying process of the sensitive yeast cells studied was attributed to
the freezing step. The suggested protective mechanism for each particular
system are vitrification and the specific interactions of trehalose with
membranes and/or proteins. The failure of maltodextrins to protect cells was
attributed to the fact that none of the suggested could operate in these
systems.
