X-Message-Number: 9535
Date: Wed, 22 Apr 1998 02:21:18 -0700 (PDT)
From: Doug Skrecky <>
Subject: sorbitol in freeze-drying

Authors
  Linders LJ.  Wolkers WF.  Hoekstra FA.  van 't Riet K.
Institution
  Department of Food Science, Wageningen Agricultural University, The
  Netherlands. LEONIELINDERS:ALGEMEEN.PK.WAU.NL
Title
  Effect of added carbohydrates on membrane phase behavior and survival of
  dried Lactobacillus plantarum.
Source
  Cryobiology.  35(1):31-40, 1997 Aug.
Abstract
  The relation between the protective effect of externally added carbohydrates
  on Lactobacillus plantarum cells during air-drying and the phase behavior of
  cell membranes was studied. The residual activity after drying could be
  improved from 44% in the control to 79 and 66% after the addition of sorbitol
  and maltose, respectively, whereas trehalose addition resulted in a residual
  activity of 30%. Membrane phase transition temperatures (Tm) were determined
  in intact hydrated and dry cells, using Fourier transform infrared
  spectroscopy. The Tm of hydrated cells was 4 degrees C, increasing to only 20
  degrees C after drying. Because endogenous soluble sugars were absent, this
  phase behavior is attributed to the structure of the predominant
  phospholipids, PG and lysyl-PG. The restricted increase of Tm is held
  responsible for the survival of part of the cells. The added maltose,
  trehalose, and sorbitol did not influence Tm in vivo. We suggest that the
  effective carbohydrates act through their free radical scavenging activity
  and not by direct interaction with the polar lipid headgroups.

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