Preparation Of Grovgel - 2

Preparing Low Acyl Gellan Gum Solutions

Low acyl gellan gum can be added to cold water with other dry or liquid ingredients and it is easily dispersed with moderate stirring. In deionized water ,the gum will typically hydrate at approximately 65o C (149oF).The hydration temperature in tap water,however will depend on the water hardness. Sequestrants that bind calcium, such as sodium citrate or phosphates,can significantly reduce the hydration temperature.

Preparation of Model Low Acyl Gellan Gum Gels

  • -Add low acyl gellan gum to cold water with moderate shear
  • -Optional,sequestrants can be added if the water is hard.
  • -Heat to 70 o c (158 -194 o F).Solution should be water clear if properly hydrated
  • -Add ions Na+,K+,Ca++,Mg++ and/or acid
  • - Cool to below 45 o
  • C (113 o F)to set the gel
  • Preparation of Fluid Gel

    Prepare as above with a gellan concentration of 0.05 – 0.1% by weight of water. After gel has set,agitate by hand or mixer to create fluid gel. Gelling salt concentrations of 5 mM Ca2+ or 1% NaCl work well.
    These are general directions only. For more specific information,please contact us.

    Characteristics of GROVGEL Gellan gum

     GROVGEL gellan gum requires the presence of either monovalent or divalent cations for gelation
     GROVGEL gels can be modified by changing the concentration and type of cation in the media Magnesium is the preferred ion for microbiological media applications In most cases it produces a thermally reversible gel. Calcium exerts the most dramatic effect on GROVGEL gel strength, producing gels that do not remelt under normal sterilization conditions. Gels made with a 0.75% concentration of GROVGEL and a 0.1% concentration of MgSO4-7H2O are comparable to gels made with 1.5% agar.
     GROVGEL media are wet enough to separate colonies fine enough to prevent migration of organisms within the get. but coarse enough to allow diffusion of macromolecular nutrients.
     GROVGEL is chemically inert to most biological growth media additives and is completely compatible with nutrient additives commonly used with agar gels.
     GROVGEL gels are optically clear and permit far greater light transmittance than equivalent gels prepared with agar. This makes them suitable for use as an analytical tool.
     GROVGEL gellan gum solutions exhibit thermally reversible viscosity changes. Viscosity decreases with increasing temperatures. but returns to its original value upon cooling. GROVGEL has good thermal stability and can withstand normal autoclaving 121oC (15 psi. 15 minutes).
     Any components that cannot be autoclaved may be added, as solutions. After autoclaving while the GROVGEL solution is between 55-60oC.
     GROVGEL gels have essentially the same shelf-life as agar gels.

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