Gums, also called hydrocolloids, are polysaccharides. Polysaccharides are polymers of simple sugar building blocks which have been in use since about 1900. Use of gums has increased throughout the century particularly in the past 40 years and today they are used in a wide variety of products and processes.
Certain micro-organisms are capable of producing polysaccharides with properties differing from those of gums from more traditional sources. The best example of such microbially-produced polysaccharides is xanthan gum. More recently discovered examples are welan gum, rhamsan gum and gellan gum.
Gellan gum, first discovered in 1978, is produced by strains of the species sphingomonas elodea. Commercially this gum is produced as an extracellular product by aqueous cultivation of the micro-organisms in a medium containing the appropriate carbon, organic and inorganic nitrogen and phosphate sources and suitable trace elements. The fermentation is carried out under sterile conditions with strict control of aeration, agitation, temperature and pH. When fermentation is complete, the produced viscous broth is pasteurized to kill viable cells prior to recovery of the gum. The gum can be recovered in several ways. Direct recovery from the broth yields the gum in its native or high acyl form. Recovery after deacylation by treatment with a base yields the gum in its low acyl [LA] form. Acyl groups present in the gum are found to influence its characteristics significantly.
Low acyl [LA] gellan gums form gels when cooled in the presence of gel-promoting cations, preferably divalent cations, such as calcium and magnesium. The gels formed are firm and brittle. High acyl [HA] gellan gums do not require the presence of cations for gel formation and the gels formed have structural and theological characteristics which are significantly affected by the acyl substitutes. Thus the properties of [HA] gellan gels differ significantly from those of [LA] gellan gels. [HA] gels are typically soft and flexible and lack thermal hysteresis.
Typical gelation temperatures for [LA] gellan gums are in the range 3O°C to 50°C, depending upon the nature and concentration of the cations present. For purposes of this patent, gelation, set and melt temperatures are defined by measurement of the elastic modulus value of the gel in an appropriate rheometer. Conditions used are a frequency of 10 radians/second with a strain level of 1-5%. In most cases, the appropriate temperature is judged by the rate of change in the modulus value. A rapid increase with cooling is the setting temperature; a sharp drop indicates the melt temperature when heating. Frequently, the temperature where the modulus goes above or below a value of 1 Pa is used as an index. Typical gelation temperatures for [HA] gellan gums are in the region of 70°C. The high gelation temperature of [HA] gellan gum can be advantageous in some applications such as fruit fillings where it can prevent flotation of the fruit.
In this dish we use it to create a very fine sheet of tomato water, that is cut out in circle and rolled around a piece of cherry tomato. Gums, also called hydrocolloids, are polysaccharides. Polysaccharides are polymers of simple sugar building blocks which have been in use since about 1900. Use of gums has increased throughout the century particularly in the past 40 years and today they are used in a wide variety of products and processes.
Certain micro-organisms are capable of producing polysaccharides with properties differing from those of gums from more traditional sources. The best example of such microbially-produced polysaccharides is xanthan gum. More recently discovered examples are welan gum, rhamsan gum and gellan gum.
Gellan gum, first discovered in 1978, is produced by strains of the species sphingomonas elodea. Commercially this gum is produced as an extracellular product by aqueous cultivation of the micro-organisms in a medium containing the appropriate carbon, organic and inorganic nitrogen and phosphate sources and suitable trace elements. The fermentation is carried out under sterile conditions with strict control of aeration, agitation, temperature and pH. When fermentation is complete, the produced viscous broth is pasteurized to kill viable cells prior to recovery of the gum. The gum can be recovered in several ways. Direct recovery from the broth yields the gum in its native or high acyl form. Recovery after deacylation by treatment with a base yields the gum in its low acyl [LA] form. Acyl groups present in the gum are found to influence its characteristics significantly.
Low acyl [LA] gellan gums form gels when cooled in the presence of gel-promoting cations, preferably divalent cations, such as calcium and magnesium. The gels formed are firm and brittle. High acyl [HA] gellan gums do not require the presence of cations for gel formation and the gels formed have structural and theological characteristics which are significantly affected by the acyl substitutes. Thus the properties of [HA] gellan gels differ significantly from those of [LA] gellan gels. [HA] gels are typically soft and flexible and lack thermal hysteresis.
Typical gelation temperatures for [LA] gellan gums are in the range 3O°C to 50°C, depending upon the nature and concentration of the cations present. For purposes of this patent, gelation, set and melt temperatures are defined by measurement of the elastic modulus value of the gel in an appropriate rheometer. Conditions used are a frequency of 10 radians/second with a strain level of 1-5%. In most cases, the appropriate temperature is judged by the rate of change in the modulus value. A rapid increase with cooling is the setting temperature; a sharp drop indicates the melt temperature when heating. Frequently, the temperature where the modulus goes above or below a value of 1 Pa is used as an index. Typical gelation temperatures for [HA] gellan gums are in the region of 70°C. The high gelation temperature of [HA] gellan gum can be advantageous in some applications such as fruit fillings where it can prevent flotation of the fruit.
In this dish we use it to create a very fine sheet of tomato water, that is cut out in circle and rolled around a piece of cherry tomato.
chehf
Certain micro-organisms are capable of producing polysaccharides with properties differing from those of gums from more traditional sources. The best example of such microbially-produced polysaccharides is xanthan gum. More recently discovered examples are welan gum, rhamsan gum and gellan gum.
Gellan gum, first discovered in 1978, is produced by strains of the species sphingomonas elodea. Commercially this gum is produced as an extracellular product by aqueous cultivation of the micro-organisms in a medium containing the appropriate carbon, organic and inorganic nitrogen and phosphate sources and suitable trace elements. The fermentation is carried out under sterile conditions with strict control of aeration, agitation, temperature and pH. When fermentation is complete, the produced viscous broth is pasteurized to kill viable cells prior to recovery of the gum. The gum can be recovered in several ways. Direct recovery from the broth yields the gum in its native or high acyl form. Recovery after deacylation by treatment with a base yields the gum in its low acyl [LA] form. Acyl groups present in the gum are found to influence its characteristics significantly.
Low acyl [LA] gellan gums form gels when cooled in the presence of gel-promoting cations, preferably divalent cations, such as calcium and magnesium. The gels formed are firm and brittle. High acyl [HA] gellan gums do not require the presence of cations for gel formation and the gels formed have structural and theological characteristics which are significantly affected by the acyl substitutes. Thus the properties of [HA] gellan gels differ significantly from those of [LA] gellan gels. [HA] gels are typically soft and flexible and lack thermal hysteresis.
Typical gelation temperatures for [LA] gellan gums are in the range 3O°C to 50°C, depending upon the nature and concentration of the cations present. For purposes of this patent, gelation, set and melt temperatures are defined by measurement of the elastic modulus value of the gel in an appropriate rheometer. Conditions used are a frequency of 10 radians/second with a strain level of 1-5%. In most cases, the appropriate temperature is judged by the rate of change in the modulus value. A rapid increase with cooling is the setting temperature; a sharp drop indicates the melt temperature when heating. Frequently, the temperature where the modulus goes above or below a value of 1 Pa is used as an index. Typical gelation temperatures for [HA] gellan gums are in the region of 70°C. The high gelation temperature of [HA] gellan gum can be advantageous in some applications such as fruit fillings where it can prevent flotation of the fruit.
In this dish we use it to create a very fine sheet of tomato water, that is cut out in circle and rolled around a piece of cherry tomato. Gums, also called hydrocolloids, are polysaccharides. Polysaccharides are polymers of simple sugar building blocks which have been in use since about 1900. Use of gums has increased throughout the century particularly in the past 40 years and today they are used in a wide variety of products and processes.
Certain micro-organisms are capable of producing polysaccharides with properties differing from those of gums from more traditional sources. The best example of such microbially-produced polysaccharides is xanthan gum. More recently discovered examples are welan gum, rhamsan gum and gellan gum.
Gellan gum, first discovered in 1978, is produced by strains of the species sphingomonas elodea. Commercially this gum is produced as an extracellular product by aqueous cultivation of the micro-organisms in a medium containing the appropriate carbon, organic and inorganic nitrogen and phosphate sources and suitable trace elements. The fermentation is carried out under sterile conditions with strict control of aeration, agitation, temperature and pH. When fermentation is complete, the produced viscous broth is pasteurized to kill viable cells prior to recovery of the gum. The gum can be recovered in several ways. Direct recovery from the broth yields the gum in its native or high acyl form. Recovery after deacylation by treatment with a base yields the gum in its low acyl [LA] form. Acyl groups present in the gum are found to influence its characteristics significantly.
Low acyl [LA] gellan gums form gels when cooled in the presence of gel-promoting cations, preferably divalent cations, such as calcium and magnesium. The gels formed are firm and brittle. High acyl [HA] gellan gums do not require the presence of cations for gel formation and the gels formed have structural and theological characteristics which are significantly affected by the acyl substitutes. Thus the properties of [HA] gellan gels differ significantly from those of [LA] gellan gels. [HA] gels are typically soft and flexible and lack thermal hysteresis.
Typical gelation temperatures for [LA] gellan gums are in the range 3O°C to 50°C, depending upon the nature and concentration of the cations present. For purposes of this patent, gelation, set and melt temperatures are defined by measurement of the elastic modulus value of the gel in an appropriate rheometer. Conditions used are a frequency of 10 radians/second with a strain level of 1-5%. In most cases, the appropriate temperature is judged by the rate of change in the modulus value. A rapid increase with cooling is the setting temperature; a sharp drop indicates the melt temperature when heating. Frequently, the temperature where the modulus goes above or below a value of 1 Pa is used as an index. Typical gelation temperatures for [HA] gellan gums are in the region of 70°C. The high gelation temperature of [HA] gellan gum can be advantageous in some applications such as fruit fillings where it can prevent flotation of the fruit.
In this dish we use it to create a very fine sheet of tomato water, that is cut out in circle and rolled around a piece of cherry tomato.
chehf
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