Pectins sequestering agents

Methods (4, IS) are available for treating calcium pectinate with acidified alcohol of such concentration that the ash constituents will be readily soluble while pectin will not be soluble. It is not necessary to remove all the calcium from the pectinate in order to disperse it in water. A calcium sequestering agent, such as sodium hexametaphosphate, when added to calcium pectinate will suppress the activity of the calcium ions, so that the pectinate can be dispersed. Pedersen (1I ) describes the use of sodium pyrophosphate to improve the solubility of low-methoxyl pectin in liquids containing calcium ions or other polyvalent metal ion. The result of this treatment is similar to that of sodium hexametaphosphate used by the authors. 

Caustic soda, without sequestering agents, is used by some breweries to clean stainless steel equipment but this normally leads to problems with residues of calcium salts that cling tenaciously to the metal. It is therefore normal to formulate a detergent mixture capable of removing, readily and entirely, the various soils encrusted on the stainless steel internal surface. Hot caustic soda solution itself will dissolve protein, lipid, cellulose, hemi-cellulose, mucilage, gums, pectins and tannins. The effects of caustic soda and the various compounds that may be added to it in solution are indicated in Table 21.3. 

EM pectins are immobilized in situ via metallic ions and need a sequestering agent to displace the counterions. Different treatments were compared between sugar beet and potato pulps [90, 91]. Before pectin extraction, a pretreatment of the plant material is necessary to inactivate enzymes (water at 85°C, 20 min). HM pectins naturally occur in sugar beet pulp and they were extracted in alkaline conditions (50 mM NaOH, pH 12) and precipitated with ethanol after neutralization to pH 6.5-7. On the contrary, for potato pulp containing an LM pectin, the... 

The calcium pectinate, as prepared, is insoluble in cold or hot water without added acid. Before it can be dispersed and utilized, use of acidified alcohol or treatment with a calcium sequestering or deionizing agent is necessary. 

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