Pectins gelation calcium pectate

The rheological behaviour in the range of LM pectin was analyzed and the sol-gel diagram established [59] for different stoichiometric ratios. In their paper, these authors determined the gel times for sodium pectate during calcium-induced gelation and the variation of the gel time with polymer concentration, stoichrometric ratio and temperature. 

Versteeg et al. (50) have isolated various multiple forms of pectin esterases in oranges and shown that they differ in affinity to pectins and pectates and in heat stability and therefore may play different roles in cloud loss phenomena. One form (about 5% of the total PE activity) was found to be much more heat stable than the other forms it was also active at low pH (2.5) and at low temperatures. Another form did not cause self-clarification for this enzyme a similar mode of attack was proposed as for fungal pectin esterases which produce low-ester pectins less sensitive to calcium. Multiple forms of pectin esterases are present in the fruits of all of the orange varieties and citrus species tested. The two isoenzymes known to be responsible for cloud loss and gelation in citrus products were found to occur in all of the component parts of the orange fruit (51). In the French cider industry the endogenous PE of apple is used for the self-clarification of apple juice (52). 

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