Pectin, slow set

The colours, flavours and remaining acid are added. Once this acid has been added the product can set. A slow set pectin is used otherwise the product could pre-set with disastrous consequences. 

The differences that were observed in breaking strength or Internal strength between the four pectin samples, all of which had a 150 SAG and a degree of methoxylatlon (DM) of 65, can be attributed to differences in molecular weigiht. Most investigations so far have worked on slow set pectins, which on the U. S. market is by far the most widely used pectin type. 

Most slow-setting pectins give optimum performance between pH 2.8 and 3.2, while rapid-setting pectins show their best behavior in the region of pH 3.0 to 3.4. Many times an addition of acid to lower the pH only 0.1 unit may be sufficient to prevent complete failure of a jelly batch. 

Jelly pH. Another factor which Influences the Internal gel strength Is the jelly pH. In the laboratory, Olllver (53) found pH differences between 2.82 and 3.12 could cause a variation In jelly grade of about 30%. The Interactions between jelly pH and gel strength Is shown In Figure 1. Acids are used to control the pH within the gelling range. The optlmlum pH Is about 3.1 and 3.4 for slow set HM pectins and rapid set pectins, respectively (47). 

Dehydration of pectin requires time to come to equilibrium (to account for slow setting or low temperature of setting of certain pectin gels). 

TIC Pretested Pectin 1694 Powd., TIC Pretested Pectin HM Rapid Set Powd., TIC Pretested Pectin HM Slow Set Powd., TIC Pretested Pectin LM 32 Powd., TIC Pretested Pectin LM 35 Powd.. See Pectin... 

Figure 4.14 Effect of pH on the gelation of rapid set and slow set HM pectin (from Ref. [40] with kind permission of Springer Science and Business Media).

The gelling time of pectin varies with type and ranges from 20-70 s (rapid set) to 180-250 s (slow set). The gel strength and gelling time are the two most important factors determining the quality of pectin (glicksman WHISTLER AND BEMILLER). 

---