Effect of citrus pectin

D.E. values for the citrus and tomato pectins were 56 and 40%, respectively. Thus, differences in D.E. levels rather than pectin source could have accounted for the superior effectiveness of citrus pectin. Mokady (80) and Judd et al. (81) confirmed that serum cholesterol reduction is most pronounced with high D.E., high-molecular-weight pectin (Table I). 

Kay, R.M. and Truswell, A.S. 1977. Effect of citrus pectin on blood lipids and fecal steroid excretion in man, Am. J. Clin. Nutr., 30 171-175. 

Phinney et al. [Ill] investigated the application of citrus pectins, as chiral selectors, to enantiomer separations in capillary electrophoresis. Successful enantioreso-lution of primaquine and other antimalarials, was achieved by utilizing potassium polypectate as the chiral selector. Changes in pH, chiral additive concentration, and capillary type were studied in relation to chiral resolution. The effect of degree of esterification of pectin materials on chiral recognition was evaluated. 

Figure 6.7 Effect of the degree of esterification (DE) of citrus pectin on its extent of self-assembly (Mw) ( ) and the character of its intermolecular pair interactions (. I2) (A) in aqueous solution (0.09 M NaCl and 0.01 M NaF) (Braudo etal, 1998).

Pfeffer et al. (82) have found that bile salt binding activity of commercial citrus pectins was lost if these products were dissolved, filtered, centrifuged, and reprecipitated before testing. Binding activity was concentrated in the residue pellet from centrifugation, which was found to be fine diatomaceous earth. This contaminant was probably introduced during filtration steps in processing and purification of pectin. The authors concluded that any hypocholesterolemic effect of commercial pectin was due solely to its diatomaceous earth contamination. 

Mixtures of the polygalacturonases or of the pectinesterases were also ineffectual. Only the combined action of at least one of the polygalacturonase fractions with one of the pectinesterase fractions was effective in clarification. Purified endopolygalacturonase alone could decrease the viscosity of a solution of citrus pectin (64% esterification), but it was completely ineffectual when apple pectin was used [90% esterified (iS6)]. 

Morris, G.A., Foster, T.J. and Harding, S.E. 2000. The effect of the degree of esterification on the hydrodynamic properties of citrus pectin, Food Hydrocolloids, 14(3) 227-235. 

The exceptionally strong influence of calcium-ions on pectin solutions especially made with HM citrus pectins can be shown by a frequency sweep. The addition of calcium leads to an increase of the complex viscosity. Additionally we can observe a stable trapping of air bubbles in the solution. This effect can not be caused by the increase of viscosity. The frequency sweeps of the solutions give the answer. The storage modulus curves show the significant increase of the elastic shares caused by the addition of calcium-ions. 

Ultrafiltration of heterogenous colloidal suspensions such as citrus juice is complex and many factors other than molecular weight contribute to fouling and permeation. For example, low MW aroma compounds were unevenly distributed in the permeate and retentate in UF in 500 kd MWCO system (10). The authors observed that the 500 kd MWCO UF removed all suspended solids, including pectin and PE. If PE is complexed to pectate in an inactive complex, then it is conceivable that release of PE from pectin with cations will enhance permeation in UF. At optimum salt concentration, less PE activation was observed at lower pH values than at higher pH (15). In juice systems, it is difficult to separate the effect of juice particulates on PE activity. Model studies with PE extracts allows UF in the absence of large or insoluble particulates and control of composition of the ultrafilter. In... 

Pectin with 62% D.E. largely counteracted the increase in liver cholesterol levels brought about by dietary cholesterol. Low ester pectin (30% D.E.), polygalacturonic acid (PGA), and 50% esterified PGA were all without effect. Conflicting reports on the efficacy of pectin as a hypocholesterolemic agent may be due to variations in these parameters. For example, citrus pectin was found to be more effective than tomato pectin in lowering serum and hepatic cholesterol levels of rats (79). 

Recently the means by which pectin lowers cholesterol levels and even the validity of this effect have been questioned. Upon finding no bile salt binding capacity for soluble pectin, Baig and Cerda (76) proposed that pectin lowered serum cholesterol levels by forming insoluble complexes with the serum low density lipoproteins (LDL) which transport circulating cholesterol. Complexing of LDL by citrus pectin was observed in vitro, but the way in which pectin or some component thereof enters the blood stream to effect such binding in vivo has not been determined. 

Cardoso et al. [13] also compared the dependency of the viscoelastic properties of mature OPE/calcium gels upon the polymer and calcium concentrations to those of the LMP. They showed that, for these variables, both pectin systems exhibited a power law dependence of the G. At pH 7, for the different concentrations of non-esterified carboxyl groups available in the pectin (o-GalA ), the PPE/calcium and citrus LMP/calcium systems exhibited similar dependencies on the calcium concentration (Fig. 8a), with a power law dependence of 2.9-3.3. Still, the gelling ability of OPE/calcium systems was more dependent on the polymer concentration than the citrus pectin. For the different calcium concentrations tested, the corresponding exponents of power law dependency were approximately 3.0 and 1.9 for OPE/calcium and citrus LMP/calcium systems, respectively (Fig. 8b). These results also confirm the lower capability of the pectic olive extracts to form, under similar ionic conditions, elastically effective junctions zones. 

An experiment was conducted in which the pH of SAG jellies was varied. The objective was to determine the effect pH has on SAG grade. Jellies were prepared at pH s between 2.3 and 3.1. The pH was varied by changing the amount of tartaric acid used. Pectin dosage was held constant at. 433g. For comparative purposes two different pectins were used, one which is known to be a pure lime peel citrus pectin, and another citrus pectin with mixed peel... 

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