Pectin available

The substrate for HGA synthesis is UDP-D-galacturonic acid (UDP-GalA) (81). UDP-GalA has been isolated from plants (59) and several pathways for its synthesis in planta have been reported (31). In vitro studies on pectin biosynthesis have been hampered since radiolabeled UDP-galacturonic acid is not commercially available. Previous researchers have used several... 

More detailed information was obtained from inspection of the time-course for product formation following degradation of pectin with enzyme combinations. Supplementation with PL1 and PL2 together caused high initial activities followed by a significant reduction after around 150 s. Further addition of PL1 or PL2 after 160 s effected no increase in product formation, probably due to exhaustion of available substrate. Alternatively, supplementation with PL3, either initially or after 160 s, stimulated a pronounced enhancement of pectinolysis. 

Schlemmer U. Decker H. (1993) On the mechanism of the copper-pectin interaction. In proceedings of Bioavailability 93 Nutritional, Chemical and Food Processing Implications of Nutrient Availability. U. Schlemmer (Ed.). Ettlingen, May 9-12, 494-500. 

Enzymes can be used to specifically modify the pectins. Pectin methyl esterase is already widely used to adjust the gelling properties of commercially available pectins. The acetyl esters also strongly affect the gelation [2,3] and removal is important for the upgrading of sugar beet pectin, extractable from a by-product of the sugar industry. 

Sunflower head residues are one of the richest sources of low-methoxyl pectin, their most important property being the ability to form gels, if correct proportions of divalent ions (usually calcium) are available. 

Pectin is found in apples and in the white membrane that surrounds the sections of oranges, grapefruits, or other citrus fruits, as well as in several other sources. Powdered pectin made from apple cores is also available, but scientists have found that eating apples or citrus fruit has a much better effect on lowering blood cholesterol levels than eating powered pectin does. They believe eating the whole fruit is better because the body also needs vitamin C to convert cholesterol into bile acids. Fruits contain vitamin C, or ascorbic acid, but the powdered pectin does not. 

Where the juice is destined for concentration it is essential for the pectin to be destroyed, or degraded, as already mentioned. Pectinase or poly(l,4-a-D-galacturonide) glycanohydrolase, in its commercially available form, is produced from fungal sources (i.e. Aspergillus sp., Rhizopus sp.). and possesses a wide variety of component activities. It operates comfortably between pH 2.5 and 6.0 and subject to supplier type can function well at specified temperatures between 30 and 60°C. Activities include... 

Enzymes should be added to the feed together with the pre-mix. Granulated enzyme products may readily be mixed with feed components, as they are based on normal feed components such as wheat or soy grits. A wide range of enzyme products are available. Enzyme products should contain specific enzyme activities necessary to degrade specific substances such as glucans, starch, protein, pectin-like polysaccharides, phytic acid, raffinose, stachyose, hemicellulose, and cellulose. 

A certain amount of evidence shows that methyl group metabolism may be affected as a result of auxin treatment—generally increased pectin-methyl esterification is observed (7). Though pectin-methyl esterification may be correlated with increased wall plasticity, there are as yet no obvious connections between general methyl group availability on the one hand and permeability, peroxidation, and mitosis on the other. 

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