Pectin production

The degradation of pectin is initiated by the action of PME, an enzyme removing methylester groups from highly methoxylated pectins. Production of incompletely deesterified pectin, probably due to end-product inhibition of PME (19, 20), may explain that an affinity of PL for both pectate and pectin is required for full pathogenicity of the bacteria. 

Pectin is obtained from unripe apples or citrus fruit. In both cases the residues left after pressing to extract juice are used for pectin production. In the fruit, pectin is responsible for the firm structure. Apples, for example, have a firm texture despite a water content of more than 85%. Pectin is sold almost exclusively in powder form. 

The present review indicates that while pectin products continue to serve as a well-established food additive for technological purposes, the application of pectins for health benefits has many potential opportunities. In the last few decades, considerable research has been done on the physiological effects of pectin in humans as a water-soluble dietary fiber supplement. Some novel pharmacological activities of pectins and pectic polysaccharides are gaining more attention. Although most natural pectins from fruits and vegetables have not been shown to have these activities, chemical and enzymatic modifications may provide useful tools for producing such products for human health care. 

More than 50% of the world s pectin production is used in making jellies, jams, marmalades and confectionery products, and the ability of the pectin to form jellies and gels is therefore a most important property. Consequently it Is the jelly of pectin expressed as the Jelly Grade which commercial value of pectins. 

The molecular weight (Mw), degree of esterification (DE), and content of anhydrous galacturonic acid (AG) of the citrus pectin are shown in Table 1. The molecular weight was estimated by intrinsic viscometry (calibrated against known pectin products), and the degree of methoxylation and the galacturonic acid content by titration. 

Pectin is widely distributed in plants. It is produced commercially from peels of citrus fruits and from apple pomace (crushed and pressed residue). It is 20-40% of the dry matter content in citrus fruit peel and 10-20% in apple pomace. Extraction is achieved at pH 1.5-3 at 60-100 °C. The process is carefully controlled to avoid hydrolysis of glycosidic and ester linkages. The extract is concentrated to a liquid pectin product or is dried by spray- or drum-drying into a powered product. Purified preparations are obtained by precipitation of pectin with ions which form insoluble pectin salts (e. g. AI +), followed by washing with acidified alcohol to remove the added ions, or by alcoholic precipitation using isopropanol and ethanol. 

In industrial practice, pectins are mostly extracted from citrus fruit peels (their albedo), which contain about 20 0% of pectin. Another source of pectin is apple pomace, containing about 10-20% pectin. The isolation of pectin is based on extraction from an acidified aqueous slurry (pH 1.5 3) at temperatures of 60-100 °C. The extracts are then concentrated by evaporation or dried. Commercial pectin products are obtained by precipitation using metal ions that form insoluble salts with pectin (e.g. Al +), or by precipitation of pectin solutions with alcohols (ethanol or propan-2-ol). 

Pectin also contains araban and galactan. Il is present in fruits, root vegetables and other plant products, and confers on jams their typical gelling property. Pectin is manufactured as a white powder, soluble in water, and used to assist the setting of jams and jellies, and for numerous other purposes. Low melhoxyl pectins, with under 7% methoxyl, give firmer gels than pectins proper. 

Pectin, which occurs in most plants as the glue which binds the cells together, is extracted commercially from citms peel and has been extracted from apple pomace. It is suggested for many no-fat products including sauces, desserts, and dressings. 

Pectin. Pectin [9000-69-5] is a generic term for a group of polysaccharides, mainly partially methoxylated polygalacturonic acids, which are located in the cell walls of all plant tissues. The main commercial sources of pectin are citms peel and apple pomace, where it represents 20—40% and 10—20% of the dry weight respectively. The pectin is extracted, the extract purified, and the pectin precipitated (50) increased extraction times lead to the production of low methoxyl pectins. 

Other Food. Tartaric acid is also used ia the manufacture of gelatin (qv) desserts and ia fmit jellies, especially ia pectin jellies for candies where a low pH is necessary for proper setting. It is used as a starch modifier ia starch jelly candies so that the product flows freely while being cast. It is used ia hard candy because its melting poiat permits it to fuse iato the "glass" and does not contribute to moisture. 

The determined macro- and microelement stmcture of mumio specifies onto the expediency of the application of this biologically active substance as a cosmetic raw material in the cosmetic compositions, which do not contain carbopol. The developed procedure for calcium and sodium ions determination in pectin-containing vegetative extracts is express and it is recommended for application at elaboration of cosmetic production compositions on the carbopol base. 

Schneider and Ziervogel (Ref 2) obtained nitric esters of pectin as intermediate products which were then esterified by means of acet anhydr to the corresponding acetates. In 1949, Rogovin, Treyvas and Shorygina (Ref 5) prepd pectin nitric esters by nitrating pectic acid for 4 hrs at 20° in a mixt composed of 48% HN03,... 

Process leaks from food and beverage production or wood leachates often produce sugars, colloidal materials, pectins, emulsions, and proteins that cause stable foams in the boiler. These lead to carryover and further steam-condensate line contamination. The temporary use of a demulsifier or defoamer as part of the water treatment program may be of particular benefit, but again the condensate is unsuitable for return to the boiler. Other process leaks include ... 

Pectin is a thickener in many products. If there is sufficient sugar in the mixture, pectin forms a firm gel. Jams and jellies are thickened with pectin. Pectin binds water, and thus keeps products from drying out. It stabilizes emulsions. 

These studies demonstrate that the processing of cactus pears into coloring preparations is feasible. It is now up to companies to exploit the enormous potential of these fruits. The by-products from Opuntia processing such as seeds and peels could be further processed into vegetable oil and pectin, respectively. 

A full understanding of the role of pectin in plant development requires elucidation of the mechanisms that regulate p>ectin biosynthesis (6). Our strategy for studying the biosynthesis of HGA was to 1) establish a PGA-GalAT assay that would allow detection of synthesized HGA, 2) characterize the enzyme in microsomal membranes, 3) characterize the product synthesized by the enzyme in microsomal membranes, and 4) solubilize the enzyme and characterize the solubilized enzyme and its product. 

---