Pectic polysaccharides of fruits

Pectic Polysaccharides of Fruits Characterization Fractional Changes and Industrial Application... 

Redgwell, R. J., Fischer, M., Kendale, E., and Maerae, E. A. (1997). Galactose loss and fruit ripening High molecular weight arabinogalac-tans in the pectic polysaccharides of fruit eell walls. P/a ta 203, 174-181. 

A traditional system for the preparation of table olives, involves a treatment of the fresh fruit with a solution of NaOH to hydrolised the bitter glycoside oleuropein, followed by a lactic fermentation in brine. The modifications that take place on pectic polysaccharides of olives (Manzanilla variety) during this process was smdied. Processing induced a net loss of polysaccharides soluble in sodium carbonate and a paralel accumulation of water and Imidazole/HCl soluble polysaccharides. A general decrease of the apparent molecular weight of water and carbonate soluble polysaccharides was also detected. 

The Pectic Polysaccharide Rhamnogalacturonan II is a major Component of the Polysaccharides present in Fruit-derived Products. 

The polysaccharide composition and structure of pectic polysaccharides present in fruit-derived products have been the aim of numerous studies [14-19]. However, the attention of scientists was focused on the analysis of rhamnogalacturonan I or so-called pectic hairy regions. As far as we know, the presence of RG-II in fruit juices has not been reported. 

Fruit-derived products used as source of pectic polysaccharides... 

On this work the main changes that take place on three pectic fractions, water, imidazoIe/HCl and carbonate soluble polysaccharides, of olive cell wall are described and related with modifications of the fruit s texture. 

It is clear that this changes on the cell wall must have important consequences on the firmness of the fruit. The breakdown of linkages between pectic polysaccharides and the matrix is likely to be an important factor on the irreversible loss of firmness. The deesterification of polysaccharides, on the other hand could have an effect of increasisng firmness. There is, however, another factor that should be taken into account, the alcali deesterification of the... 

Uronic acid in the form of galacturonic acid is a major component of the pectic polysaccharide rhamnogalacturonan, which is present in large amounts in the cell walls of most fruits and vegetables. Small amounts of glucuronic acid and 4-O-methylglu-curonic acid have also been detected in cell walls. 

Cellulose and complex pectic polysaccharides are the main matrix of the water-insoluble residue after centrifugation of fruit and vegetable homogenates. The use of pectinolytic enzymes is therefore necessary to solubilize the solid sample. Pectinolysis is known to degrade efficiently large pectic polysaccharides, but some of them, for example, rhamnogalacturonan-II, are considered to be resistant to pectinolytic enzymes [45]. A mixture of commercial products Rapi-dase LIQ and Pectinex Ultra-SPL , was reported for the release of metal-complexes from the solid parts of edible plants, fmits, and vegetables [45]. 

Plants contain signiFcant concentrations of polysaccharides of which the potentially negatively charged oxygen functions can bind cations electrostatically or chelate them via polyhydroxy groups [89]. Particular attention was attracted by a structurally complex pectic polysaccharide rhamnogalacturonan-II (RG-II) [90]. This ubiquitous component of primary plant cell walls forms dimers cross-linked by 1 2 borate diol esters (dRG-II) that were found to complex in vitro sped be divalent cations and the majority of Ba, Pb, Sr, and rare earth elements (REEs) in fruit and vegetables [45, 91]. 

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. 

The occurrence of a terminally-linked p-L-Ar in the arabinan pectic polysaccharides has only been described for the olive fruit. This odd feature can be used as a marker of authenticity for the presence of olive pulp in matrices containing pectic polysaccharides. Moreover, as showed by Cardoso et al. [38], ripening of the olive fruit causes the disappearance of the characteristic arabinan terminally-linked p-L-Ar residue (Fig. 6), and thus its quantification can be useful for the evaluation of the ripeness of the olive fruit. 

FRACTIONAL CHANGES OF PECTIC POLYSACCHARIDES IN DEVELOPING FRUITS... 

The examination of physical and chemical properties of pectic polysaccharides, extracted from fruits, peels of the fraits has an important area since pectin is extensively used in industries, particularly in frait processing sector. The objective of the review... 

Das, A. and Majumder, K. (2010). Eraetional changes of pectic polysaccharides in different tissue zones of developing guava (Psidium guaiava L.) fruits. Scientia Horticulturae 125, 406-410. 

Majumder, K. and Mazumdar, B. C. (2005). Ethephon-induced fractional changes of pectic polysaccharides in developing cape gooseberry Physalis peruviana L.) fruits. Journal of the Science of Food and Agriculture 85, 1222-1226. 

Pectin is a long chain of pectic acid and pectinic acid molecules. Because these acids are sugars, pectin is categorized as a polysaccharide. It is prepared from citrus peels and the remains of apples after they are squeezed for juice. In the plant, pectin is the material that joins the plant cells together. When fungus enzymes break down the pectin in fruit, the fruit gets soft and mushy. 

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