A METHOD FOR THE DETERMINATION OF URONIC ACIDS<sup>1</sup>

Dickson, A. D.; Otterson, Henry; Link, Karl Paul

doi:10.1021/ja01365a048

Cited by 78 publications

(11 citation statements)

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“…The total pectic inaterial in the alcohol-insoluble solids may be determined from tlie carbon dioxide produced in decarboxylation of the galacturonic acid. The decarboxylation process is performed by boiling a linown aliquot of the sample with either 12 or 19% hydrochloric acid (2,3). During the hydrolysis, the galacturonic acid decomposes into furfural, carbon dioxide, and water.…”

Section: Alcohol-insoluble Solids Of Citrus Peel Although the Alcohomentioning

confidence: 99%

METHODS OF ANALYSIS OF SOLUBLE CARBOHYDRATES AND PECTIC SUBSTANCES OF CITRUS FRUITS ^a

Sinclair

Jolliffe

1960

Journal of Food Science

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During an extended investigation into tlie seasonal changes in the chemical constituents of citrus fruit tissues, it was found that the carbohydrates liatl to be separated into soluble and insoluble fractions before chemical nietliotls could be subsequently used for deterniining tlie various constituents in the fruits. It is well Imo\vn that SOX alcohol is used to separate the colloidal iind noncolloitlal carbohydrate and nitrogen conipouticls in the analysis of plant materials. The alcohol-soluble fraction of plant tissues consists mainly of iiiono-antl disaccliaritle~, which, with the starch and destrins, serve as readily available sources of energy for tlie iiving cells. 'I lie alcoliol-ins~~l~rl~~e solids include the cell-wall or structural components, such as cellulose, lignin, proteins, pectic sul,stances, antl hemicelluloses, which are closely related in the plant, especially the last two.The composition ant1 nature o f citrus fruits are such that they afford many interesting proldenis of research for tlie plant I)iocliemist. l'lie peel, whicli is composed of t\vo clistiiict portions, the llavech or epicarp and the all)etlo or mesocarp, is easily separated from the pulp, ivliich is the edible portion of the fruit. 'lhe flavedo, the outer portion of the peel, is composed chiefly of caroteiioid pigments, yitaniiiis, antl essential oils. Tlie albedo, the spongy inner portion of the peel, is composed chiefly of celluloses, so1ul)le carl~ohydrates, pectic substances ( protopectin and pectin), Aavonoitls, amino acid;, and vitamins.( hi the other liantl, the pulp of citrus fruits, unlike that of most edible fruits, is divided into segments (carpels), the \valls of \vhich are not readily permeable : antl each segment is composed of hundreds of units (vesicles, juice sacs), the walls of which are still more iniperniea1,le. especially laterally. 'The vesicles or juice sacs which are located within the segments are composed of celluloses, heniicelluloses, protopectin, pectin, sugars, flavonoids, amino acids, vitamin C, mineral salts, and other nutrients. l h e juice of tlie etli1)le portion of citrus fruits is located in tlie vesicles. The solulde constituents in the juice are composed of so1ul)le carbohydrates (glucose, fructose, and sucrose), organic acids (chiefly citric acid), vitamin C, vitamin H comples, mineral salts, a small concentration of pectic materials, and niany other nutrients.l'he results presented in this paper are concerned with the schematic arrangements used in tlie separation and fractionation of the peel, pulp, and juice of citrus fruits. These schemes have been allplied very successfully in the separation of the pectic substances froln the soluble carbohydrates and other soluble materials so that a biochemical study can be made of tlie different forms of pectic materials occurring naturally in citrus fruits.

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Section: Alcohol-insoluble Solids Of Citrus Peel Although the Alcohomentioning

confidence: 99%

METHODS OF ANALYSIS OF SOLUBLE CARBOHYDRATES AND PECTIC SUBSTANCES OF CITRUS FRUITS ^a

Sinclair

Jolliffe

1960

Journal of Food Science

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“…Acetyl groups were determined by Clark's semimicro method (6). Uronic acid anhydride was estimated by a modification of the method of Dickson et al (7) in which the carbon dioxide produced by decarboxylation was removed in a stream of carbon-dioxide-free nitrogen in an all glass apparatus. When only small amounts of material were available the micro method of Tracy was more convenient and equally satisfactory (26).…”

Section: Materials a N D Methodsmentioning

confidence: 99%

Hemicelluloses of Wheat Straw

Adams¹,

Castagne²

1951

Can. J. Chem.

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Various hemicellulose fractions were extracted from wheat straw holocellulose (extractive and pectin free) by successive treatments with cold and hot water, 0.5y0, l.Oyo, and 2.0y0 potassium hydroxide and were recovered by precipitation with alcohol. Approximately 25% of the holocellulose material was removed, one half being in the hot water soluble fraction. The original holocellulose, the extracted residue, and the recovered fractions were analyzed for pentosan, uronic acid anhydride, acetyl, methoxyl, and ash content. In general, the more soluble fractions had a higher uronic acid and methoxyl content; the less soluble had a higher pentosan content and a more negative rotation [a];o. Intrinsic viscosity measurements indicated that all fractions had a degree of polymerization of 25-30. Hydrolysis of the main fraction yielded D-xylose, L-arabinose, D-glucose; in addition D-galactose was found in the water soluble fractions. Quantitative determinations of the sugars in the hydrolyzates showed that D-xylose predominated, with L-arabinose, D-glucose, and D-galactose (when present) in progressively smaller amounts. On hydrolysis all fractions yielded a n acidresistant uronic acid complex that contained D-xyloSe and a uronic acid tentatively identified as monomethoxyl galacturonic acid.

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“…183 The carbon dioxide released on healing with 12% hydrochloric acid may be determined titrimetrically, 184 ' 185 gravimetrically, 186 or manometrically. Uronic Acids.-Uronic acids are labile in acid media and readily undergo decarboxylation.…”

Section: Quantitative Analysis Of the Sugarsmentioning

confidence: 99%

Analytical Methods for Carbohydrates

Aminoff¹,

Binkley²,

Schaffer³

et al. 1970

The Carbohydrates

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A METHOD FOR THE DETERMINATION OF URONIC ACIDS¹

Cited by 78 publications

References 0 publications

METHODS OF ANALYSIS OF SOLUBLE CARBOHYDRATES AND PECTIC SUBSTANCES OF CITRUS FRUITS ^a

METHODS OF ANALYSIS OF SOLUBLE CARBOHYDRATES AND PECTIC SUBSTANCES OF CITRUS FRUITS ^a

Hemicelluloses of Wheat Straw

Analytical Methods for Carbohydrates

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A METHOD FOR THE DETERMINATION OF URONIC ACIDS1

Cited by 78 publications

References 0 publications

METHODS OF ANALYSIS OF SOLUBLE CARBOHYDRATES AND PECTIC SUBSTANCES OF CITRUS FRUITS a

METHODS OF ANALYSIS OF SOLUBLE CARBOHYDRATES AND PECTIC SUBSTANCES OF CITRUS FRUITS a

Hemicelluloses of Wheat Straw

Analytical Methods for Carbohydrates

Contact Info

Product

Resources

About

A METHOD FOR THE DETERMINATION OF URONIC ACIDS¹

METHODS OF ANALYSIS OF SOLUBLE CARBOHYDRATES AND PECTIC SUBSTANCES OF CITRUS FRUITS ^a

METHODS OF ANALYSIS OF SOLUBLE CARBOHYDRATES AND PECTIC SUBSTANCES OF CITRUS FRUITS ^a