Carbohydrate Fractions of Grapefruit Peel

Sinclair, Walton B.; Crandall, Paul R.

doi:10.1086/335583

Cited by 12 publications

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“…The alcohol insoluble solids was9.5% and 10.5% for red and white respectively (on fresh weight basis) which amounted to 38.0% and 42.0% (on dry weight basis). This value is higher than the value (33.69%) estimated by other researchers [39]. Table 2 summarized our findings of the AIS taken from grapefruit peels which contained (7.05 %, 7.17%) moisture, (3.37%, 3.275%) ash, (0.083%, 0.062%) protein, (0.089%, 0.079%) lignin, for red and white type respectively.…”

Section: Physicochemical Analysismentioning

confidence: 50%

Extraction and Characterization of Pectin from Grapefruit Peels

Mohamed¹

2016

MOJFPT

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Grapefruit peels were analyzed for different attributes such as moisture, ash, protein, crude fiber titratable acidity, sugars, ascorbic acid, calcium, magnesium, alcohol insoluble solids (AIS) and total pectin. AbstractThe present study was focused on the potential of red and white grapefruit peel as a source of pectin. Grapefruit peels were treated with 95% alcohol and the obtained alcohol-insoluble solids (AIS) were subjected to a sequential extraction with hot distilled water and hot 0.5% HCl. Comparative investigations were carried out with purified commercial citrus pectin. Chemical and physicochemical characterization of all pectin was accomplished. The yield of grapefruit peel pectin was 25% (dwb) It was found that pectin of the two types of grapefruit peels were similar in anhydrouronic acid content (AUА 60.95%). The grapefruit peel pectin for the red and white differed in their degree of esterification (DM 51.24-55.01%) and 50.848% for corresponding citrus pectin. Both grapefruit peel pectin were higher in their methoxyl content 8.875% for the red and 7.542% for the white, while corresponding citrus pectin was 6.798%. The acetyl content for the white grapefruit peel pectin was 1.634% and for the red was 0.55%, lower in comparison with the corresponding citrus pectin of 0.624. The grapefruit peel pectin contained L-arabinose, D-galactose, L-rhamnose and D-xylose. Gel-forming property of grapefruit peel pectin was of good quality similar to commercial pectin.

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Section: Physicochemical Analysismentioning

confidence: 50%

Extraction and Characterization of Pectin from Grapefruit Peels

Mohamed¹

2016

MOJFPT

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“…The major organic acid in the peel is L-quinic (Ting and Deszyck, 1959)) which has an equivalent weight nearly three times that of malic or citric acids. Sinclair and Crandall (1949) and Sinclair and Jolliffe (1960) found that total sugar accounted for about 60r0 of the total alcohol-soluble solids in grapefruit peel, and for 55.4 and 72.7% in the peel of Valencia and navel oranges, respectively. These values are lower than those found in the present experiment.…”

Section: Discussionmentioning

confidence: 99%

“…Economically these are probably also more valuable than any other group of substances found in the peel. Sinclair and co-workers (Sinclair and Crandall, 1949;Sinclair and Jolliffe, 1960) found that over two-thirds of the dry weight of mature grapefruit peel was alcohol-soluble. In the orange this value was over 50% (Sinclair and Crandall, 1953).…”

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The Carbohydrates in the Peel of Oranges and Grapefruit^a

Ting

Deszyck

1961

Journal of Food Science

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The carbohydrates of the citrus peel were divided according to their solubility in 80% ethanol. The alcohol-soluble solids were composed of about 80% total sugars. Free xylose was found in trace amounts. Glucose, fructose, and sucrose were the main sugars present. Sucrose content of the peel was in general lower than the total reducing sugars. The alcohol-insoluble solids were separated into "pectic substance," "hemicellulose," and "cellulose" fractions by extracting with different solvents. The "pectic substance" fraction upon hydrolysis yielded arabinose, galactose, and galacturonic acid. "Hemicellulose" fraction contained xylose, arabinose, galactose, glucose, and some uranic acids in its hydrolysate. In the "cellulose" fraction, glucose was dominant with some xylose and arabinose being also present.Traces of galactose and some uranic acids and in some cases mannose were found. On the average only between 53 and 70 per cent of the alcohol-insoluble solids were recovered as carbohydrates in the peel of various citrus varieties.

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“…The total pectic substances of the saiiiples are therefore composed of the sum of the water-soluble and acid-soluble pectic materials. l h e experimental values on tlie water-and acid-soluble pectic substances of citrus fruit tissues are published elsewhere SUMMARY (5, 6,7,8).…”

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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Carbohydrate Fractions of Grapefruit Peel

Cited by 12 publications

References 3 publications

Extraction and Characterization of Pectin from Grapefruit Peels

Extraction and Characterization of Pectin from Grapefruit Peels

The Carbohydrates in the Peel of Oranges and Grapefruit^a

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

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Carbohydrate Fractions of Grapefruit Peel

Cited by 12 publications

References 3 publications

Extraction and Characterization of Pectin from Grapefruit Peels

Extraction and Characterization of Pectin from Grapefruit Peels

The Carbohydrates in the Peel of Oranges and Grapefruita

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

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The Carbohydrates in the Peel of Oranges and Grapefruit^a

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