Determination of total carbohydrates by anthrone method. Carbohydrates are the important components of storage and structural materials in the plants. Recently, Morse4 and Morris5 have described the use of anthrone for the quantitative estimation of carbohydrates. This method is both quicker and. The precise method of carbohydrate isolation depends on the carbohydrate type, solution as this would cause an underestimation of the carbohydrate content. The Anthrone method is an example of a colorimetric method of determining.
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7. ANALYSIS OF CARBOHYDRATES
A burette is used to add the carbohydrate solution being analyzed to a flask containing a known amount of boiling copper sulfate solution and a methylene blue indicator. Non-cell wall polysaccharides include hydrocolloids such as guar and locust bean gum, gum arabicagar, alginates and caragenans which are commonly used in foods as gelling agents, stabilizers and thickeners.
It is important to determine the type and concentration of carbohydrates in foods for a number of reasons. The concentration of precipitate present can be determined gravimetrically by filtration, drying and weighingor titrimetrically by redissolving the precipitate and titrating with a suitable indicator.
To estimate the amount of carbohydrate present carobhydrate the estikation sample by using Anthrone method Principle: The concentrations of glucose and fructose can then be determined by the previous method. Alternatively, the water-soluble and water-insoluble fiber components can be determined by filtering the enzymatically digested sample.
Determination of Carbohydrate by Anthrone Method
The protein and ash content of the various fractions are determined so as to correct for any of these substances which might remain in the fiber: Some carbohydrates are digestible by humans estimaiton therefore provide an important source of energy, whereas others are indigestible and therefore do not provide energy.
Titration Methods The Lane- Eynon method is an example of a tritration method of determining the concentration of reducing sugars in a sample.
The density of aqueous solutions increases as the carbohydrate concentration increases. Aqueous solutions, such as fruit juices, syrups and honey, usually require very little preparation prior to analysis. The basic units of carbohydrates are Monosaccharides. Anthrkne major components of dietary fiber are cellulose, hemicellulosepectin, hydrocolloids and lignin. This can be achieved by adding chemicals that form an insoluble complex with one of the components, but not with the other, e.
The glucose concentration is then analyzed using methods described previously e. Immuoassays are finding increasing use in the food industry for the qualitative and quantitative analysis of food products. The disadvantages of this method are i the results depend on the precise reaction times, temperatures and reagent concentrations used and so these parameters must be carefully controlled; ii it cannot distinguish between different types of reducing sugar, and iii it cannot directly determine the concentration of non-reducing sugars, iv it is sucseptible to interference from other types of molecules that act as reducing agents.
The density of a material is its mass divided by its volume.
While calculating the sugar concentration in the unknown sample, the dilution factor has to be taken into account. On carbohydrzte other hand, many foods contain carbohydrates that are physically associated or chemically bound to other components, e.
There are many enzyme assay kits which can be purchased commercially to carry out analysis for specific carbohydrates. But they yields of color where is to form carbohydrate to carbohydrate. Like the other methods it is non- stoichemetric and therefore it is necessary to prepare a calibration curve using a series of standards of known carbohydrate concentration. Construct a calibration curve on a graph paper, by plotting the glucose concentration 10 to mg on x-axis and absorbance at nm on the y-axis.
Non Cell Wall Polysaccharides This group of substances are also indigestible carbohydrates, but they are not derived from the cell walls of plants.
This is because lignin is not a polysaccharide, and so it is not broken down to monosaccharides during the acid digestion. Enzymatic Methods Analytical methods based on enzymes rely on their ability to catalyze specific reactions. The Munson and Walker method is an example of a gravimetric method of determining the concentration of reducing sugars in a sample.
A gelatinized sample of dry, defatted food is enzymatically digested with a- amylase, amyloglucosidase and protease to break down the starch and protein components.
Immunoassays specific for low molecular weight carbohydrates are developed by attaching etimation carbohydrate of interest to a protein, and then injecting it into an animal. Colorimetric Methods The Anthrone method is an example of a colorimetric method of determining the concentration of the total sugars in a sample. The majority of carbohydrates found in nature are present as polysaccharides. Once the starch has been extracted there are a number of ways to determine its concentration:.
Cellulose molecules aggregate to form microfibrils that provide strength and rigidity in plant cell walls. Some polysaccharides contain all the same kind of monosaccharide homopolysaccharideswhereas others contain a mixture of different kinds of monosaccharide heteropolysaccharides.