The Reactions Of Carbohydrates

Carbohydrates, or sachharides are sugars and starches offering energy for all of us humans and animals. In this experiment, carbohydrates are examined with different reagents, and two unknown samples are evaluated to determine their id. For the identification of anonymous carbohydrate test, seven different sugars and two unfamiliar samples with one ml quantity was located in separate test tubes. It had been examined with Iodine test, wherein one ml of iodine reagent was added to each test. For Benedict, Barfoed, Seliwanoff, and 2, 4-DNP test, one ml of the corresponding reagent was supplemented on each carbohydrate test and they were heated up in a drinking water bath later on. Results and effect was considered and observed so the identity of both unknown samples can be identified. After carefully examining the data, the unknown examples were recognized to be Fructose and Ribose. On another part, hydrolysis of starch, fifty ml of five percent starch solution was placed in a one hundred ml beaker and five ml of concentrated HCl was added. It was heated while protected in foil. One ml of samples was placed in two specific test tubes; the first one was supplemented with one ml of iodine reagent and the other one with Benedict's reagent. The heating up was continuing and the process was repeated every five minutes until the formation of blue-black complex in iodine test, and development of brick red colorization for the Benedict's test. It required ten minutes until blue-black organic and brick red colorization was shaped.

INTRODUCTION

Carbohydrates are carbon chemical substances which contain great levels of hydroxyl groups. The easiest carbohydrates also comprise either an aldehyde moiety ( polyhydroxyaldehydes ) or a ketone moiety (polyhydroxyketones). All sugars can be categorized as monosacchrides, oligosaccharides or polysaccharides. Somewhere from two to ten monosaccharide items, connected by glycosidic bonds, make up an oligosaccharide. Polysaccharides are much bigger, having hundreds of monosaccharide systems. The lifetime of the hydroxyl groupings permits sugars to interrelate with the aqueous nature and to take part in hydrogen bonding, both inside and between chains. Derivatives of glucose can contain nitrogen, phosphate and sulfur compounds. Carbohydrates also can unite with lipids to form glycolipids or with protein to create glycoproteins. [1]

MATERIALS AND METHODS

Identification of Mysterious Carbohydrate Sample

One ml of carbohydrate sample was added in two separate test pipes. One ml of Molisch reagent were added in the first test pipe and 1ml of conc. H2SO4 where put into another one. Results were noticed and another 9, 1ml examples of different carbohydrates where well prepared for and analyzed with the next: Iodine test, each test tube was added 1ml of iodine reagent. For the next tests, Benedict, Barfoed, Seliwanoff, and 2, 4-DNP, 1ml of these individual reagent was added in each tube and were simultaneously heated afterwards in a drinking water bath. Finally, the unknown samples was weighed against the other samples they were identified to be Fructose and Ribose.

Hydrolysis of Starch

A 50ml of 5% solution was placed in a 100ml beaker and 5ml of conc. HCl was added. It was protected with foil and heated up. Then 1ml of sample was located in two independent test tubes and 1 ml of iodine reagent was added with the first one and 1 ml of Benedict's reagent was added on the second. It was continued and repeated until the formation of blue-black organic in iodine and development of brick red colorization in Benedict's reagent.

RESULTS AND DISCUSSION

The desk below summarizes the excellent results for carbohydrates analyzed with different reagents.

Table 1. Positive Reactions for Sugars Test

Test

Positive Color Change

Molisch

Deep purple

Iodine

Blue black

Benedict

Rust colored

Barfoed

Rust colored (monosaccharides)

Seliwanoff

Red color after heat

2, 4-DNP

Yellow black

Carbohydrates can be recognized through different testing. Molisch test which really is a general test for those carbohydrates that provides a deep purple color for a confident effect. Iodine test favorably reacts on the existence of starch giving a blue-black color. On the other hand, Benedict's test is utilized to determine the occurrence of reducing sugar that produce rust-red color. Barfoed's test is used for discovering monosaccharides that likewise have a rust-red color for an optimistic result. On the other hand, Seliwanoff is employed to distinguish monosaccharide ketones that gives a red colorization after heating. And lastly, 2, 4DNP is also an over-all test for those carbohydrates aside from starch which has a yellow-black color because of its positive reaction

The results of the experiments where removed, and the data were compared and thoroughly examined to identify the personal information of the two 2 unknown samples that was distinguished to be Fructose for unidentified 1 and Ribose for the unknown 2.

Table 2. Result of Carbohydrate Samples

Samples

Molisch

Iodine

Benedict

Barfoed

Seliwanoff

2, 4-DNP

Glucose

+

-

+

++

-

+

Galactose

+

-

+

++

-

+

Ribose

+

-

++

+

-

+

Fructose

++

-

+

++

++

++

Lactose

+

-

+

-

-

+

Sucrose

++

-

-

-

False +

++

Starch

+

++

-

-

-

-

Unknown 1

++

-

+

++

++

++

Unknown 2

+

-

+

+

-

+

Identity of Unknown 1

Fructose

Identity of Unknown 2

Ribose

Legend: ++ fast response + slow effect - no reaction

Molisch's Test is a hypersensitive chemical test for many carbohydrates, and some compounds comprising glucose in a distributed form, predicated on the dehydration of carbohydrate by sulfuric to generate an aldehyde (furfural or a derivative) that is then compresses with the phenolic framework resulting in a deep-purple colored mixture. [2]

Figure 1. Result of Glucose with Molisch Test

Starch is a polysaccharide that can be simply recognized by the iodine test. The many glucose items in starch lock in the I2 substances and appearance as dark blue-black organic. [3]

Figure 2. Framework of Starch

Most disaccharides and polysaccharides can be simplified to their monosaccharide subunits by a way called hydrolysis. In live systems, substances known as enzymes assists this break down. Hydrolysis of starch is vital for the organism to employ the sugar monomers. A substance hydrolysis can be carried out in the lab by home heating the polysaccharides with acid in the occurrence of drinking water. [4]

Table 3. Hydrolysis of Starch

Time (min)

Color w/ Benedict's test

Time (min)

Color w/ Iodine test

5

Blue

5

Bluish black

10

Brick Red

10

Light Brown

The change in iodine color with the accumulation of starch and enzyme solution will signify starch hydrolysis. In case the iodine turns blue-black, this implies the presence of starch, which means denatured enzyme. In the event the iodine remains orange-yellow color, it shows the lack of starch, thus the proper function of amylase. In Benedict's test, as the temp increases, development of brick red colorization begins; this is due to recognition of sugar. [5]

Figure 3. Result of Glucose with Benedict's Test

All monosaccharides and numerous disaccharides diminish feeble oxidizing brokers like Cu2+ ion. These carbohydrates are called minimizing sugars Benedict's reagent changes color form blue to brick red in the occurrence of reducing sugars. [4]

Reducing glucose is a glucose that, in a mixture, comes with an aldehyde or a ketone group. The enolization of sugar under alkaline environments is a substantial contemplation in reduction tests. The capability of a sugars to tone down alkaline test reagents is determined by the promptness of the aldehyde or keto group for reduction reactions. [3]

Figure 4. Reaction of Sugars with Seliwanoff Test

Seliwanoff's test is used to differentiatealdohexoses from ketohexoses. A ketohexose just like fructose will generate a deep red color with Seliwanoff's reagent while an aldohexose will display a light red color and requires a longer time to create the color. This test is dependant on the fact that, when settled burning, ketoses are more precipitously dehydrated than aldoses. [4]

Figure 5. Reaction of Sugars with Barfod's Test

Barfoed's reagent is composed of copper acetate in acetic acidity and can not be reactive as Benedict's reagent. Additionally it is stable so that it can be only reduced by monosaccharids but not less authoritative lowering sugars. Dissacharides may also respond with this reagent, however the response is much less fast when compared to monosaccharides. [3]

Figure 6. Reaction of Carbohydrates with 2, 4-DNP Test

2, 4-DNP test can behave with both ketone and aldehyde. Therefore it's also an over-all test for all sugars except starch. A good reaction results to a yellow-black color. Thus, absence of yellow-black color shows negative consequence.

When it comes to Diabetes test, urine taxing is n necessary part of complete physical test program. Urine test assists with diagnosing the state of your body and give important diagnosis. [6]

Benedict's test is utilized to sense the occurrence or absence of sugar in the urine is tremendously easy and should be leant by every diabetic. Even when glucose has been found to be in the urine, the analysis of diabetes should be completed by blood-sugar analysis. [6]

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