Category: Chemistry Notes PPT

For the students of Chemistry, it is important to learn about the process of Filtration, but there is one thing that the students always have to keep in mind, which is that the explanation of the topic must be done in a language that is easy for the students to understand, otherwise instead of clearing the concept of filtration, the explanation only complicates it. Therefore, to make it easy for the students to understand, provides a complete explanation of the Filtration, along with its definition, process, and examples.

Understanding the Concept of Filtration

In liquid and gaseous fluids, the solid particles are always present, and the process which is used in order to remove such solid particles from the liquid and gaseous fluids is known as Filtration. What generally happens here, is that the medium which is used as a filter, allows the liquid fluid to pass through but retains the solid particles inside it, and hence the liquid fluid is filtered. An interesting fact about filtration is that the process of filtration is used not only for the liquid fluid, but it is also used for filtration of electricity, light, sound, but of course, the method is different.

The process of filtration has been known to humans for so many years now. Earlier humans used to dig a hole in the sand on the bank of the river, in such a manner that it has a depth below the level of the river water level, therefore the water enters into the hole and gets filtered by the sand. The modern process of filtration works on the same principle, but the only difference is that it works on a large scale with the use of sophisticated machinery.

While opening the bonnet of cars we must have observed that most of the people were cleaning the car air filter which had collected dust in its long run. In a similar way, in our room, we must have cleaned the filter attached in front of an air conditioner to remove the dust.

 

Filtration Definition

Filtration is a physical process by which the solid particles are separated from liquids or gases using a filter or a membrane as a medium that retains solid particles and let the liquid or gases pass through the membrane or filter. 

 

What is Filtration?

Filtration Process: A filter or a membrane is used to separate substances in two different states and the process is called the filtration process. The physical states in which the substances can occur are solid and liquid or solid and gas. Here, generally, the filters are physical, biological, or mechanical in nature. 

The fluid that is filtered out is called the filtrate and the solid that remains or is collected on the filter is the residue. The thin filter medium is a barrier that is crossed by very minute particles of liquid whereas big grains stay on the filter.

 

Filtration Diagram

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This kind of filtration is most common using gravity to settle the matter first. The mixture is then poured on a filter paper and through the gravitational pull, the water drips which is collected as filtrate, and the residue remains in the filter paper itself.

Filters in Use: Filtration Examples: Some of the most common filter aids used were silica, diatomaceous earth, cellulose, and perlite. They can be used alone or with paper filters.

A very simple and proven example of filtration is that if we have sand, salt, and water in a beaker, then the salt gets dissolved in water whereas sand remains as such and it settles down at the bottom of the beaker. Now, we need to separate sand from saltwater, which can be done easily by means of filtration process using a Whatman filter paper of Grade 1. The sand remaining on the filter paper is called a residue, whereas saltwater now called the filtrate passes through the filter paper and is collected in a beaker. Another good example is the filtration of the air from dust in an air conditioner. Here, pure air is sucked inside by the air conditioner containing dust. This dust is never seen through naked eyes. So, when a filter is attached in front of the AC the dust is collected on the filter and we receive pure air which is an example of filtration of solid in gas.

Applications of Filtration

In our daily life, we apply the process of filtration in many ways. A few examples are:

• We filter the hot tea using a mesh filter, where milk has dissolved the juices of tea leaves and sugar that is filtered out as filtrate whereas tea dust or leaves remains as a residue. We brew coffee powder in hot water after filtering the liquid coffee is the filtrate and the large particle or coffee dust remains as a residue.

• Nowadays vacuum cleaners are used with attached filters to soak the dust inside.

• In rainwater harvesting, the rainwater is stored in a tank. This water is passed through pumps into several sedimentary tanks and filters and then made disinfectant before using it for household purposes. In this way, the soil, sand, and other biological organisms like insects are filtered out to get clean water.

• In our kidneys, blood is constantly filtered through the microscopic filter, glomerulus, where the essential nutrients are absorbed back and urea is a toxic residue that is collected in the kidney and discharged out of the body.

• Many oils are scented and full of nutrients by absorbing the essential oils of other flowers, fruits, and nuts. They are then filtered and used as medicinal remedies.

• In laboratories, filtration is a very important process. Many oil-based substances are dissolved in oil and water-based substances that do not dissolve remain as residue that can be again dissolved in water and used.

 

Seven Steps of Water Purification Process

The detailed steps followed for water treatment depend solely on the nature of raw water and the required standard of water quality used in the industry and households. General steps used for purification of drinking water include:

1. Aeration of Water: Raw water is collected in a large aeration tank. Air is passed through the water by means of perforated pipes. Aeration removes bad odors and [CO_{2}]. Some of the unwanted metals such as manganese, iron in the water can be removed by precipitating them as hydroxides.

2. Storage or Settling of Dust and Wastes: Aerated water is kept in a settling tank for 10 to 15 days. By this process solids as well as heavier metals settle down at the bottom of the tank which makes the water clear. Pathogenic bacteria gradually die as well as some of the organic matter in the water gets oxidized during storage.

3. Coagulation Tank: Water is then placed in the coagulation tank. Some precipitating agents, such as lime, alum, etc. are mixed in the water. These agents from Aluminium hydroxide, [Al(OH)_{3}] precipitate when it is mixed with water. Thus, suspended solids absorbed on the surface of the lime/alum particles are precipitated out of the water and settle down at the bottom of the tank.

4. Filtration: Water is then passed through sand in a gravity filter. Here, about 98% of microorganisms and other impurities are eliminated.

Gravity water filter tank has the basic three layers: 

• Top Layer: It is a fine layer of 1-m thickness.

• Middle Layer: It is a 0.3- to 0.5-m thick layer of coarse sand granules.

• Bottom Layer: It is a 0.3- to 0.5-m thick layer of white gravel. 

5. Collection Tank: At the bottom of the filter bed there is a collection tank that collects the filtered water. 

6. Disinfecting the Water: Disinfectants like chlorine kill pathogens as well as other microorganisms in water.

7. Overhead Storage Tank: Disinfected water is pumped into this tank to keep water for domestic distribution.

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A formal charge (F.C. or q) is the charge assigned to an atom in a molecule in the covalent view of bonding, assuming that electrons in all chemical bonds are shared equally between atoms, regardless of relative electronegativity.

The formal charge is the difference between an atom’s number of valence electrons in its neutral free state and the number allocated to that atom in a Lewis structure.

When choosing the optimum Lewis structure (or predominant resonance structure) for a molecule, it is important to keep the formal charge on each of the atoms as low as feasible.

The following equation can be used to compute the formal charge of an atom in a molecule:

F = V – L – [frac{B}{2}]

Where,

F = Formal Charge

V = Valence Electron of the neutral atom in isolation

L = Number of non-bonding valence electrons on this atom in the molecule

B = Total number of electrons shared in bonds with other atoms in the molecule

Formula, Calculation, Importance, and Example

The formula for computing a formal charge is:

(Number of valency electrons in neutral atom)-(electrons in lone pairs + 1/2 the number of bonding electrons)

The number of bonding electrons divided by two equals the number of bonds that surround the atom, hence this expression can be reduced to:

Formal Charge = (number of valence electrons in neutral atom)-(non-bonded electrons + number of bonds)

Example 1:

Take the compound BH4 or tetrahydrdoborate.

Boron (B) possesses three valence electrons, zero non-bonded electrons, and four bonds around it.

This changes the formula to 3-(0+4), yielding a result of -1.

Let us now examine the hydrogen atoms in BH4. One valence electron, zero non-bonded electrons, and one bond make up hydrogen.

In BH4, the formal charge of hydrogen is 1-(0+1), resulting in a formal charge of 0.

Example 2:

Calculate the formal charge on the following:

O atoms of O3

Cl atom in HClO4- ion

S atom in HSO4- ion

Ans: We are showing how to find a formal charge of the species mentioned.

Formal charge on O1: 6 – 6/2 – 2 = +1

Formal charge on O2: 6 – 4/2 – 4 = 0

Formal charge on O3: 6 – 2/2 – 6 = -1

Formal charge on Cl atom of HClO4 ion: 7 – 8/2 – 0 = 3

Formal charge on S atom of HSO4- ion: 6 – 8/2 – 0 = 2

Significance

1. Molecular Structure

An atom in a molecule should have a formal charge of zero to have the lowest energy and hence the most stable state. If there are numerous alternatives for a molecule’s structure, this gives us a hint: the one with the least/lowest formal charges is the ideal structure.

2. Resonance

While formal charge can indicate a molecule’s preferred structure, the problem becomes more complicated when numerous equally preferred structures exist. This condition could point to resonance structures, especially if the structures have the same atom arrangement but different types of arrangements of bonds.

3. Reactivity

The formal charge of a molecule can indicate how it will behave during a process. A negative formal charge indicates that an atom is more likely to be the source of electrons in a reaction (a nucleophile). If it has a positive one, on the other hand, it is more likely to take electrons (an electrophile), and that atom is more likely to be the reaction’s site.

It’s also worth noting that an atom’s formal charge differs from its actual charge. Formal charge ignores electronegativity and assumes that electrons in a bond are uniformly distributed.

It’s only a courtesy that’s utilized to make molecular structures and reaction mechanisms more understandable. The actual charge, on the other hand, is based on the electronegativities of the atoms and the polarity of the bonds and looks at the actual electron density.

Importance Of Formal Charge 

Now that we know what is the formal charge and we are familiar with the process for calculating a formal charge, we will learn about its importance. 

• The formal charge is a theoretical concept, useful when studying the molecule minutely. It does not indicate any real charge separation in the molecule. This concept and the knowledge of ‘what is formal charge’ is vital.

• The formal charge is crucial in deciding the lowest energy configuration among several possible Lewis structures for the given molecule. Therefore, calculating formal charges becomes essential.

• Knowing the lowest energy structure is critical in pointing out the primary product of a reaction. This knowledge is also useful in describing several phenomena.

• The structure of least energy is usually the one with minimal formal charge and most distributed real charge. 

Besides knowing what is a formal charge, we now also know its significance. 

Fun Facts On Formal Charge 

• In organic chemistry, convention governs that formal charge is essential for depicting a complete and correct Lewis-Kekulé structure. However, the same does not apply to inorganic chemistry.  

• The structure variation of a molecule having the least amount of charge is the most superior. 

• The differences between formal charge and oxidation state led to the now widely followed and much more accurate valence bond theory of Slater and the molecular orbital theory of Mulliken.

A rearrangement reaction is a class of organic reactions, in this class, a molecule’s carbon skeleton undergoes rearrangement to produce a structural isomer of the original molecule. A substituent moves within the same molecule from one atom to another atom frequently.

Different Rearrangement Reactions:

Curtius Rearrangement or Curtius Reaction:

Curtius’ reaction includes the heating of an acyl azide. This acyl azide loses nitrogen and then gets rearranged to an isocyanate.

Claisen Rearrangement:

The typical claisen rearrangement is the first and slow step of the isomerization of allyl and aryl ethers to ortho alkylated phenols. A cyclohexanone is generated in the actual rearrangement step. It is a [3,3]-sigmatropic rearrangement.

Beckmann Rearrangement:

In this particular rearrangement reaction, an oxime is transformed into an amide.

Hofmann Rearrangement:

The Hofmann rearrangement occurs from the treatment of a primary amide with bromine and hydroxide ion in water. This results in the formation of an amine in which the carbonyl group of the starting amide is lost.

Fries Rearrangement: You are going to study about this rearrangement in detail here.

About Fries Rearrangement:

Fries rearrangement is an exciting reaction in organic chemistry. Fries Rearrangement is a rearrangement reaction of organic chemistry in which an aryl ester is converted to a hydroxy aryl ketone with the assistance of aqueous acid and a Lewis acid catalyst.

In Fries Rearrangement reaction, an acyl group of the phenolic ester gets transferred to the aryl ring. It is also interesting to observe that Fries rearrangement is selective to ortho and para positions, which means that, the acyl group gets attached to the ortho position or para position of the aryl ring. This particular selectivity of the reaction is managed by making specific changes in the reaction conditions (the reaction conditions include the temperature under which the response is made or the solvent used for the reaction).

Example-First phenol is converted to phenylacetate.

For this reaction to take place, phenol is treated with a base (NaOH) in the presence of pyridine to produce a phenoxide ion. And then sodium phenoxide is formed. Sodium phenoxide is later treated with acetyl chloride to produce an ester. In this reaction, NaCl is released. The ester produced is phenylacetate.

When phenylacetate is subjected to a Lewis acid (AlCl₃), rearrangement occurs, and ortho hydroxy acetophenone and para hydroxy acetophenone is produced. This particular rearrangement is called fries rearrangement.

There have been many efforts to determine a particular mechanism for Fries rearrangement. A conclusive reaction mechanism for the Fries rearrangement is yet to be determined. There has been evidence for inter-and intramolecular mechanisms which were obtained by crossover experiments with mixed reactants. The Reaction progress is independent of solvent or substrate. There is a widely accepted mechanism present though. This mechanism involves the formation of a carbocation intermediate.

Fries Rearrangement Mechanism

At first, the carbonyl oxygen of the acyl group gives rise to a complex with a Lewis acid catalyst (Aluminium chloride). Since the carbonyl oxygen has more number of electrons, it is, hence, a better Lewis base. Therefore, the formation of this complex with the carbonyl oxygen is favoured over the construction of the complex with the phenolic oxygen.

Thus, the bond between the acyl complex and the phenolic oxygen gets polarized; this results in the rearrangement of the AlCl₃ bond to the phenolic oxygen. This furthermore leads to the formation of the acylium carbocation. The acylium carbocation now attacks the aromatic ring utilizing the electrophilic aromatic substitution reaction.

It is also of utmost importance to note that the orientation of this electrophilic aromatic substitution is highly dependent on temperature. Lower reaction temperatures facilitate substitution at the para position. Relatively high temperatures lead to substitution at ortho positions.

The usage of non-polar solvents in this rearrangement reaction also favours the substitution at the ortho position. Highly polar solvents enable para-substituted products in this rearrangement reaction. This particular rearrangement reaction and its mechanism are called fries rearrangement reaction.

Limitations of Fries Rearrangement:

The essential limitations of Fries rearrangement are as follows:

• Due to its relatively severe reaction conditions, only esters with somewhat less reactive acyl components can be used in this reaction.

• Relatively lower yields are received when heavily substituted acyl components are used.

• When deactivating or meta-directing groups are present on the aromatic ring, this also results in relatively lower yields.

Photo-Fries Rearrangement:

A photochemical variation is also possible in addition to the normal thermal phenyl ester reaction. The photo-Fries rearrangement can give [1,3] and [1,5] products. This includes a radical reaction mechanism. This reaction is can also be done by deactivating substituents on the aromatic group. Since the yields are low, this procedure is not recommended for commercial production.

Anionic Fries Rearrangement:

In this type of Fries rearrangement, ortho-metalation of aryl esters, carbonates, carbamates, with a strong base leads to the rearrangement to produce the ortho-carbonyl species.

It is used in the synthesis of aromatic ring compounds such as aromatic halides and aromatic aldehydes. It is similar to the Friedel-Crafts reaction. It is named after German Chemist Ludwig Gattermann. It is also known as Gattermann Formylation. In Gattermann Reaction for the formation of aromatic halide diazonium salt reacts with copper powder in presence of corresponding halogen acid. It is a substitution reaction. 

Gattermann Reaction can be written as Follows –  

How is Diazonium Salt Formed? 

Aromatic amine reacts with nitrous acid and mineral acid to form diazonium salt and produces water as a side product. This reaction is known as Diazotization Reaction.

Reaction can be written as follows- 

ArNH₂               +            HNO₂                    +      HX        🡪          RN₂+X–       +         H₂O           

Aromatic amine nitrous acid        mineral acid        Diazonium salt      water

Diazotization of Aniline

It is done by treating aniline with sodium nitrate and HCl at the temperature of 273K. the reaction involved is given below – 

Synthesis of Aromatic Aldehyde by Gattermann Reaction 

Gattermann Reaction Mechanism 

The mechanism of the Gattermann Reaction is explained for the formation of aromatic aldehydes. The reaction takes place by following four steps – 

Step 1. Formation of Formimino Chloride 

Hydrogen cyanide reacts with hydrogen chloride and forms chloride. 

The reaction can be written as follows – 

Step 2. Formation of Electrophile 

Formimino chloride reacts with lewis acid catalysts (such as AlCl3) and forms cations. The reaction is given below – 

Step 3. Attack of Electrophile on Benzene Ring 

Formimino cation (electrophile) attacks benzene rings and forms benzylamine. The reaction is given below –

Step 4. Hydrolysis of Benzylamine 

Hydrolysis of benzylamine takes place in this step. Which results in the formation of benzaldehyde. The reaction is given below – 

Applications of Gattermann Reaction 

• It is used for the formation of chlorobenzene and bromobenzene. 

• It is used for the formation of benzaldehydes. 

• Products of Gattermann Reaction such as benzaldehydes and haloarenes etc. are used in various fields such as pharmaceuticals, agricultural, medicinal etc. 

• It is used in the formation of aromatic halides and aromatic aldehydes. 

If you want to learn all name reactions and their mechanisms then check out articles available on such as Important name reactions for Class 12 Chemistry, Cannizzaro reaction, Friedel-craft reaction, Gattermann-Koch reaction mechanism etc. If you want to get free PDFs of NCERT Solutions, Study material, mock tests, revision notes etc. then register yourself on or download learning app for Class6-10, IITJEE & NEET.

Talking about the Gattermann Reaction, when the synthesis of any aromatic ring compounds like aromatic halides and aromatic aldehydes. There is one more reaction that is somewhat similar to the Gattermann Reaction, and it is known as the Friedel Crafts reaction. This reaction is named after the famous chemist, the German Ludwig Gattermann. It is sometimes also known as Gattermann Formulation. While using this reaction, when we are forming aromatic halide diazonium salt is reacted with copper powder in the presence of corresponding halogen acid. It is also a substitution reaction.

The Formation of Diazonium Salt

Only when the aromatic amine is reacted with mineral acid and nitrous acid, the diazonium salt is formed. This whole process also has a side product that is water. The whole reaction is known as Diazotization Reaction. This reaction can also be written as the following chemical equation:

ArNH₂ + HNO₂ + HX + RN₂ +X^– + H₂O

The Mechanism of Gattermann Reaction

There are a certain number of steps that need to be followed in order to complete the Gattermann Reaction. This process consists of 4 steps, which are given below:

The first and foremost step in order to create a Gattermann Reaction is to create a Formimino Chloride. In this, hydrogen chloride reacts with hydrogen cyanide which in turn forms Formimino chloride.

The next step is to create Electrophile. As a result, the formimino chloride is reacted with a lewis acid catalyst and helps in the formation of forming cation, which is also known as Electrophile.

The third step explains how the Formimino cation (Electrophile) attacks benzene rings and in the result forms benzylamine.

The fourth step is also one of the most interesting and important steps. In this step, the hydrolysis of Benzylamine occurs. Which in turn produces benzaldehyde.

Now, let us discuss some of the major applications of the Gattermann Reaction.

The applications are given below:

• It can be used to form aromatic halides and aromatic aldehydes.

• There are many products of the Gattermann Reaction, such as benzaldehydes and haloarenes, etc. These elements in turn are used in various applications or fields of agriculture, pharmaceuticals, medicine, etc.

• It is also used to form benzaldehydes.

• It is also used to form chlorobenzene and bromobenzene.

All these applications are also the use-cases of the Gattermann Reaction. These uses are the majority in the chemical field.

Glycogen is a polysaccharide (abundant carbohydrate) of glucose that serves as a source to store energy in fungi and animals. The polysaccharide structure of glucose gives the basic storage form of glucose in the body. Glycogen is produced and stored in the liver cells and hydrated muscles with the four parts of water. It is the secondary long-term energy storage. Muscle glycogen can be quickly converted into glucose by muscle cells and liver glycogen converts into glucose for use throughout the body including the central nervous system. 

Structure of Glycogen

Glycogen is built with long polymer chains of glucose units bonded with alpha acetal linkage. This acetal linkage is formed by combining the carbonyl group and the alcoholic group. If the carbonyl group is an aldehyde group i.e (-CHO) and also known as hemiacetal if there is a ketonic group. If 2 alkoxy groups are bonded to the same carbon atom, it belongs to the acetal group.

Glycogen is the analog of starch i.e., glucose polymer, in plants, it acts as energy storage. It has the same structure as amylopectin which is a starch, more widely branched and compacted than starch. This polymer of glucose residues is linked by a -(1,4) and a-(1,6)- glycosidic bonds. It is found in different cell types in the form of granules in the cytoplasm and plays a vital role in the glucose cycle. It is an energy reserve that is easily mobilized to meet the needs for glucose.

Every glycogen granule has its core in protein as the glycogen is synthesized. Glycogen is stored in the hydrated form In muscles, liver, and fat cells.

Functions of Glycogen

Liver glycogen acts as a reserve to store glucose released by the hepatocyte when there is a necessity to maintain normal blood sugar levels. There is about  40 kcal in body fluids while after a fasting night hepatic glycogen can provide about 600 kcal.

In skeletal and cardiac muscles, glucose from glycogen reserves remains within the cells and can be used as an energy source from muscle work.

The brain consists of a small quantity of glycogen in astrocytes. It gets produced during sleep and can be mobilized upon walking. Glycogen reserves also guarantee a moderate level of protection against hypoglycemia.

It has a specific role in fetal lung type II pulmonary cells. These cells start to produce glycogen at about 26 weeks of gestation and can synthesize pulmonary surfactant.

Other Tissues

Glycogen can also be found in smaller amounts in other tissues like kidney, white blood cells, and red blood cells and in addition to the muscle and liver cells. In order to provide the energy needs of the embryo, the glycogen will be used to store the glucose in the uterus. The glycogen after the breakdown will enter the glycolytic or pentose phosphate pathway or it will be released into the bloodstream. 

Bacteria and Fungi

Microorganisms like bacteria and fungi possess some mechanisms for storing the energy to deal with the limited environmental resources; here the glycogen represents the main source for the storage of energy. The nutrient limitations such as low levels of phosphorus, carbon, sulfur or nitrogen can stimulate the glycogen formation in yeast. 

The bacteria synthesize glycogen in response to the readily available carbon energy sources with restriction of other required nutrients. The yeast sporulation and bacterial growth are associated with glycogen accumulation. 

Metabolism of Glycogen

The glycogen homeostasis which is a highly regulated process will allow the body to release or store the glucose depending upon its energetic needs. The steps involved in glycogen metabolism are glycogenesis or glycogen synthesis and glycogenolysis or glycogen breakdown.

Glycogenesis or Glycogen Synthesis

The glycogenesis requires energy that is supplied by Uridine Triphosphate (UTP). glucokinase or hexokinase first phosphorylate the free glucose to form glucose-6 phosphate which will be then converted to glucose-1 phosphate by the phosphoglucomutase. The UTP glucose-1 phosphate catalyzes the activation of glucose in which the glucose-1 phosphate and UTP react to form UDP glucose.

The protein, glycogen catalyzes the attachment of UDP glucose, itself in the glycogen synthesis. Glycogenin contains a tyrosine residue in each subunit that will serve as an attachment point for the glucose; further glucose molecules will be then added to the reducing end of the previous glucose molecule in order to form a chain of nearly eight glucose molecules. By adding glucose through α-1, 4 glycosidic linkages the glycogen synthase then extends.

The branching catalyzed by amyloid 1- 4 to 1- 6 transglucosidase is called the glycogen branching enzyme. A fragment of 6- 7 glucose molecules gets transferred from the glycogen branching enzyme from the end of a chain to the C6 of a glucose molecule that is situated further inside of the glucose molecule and forms α-1, 6 glycosidic linkages.

Glycogenolysis or Glycogen Breakdown

The glucose will be detached from glycogen through the glycogen phosphorylase which will eliminate one molecule of glucose from the non-reducing end by yielding glucose-1 phosphate. The glycogen breakdown that generates glucose- 1 phosphate is converted to glucose- 6 phosphates and this is the process that requires the enzyme phosphoglucomutase.

Phosphoglucomutase will transfer a phosphate group from a phosphorylated serine residue within the active site to C₆ of glucose- 1 phosphate and it will be attached to the serine within the phosphoglucomutase and then the glucose- 6 phosphates will be released. 

Glycogen phosphorylase will not be able to cut glucose from branch points, so the debranching will require 1- 6 glucosidase, glycogen debranching enzyme (GDE) or 4- αglucanotransferase which will have glucosidase activities and glucosyltransferase. 

Nearly four residues from a branch point, the glycogen phosphorylase will be unable to remove the glucose residues.

The GDE will cut the final three residues of the branch and it will attach them to C₄ of a glucose molecule at the end of another branch and then eliminate the final α- 1- 6 linked glucose deposit from the branch point.

Glycogen and Diet

The food is taken, and the activities done can influence the production of glycogen and the way the body will function. With a low- carb diet, the primary source for glucose synthesis i.e. the carbohydrate will be suddenly restricted.

During the start of a low- carb diet, the glycogen stores will be severely depleted which will result in symptoms of mental dullness and fatigue. Then when the body starts to adjust and renew its glycogen stored then the body will return to the normal stage. Any weight loss effort can trigger this effect to some extent.

At the starting of a low- carb diet, the body will experience a huge drop in weight which will plateau and may even increase after a period of time. This is mainly because of the glycogen which will be composed mainly of water that will be 3- 4 times the weight of glucose itself.

The rapid depletion of glycogen at the beginning of the diet will trigger the rapid loss of water weight. Then, when the glycogen stores are renewed, the water weight returns causing weight loss to halt. It is necessary to keep in mind that this is caused by the temporary gain in water weight and not the fat and the fat loss can continue in spite of this short-term plateau effect.

During exercise, the body undergoes glycogen depletion and most of the glycogen will be depleted from the muscle. So while doing exercise, the person can use carbohydrate loading which means the consumption of large amounts of carbohydrates in order to increase the capacity for the storage of glycogen. Glycogen is different from the hormone glucagon and it also plays an important role in carbohydrate metabolism and blood glucose control. 

What is Gum Arabic?

Gum arabic, also called gum acacia, is a tree exudate obtained from the Acacia Senegal branches and stems.

Gum arabic majorly comprises high molecular weight polysaccharides including their calcium, magnesium, and potassium salts, that of hydrolysis, which yields arabinose, galactose, rhamnose, and glucuronic acid. It is a purely vegetable product and a harmless edible biopolymer. Sometimes, Gum Arabic from Acacia Senegal is also referred to as Talha.

Other names of gum arabic are gum acacia, acacia gum, Arabic gum, Indian guma, acacia, and Senegal gum. The term “gum arabic” was derived as this gum was shipped to Europe from Arabian ports in former times. Although the term “Arabic” deserves to be capitalized, yet “gum arabic” is considered as a predominant spelling.

Gum Arabic Structure

The structure of gum arabic is given below.

Properties of Gum Arabic

Let us look at some properties of Gum Arabic.

Physical Properties of Gum Arabic

The physical properties of gum arabic are tabulated below.

Chemical Properties of Gum Arabic

Production of Gum Arabic

While gum arabic is harvested in Sudan, West Asia, and Arabia since ancient times, the sub-Saharan acacia gum is considered as a prized export. The exported gum has come from the acacia trees band that once covered most of the Sahel region, the Sahara Desert’s southern littoral, running from the Atlantic Ocean to the Red Sea. 

Now, we can find the main populations of gum-producing Acacia species in Senegal, Mauritania, Mali, Nigeria, Chad, Somalia, Ethiopia, Tanzania, and Kenya. Acacia is tapped for gum arabic by stripping bits off the bark, where the gum exudes. 

Acacia gum remains the main export of several African nations, which is traditionally harvested by the seminomadic desert pastoralists in transhumance cycle course, including Niger, Sudan, and Chad. As of 2019, a total world gum arabic exports have estimated at 160,000 tonnes, having recovered from the 1987–1989; 2003–2005 crises caused by the destruction of trees by the locust desert.

Functions of Gum Arabic

Let us discuss some industries where gum arabic is used.

Photography

The process of historical gum bichromate photography uses gum arabic, which is mixed with potassium dichromate or ammonium and a pigment to create a coloured photographic emulsion, becomes relatively insoluble in the water upon exposure to ultraviolet light. Also, acacia gum binds the pigments permanently onto the paper in the final print.

Printmaking

Gum arabic can be used to protect and etch an image in lithographic processes, both from aluminum plates and traditional stones. In the lithography method, gum by itself can be used to etch very light tones, like those made with a number-five crayon. Nitric acid, tannic acid, or phosphoric acid is added in different concentrations to the acacia gum in etching the darker tones up to dark blacks. 

The process of etching also creates a gum adsorb layer within the matrix that causes to attract water by ensuring the oil-based ink is not sticky in those areas. The gum is also important in the paper lithography process, which is printed from an image created by a photocopier or laser printer.

Fuel Charcoal

Gum arabic can also be used as a binding agent in fuel charcoal making. Charcoal, which is made from the plant of taifa, is powdery, and thus to form charcoal cakes, the gum arabic is mixed with this powder and allowed to dry. Fuel charcoal, which is made from the gum arabic and taifa plant, is burnt in the kitchen in the cooking process of food in Senegal and some other African countries.

Uses of Gum Arabic

Some of the uses of Gum Arabic are listed below.

• The gum usage produces a more transparent effect than the glair, which is why the colour tends to be laid more thinly and appear darker and richer.

• Used more generously compared to glair, if a little amount of honey or sugar is added to keep it from becoming brittle.

• In brewing, gum arabic can be used as an agent to promote foam adhesion to glass and as a foam stabilizer.

• Gum arabic can be used as a basic ingredient of familiar foods like marshmallows, chewing gum, and licorice.

• Professional bartenders widely use gum or Gum syrup to prepare a few cocktails. These are essentially prepared with sugar water and addition of gum arabic for a pleasing taste.

• It is also used as a clarity stabilizer in the chemical treatment of wines.

Did You Know?

Gum arabic can be defined as a complex mixture of polysaccharides and glycoproteins. It is also the original source of arabinose sugars and ribose. Primarily, gum arabic is used in the food industry as a stabilizer.

The side effects of gum arabic include allergic reactions, adverse effects in clinical trials, which include early morning nausea, unpleasant mouth sensation, bloating, and moderate diarrhoea.