CONTENTS

01 From Editor’s Desk

02 Message

03 Seminar Topics

i. Food additives ii. Chemistry of Ice cream iii. Noble prize hatching Cryo- electron

spectroscopy iv. Pesticides v. Caffeine

Sl No. TOPICS

E-Quest the e-journal of P.G. Department of Chemistry, is

coming out to break the status quo. It aspires to keep the academic excellence on wings of fire. The students and faculty members of Vikram Deb Autonomous College are not just followers but they are leaders. In the pages of the e-journal, they have proved their worth. The pages of the journal are vibrant. This is a promising thrust on changes for the better. It would leave its mark on sands of time.

We are all hopeful that this e-journal would give our students strength enough to give shape to their dreams.

Mr. Ranjan Kumar Pradhan

Editor

From Editor’s Desk..

Dr. (Mrs.)Rachana Acharya

PRINCIPAL

Mr. Ranjan Kumar Pradhan

HEAD, CHEMISTRY

MESSAGES

I am extremely delighted to publish e-Quest the quarterly

magazine of our Department to highlight the innovative

activities of our students and faculty members.

I wish all the best of the e-magazine.

Publication of e-quest is a commendable effort. It exposes the hidden

talent of our faculty members and students. The students add

something new to the academic records and the teachers make our

future brighter with their research. I hope this monthly publication

will bring all our achievements to light. This may be received as an

invitation to a prosperous brave new world.

Food Additives

Bishnupriya Hota (PG 2nd year 2018-2019)

Food is any nutritious substance that people or animals eat or drink or that

plants absorb in order to maintain life, growth and maintain energy. There are 4

basic energy sources: fats, proteins, carbohydrates and alcohol. The 6 essential

nutrients in food include carbohydrates, proteins, fat, vitamins, minerals and water.

The substances is ingested by an organism and assimilated by the organism’s cells

to provide energy, maintain life, or stimulate growth.

Introduction

The chemicals which are added to food to improve its selflife, taste, odour and

appearance are called food additives. According to WHO, “ Food additives are

substances which are added either intentionally to food , generally in small

quantities to improve their appearance , flavour , texture , or other secondary

properties or find their way otherwise, into food during handling processing, or

distribution.”

Some additive have been used for centuries for example

preserving food by pickling using vinegar, salting as with bacon ,

preserving sweets or using Sulphur dioxide as with wines.

History

Our distance ancestors likely smoked meat to improve its taste and

submerged it into salt water as preservative. The proliferation of the species trade

which began as earlier as 3000 bc laid to increased demand for additives to

enhance the taste of food. During this time, it is possible that our ancestors

discovered the preservation benefits of sugar. Historical records also include the

uses of species to preserve meat and inhibit the growth of bacteria.

General principle for use of food additives

1. It must be ascertained that the real need exists for the use.

2. It does not cause any adverse physiological and harmful effects even upon

regular use over a long period

3. It should not reduce the nutritive value of the food.

4. It should confirm the agreed specifications.

5. Where possible legislation should define permissible maximum quantities

for given additive.

6. Even when the additive is considered harmless it is advisable to use as little

as possible .

7. All food additive should be kept under continuous observation and should be

reevaluated whenever required.

Types of food additives

1. Antioxidants

Antioxidants are chemical substances which are added to processed food

to prevent the oxidation of fats and subsequent spoilage of food. These chemicals

are often used in processed food such as potato chips , breakfast cerlacs, biscuits

etc to prevent fat rancidation.

e.g., Butylated hydroxyl toluene, Butylated hydroxylanisole(BHA), Ascorbic acid,

Sulphur dioxide

RANCIDATION OF FATS:

It is a process which causes a substance to become rancid. It refers to the

hydrolysis or autoxidation of unsaturated bonds present in fats to form a

complex mixture of volatile acids, aldehyde, ketone and acids.

2. Sweetners

A substance which is used to impart sweet taste to food or drinks are

generally called sweeteners. They can be natural like Sucrose and Fructose

or Artificial like Saccharin, Cyclamate etc.

Natural sweeteners:

These are exists or pare produced by nature without added chemicals or

Machinery. E.g., stevia(E960), Xylitol(E967), erythritol(E968) etc.

Artificial sweeteners

These are synthetic sugars substitute but may be derived from naturally

occurring substances, including herbs , or sugar itself .These are also known as

intense sweeteners. Saccharin are very useful for diabetics patients as they cant be

broken down in human body and excreted as such. E.g., Sucralose(E955),

Sachharine(E954) etc.

3. Food color Food coloring or color additive is any dye or pigment or

substance that imparts color when it is added to food or drink.

e.g., Titanium Dioxide(E171), Aluminium(173), Caramel Color(E150) etc.

Banned food colors:

Green 1,red 1:promote liver cancer

Orange 1,orange 2,violet 1,red 2,red 32:carcinogenic

Yellow 3 & 4: promote heart damage.

4. Preservatives

Chemicals which are capable of inhibiting or arresting the process of

fermentation, acidification or any other decomposition of food are called

preservatives.

e.g., Benzoic acid(E210), Sulphur dioxide(E220), Sorbic acid(E200) etc.

Unhealthness & disadvantages

ALGINIC ACID- Birth defects,complication in pregnancy.

ALPHA-TOCOPHEROL- Concentrated suplements might bring on toxicity

symptoms such as cramps ,weakness,double vision.

BROMINATED VEGETABLE OIL(BVO): memory loss,,loss of muscle

coordination,deadly poison especially for children.

CARRAGEENAN : causes ulcers , digestive cancers

COCHINEAL EXTRACT- Contains about 90% insect body fragment

HIGH FRUCTOSE CORN SYRUP(HFCS)- Elevated cholesterol, premature

ageing.

MANNITOL – Intestinal discomfort, gas, bloasting.

Conclusion

A food is undoubtedly considered to be the best . However with the advancement

of time we need low calories , functional food additives and food additive are

inseparable part of it. There are a number of benefits of using food additive but

potential health hazards of consuming excess of chemical are matter of concerns.

Now there is need of development of safer food additives and up gradation of

analytic techniques to ascertain quality of it.

References:

1.https://en.m.wikipedia.org/.../food

2.www.libertychemical.com

3.https://more_chem-food_additive.Org

Chemistry of Ice cream

Malaya Ranjan Mallik (PG 2nd year 2018-2019)

Introduction

Ice-cream is a combination of air, ice crystals, fat globules and a liquid syrup.

These are combined to make a colloid, a solution with very small insoluble particle

suspended in it. Generally this is a sweetened frozen food typically eaten as

a snack or dessert. It is usually made from dairy products, such as milk and cream,

and often combined with fruits or other ingredients and flavors.

Typically, flavourings and colourings are added in addition to stabilizers.

The meaning of the phrase "ice cream" varies from one country to another. Phrases

such as "frozen custard", "frozen yogurt", "sorbet", "gelato", and others are used to

distinguish different varieties and styles.

The History of Ice Cream

Ice cream's origins are known to reach back as far as the second century B.C.,

although no specific date of origin nor inventor has been undisputably credited

with its discovery. We know that Alexander the Great enjoyed snow and ice

flavored with honey and nectar. Biblical references also show that King Solomon

was fond of iced drinks during harvesting. During the Roman Empire, Nero

Claudius Caesar (A.D. 54-86) frequently sent runners into the mountains for snow,

which was then flavored with fruits and juices.

Over a thousand years later, Marco Polo returned to Italy from the Far East with a

recipe that closely resembled what is now called sherbet. Historians estimate that

this recipe evolved into ice cream sometime in the 16th century. England seems to

have discovered ice cream at the same time, or perhaps even earlier than the

Italians. "Cream Ice," as it was called, appeared regularly at the table of Charles I

during the 17th century. France was introduced to similar frozen desserts in 1553

by the Italian Catherine de Medici when she became the wife of Henry II of

France. It wasn't until 1660 that ice cream was made available to the general

public.

Ice Cream for America

The first official account of ice cream in the New World comes from a letter

written in 1744 by a guest of Maryland Governor William Bladen. The first

advertisement for ice cream in this country appeared in the New York Gazette on

May 12, 1777, when confectioner Philip Lenzi announced that ice cream was

available "almost every day." Records kept by a Chatham Street, New York,

merchant show that President George Washington spent approximately $200 for

ice cream during the summer of 1790.

Ice cream became an edible morale symbol during World War II. Each branch of

the military tried to outdo the others in serving ice cream to its troops. In 1945, the

first "floating ice cream parlor" was built for sailors in the western Pacific. When

the war ended, and dairy product rationing was lifted, America celebrated its

victory with ice cream. Americans consumed over 20 quarts of ice cream per

person in 1946.

Composition of ice-cream

Ingredients and standard quality definitions

In the U.S., ice cream must have the following composition:[37]

greater than 10% milkfat and usually between 10% and as high as 16% fat in

some premium ice creams

9 to 12% milk solids-not-fat: this component, also known as the serum solids,

contains the proteins (caseins and whey proteins) and carbohydrates (lactose)

found in milk

12 to 16% sweeteners: usually a combination of sucrose and glucose-

based corn syrup sweeteners

0.2 to 0.5% stabilisers and emulsifiers

55% to 64% water, which comes from the milk or other ingredients.

These compositions are percentage by weight. Since ice cream can contain as

much as half air by volume, these numbers may be reduced by as much as half if

cited by volume. In terms of dietary considerations, the percentages by weight are

more relevant. Even the low-fat products have high caloric content: Ben and Jerry's

No-Fat Vanilla Fudge contains 150 calories (630 kJ) per half-cup due to its high

sugar content.[38]

According to Canadian Food and Drug Regulations, ice cream in Canada must be

at least 10 percent milk fat, and must contain at least 180 grams of solids per liter.

When cocoa, chocolate syrup, fruit, nuts, or confections are added, the percentage

of milk fat can be 8 percent.[39]

Physical properties

Ice cream is considered as a colloidal system. It is composed by ice cream crystals

and aggregates, air that does not mixes with the ice cream by forming small

bubbles in the bulk and partially coalesced fat globules. This dispersed phase made

from all the small particles is surrounded by an unfrozen continuous phase

composed by sugars, proteins, salts, polysaccharides and water. Their interactions

determine the properties of ice cream, whether soft and whippy or hard.[40]

Ostwald ripening

Ostwald ripening is the explanation for the growth of large crystals at the expense

of small ones in the dispersion phase. This process is also called migratory

recrystallization. It involves the formation of sharp crystals. Theories about

Ostwald recrystallization admit that after a period of time, the recrystallization

process can be described by the following equation:

r = r (0) + Rt exp(1/n)

Where

r (0) = the initial size,

n = order of recrystallization,

t = time constant for recrystallization that depends on the rate R (in units of size/

time).

To make ice cream smooth, recrystallization must occur as slowly as possible,

because small crystals create smoothness, meaning that r must decrease

Advantage: A Source of energy

Although, the nutritional content of ice cream varies among brands and types, in

general it is an excellent source of energy. Ice cream is rich in carbohydrates,

proteins which make it an energy dense food. It is also rich in calcium and

phosphorous. Both Ca and P promote strong , healthy bones. Ice cream is a good

choice when you need energy or if you are pursing a program to gain weight.

Disadvantages: fat and sugar content

Ice cream is a high- fat food. Milk fat is largely cholesterol, a saturated fat. When

your blood cholesterol level is too high, it can build up as plaque, a fatty deposit in

your arteries that interferes with blood flow and raises your risk of heart disease

and stroke.

Consumption of too much sugar may contribute to health problems such

as weight gain, cavities and increased level of blood triglycerides, another

unhealthy type of fat.

Conclusion

To lower our risk due to consumption of ice cream for high cholesterol and sugar

related problems, we have to consume ice cream in moderation or choose a low-fat

ice cream substitute.

Reference:-

^ "Who Invented Ice Cream? - Ice Cream Inventor". www.icecreamhistory.net.

Retrieved 2018-08-31. History of ice creams begun around 500 B.C. in the Persian

Empire where ice was used in combination with grape juices, fruits, and other

flavors to produce very expensive and hard to produce summertime treats.

^ "History of Ice Cream". thenibble.com.

^ The origin of ice-cream, BBC. Retrieved 26 October 2009.

^ Olver, Lynne (30 September 2007). "ice cream & ice". Food Timeline.

Retrieved 9 August 2008.

^ Goff, H. Douglas. "Ice Cream History and Folklore". Dairy Science and

Technology Education Series. University of Guelph. Retrieved 9 August 2008.

^ "To Ice Cream" in Project Gutenberg's Mrs. Mary Eales's Receipts(1733), by

Mary Eales

^ "The History of Ice Cream - International Dairy Foods

Association". www.idfa.org. Retrieved 14 March 2018.

^ Stradley, Linda (2004). "History of Ice Cream Cone". What's Cooking America.

Retrieved 9 August 2008.

^ "History of Ice Cream Cones". Retrieved 24 November 2009.

^ Pat Kendall, Ph.D., R.D. (31 March 2003). "Gluten sensitivity more widespread

than previously thought". Colorado State University Extension.

^ "Colloidal and surface phenomenal aspects of ice cream"

^ Tharp, Ph.D., Bruce; Young, Ph.D., L. Steven (2013). Tharp and Young on Ice

Cream (First ed.). Lancaster, PA: DEStech Publications. p. 410. ISBN 978-1-

932078-68-8. Retrieved 30 December 2014.

^ Gobel, Greg (1 May 2015). "The Vought F4U Corsair". www.airvectors.net.

^ Rosenberg, Zach (August 2018). "DIY Ice Cream in Wartime". Air &

Space/Smithsonian. Retrieved 22 August 2018.

^ Goff, H. Douglas. "Ice Cream Ingredients". Dairy Science and Technology

Education Series. University of Guelph. Retrieved 9 August 2008.

^ Kendall, Pat (25 June 2000). "Ice Cream – What's in a Scoop?". Colorado State

University. Archived from the original on 30 May 2008. Retrieved 9 August 2008.

^ "Business Outlook: ice cream manufacturing (based on a report to be found

through www.ibisworld.com.au)". Reed Business Information. 2005. Archived

from the original on 27 April 2006. Retrieved 3 March 2006.

^ "Ice Cream – UK – September 2009". just-food.com. Aroq Ltd. September 2009.

Retrieved 18 November 2009.

^ Weinstein, Bruce (1999). "Peach Ice Cream, Philadelphia Style". CondéNet, Inc.,

reprinted from William Morrow and Co.'s The Ultimate Ice Cream Book.

Retrieved 24 September 2008.

^ "The Ice House – ice trade and ice cream". Retrieved 17 November 2009.

^ Weir, Robert J. (2004). "An 1807 Ice Cream Cone: Discovery and Evidence".

Historicfood.com. Retrieved 4 January 2009.

^ Stradley, Linda (2004). "Ice Cream Cone, History of Ice Cream Cone".

Whatscookingamerica.net. Retrieved 4 January 2009

Noble Prize Hatching Cryo-electron Spectroscopy

Murali Mohan Nayak (PG 2nd year 2018-2019)

Introduction

Cryo-electron microscopy or electron

cryomicroscopy, is a form of transmission (TEM)

where the sample is studied at cryogenic

temperature (generally liquid-nitrogen

temperature)

WHY ONLY Cryo-EM???

Some materials – particularly bimolecular – are not compatible with the high-

vacuum conditions and intense electron beams used in traditional TEMs. The water

that surrounds the molecules evaporates, and the high energy electrons burn and

destroy the molecules. Cryo-EM uses frozen samples, gentler electron beams and

sophisticated image processing to overcome these problems.

X-Ray diffraction can give very high resolution structures of bio-molecules,

and several Nobel prizes have been awarded for just that. But to get an x-ray

structure, you need to be able to crystallize the molecule. Many proteins won’t

crystallize at all. And in some cases, the process of crystallization alters the

structure, so it’s not representative of what the molecule looks like in real life.

Cryo-EM doesn’t require crystals, and it also enables scientists to see how bio-

molecules move and interact as they perform their functions, which is much more

difficult using crystallography.

History

Jacques Dubochet, Joachim Frank and Richard Henderson were awarded the

prize on 4 October 2017 for their work in developing cryo-electron microscopy

(cryo-EM), a technique that fires beams of electrons at proteins that have been

frozen in solution, to deduce the bio-molecules Joachim Frank’s major

contribution to the field was in processing and analysing cryo-EM images.

He developed computational methods for taking images of multiple, randomly-

oriented proteins within a sample and compiling them into sets of similar

orientations to obtain sharper 2D images. He could then construct a 3D image from

these 2D projections. He used his algorithms to generate images of the ribosome –

a massive structure made of several proteins and RNA strands, which is

responsible for translating RNA into protein inside cells.

It was James Dubochet who put the ‘cryo’ into cryo-EM. He developed a method

for freezing water-based TEM samples so rapidly that the water forms a disordered

glass, rather than crystalline ice. This is important because ordered ice crystals

would strongly diffract the microscope’s electron beam, obscuring any information

about the molecules being studied.

Catapulting the sample into a bath of liquid nitrogen-cooled ethane freezes the thin

film of water on a TEM sample so quickly that the water molecules don’t have

time to arrange into a crystalline lattice. In this ‘vitrified’ sample, the water is

disordered but the 3D structure of the biomolecules in the sample is retained.

Dubochet created the first images of various viruses using vitrified water samples.

CONSTRUCTION OF CRYO-EM :

The set-up for the highly efficient cryo electron microscopy can be discussed as

follows

structure.

s

Resolution revolution:

Although the research recognized by the Nobel Committee was conducted in the

1970s and 1980s, it laid the groundwork for what many scientists have dubbed a

revolution in recent years. Subsequent improvements in the sensitivity of electron

microscopes and in software used to transform their images into 3D structures have

caused many labs to favour the technique over X-ray crystallography.

the Cryo-electron microscopy of proteins such as this β-galaxtosidase enzyme has

progressed from the low-resolution density map on the left to the atomic

coordinates on the right.

Application:

During the recent outbreak of zika -virus in Brazil, a group of researchers

generated a high-resolution 3D image of virus structure in few months, which

provided a starting point for its treatment.

Conclusion

For decades, biologists have used X-ray crystallography — blasting X-rays at

crystallized proteins — to image biomolecular structures. But labs are now racing

to adopt the cryo-EM method, because it can take pictures of proteins that can’t

easily be formed into large crystals. The tool has “moved biochemistry into a new

era”, says the Royal Swedish Academy of Sciences (UCSF), which awards prize.

REFERENCES:

1. https://www.chemistryworld.com/3158.

2. https://en.m.Wikipedia.org.

3. https://www.fei.com.

4. https://www.theguardian.com.

5. https://www.sciencedirect.com

6. https://www.nature.com.

Pesticides

Sibani Barad (PG 2nd year 2018-2019)

Introduction

Pesticides are substances that are meant to control pests, including

weeds. The term pesticide includes all of the following: herbicide, insecticides,

nematicide, molluscicide, piscicide, avicide, rodenticide, bactericide etc.

In general, a pesticide is a chemical or biological agent (such as a virus, bacterium,

or fungus) that deters, incapacitates, kills, or otherwise discourages pests.

History

Since before 2000 BC, humans have utilized pesticides to protect their crops. The

first known pesticide was elemental sulfur dusting used in ancient Sumer about

4,500 years ago in ancient Mesopotamia. The Rig Veda, which is about 4,000

years old, mentions the use of poisonous plants for pest control. By the 15th

century, toxic chemicals such as arsenic, mercury, and lead were being applied to

crops to kill pests. In the 17th century, nicotine sulfate was extracted

from tobacco leaves for use as an insecticide. The 19th century saw the

introduction of two more natural pesticides, pyrethrum, which is derived

from chrysanthemums, and rotenone, which is derived from the roots of

tropical vegetables. Until the 1950s, arsenic-based pesticides were dominant. Paul

Muller discovered that DDT was a very effective insecticide. Organo chlorines

such as DDT were dominant, but they were replaced in the U.S. by

organophosphates and carbamates by 1975. Since then, pyrethrin compounds have

become the dominant insecticide. Herbicides became common in the 1960s, led by

"triaging and other nitrogen-based compounds, carboxylic acids such as 2,4-

dichlorophenoxyacetic acid, and glyphosate".

Types

Pesticides can also be considered as either biodegradable pesticides, which will be

broken down by microbes and other living beings into harmless compounds, or

persistent pesticides, which may take months or years before they are broken

down: it was the persistence of DDT, for example, which led to its accumulation in

the food chain and its killing of birds of prey at the top of the food chain.

1. Insecticides

Neonicotinoids are a class of neuro-active insecticides chemically similar

to nicotine. Imidacloprid, of the neonicotanoid family, is the most widely used

insecticide in the world. In 2013, the European Union and a few non EU countries

restricted the use of certain neonicotinoids.

Organophosphate and carbamate insecticides have a similar mode of action. They

affect the nervous system of target pests (and non-target organisms) by

disrupting acetylcholinesterase activity, the enzyme that regulates acetylcholine, at

nerve synapses. This inhibition causes an increase in synaptic acetylcholine and

over-stimulation of the parasympathetic nervous system. Many of these

insecticides, first developed in the mid 20th century, are very poisonous. Although

commonly used in the past, many older chemicals have been removed from the

market due to their health and environmental effects (e.g. DDT, chlordane,

and toxaphene). However, many organophosphates are not persistent in the

environment.

Pyrethroid insecticides were developed as a synthetic version of the naturally

occurring pesticide pyrethrin, which is found in chrysanthemums. They have been

modified to increase their stability in the environment. Some synthetic pyrethroids

are toxic to the nervous system.

2. Herbicides

A number of sulfonylureas have been commercialized for weed control,

including: amidosulfuron, flazasulfuron, terbacil, nicosulfuron, and triflusulfuron-

methyl. These are broad-spectrum herbicides that kill plants weeds or pests by

inhibiting the enzyme acetolactate synthase. In the 1960s, more than 1 kg/ha

(0.89 lb/acre) crop protection chemical was typically applied, while sulfonylureates

allow as little as 1% as much material to achieve the same effect.

3. Biopesticides

Biopesticides are certain types of pesticides derived from such natural materials as

animals, plants, bacteria, and certain minerals. For example, canola oil and baking

soda have pesticidal applications and are considered biopesticides. Biopesticides

fall into three major classes:

Microbial pesticides which consist of bacteria, entomopathogenic fungi or

viruses (and sometimes includes the metabolites that bacteria or fungi produce).

Biochemical pesticides or herbal pesticides are naturally occurring

substances that control pests and microbial diseases.

Plant-incorporated protectants (PIPs) have genetic material from other

species incorporated into their genetic material (i.e. GM crops). Their use is

controversial, especially in many European countries.

Classified by type of pest :-

Pesticides that are related to the type of pests are:

Type Action

Algicides Control algae in lakes, canals, swimming pools, water tanks, and other sites

Antifouling agents Kill or repel organisms that attach to underwater surfaces, such as boat bottoms

Antimicrobials Kill microorganisms (such as bacteria and viruses)

Attractants

Attract pests (for example, to lure an insect or rodent to a trap). (However, food is not

considered a pesticide when used as an attractant.)

Biopesticides

Biopesticides are certain types of pesticides derived from such natural materials as

animals, plants, bacteria, and certain minerals

Biocides Kill microorganisms

Disinfectants and

sanitizers Kill or inactivate disease-producing microorganisms on inanimate objects

Fungicides Kill fungi (including blights, mildews, molds, and rusts)

Fumigants Produce gas or vapor intended to destroy pests in buildings or soil

Herbicides Kill weeds and other plants that grow where they are not wanted

Insecticides Kill insects and other arthropods

Miticides Kill mites that feed on plants and animals

Microbial pesticides

Microorganisms that kill, inhibit, or out compete pests, including insects or other

microorganisms

Molluscicides Kill snails and slugs

Nematicides Kill nematodes (microscopic, worm-like organisms that feed on plant roots)

Ovicides Kill eggs of insects and mites

Pheromones Biochemicals used to disrupt the mating behavior of insects

Repellents Repel pests, including insects (such as mosquitoes) and birds

Rodenticides Control mice and other rodents

Uses

Pesticides are used to control organisms that are considered to be harmful. For

example, they are used to kill mosquitoes that can transmit potentially deadly

diseases like West Nile virus, yellow fever, and malaria. They can also

kill bees, wasps or ants that can cause allergic reactions. Pesticides can prevent

sickness in humans that could be caused by moldy food or diseased produce.

Herbicides can be used to clear roadside weeds, trees, and brush. They can also kill

invasive weeds that may cause environmental damage. Pesticides are used in

grocery stores and food storage facilities to manage rodents and insects that infest

food such as grain.

DDT, sprayed on the walls of houses, is an organochlorine that has been used to

fight malaria since the 1950s. Recent policy statements by the World Health

Organization have given stronger support to this approach. However, DDT and

other organochlorine pesticides have been banned in most countries worldwide

because of their persistence in the environment and human toxicity.

ADVANTAGES

Pesticides can save farmers' money by preventing crop losses to insects and other

pests; in the U.S., farmers get an estimated fourfold return on money they spend on

pesticides. One study found that not using pesticides reduced crop yields by about

10%. Another study, conducted in 1999, found that a ban on pesticides in the

United States may result in a rise of food prices, loss of jobs, and an increase in

world hunger.

There are two levels of benefits for pesticide use, primary and secondary. Primary

benefits are direct gains from the use of pesticides and secondary benefits are

effects that are more long-term.

CONCLUSION

The National Research Council charged this committee with providing insight and

information on the future of chemical pesticide use in United States agriculture.

The committee was charged to:

Identify the circumstances under which chemical pesticides may be required

in future pest management.

Determine what types of chemical products are the most appropriate tools

for ecologically based pest management.

Explore the most promising opportunities to increase benefits and reduce

health and environmental risks of pesticide use.

Recommend an appropriate role for the public sector in research, product

development, product testing and registration, implementation of pesticide use

strategies, and public education about pesticides.

References

1. ^ "Basic Information about Pesticide Ingredients". US Environmental

Protection Agency. Apr 2, 2018. Retrieved Dec 1,2018.

2. ^ Randall C, et al. (2014). "Pest Management". National Pesticide

Applicator Certification Core Manual (2nd ed.). Washington: National Association

of State Departments of Agriculture Research Foundation.

3. ^ Jump up to:a b "International Code of Conduct on the Distribution

and Use of Pesticides" (PDF). Food and Agriculture Organization of the United

Nations. 2002. Archived from the original (PDF) on 4 April 2013.

4. ^ Jump up to:a b Gilden RC, Huffling K, Sattler B (January 2010).

"Pesticides and health risks". Journal of Obstetric, Gynecologic, and Neonatal

Nursing. 39 (1): 103–10. doi:10.1111/j.1552-6909.2009.01092.x. PMID 20409108.

5. ^ Jump up to:a b "Educational and Informational Strategies to Reduce

Pesticide Risks". Preventive Medicine. 26 (2): 191–200.

1997. doi:10.1006/pmed.1996.0122. ISSN 0091-7435. PMID 9085387.

6. ^ "Types of Pesticide Ingredients". US Environmental Protection

Agency. Jan 3, 2017. Retrieved Dec 1, 2018.

7. ^ Jump up to:a b c d e Kamrin MA (1997). Pesticide Profiles: Toxicity,

Environmental Impact, and Fate (1st ed.). Boca Raton: CRC. ISBN 978-

1566701907. OCLC 35262311.

Caffeine Leeja Rani Samantray(PG second year 2018-2019)

Introduction

Caffeine is a central nervous system (CNS) stimulant of

the methylxanthine class. It is the world's most widely consumed psychoactive

drug.There are several known mechanisms of action to explain the effects of

caffeine. Caffeine also stimulates certain portions of the autonomic nervous

system.

Caffeine is a bitter, white crystalline purine, a methylxanthine alkaloid, and is

chemically related to the adenine and guanine bases of deoxyribonucleic

acid(DNA) and ribonucleic acid (RNA). It is found in the seeds, nuts, or leaves of

a number of plants native to Africa, East Asia and South America, and helps to

protect them against predator insects and to prevent germination of nearby

seeds. The most well-known source of caffeine is the coffee bean, a misnomerfor

the seed of Coffea plants. Caffeine-containing drinks, such as coffee, tea, and cola,

are very popular; as of 2014, 85% of American adults consumed some form of

caffeine daily, consuming 164 mg on average.

History:

in1819, the German chemist Friedlieb Ferdinand Runge isolated relatively pure

caffeine for the first time; he called it "Kaffebase" (i.e., a base that exists in

coffee).]According to Runge, he did this at the behest of Johann Wolfgang von

Goethe. In 1821, caffeine was isolated both by the French chemist Pierre Jean

Robiquet and by another pair of French chemists, Pierre-Joseph

Pelletier and Joseph Bienaimé Caventou, according to Swedish chemist Jöns Jacob

Berzelius in his yearly journal. Furthermore, Berzelius stated that the French

chemists had made their discoveries independently of any knowledge of Runge's or

each other's work.] However, Berzelius later acknowledged Runge's priority in the

extraction of caffeine, stating: "However, at this point, it should not remain

unmentioned that Runge (in his Phytochemical Discoveries, specified the same

method and described caffeine under the name Caffeebase a year earlier than

Robiquet, to whom the discovery of this substance is usually attributed, having

made the first oral announcement about it at a meeting of the Pharmacy Society in

Paris."

Pelletier's article on caffeine was the first to use the term in print (in the French

form Caféine from the French word for coffee: café).

use:-

Medical

Caffeine is used in:

Bronchopulmonary dysplasia in premature infants for both prevention[ and

treatment.It may improve weight gain during therapy and reduce the incidence

of cerebral palsy as well as reduce language and cognitive delay. On the other

hand, subtle long-term side effects are possible.

Apnea of prematurity as a primary treatment,but not prevention. Orthostatic

hypotension treatment.

Some people use caffeine-containing beverages such as coffee or tea to try to

treat their asthma. Evidence to support this practice, however, is poor. A It

appears that caffeine improves airway function in people with asthma,

increasing forced expiratory volume (FEV1) by 5% to 18%, with this effect

lasting for up to four hours. Enhancing performance

Cognitive

Caffeine is a central nervous system stimulant that

reduces fatigue and drowsiness.] At normal doses, caffeine has variable effects on

learning and memory, but it generally improves reaction time, wakefulness,

concentration, and motor coordination. The amount of caffeine needed to produce

these effects varies from person to person, depending on body size and degree of

tolerance. The desired effects arise approximately one hour after consumption, and

the desired effects of a moderate dose usually subside after about three or four

hours. Caffeine can delay or prevent sleep and improves task performance during

sleep deprivation. Shift workers who use caffeine make fewer mistakes due to

drowsiness. A systematic review and meta-analysis from 2014 found that

concurrent caffeine and L-theanine use has synergistic psychoactive effects that

promote alertness, attention, and task switching; these effects are most pronounced

during the first hour post-dose.

Physical

Caffeine is a proven ergogenic aid in humans. Caffeine improves athletic

performance in aerobic (especially endurance sports)

and anaerobic conditions. Moderate doses of caffeine (around 5 mg/kg) can

improve sprint performance, cycling and running time trial

performance, endurance (i.e., it delays the onset of muscle fatigue and central

fatigue), and cycling power output.Caffeine increases basal metabolic rate in

adults.

Caffeine improves muscular strength and power, and may enhance muscular

endurance. Caffeine also enhances performance on anaerobic tests. Caffeine

consumption before constant load exercise is associated with reduced perceived

exertion. While this effect is not present during to exhaustion exercise,

performance is significantly enhanced. This is congruent with caffeine reducing

perceived exertion, because exercise to exhaustion should end at the same point of

fatigue. Caffeine also improves power output and reduces time to completion in

aerobic time trials.

Specific populations

Adults

For the general population of healthy adults, Health Canada advises a daily intake

of no more than 400 mg.

Children

In healthy children, caffeine intake produces effects that are "modest and typically

innocuous".] There is no evidence that coffee stunts a child's growth. For children

age 12 and under, Health Canada recommends a maximum daily caffeine intake of

no more than 2.5 milligrams per kilogram of body weight. Based on average body

weights of children, this translates to the following age-based intake limits:

Age range Maximum recommended daily caffeine intake

4–6 45 mg (slightly more than in 12 oz of a typical caffeinated soft drink)

7–9 62.5 mg

10–12 85 mg (about ½ cup of coffee)

Effects:-

Physical

Caffeine can increase blood pressure and cause vasoconstriction. Coffee and

caffeine can affect gastrointestinal motility and gastric acid secretion. Caffeine in

low doses may cause weak bronchodilation for up to four hours in asthmatics. In

postmenopausal women, high caffeine consumption can accelerate bone loss.

Doses of caffeine equivalent to the amount normally found in standard servings of

tea, coffee and carbonated soft drinks appear to have no diuretic action. However,

acute ingestion of caffeine in large doses (at least 250–300 mg, equivalent to the

amount found in 2–3 cups of coffee or 5–8 cups of tea) results in a short-term

stimulation of urine output in individuals who have been deprived of caffeine for a

period of days or weeks. This increase is due to both a diuresis (increase in water

excretion) and a natriuresis (increase in saline excretion); it is mediated via

proximal tubular adenosine receptor blockade. The acute increase in urinary output

may increase the risk of dehydration. However, chronic users of caffeine develop

a tolerance to this effect and experience no increase in urinary output.

Psychological

Minor undesired symptoms from caffeine ingestion not sufficiently severe to

warrant a psychiatric diagnosis are common and include mild anxiety, jitteriness,

insomnia, increased sleep latency, and reduced coordination. Caffeine can have

negative effects on anxiety disorders. According to a 2011 literature review,

caffeine use is positively associated with anxiety and panic disorders. At high

doses, typically greater than 300 mg, caffeine can both cause and worsen

anxiety. For some people, discontinuing caffeine use can significantly reduce

anxiety. In moderate doses, caffeine has been associated with reduced symptoms

of depression and lower suicide risk.

Increased consumption of coffee and caffeine is associated with a decreased risk of

depression.

Some textbooks state that caffeine is a mild euphoriant, others state that it is not a

euphoriant, and one states that it is and is not a euphoriant.

Caffeine-induced anxiety disorder is a subclass of the DSM-5 diagnosis of

substance/medication-induced anxiety disorder.

Beverages

Coffee

The world's primary source of caffeine is the coffee "bean" (the seed of the coffee

plant), from which coffee is brewed. Caffeine content in coffee varies widely

depending on the type of coffee bean and the method of preparation used;even

beans within a given bush can show variations in concentration. In general, one

serving of coffee ranges from 80 to 100 milligrams, for a single shot (30 milliliters)

of arabica-variety espresso, to approximately 100–125 milligrams for a cup (120

milliliters) of drip coffee. Arabica coffee typically contains half the caffeine of

the robusta variety. In general, dark-roast coffee has very slightly less caffeine

than lighter roasts because the roasting process reduces caffeine content of the

bean by a small amount.

Tea

Tea contains more caffeine than coffee by dry weight. A typical serving, however,

contains much less, since less of the product is used as compared to an equivalent

serving of coffee. Also contributing to caffeine content are growing conditions,

processing techniques, and other variables. Thus, teas contain varying amounts of

caffeine. Tea contains small amounts of theobromine and slightly higher levels

of theophylline than coffee. Preparation and many other factors have a significant

impact on tea, and color is a very poor indicator of caffeine content. Teas like the

pale Japanese green tea, gyokuro, for example, contain far more caffeine than

much darker teas like lapsang souchong, which has very little.

Soft drinks and energy drinks

Caffeine is also a common ingredient of soft drinks, such as cola, originally

prepared from kola nuts. Soft drinks typically contain 0 to 55 milligrams of

caffeine per 12 ounce serving. By contrast, energy drinks, such as Red Bull, can

start at 80 milligrams of caffeine per serving. The caffeine in these drinks either

originates from the ingredients used or is an additive derived from the product

of decaffeination or from chemical synthesis. Guarana, a prime ingredient of

energy drinks, contains large amounts of caffeine with small amounts of

theobromine and theophylline in a naturally occurring slow-release excipient.

Chocolate

Chocolate derived from cocoa beans contains a small amount of caffeine. The

weak stimulant effect of chocolate may be due to a combination of theobromine

and theophylline, as well as caffeine. A typical 28-gram serving of a

milk chocolate bar has about as much caffeine as a cup of decaffeinated coffee. By

weight, dark chocolate has one to two times the amount of caffeine as coffee: 80–

160 mg per 100 g. Higher percentages of cocoa such as 90% amount to 200 mg per

100 g approximately and thus, a 100-gram 85% cocoa chocolate bar contains about

195 mg caffeine.

Tablets(advantages)

Tablets offer several advantages over coffee, tea, and other caffeinated beverages,

including convenience, known dosage, and avoidance of concomitant intake of

sugar, acids, and fluids. Manufacturers of caffeine tablets claim that using caffeine

of pharmaceutical quality improves mental alertness. These tablets are commonly

used by students studying for their exams and by people who work or drive for

long hours.

Advantages and disadvantages

Caffeine can have both positive and negative health effects. It can treat and prevent

the premature infant breathing disorders bronchopulmonary dysplasia of

prematurity and apnea of prematurity. Caffeine citrate is on the WHO Model List

of Essential Medicines. It may confer a modest protective effect against some

diseases, including Parkinson's disease. Some people experience sleep

disruption or anxiety if they consume caffeine, but others show little disturbance.

Evidence of a risk during pregnancy is equivocal; some authorities recommend that

pregnant women limit consumption to the equivalent of two cups of coffee per day

or less.

Conclusion

caffeine is very potent,yet unrecognized drug.although there are beneficial side

effects to caffiene intake,the negative effects clearly indicate that one should limit

their caffeine consumption.many organ systems are adversely affected by high

amounts of caffeine consumption, including the heart ,stomach,respiratory and

reproductive organs.young children and older people must be much more careful

in monitoring their caffeine intake and should limit themselves to less than 100mg

of caffeine per day.

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