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BIOLOGY Nutrition: Alejandra Guerrro, Ana Lawrence, Daniela Maury, Sandra Saumett

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by sandra saumett on 2 March 2012

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Transcript of BIOLOGY Nutrition: Alejandra Guerrro, Ana Lawrence, Daniela Maury, Sandra Saumett

PROTEINS by: Alejandra guerrero, Ana Lawrence, Daniela Maury
Testing for biochemicals is measuring the amount or activity of a particular enzyme or protein in a sample of blood or urine or other tissue from the body.
TESTING FOR LIPIDS Lipids are one of the four molecules that made up life and are characterized because they do not dissolve in water but in ethanol If fats and oils are insoluble in water
this means that an aqueous solution
could not be used to carry out a biochemical test but due to their features a physical test can and it is called the emulsion test. Other tests include Grease Spot Test and the Sudan Stain Test. However the emulsion test is the most common The ethanol emulsion test is a food test which determines the manifestation of natural compounds called lipids which includes fats and oils Procedure
Add a few drops of the liquid food sample to a dry test tube.
Add 2 cm3 ethanol and shake it thoroughly
Add 2 cm3 of deionized water.
Make observations.
Results and interpretation
The test is positive if a layer of cloudy white suspension forms at the top of the solution (Milky white emulsion). Foods with high lipid content have a ‘higher’ layer than foods with less Results and interpretation
the test is negative if Solution remains colourless. No emulsion is formed. TESTING FOR PROTEINS Proteins are complex, specialized molecules composed of carbon, oxygen, hydrogen, nitrogen and sometimes sulfur. The building blocks of proteins are amino acids.
They are complex molecules that play critical roles in the body.
They do most of the work in cells and are required for the structure, function, and regulation of the body’s tissues and organs. Proteins also play an important part in the immune system (antibodies), oxygen transport (hemoglobin), movement (muscles) etc.
The building blocks of proteins are amino acids. There are 20 different amino acids that combine to form polypeptides (proteins).

The Biuret Test is used to determine the presence of peptide bonds in protein and it may also be extended to measure the concentration of total protein.
1. Add 2 cm3 of the liquid food sample*to a clean, dry test tube
2. Add 2 cm3 of Biuret Reagent.
3. Repeat steps 1 and 2 with de-ionized water to prepare a negative control and with albumin (egg white) to prepare a postive control.
4. Shake well and allow the mixture to stand for 5 minutes.
5. Observe any color change.
Results and interpretation
The test is positve if The solution turns from blue to violet( purple)
The solution turns from blue to pink
results and interpretation
the test is negative is there is no change in the solution
TESTING FOR STARCH Starch or amylum is a carbohydrate consisting of a large number of glucose units joined together by glycosidic bonds. This polysaccharide is produced by all green plants as an energy store. It is the most common carbohydrate in the human diet and is contained in large amounts in such staple foods as potatoes, wheat, corn, rice, and cassava. The Iodine Test for Starch is used to determine the presence of starch in biological materials

The principle of the test, as it helps explain how starch acts as an indicator for Redox Titrations or in the 'Iodine Clock Reaction'.

1.Add 10 cm3 of the liquid food sample to a clean, dry test tube.
2.Add about 5 drops of iodine solution to the test tube.
3.Note any colour changes.
4.To prepare a control, perform steps 1 -3 for de-ionized water

Results and interpretation
The test is positive if A blue-black colour develops
The test is negative if the solution remains brown
Starch is a storage molecule found only in plants. Only plants and plant-based foods should test positive for the presence of starch. TESTING FOR GLUCOSE Sugars are classified as reducing or non-reducing based on their ability to act as a reducing agent during the Benedict's Test. A reducing agent donates electrons during a redox reaction and is itself oxidized. Reducing sugars are simple sugars and include all monosaccharides and most disaccarides. Some examples of monosaccharides are glucose, fructose and galactose.Examples of reducing disaccharides are lactose and maltose. The Benedict's Test for Reducing Sugars is used to determine the presence of reducing sugars.
There is a Benedict's Test for non-reducing sugars as well. Benedict's solution is the principle reagent in the Benedict's Tests.
The Fehling's Tests for reducing as well as for non-reducing sugar are alternatives to the Benedict's Test. Although based on the same principle, the Fehling's Test is less sensitive. It is also less convenient as the Fehling's Reagents - Fehling's A and B - have to be kept separate until the test is conducted.
1.A liquid food sample
2.Add 2 cm3 of the sample solution to a test tube.
3.Add an equal volume of Benedict's solution to the test tube and swirl or vortex the mixture.
4.Leave the test tube in a boiling water bath for about 5 minutes, or until the colour of the mixture does not change.
5.Observe the colour changes during that time as well as the final colour.
6.To prepare a control, repeat steps 3-5 using 2 cm3 of distilled water instead of sample solution.
Results annd interpretation
GREEN:Trace amounts of reducing sugar present
YELLOW: Low amounts of reducing sugar present
ORANGE: Moderate amounts of reducing sugar present
RED: Large amounts of reducing sugar present During the experiment, the colours of the mixture transition in this order:
blue--> green--> yellow--> orange--> red
The final colour may be any of the colour depending on the quantity of reducing sugar present. If you do no observe the red colour, it does not mean that your experiment has not worked out well. It is important to note that the Benedict's Test for Reducing Sugars is not specific to any one type of reducing sugar, and that the colour corresponds to the total reducing sugar present. What are microorganisms?
They are small, living forms of life, which cannot be seen with the naked eye. Bacteria, yeasts, and molds are three common types of microorganisms. People often confuse and, almost always, misunderstand functions of microorganisms, which are just as real and alive as students are in a classroom. Microorganisms eat and grow; they reproduce and die. And they are everywhere. Microorganisms are widely used in the food industry to produce various types of foods that are both nutritious and preserved from spoilage because of their acid content.They are often use in Dairy foods, bread and other fermentated food… Dairy Food Yoghurt can be done, by adding bacteria (lactobacillus) into the milk. Bacteria turns sugar in milk into lactic acid. Milk clots and thickens into yogurt. Then as it cools down and t has been sterilized, fruit/nuts can be added. Cheese is also made with lactobacillus.
The lactobacillus is added to the milk then
just like the yogurt, the bacteria turns
sugar in milk into lactic acid and the milk
curdles. Enzyme is used to turn curdled
milk into curds and whey. Curds separated
off and left to ripen into cheese. Bread Bread is made, by mixing yeast (a fungus), sugar, flour and water into a dough. Yeast turns sugar to ethanol and carbon dioxide, which makes bread rise Made by adding yeast to grape juice. Yeast turns sugar in juice into ethanol (alcohol) and carbon dioxide. Also... Cucumbers are fermented by Leuconostoc and lactobacillus to produce pickles. Wine Other fermentated food examples... Fermentation Fermentation is the conversion of a carbohydrate such as sugar into an acid or an alcohol. More specifically, fermentation can refer to the use of yeast to change sugar into alcohol or the use of bacteria to create lactic acid in certain foods. Fermentation occurs naturally in many different foods in the right conditions, but it has also been intentionally use for many thousands of years. All of the previous examples share common features, which are... Organisms require a source of food, including amino acids for protein and carbohydrates for energy.... And also require good conditions of temperature, pH, water and oxygen concentration for better efficiency. What is the economic importance of yeast? B
king and Bre
ng Yeast has been use for a long time. It is use in baking and brewing, which are basically in other words bread and wine. With yeast there will be no bread or alcoholic drinks such as wine and beer. Thinking economically, it will affect baked good industries and of course beer companies or industries which have been out there for a long time (since beer was discovered a long time ago). Baking is the technique of prolonged cooking of food by dry heat acting by convection. In which flour, sugar and salt are mixed with yeast, this process is called kneading and produces dough. The dough is heated up and after a couple minutes the bread is done.
It has been around for a long time but everytime it seems to be getting better, healthier and easier. Bread has become a fundamental food in our daily lifes, it has become part of a good diet. Brewing is the production of beer through steeping a starch source (commonly cereal grains) in water and then fermenting with yeast. Many people say that brewing was a method develop by the agent egypt a very long time ago by accident and since then it has been part of our lifes. Now a days, brewing is used in beer companies,delivering adults drinks such as beers or wines.
what is food ?
food is any nutritious substance that people or animals eat or drink, or that plants absorb, in order to maintain life and growth. in food words food is the way we get our nutrients but we cannot abuse with food because as the same way food gives us the necessarily nutrients to get a good life it can take our life away. what is a carbohydrate ?

there are two kinds of carbohydrates with are simple and complex.
simple carbohydrates are known also as sugars.
natural sugars are form in vegetable and fruits for example an apple has natural sugar, etc.
while refined sugars are found in not that healthy like pizza, sweets and snack bars, etc.

complex carbohydrates are also referred to starch or starchy food.
natural complex carbohydrates are found in banana, beans, brown rice, etc.
while Complex carbohydrates as refined starches are found in biscuit, white rice, whit bread, etc. fuction in humans of carbohydrates:
this is a important source of energy for humans. Glucose is oxidised in respiration to release energy for activ transport, etc. Excess of carbohydrate can be stored as glycogen and as fat
what are lipids?

Lipids are diverse compounds that are grouped together since they are insoluble in water, but soluble in nonpolar solvents such as ethanol. Common lipid types include fats, phospholipids, and steroids. These lipids have various functions in the body Lipids functions in humans:
lipids are specially vulnerable as an energy store because they're insoluble in water. Steroid hormones, including sex hormones, are made from cholesterol
what are proteins?
From hair to fingernails, protein is a major functional and structural component of all our cells. Protein provides the body with roughly 10 to 15 per cent of its dietary energy, and is needed for growth and repair.Proteins are large molecules made up of long chains of amino acid subunits. Some of these amino acids are nutritionally essential as they cannot be made or stored within the body and so must come from foods in our daily diet. Proteins function in humans:
-transport molecules
-structural materials, as in muscles
-in defence agaisnt diseases Healthy diet
Having a healthy diets helps us from avoiding certain diseases with could cause our death as obesity, heart disease, diabetes, hypertension and cancer in few words help us to have a "healthy life" .
A healthy diet involves consuming appropriate amounts of all essential nutrients and an adequate amount of water. Nutrients can be obtained from many different foods, so there are numerous diets that may be considered healthy. A healthy diet needs to have a balance of macronutrients (fats, proteins, and carbohydrates. Why vitamins and minerals are important?
Vitamins and minerals are substances that are found in foods we eat. Your body needs them to work properly, so you grow and develop just like you should. When it comes to vitamins, each one has a special role to play. For example:

Vitamin D in milk helps your bones.
Vitamin A in carrots helps you see at night.
Vitamin C in oranges helps your body heal if you get a cut.
B vitamins in leafy green vegetables help your body make protein and energy
while minerals help to
Just like vitamins , minerals help your body grow, develop, and stay healthy. The body uses minerals to perform many different functions — from building strong bones to transmitting nerves impulses. Some minerals are even used to make hormones or maintain a normal heartbeat
Where we can find minerals and vitamins and some symptoms of deficciency:
vitamins can be found liver,dairy products,eggs .
Some symtoms of deficiency are poor night vision .While minerals can be found in red meet, liver and some leafy vegetables. Some symptoms of deficiency are anemia, weak bones, poor clotting of blood, uncontolled muscles contractions Water:
water forms more than half our body. two thirds of this water is cytoplasm of cells, and the other third is from fluid and blood plasma.
water can be obtained in three main ways:
-as a drink
-in food, specially salad food such as tomatoes and lettuces
-from metabolic processes Why fibre is important?

Fibre is very impotent in a healthy diet. this is because it helps your digestive system to process food and absorb nutrients. It also lowers blood cholesterol and helps to control blood sugar levels, which in turn controls appetite. it also contains gums a pectins with help to low cholesterol levels and to control bold sugar

summary of a balanced diet:
Malnutrition and famine A famine is a widespread scarcity of food, caused by several factors including crop failure, overpopulation, or government policies. This phenomenon is usually accompanied or followed by regional malnutrition,starvation, epidemic, and increased mortality. Every continent in the world has experienced a period of famine throughout history. Many countries continue to have extreme cases of famine. It is caused by a number of of natural problems and socioo-political factors such as alcohol, drug abuse, poverty and war

What causes famine •Increasing population: as the number of people increases the number of needs increases too. At the same time, the same amount of land available for food production decreases. •Drought: global warming is affecting us, water is a essencial factor for plants to grow, and if there is no rain, the rainfall patterns may be altered and the it will reduce the crop yield •Flooding: fertile soil can be washed away and there would be no plantations. Can famine be stopped? Enough food is produced to feed every person in the universe since agriculture is extremely develop in many parts however the food is not evenly distributed. Some people expect that with food aids should be reserved for disasters but industrialized countries invest more in creating schools for poor people in order to receive education. •Unequal distribution of food: the world is distributed in a uneven way, this means that some areas produce more food than others because of a more suitable environment . • Coast of fuel and fertilizer: crop yield may be low in development areas because of poor farmers which cant afford fertilizer. What is famine responsible for Famine can cause several problems. For example, it is responsible for:
•The low availability to buy food
•Diseases that affect children
•Low life expectancy
THE END what are residues?
are things added to increase food production, because of poor food production techniques. some chemicals may remain as residues,and which cause for human health cause concern for human health are:
pesticides: may become concentrated in food chains, causing harm to the top consumers.
fertilisers: nitrates and phosphates may leach into water supplies which cause problems in babies fed on reconstituted powered milk
antibiotics: used to prevent infection of cattle and poultry . may lead to the selection of antibiotics-resistant strains of microbes.
hormones: used to boost the growth rate of chickens. this may cause humans males to develop feminine characteristics

Balancing energy and energy demand: problems causing malnutrition. Food is the fuel that drives life processes Measuring the energy in food.

The energy in food is released by respiration, which is a kind of combustion; when the food is burned, the energy find it’s was to our body. The energy value is found using a food calorimeter or bomb calorimeter. The energy value of food can be calculated as follows: The three main energy – providing organic molecules in food are: fats, carbohydrates, and proteins.

Fats 39 kJ per g
Proteins 20 kJ per g
Carbohydrates 17 kJ per g

Carbohydrates are the ones that supply us most of the energy.
Storing excess food The body can only store a limited amount of glycogen, but still can store an unlimited amount of fat. If there is over nutrition, which means having high levels of energy that hasn't been used, there has to be body mass loss. Losing body mass The only two ways of losing body mass are: Eating less 'high - energy' food. Eating less food with a high energy level, will reduce the energy intake, making it easier for the body to lose the unnecesary mas. Taking more excersice this will increase the energy use from the stored 'high level' food that you've eaten. Problems causing malnutrition Undernutrition Which also means: too little food.
In developing countries of the world, children do not have the ability to afford the neccesary foods to have a healthy diet which leads to two strange deseases of malnutrition. Kwashiorkor. The child hasn't received enough of his or hers
mothers milk, and is forced into a diet that is too high
in carbohydrate. The child might be receiving enough
'energy' food, but because it is poor in protein, mental
and physical development are often impaired. Marasmus The child presents symptoms of general starvation like liver swelling as well as broken body tissues. The body tissues waste away, and the child becomes very skinny with wrinkled skin. Other diseases
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