Sunday, 16 June 2013

carbohydrates


Carbohydrate?


Carbohydrates are organic compounds that can be broken up to produce energy. The most basic building block in carbohydrates is a sugar consisting of carbon, hydrogen and oxygen.

The compounds differ in the links formed between those molecules. For example, a complex carbohydrate can have a number of different sugar molecules linked together.

A simple carbohydrate, on the other hand, will have a small number of these molecules linked together. Energy is released when these links, in either simple or complex carbohydrates, are broken. 

Bread


In bread carbohydrates is abundantly found which is also the main source of energy in a diet. During digestion, a series of enzymatic reactions break down the complex carbohydrates in bread into simple carbohydrates that are easily absorbed in the small intestine. Complex carbohydrates require enzymes such as salivary amylase, pancreatic amylase and maltose for digestion.

Complex carbohydrates include starch and fiber, which are polysaccharides made up of long chains of glucose units bonded together.

Carbohydrates consist of the elements carbon (C), hydrogen (H) and oxygen (O) with a ratio of hydrogen twice that of carbon and oxygen

chemical structure of starch
simple structure of glucose and starch



In their basic form, carbohydrates are simple sugars or monosaccharides. These simple sugars can combine with each other to form more complex carbohydrates. 

The combination of two simple sugars is a disaccharide

Carbohydrates consisting of two to ten simple sugars are called oligosaccharides, and those with a larger number are called polysaccharides.

FATTY ACIDS

 

 
Fatty Acid in Bread: Oleic acid
Fatty Acid in Ice Cream: Triglycerides

Fatty acids have been categorised into 3 groups: unsaturated, saturated and trans-saturated, the last category being the worst. Trans-fats occur naturally but also increase in amounts by certain food processing like deep frying.


 
Triglycerides are fatty acids found in ice-cream which are broken down inside the human body by the enzyme lipase to form first diglycerides and then monoglycerides.


 
 
Emulsions occur when two substances that do not naturally mix together are forced together by applying a form of energy to create a new mixture. Ice cream is also an emulsion as it is made of egg yolk which contains lecithin , where water molecules are asked to bind to fatty molecules.


 
 
 

Oleic acid is a monounsaturated fatty acid found naturally in many plant sources and animal products. Oleic acid has the molecular formula C18H34O2 and is usually found trapped in triglycerides.
It is an omega-9 fatty acid, and as such is considered one of the healthier sources of fat in the diet.
It can lower total cholesterol levels by raising blood concentrations of high-density lipoproteins while reducing low-density lipoproteins, also known as the “bad” cholesterol. It has been shown to slow the development of heart disease and also promotes the production of antioxidants, elements that can help trap harmful free radicals in the body.


 

Sources: http://www.wisegeek.org/what-is-oleic-acid.htm
               http://giapo.com/2013/04/mono-and-diglicerides/

Biology E-learning : Bread and Ice cream - Protein


The food we have chosen are bread and ice cream. 
To achieve at least 100% RDI, at least 50g of proteins, 65g of lipids (fat) and 300g of carbohydrates are needed.
350g of bread and 200g of can ice cream would provide at least 100% RDI for all three nutrients (51.8g of proteins, 68.3g of lipids (fat) and 318g of carbohydrates).
Combined mass of both food products = 350g + 200g = 550g 

Protein in bread: Gluten 
Protein (enzyme) present in ice cream: Amylase

Gluten: 
Gluten is a protein composite found in foods processed from wheat and related grain species. Gluten gives elasticity through dough, helping it rise and keep its shape and often gives the final product a chewy texture. Gluten may also be found in some cosmetics, hair products, and other dermatological preparations.
Primary structure: linear sequence and number of amino acid residues which make up the polypeptide chain. The bond involved at this level is the peptide bond.
Secondary structure: The repetitive folding or coiling of the polypeptide chain. As a result of hydrogen bonds formed at regular intervals between the -C=O and -NG groups of neighbouring amino acid residues on the backbone of the polypeptide chains. 


2xfr b amylase.png
β-Amylase
Amylase
β-Amylase
Another form of amylase, β-amylase is also synthesized by plants. Working from the non-reducing end, β-amylase catalyzes the hydrolysis of the second α-1,4 glycosidic bond, cleaving off two glucose units (maltose) at a time. 
Both α-amylase and β-amylase are present in seeds; β-amylase is present in an inactive form prior to germination, whereas α-amylase and proteases appear once germination has begun. cereal grain amylase is key to the production of malt. Many microbes  also produce amylase to degrade extracellular starches. Animal tissues do not contain β-amylase, although it may be present in microorganisms contained within the digestive tract. The optimum pH for β-amylase is 4.0-5.0
Being a β-amylase,
Primary structure: Linear sequence and number of amino acid residues which make up the polypeptide chain
Secondary structure: Its has beta pleated sheet. it is formed when a single polypeptide chain folds back and forth, or when two regions of the polypeptide chain lie parallel to each other, to form sheets. The structure is stabilized by large numbers of hydrogen bonds form between the C=O and NH groups of one part of the backbone and adjacent part in the parallel regions that hold the structure together. Tertiary structure: 3 Dimensional shape a protein which is formed from extensive bending and folding of the polypetide.