“Carbohydrates are polyhydroxy aldehydes or ketones, or substances that yield such
compounds on hydrolysis”.
• Carbohydrates have the empirical formula (CH2O)n.
• Carbohydrates, or carbs, are sugar molecules. Along with proteins and fats
• Carbohydrates are one of three main nutrients found in foods and drinks.
• Polysaccharides are major classes of biomolecules.
• They are long chains of carbohydrate molecules, composed of several smaller
• These complex bio-macromolecules functions as an important source of
energy in animal cell and form a structural component of a plant cell.
• Polysaccharides can be a straight chain of monosaccharides known as linear
• It can be branched known as a branched polysaccharide.
• Starch is a complex carbohydrate.
• Most plants store energy as starch, including fruits and vegetables.
• Starch is the carbohydrate result of plants which is the important dietary source
animals including man.
• High content of starch is found in cereals, tubers, vegetables
• Starch is homopolymer composed of units held by α-glucosidic bonds.
• Starch, or amylum, is a complex carbohydrate that exists in many foods,
including grains, vegetables, and fruits.
• Starch is made up of two types of glucose molecules: amylose and
• Amylose is a linear chain of glucose molecules, while amylopectin is
• The proportion of amylose and amylopectin in starch varies depending on the
• Starch consists of 2-polysaccharide components
water soluble amylose(15-20%)
water insoluble amylopectin(80-85%).
• Starch is a tasteless, fluffy white powder that is insoluble in cold water, alcohol,
and other solvents.
• Starch is a polysaccharide made up of 1,4 linkages between glucose monomers.
• The chemical formula of the starch molecule is (C6H10O5)n.
14. Structure of Starch
• Starch is made up of long chains of sugar molecules that are connected
• In starch molecule, α-D-Glucopyranose units are linked with each other
through oxygen atoms at carbon atom no. 4.
• As case of maltose, 23 glucose units linked to form Starch molecules.
16. Digestion of Starch
• The digestion of starch begins in the mouth, where enzymes called amylases
break down some of the starch into simpler sugars.
• The process continues in the small intestine, where more enzymes break down
the remaining starch into glucose, which can then be absorbed into the
17. Digestion of Starch
• Some people have difficulty digesting starch, a condition known as starch
• This can cause symptoms such as bloating, gas, and diarrhea.
18. Properties of Starch
• White amorphous powder having no taste and no odor
• Its granules consists of two polysaccharides units i.e. amylase and amylo
pectin insoluble in water but swells up to form a gel in water.
Reaction with Iodine:
• Soluble Starch gives blur colour with iodine. The colour disappears on
heating to 80°C and reappears on cooling.
Effect of Heat:
• On heating Starch to 200-250°C, it is changed to dextrin having low
• Dextrin is used in Calico printing
19. Uses of Starch
Starch is a carbohydrate that has a variety of uses, both as a food ingredient and
in other industries:
• Starch is a common food ingredient used to thicken, stabilize, and texturize
foods such as sauces, gravies, puddings, and soups.
• It is also a major energy source for humans and is found in staple foods such as
potatoes, rice, corn, and wheat.
• Starch is used as a binder in the production of paper to improve its strength and
• Starch is used as a sizing agent in the production of textiles to make the fibers stiff
and easier to handle during the weaving process.
• Starch is used as a filler in the production of tablets and capsules, as well as a
coating to improve the stability and shelf life of the drugs.
Starch can be modified to produce adhesives for paper products and other
Starch can be used as a raw material to produce biodegradable plastics, which are
more environmentally friendly than traditional petroleum-based plastics.
• Starch is a complex carbohydrate that is an important part of many people's
• It provides energy and can be found in a wide variety of foods.
• While it has many industrial applications, it is important to consume a
variety of foods to ensure a balanced diet.