23-06-2014, 11:59 AM
Chemistry Investigatory
[attachment=65195]
INTRODUCTION
Yogurt is a fermented milk product (soy milk, nut milks such as almond milk,
and coconut milk can also be used) produced by bacterial fermentation
of milk. The bacteria used to make yogurt are known as "yogurt cultures".
Fermentation of lactose by these bacteria produces lactic acid, which acts on
milk protein to give yogurt its texture and its characteristic tang.
Yogurt is nutritionally rich in protein, calcium, riboflavin, Vitamin B6 and
Vitamin B12. It has nutritional benefits beyond those of milk. Individuals
who are lactose intolerant can sometimes tolerate yogurt better than other
dairy products, because the lactose in the milk is converted to glucose and
galactose, and partially fermented to lactic acid, by the bacterial culture.
Yogurt containing live cultures has been found effective in a randomized trial
at preventing antibiotic-associated diarrhea. Yogurt contains varying amounts
of fat. There is non-fat (0% fat), low-fat (usually 2% fat) and plain or whole
milk yogurt (4% fat). A study published in the International journal of
obesity (11 January 2005) also found that the consumption of low-fat yogurt
can promote weight loss, relative to a gelatin placebo.
Yogurt is a valuable health food for both infants and elderly persons. For
children, it is a balanced source of protein, fats, carbohydrates, and minerals.
For senior citizens, who usually have more sensitive colons or whose
intestines have run out of lactase, yogurt is also a valuable food. Elderly
intestines showed declining levels of bifidus bacteria, which allow the growth
of toxin-producing and, perhaps, cancer-causing bacteria. Yogurt may help
prevent osteoporosis, reduce the risk of high blood pressure.
Carbohydrates
Carbohydates are compounds with the general formula Cx(H2O)y. These
compounds are called carbohydrates because they can be treated with
compounds of carbon. Carbohydrates are the major source of energy in
human body. In addition they are used as biofuels and are constituents of cell
membranes
Fats
Fats consist of a wide group of compounds that are generally soluble in
organic solvents and generally insoluble in water. Chemically, fats
are triglycerides: triesters of glycerol and any of several fatty acids
Proteins
Proteins are large biological molecules, or macromolecules, consisting of one
or more chains of amino acid residues. Proteins perform a vast array of
functions within living organisms, including catalyzing metabolic
reactions, replicating DNA, responding to stimuli, and transporting molecules
from one location to another. Proteins differ from one another primarily in
their sequence of amino acids, which is dictated by the nucleotide
sequence of their genes, and which usually results in folding of the protein
into a specific three-dimensional structure that determines its activity
Procedure
Molisch’s Test
Take 1-2 ml of aq. solution of yogurt and a few drops of Molisch’s reagent
(10% alcoholic solution of starch). Put one ml of conc. H2SO4 slowly along
the side of the test tube
Chemistry of this test: Conc. H2SO4 converts carbohydrate to furfural or it’s
derivative which further reacts with alpha-napthol to give a coloured product.
2. Iodine Test
To the aq. suspension of the add 1-2 drops of iodine solution.
Conclusion
Yogurt contains carbohydrates but no starch
[attachment=65195]
INTRODUCTION
Yogurt is a fermented milk product (soy milk, nut milks such as almond milk,
and coconut milk can also be used) produced by bacterial fermentation
of milk. The bacteria used to make yogurt are known as "yogurt cultures".
Fermentation of lactose by these bacteria produces lactic acid, which acts on
milk protein to give yogurt its texture and its characteristic tang.
Yogurt is nutritionally rich in protein, calcium, riboflavin, Vitamin B6 and
Vitamin B12. It has nutritional benefits beyond those of milk. Individuals
who are lactose intolerant can sometimes tolerate yogurt better than other
dairy products, because the lactose in the milk is converted to glucose and
galactose, and partially fermented to lactic acid, by the bacterial culture.
Yogurt containing live cultures has been found effective in a randomized trial
at preventing antibiotic-associated diarrhea. Yogurt contains varying amounts
of fat. There is non-fat (0% fat), low-fat (usually 2% fat) and plain or whole
milk yogurt (4% fat). A study published in the International journal of
obesity (11 January 2005) also found that the consumption of low-fat yogurt
can promote weight loss, relative to a gelatin placebo.
Yogurt is a valuable health food for both infants and elderly persons. For
children, it is a balanced source of protein, fats, carbohydrates, and minerals.
For senior citizens, who usually have more sensitive colons or whose
intestines have run out of lactase, yogurt is also a valuable food. Elderly
intestines showed declining levels of bifidus bacteria, which allow the growth
of toxin-producing and, perhaps, cancer-causing bacteria. Yogurt may help
prevent osteoporosis, reduce the risk of high blood pressure.
Carbohydrates
Carbohydates are compounds with the general formula Cx(H2O)y. These
compounds are called carbohydrates because they can be treated with
compounds of carbon. Carbohydrates are the major source of energy in
human body. In addition they are used as biofuels and are constituents of cell
membranes
Fats
Fats consist of a wide group of compounds that are generally soluble in
organic solvents and generally insoluble in water. Chemically, fats
are triglycerides: triesters of glycerol and any of several fatty acids
Proteins
Proteins are large biological molecules, or macromolecules, consisting of one
or more chains of amino acid residues. Proteins perform a vast array of
functions within living organisms, including catalyzing metabolic
reactions, replicating DNA, responding to stimuli, and transporting molecules
from one location to another. Proteins differ from one another primarily in
their sequence of amino acids, which is dictated by the nucleotide
sequence of their genes, and which usually results in folding of the protein
into a specific three-dimensional structure that determines its activity
Procedure
Molisch’s Test
Take 1-2 ml of aq. solution of yogurt and a few drops of Molisch’s reagent
(10% alcoholic solution of starch). Put one ml of conc. H2SO4 slowly along
the side of the test tube
Chemistry of this test: Conc. H2SO4 converts carbohydrate to furfural or it’s
derivative which further reacts with alpha-napthol to give a coloured product.
2. Iodine Test
To the aq. suspension of the add 1-2 drops of iodine solution.
Conclusion
Yogurt contains carbohydrates but no starch