to test the presence of food samples on butter and any five things with overservation
Answers
Answer:
Test for Carbohydrates:
Molisch’s test – Given sample food + Molisch’s reagent → Purple or violet ring confirms the presence of carbohydrate.
Fehling’s test – Given sample food + Fehling’s reagent → Red precipitate confirms the presence of carbohydrates
Benedict’s test – Given sample food + Benedict’s reagent → Red precipitate confirms the presence of carbohydrates.
Tollen’s test – Given sample food + Tollen’s reagent → Silver mirror confirms the presence of carbohydrates.
Iodine test – Given sample food + Iodine solution → Blue colour solution confirms the presence of starch.
Test for Proteins:
Biuret test – Given sample food + Aqueous copper sulfate → Violet colouration confirms the presence of Proteins
Xanthoproteic test – Given sample food + Nitric acid → Yellow colour solution confirms the presence of proteins.
Millions test – Given sample food + Mercuric sulfate in the presence of sodium nitrite and sulfuric acid → Brick red colour solution confirms the presence of proteins.
Ninhydrin test – Given sample food + Pyridine solution of ninhydrin → Violet colour solution confirms the presence of proteins.
Test for Oils and Fats:
Solubility test – Given sample food + Chloroform or alcohol → Miscible with chloroform and immiscible with water the fat presence is confirmed.
Translucent spot test – Given sample food + rubbed between the folds of filter paper → presence of translucent spot then the presence of fats is confirmed.
Acrolein test – Given sample food + Potassium bisulfite KHSO4 → Pungent irritating odor then the presence of fats or oil is confirmed.
Materials Required:
Molisch’s reagent
Fehling’s reagent
Benedict’s reagent
Tollen’s reagent
Iodine solution
Copper sulfate solution
Sodium hydroxide
Nitric acid
Mercuric sulfate
Sodium nitrite
Alcohol
Chloroform
Filter paper
Potassium bisulfate
Concentrated hydrochloric acid
Furfural solution
Test tubes
Test tube holder
Water bath
Dropper
Stirrer
Bunsen burner
Apparatus Setup:
Tests of Carbohydrates, Fats and Proteins in Given Food Stuffs
Procedure:
To test the presence of carbohydrates, proteins, fats and oils in the given food sample, first the extract of the given foodstuff should be prepared. Dry the given foodstuff in the mortar with a pestle or by boiling with minimum quantity of water extracting with a small quantity of an organic solvent after grinding the foodstuff.
Some of the examples of preparing extract of food stuff is given below.
For potatoes – cut to slices and boil with water.
For butter – test directly
For grapes – Extract the juice.
For boiled egg – take the white portion grind and shake with water.
Observation and Inference:
Food stuff For carbohydrates For proteins For oils and fats
butter
potatoes
butter
boiled egg
Results and Discussions:
The given food sample contains _________ (carbohydrates/ proteins/ fats).
Precautions:
Always use minimum quantity of reagents and freshly prepared ones to test the sample food.
Use droppers to take the reagents from the bottle.
Use lab aprons and hand gloves during the experiment.
Also, Check ⇒ Properties of Maltose
Keep visiting BYJU’S to learn more about class 12 CBSE chemistry practicals.
Frequently Asked Questions on Tests of Carbohydrates, Fats and Proteins in Given Food Stuffs
Mention the major types of carbohydrates.
The main types of carbohydrates are monosaccharides, disaccharides and polysaccharides.
Name the bond which holds the monomer units of proteins together?
Peptide bond are the bonds which hold together the monomer units of proteins.
What is called denaturation of proteins?
Denaturation of proteins involves both secondary and tertiary structures being disrupted and potentially destroyed. Because denaturation reactions are not strong enough to break peptide bonds, after a denaturation process, the primary structure (amino acid sequence) remains the same.
Name some of the food source rich in carbohydrates?
Milk, ice cream, yogurt, fruit, whole juice of fruits and grains. Bread, rice, cereal, crackers. Legumes. Beans and other proteins based on plants. Vegetables that are starchy. Maize and potatoes. Sugary candy. Limit it! Soda, sweets, cookies, desserts, etc.
What is the colour of precipitate formed if millon’s reagent is added to food solution having proteins?
Yellow colour precipitate is formed when millon’s reagent is added to food solution having proteins.