How to test different components of food?

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What is Starch?Starch is a type of carbohydrate Different Foods Containing Starch Whole Wheat Bread Potato Brown Rice Kidney Beans How to check for presence of Starch in Food Item?Take small part of food item Put it in dish Put 2 – 3 drops of Dilute Iodine Solution Check If it turns blue black Yes No Contain Starch Do not Contain Starch Do not Contain Starch Activity 3.5 Take a small quantity of the food items such as a slice of potato, cucumber, bread, some boiled rice, boiled gram, crushed peanuts, oil, butter and crushed coconut. You can take other food items too for testing. Fig. 3.7: Testing for the presence of starch in various food items Place a small piece of each item on a separate dish. With the help of a dropper, put 2-3 drops of diluted iodine solution on each food item (Fig. 3.7). Observe if there are any changes in the colour of the food items. Have they turned blue-black? Record your observations in Table 3.3. blue-black colour indicates the presence of starch.How to check for presence of Fats in Food Item?Take small part of food item Place each food item on a separate piece of paper Wrap the paper around the food and press it Food Item contains a little water and allow it to dry An oily patch Yes No Contain fat Do not Contain fat Activity 3.6 Take a small part of the food items that you tested for the presence of starch in Activity 3.5. Place each food item on a separate piece of paper. Wrap the paper around the food and press it. Be careful not to tear the paper. If a food item contains a little water, allow the paper to dry.How to check for presence of Proteins?Take small part of food item tested in previous activities Make a paste or powder of the food item Put about half teaspoon of each food item in a separate clean test tube Add 2 - 3 teaspoons of water to each test tube and shake them well Add two drops of copper sulphate solution to each test tube using a dropper Take another dropper and add 10 drops of caustic soda solution to each tube Shake well and leave the test tubes undisturbed for a few minutes Yes No Contain Proteins Do not Contain protein Activity 3.7 This activity may be demonstrated by the teacher. Take the food items tested in previous activities. Make a paste or powder of the food item using pestle and mortar (Fig. 3.8). Put about half teaspoon of each food item in a separate clean test tube. Add 2-3 teaspoons of water to each test tube and shake them well. Add two drops of copper sulphate solution to each test tube using a dropper. Now, take another dropper and add 10 drops of caustic soda solution to each tube (Fig. 3.8). Shake well and leave the test tubes undisturbed for a few minutes. Fig. 3.8: Testing for the presence of protein in various food itemsTable 3.3 :-Table 1: Table 3.3: Exploring nutrients present in various food items \captionsetup{labelformat=empty} Name of the food item Colour of the food item for starch test Oily patch for fat test Colour of the food item for protein test Starch present (Yes/ No) Fat present (Yes/ No) Protein present (Yes/ No) Before iodine test After iodine test Prediction (Yes/No) Observation (Yes/No) Before protein test After protein test Potato White Blue - Black No No Colourless No change Yes No No Cucumber Greenish No change No No Colourless No change No No No Boiled rice White Blue - Black No No Colourless No change Yes No No Boiled gram Brownish No change No No Light - Yellow Violet Colour No No Yes Peanuts Brown No change Yes Yes Light - Yellow Violet Colour No Yes Yes Bread/ Chapati Brownish Blue - Black No No Colourless No change Yes No No Butter Yellowish No change Yes Yes Colourless No change No Yes No Coconut White No change Yes Yes Light - Yellow Violet Colour No Yes Yes Milk White No change Yes Yes Light - Yellow Violet Colour No Yes Yes