Chapter 1: Components of Food & Deficiency Diseases
भोजन के घटक एवं अभावजन्य रोग (कार्बोहाइड्रेट, प्रोटीन एवं विटामिन)
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- Major nutrients in human food: Carbohydrates, Proteins, Fats, Vitamins, and Minerals. In addition, dietary fibres (roughage) and water are essential.
- Starch Test (Carbohydrates): Adding 2-3 drops of dilute Iodine solution turns the food item Blue-Black.
- Protein Test: Adding 2 drops of Copper Sulphate (CuSO4) solution followed by 10 drops of Caustic Soda (NaOH) solution turns the mixture Violet.
- Fat Test: Rubbing food on white paper produces an oily translucent patch that lets light pass through faintly.
- Energy comparison: Fats yield much more energy than the same amount of carbohydrates.
- Deficiency Diseases: Scurvy (Vitamin C, bleeding gums), Rickets (Vitamin D, soft bent bones), Beriberi (Vitamin B1, weak muscles), Night blindness (Vitamin A, poor night vision), Goitre (Iodine, swollen thyroid gland in neck), Anaemia (Iron, low hemoglobin).
- Roughage (Dietary Fibre): Mainly provided by plant products (whole grains, pulses, potatoes, fresh fruits, vegetables). Does not provide energy but adds bulk to undigested food and helps in bowel movement.
- Trap: CBSE tests reagent colors. Starch turns BLUE-BLACK with Iodine (not red or green). Protein turns VIOLET with CuSO4 + NaOH (not blue).
- Trap: CBSE states roughage provides high calories. Correct: Roughage provides NO energy; its role is facilitating peristalsis and removing undigested waste.
- Trap: CBSE claims Vitamin C can be stored in the body. Correct: Vitamin C is water-soluble and is easily destroyed by cooking heat.
NCERT Core Facts: Food Nutrients, Reagent Tests & Deficiency States
In CTET Paper 2 Science, questions on nutrient testing reagents, deficiency disorders, and energy yields appear every year.
1. Laboratory Diagnostic Reagent Tests for Nutrients
| Nutrient | Testing Reagent | Positive Test Observation |
|---|---|---|
| Starch (Carbohydrate) | Dilute Iodine Solution | Color changes to Blue-Black |
| Protein | Copper Sulphate ($CuSO_4$) + Caustic Soda ($NaOH$) | Color changes to Violet |
| Fats | White Paper Rubbing | Leaves a permanent oily translucent patch |
2. Vitamins & Minerals Deficiency Disorders
| Vitamin / Mineral | Deficiency Disease / Disorder | Key Symptoms |
|---|---|---|
| Vitamin A | Loss of vision (Night Blindness) | Poor vision in dim light; complete loss of night vision. |
| Vitamin $B_1$ | Beriberi | Weak muscles and very low energy to work. |
| Vitamin C | Scurvy | Bleeding gums; wounds take an abnormally long time to heal. Readily destroyed by heating. |
| Vitamin D | Rickets | Bones become soft, fragile, and bent (bow legs). |
| Calcium | Bone and tooth decay | Weak brittle bones, frequent dental cavities. |
| Iodine | Goitre | Glands in the neck appear swollen; mental disability in children. |
| Iron | Anaemia | Low hemoglobin; physical weakness, fatigue, pale skin. |
3. High-Yield CTET Exam Traps
- Water Soluble vs Fat Soluble:
- Water Soluble: Vitamin B complex and Vitamin C.
- Fat Soluble: Vitamins A, D, E, and K.
- Roughage: Roughage does not provide any nutrients or calories to our body, but is an essential component because it adds bulk and helps get rid of undigested food.
Test Your Mastery: Components of Food & Deficiency Diseases
Authentic CBSE exam questions tested directly from this NCERT chapter.
A student adds 2 drops of Copper Sulphate solution and 10 drops of Caustic Soda solution to a test tube containing a food paste. The appearance of a violet color indicates the presence of:
एक छात्र एक खाद्य पेस्ट वाली परखनली में कॉपर सल्फेट के घोल की 2 बूँदें और कास्टिक सोडा के घोल की 10 बूँदें मिलाता है। बैंगनी रंग का दिखाई देना किसकी उपस्थिति को दर्शाता है?
Deficiency of which of the following vitamins causes bleeding of gums and slow healing of wounds?
निम्नलिखित में से किस विटामिन की कमी से मसूड़ों से खून आने लगता है और घाव भरने में अधिक समय लगता है?
Which of the following components of our food does NOT provide any nutrients or energy to the body, yet is essential for good health?
हमारे भोजन का कौन सा घटक शरीर को कोई पोषक तत्व या ऊर्जा प्रदान नहीं करता, फिर भी अच्छे स्वास्थ्य के लिए आवश्यक है?
What color does starch turn when tested with dilute iodine solution?
It turns blue-black.
Which chemical reagents are used to detect the presence of proteins in food?
Copper sulphate solution (CuSO4) and Caustic soda (sodium hydroxide, NaOH), which together produce a violet color in the presence of proteins.
Which vitamin is easily destroyed by heat during cooking?
Vitamin C (ascorbic acid) is sensitive to heat and is easily destroyed during cooking.