BharatNotes Overview
Biochemistry and food chemistry form one of the most consistently tested areas in UPSC Prelims, particularly vitamins and their deficiency diseases, food preservation techniques, and the basics of biomolecules. This chapter covers the four major classes of biomolecules (carbohydrates, proteins, lipids, and nucleic acids), vitamins and minerals with their deficiency diseases, enzymes, and food safety — including adulteration detection and preservation methods.
Exam Strategy: The vitamin-deficiency disease table is a Prelims favourite — memorise it thoroughly. Questions on food preservation (pasteurisation, irradiation, lyophilisation) and food adulteration (FSSAI role) appear regularly. For Mains GS3, understanding of food security, nutrition programmes, and FSSAI's regulatory framework is valuable.
Carbohydrates
Carbohydrates are organic compounds made of carbon, hydrogen, and oxygen, with the general formula C_x(H₂O)_y. They are the primary source of energy for living organisms.
Classification of Carbohydrates
| Type | No. of Sugar Units | Examples | Key Facts |
|---|---|---|---|
| Monosaccharides | 1 | Glucose (C₆H₁₂O₆), Fructose, Galactose | Simplest sugars; cannot be hydrolysed further |
| Disaccharides | 2 | Sucrose (glucose + fructose), Lactose (glucose + galactose), Maltose (glucose + glucose) | Formed by condensation of two monosaccharides |
| Oligosaccharides | 3–10 | Raffinose, Stachyose | Found in legumes; can cause flatulence |
| Polysaccharides | Many (100s–1000s) | Starch, Glycogen, Cellulose, Chitin | Storage and structural functions |
Important Polysaccharides
| Polysaccharide | Found In | Function |
|---|---|---|
| Starch | Plants (potatoes, rice, wheat) | Energy storage in plants |
| Glycogen | Animals (liver, muscles) | Energy storage in animals ("animal starch") |
| Cellulose | Plant cell walls | Structural support; humans cannot digest it (dietary fibre) |
| Chitin | Exoskeleton of arthropods, fungal cell walls | Structural polysaccharide |
| Inulin | Chicory root, garlic, onion | Prebiotic dietary fibre; used to test kidney function |
Prelims Tip: Cellulose is the most abundant organic compound on Earth. Humans lack the enzyme cellulase needed to digest it, but it serves as essential dietary fibre. Ruminants (cows, goats) can digest cellulose because of cellulase-producing bacteria in their rumen.
Proteins
Proteins are polymers of amino acids linked by peptide bonds. They are essential for growth, repair, enzyme activity, immunity, and virtually every biological process.
Amino Acids
- There are 20 standard amino acids used by the human body
- Essential amino acids (9) — cannot be synthesised by the body; must be obtained from diet (e.g., leucine, lysine, tryptophan, valine, methionine, phenylalanine, threonine, isoleucine, histidine)
- Non-essential amino acids (11) — can be synthesised by the body
Protein Structure
| Level | Description |
|---|---|
| Primary | Linear sequence of amino acids in a polypeptide chain |
| Secondary | Local folding into alpha-helix or beta-sheet structures |
| Tertiary | 3D shape of the entire polypeptide chain |
| Quaternary | Association of two or more polypeptide chains (e.g., haemoglobin has 4 subunits) |
Denaturation
Denaturation is the loss of a protein's 3D structure (and hence its biological function) due to heat, pH change, or chemical agents. Example: cooking an egg causes the albumin protein to denature (it turns white and solid).
Types of Proteins by Function
| Type | Function | Examples |
|---|---|---|
| Structural | Provide support and shape | Collagen (connective tissue), Keratin (hair, nails) |
| Enzymatic | Catalyse biochemical reactions | Amylase, Pepsin, DNA polymerase |
| Transport | Carry molecules | Haemoglobin (oxygen), Albumin (fatty acids) |
| Hormonal | Chemical messengers | Insulin, Growth hormone |
| Defensive | Immune protection | Antibodies (immunoglobulins) |
| Contractile | Movement | Actin, Myosin (muscle contraction) |
Lipids (Fats and Oils)
Lipids are hydrophobic biomolecules that include fats, oils, waxes, and steroids. They serve as energy reserves, insulation, and components of cell membranes.
Types of Fatty Acids
| Type | Chemical Feature | State at Room Temp | Sources | Health Impact |
|---|---|---|---|---|
| Saturated | No C=C double bonds | Solid (fats) | Butter, ghee, coconut oil, animal fat | Excess raises LDL cholesterol |
| Monounsaturated (MUFA) | One C=C double bond | Liquid (oils) | Olive oil, mustard oil, groundnut oil | Heart-healthy; lowers LDL |
| Polyunsaturated (PUFA) | Two or more C=C double bonds | Liquid (oils) | Sunflower oil, soybean oil, fish oil | Contains omega-3 and omega-6 |
| Trans fats | Artificially hydrogenated unsaturated fats | Solid | Vanaspati, margarine, processed foods | Most harmful; raises LDL, lowers HDL |
Important: FSSAI has capped trans fat content in oils and fats at 2% (effective from 1 January 2022), aligning with WHO recommendations. India became one of the first countries to adopt this stringent limit. Trans fats are linked to cardiovascular disease.
Cholesterol
- A type of lipid (steroid) essential for cell membrane structure, vitamin D synthesis, and hormone production
- HDL (High-Density Lipoprotein) — "good cholesterol"; removes cholesterol from arteries
- LDL (Low-Density Lipoprotein) — "bad cholesterol"; deposits cholesterol in artery walls
Vitamins
Vitamins are organic compounds required in small quantities for normal metabolic functioning. The body generally cannot synthesise them (except vitamin D and vitamin K in limited amounts), so they must be obtained from the diet.
Fat-Soluble Vitamins (A, D, E, K)
These dissolve in fat, are stored in the liver and adipose tissue, and do not need daily replenishment.
| Vitamin | Chemical Name | Major Sources | Deficiency Disease | Key Function |
|---|---|---|---|---|
| A | Retinol | Carrot, spinach, liver, milk, eggs, fish | Night blindness, Xerophthalmia (dry eyes, corneal damage) | Vision, immune function, skin health |
| D | Calciferol | Sunlight, fish liver oil, egg yolk, fortified milk | Rickets (children), Osteomalacia (adults) | Calcium absorption, bone growth |
| E | Tocopherol | Vegetable oils, nuts, seeds, green leafy vegetables | Haemolytic anaemia, nerve damage (rare) | Antioxidant, protects cell membranes |
| K | Phylloquinone (K₁), Menaquinone (K₂) | Green leafy vegetables, soybean oil; K₂ produced by gut bacteria | Excessive bleeding, poor blood clotting | Blood clotting (synthesis of prothrombin) |
Water-Soluble Vitamins (B-complex and C)
These dissolve in water, are not stored in the body (except B₁₂), and must be consumed regularly.
| Vitamin | Chemical Name | Major Sources | Deficiency Disease | Key Function |
|---|---|---|---|---|
| B₁ | Thiamine | Whole grains, legumes, pork, nuts | Beriberi (nerve and heart damage) | Carbohydrate metabolism |
| B₂ | Riboflavin | Milk, eggs, green vegetables, liver | Ariboflavinosis (cracked lips, sore throat) | Energy production, cell function |
| B₃ | Niacin | Meat, fish, groundnuts, whole grains | Pellagra (dermatitis, diarrhoea, dementia — the "3 Ds") | NAD/NADP synthesis, energy metabolism |
| B₅ | Pantothenic Acid | Meat, eggs, broccoli, avocados | Fatigue, numbness (rare) | Coenzyme A synthesis |
| B₆ | Pyridoxine | Poultry, fish, potatoes, bananas | Anaemia, dermatitis, confusion | Amino acid metabolism, haemoglobin synthesis |
| B₇ | Biotin | Egg yolk, nuts, soybeans, liver | Dermatitis, hair loss (rare) | Fat and carbohydrate metabolism |
| B₉ | Folic Acid | Dark green leafy vegetables, legumes, citrus, liver | Megaloblastic anaemia, neural tube defects in foetus | DNA synthesis, cell division |
| B₁₂ | Cyanocobalamin | Meat, fish, eggs, dairy (not in plant foods) | Pernicious anaemia, nerve damage | Red blood cell formation, nerve function |
| C | Ascorbic Acid | Citrus fruits, amla, guava, tomato, capsicum | Scurvy (bleeding gums, skin spots, joint pain) | Collagen synthesis, antioxidant, iron absorption |
Mnemonic for Pellagra (B₃ deficiency): The "3 Ds" — Dermatitis, Diarrhoea, Dementia. If untreated, a 4th D — Death.
Key Distinction: Vitamin B₁₂ is the only water-soluble vitamin stored in the body (in the liver, for up to 3–5 years). It is also the only vitamin that contains a metal ion (cobalt). Strict vegetarians/vegans are at risk of B₁₂ deficiency since it is absent in plant-based foods.
Minerals
Minerals are inorganic elements essential for various physiological functions.
| Mineral | Major Sources | Deficiency Disease / Effect | Key Function |
|---|---|---|---|
| Iron (Fe) | Spinach, liver, red meat, jaggery, dates | Anaemia (fatigue, pallor, weakness) | Haemoglobin synthesis, oxygen transport |
| Calcium (Ca) | Milk, cheese, ragi, green leafy vegetables | Osteoporosis, rickets (with Vitamin D deficiency) | Bone and teeth formation, muscle contraction, nerve signalling |
| Iodine (I) | Iodised salt, seafood, seaweed | Goitre (enlarged thyroid), Cretinism (in children) | Thyroid hormone (T₃, T₄) synthesis |
| Zinc (Zn) | Meat, shellfish, legumes, seeds, nuts | Stunted growth, impaired immunity, delayed wound healing | Enzyme function, immune response, wound healing |
| Phosphorus (P) | Dairy, fish, meat, nuts | Weak bones and teeth (rare) | Bone structure, ATP synthesis, DNA/RNA |
| Sodium (Na) | Table salt, processed foods | Hyponatremia (muscle cramps, confusion) | Fluid balance, nerve impulse transmission |
| Potassium (K) | Banana, potato, coconut water, spinach | Hypokalaemia (muscle weakness, heart irregularities) | Nerve and muscle function, fluid balance |
| Fluorine (F) | Fluoridated water, tea, fish | Dental caries (too little); Fluorosis (excess — mottled teeth, bone deformities) | Strengthens tooth enamel |
Prelims Alert: India's National Goitre Control Programme (renamed National Iodine Deficiency Disorders Control Programme — NIDDCP) mandates the use of iodised salt. Iodine deficiency is the most common cause of preventable intellectual disability worldwide.
Enzymes
What Are Enzymes?
Enzymes are biological catalysts — proteins that speed up chemical reactions in living organisms without being consumed in the process. They lower the activation energy required for a reaction.
Key Properties of Enzymes
| Property | Detail |
|---|---|
| Specificity | Each enzyme acts on a specific substrate (lock-and-key model) |
| Optimal pH | Most enzymes work best at a specific pH (pepsin: pH 2, trypsin: pH 8) |
| Optimal Temperature | Most human enzymes work best at 37 °C; denatured at high temperatures |
| Reusability | Enzymes are not consumed; they can be used repeatedly |
| Naming | Usually named after substrate + "-ase" suffix (e.g., lipase breaks down lipids) |
Important Digestive Enzymes
| Enzyme | Source | Substrate | Product |
|---|---|---|---|
| Salivary Amylase (Ptyalin) | Saliva (mouth) | Starch | Maltose |
| Pepsin | Stomach (gastric juice) | Proteins | Peptides |
| Trypsin | Pancreas (small intestine) | Proteins | Peptides and amino acids |
| Lipase | Pancreas | Fats (lipids) | Fatty acids + Glycerol |
| Lactase | Small intestine | Lactose | Glucose + Galactose |
| Sucrase | Small intestine | Sucrose | Glucose + Fructose |
Key Concept: Lactose intolerance occurs when the body produces insufficient lactase enzyme, making it unable to digest lactose (milk sugar). It is common in adults, especially in East Asian and some Indian populations.
Industrial Applications of Enzymes
| Application | Enzyme Used |
|---|---|
| Brewing and baking (fermentation) | Zymase (from yeast) |
| Cheese making | Rennet (rennin) |
| Biological detergents | Protease, lipase, amylase |
| Tenderising meat | Papain (from papaya) |
| Contact lens cleaning solutions | Protease |
| Biofuel production | Cellulase |
Nucleic Acids — DNA and RNA Basics
DNA (Deoxyribonucleic Acid)
| Feature | Detail |
|---|---|
| Structure | Double helix (discovered by Watson and Crick, 1953; X-ray data by Rosalind Franklin) |
| Sugar | Deoxyribose |
| Bases | Adenine (A), Thymine (T), Guanine (G), Cytosine (C) |
| Base Pairing | A=T (2 hydrogen bonds), G≡C (3 hydrogen bonds) |
| Function | Stores genetic information; blueprint for protein synthesis |
| Location | Nucleus (mainly), mitochondria, chloroplasts |
RNA (Ribonucleic Acid)
| Feature | Detail |
|---|---|
| Structure | Single-stranded (usually) |
| Sugar | Ribose |
| Bases | Adenine (A), Uracil (U), Guanine (G), Cytosine (C) |
| Types | mRNA (messenger), tRNA (transfer), rRNA (ribosomal) |
| Function | Reads genetic code from DNA and translates it into proteins |
Prelims Tip: Chargaff's rule states that in DNA, the amount of adenine equals thymine (A = T) and guanine equals cytosine (G = C). This rule does not apply to single-stranded RNA.
Food Adulteration and FSSAI
Food Safety and Standards Authority of India (FSSAI)
| Detail | Information |
|---|---|
| Established | 2006, under the Food Safety and Standards Act, 2006 |
| Operational | 2011 (replaced the Prevention of Food Adulteration Act, 1954) |
| Mandate | Lay down science-based food safety standards; regulate manufacture, storage, distribution, sale, and import of food |
| Parent Ministry | Ministry of Health and Family Welfare |
| Logo/Mark | FSSAI license number on packaged food; "Eat Right India" campaign |
Common Food Adulterants
| Food Item | Common Adulterant | Detection Method |
|---|---|---|
| Milk | Water, starch, urea, detergent | Lactometer (water); iodine test (starch) |
| Honey | Sugar syrup, jaggery | Dissolve in water — pure honey does not dissolve easily |
| Turmeric | Metanil yellow (toxic dye), lead chromate | Add HCl — adulterated turmeric turns pink/violet |
| Chilli powder | Brick powder, Sudan dye | Add water — brick powder settles; chemical tests for dyes |
| Mustard seeds | Argemone seeds | Visual inspection (argemone seeds are rough, dark) |
| Tea | Used tea leaves, iron filings | Magnet test (iron); colour test on damp paper |
| Ghee | Vanaspati, animal fat | Baudouin test (for sesame oil in vanaspati) |
Food Preservation Methods
Food preservation prevents microbial growth and spoilage, extending shelf life.
| Method | Principle | Examples |
|---|---|---|
| Refrigeration / Freezing | Low temperature slows microbial growth and enzyme activity | Home refrigerators (2–8 °C), deep freezing (−18 °C) |
| Pasteurisation | Heating to a specific temperature for a set time to kill pathogens without altering taste | Milk (72 °C for 15 seconds — HTST method), fruit juices |
| Sterilisation | Heating to high temperature to kill all microorganisms | Canned foods (121 °C at 15 psi in autoclave) |
| Dehydration / Drying | Removing moisture to prevent microbial growth | Sun-drying (fish, grains), spray drying (milk powder) |
| Lyophilisation (Freeze-Drying) | Freezing followed by vacuum sublimation of ice | Instant coffee, astronaut food, vaccines |
| Canning | Sealing food in airtight containers after heat treatment | Canned fruits, vegetables, fish (invented by Nicolas Appert, 1810) |
| Salting / Sugaring | High salt/sugar concentration causes osmotic dehydration of microbes | Pickles (salt), jams and jellies (sugar) |
| Smoking | Smoke contains antimicrobial chemicals (formaldehyde, phenols) | Smoked fish, smoked meat |
| Chemical Preservatives | Added chemicals inhibit microbial growth | Sodium benzoate (soft drinks), potassium sorbate, vinegar (acetic acid) |
| Food Irradiation | Controlled exposure to ionising radiation (gamma rays, electron beams, X-rays) destroys microorganisms | Spices, onions, potatoes (approved in India since 1994, expanded 1998, 2001); does NOT make food radioactive |
| Vacuum Packing | Removing air prevents aerobic microbial growth | Meat, cheese, nuts |
| Fermentation | Controlled microbial action produces acids or alcohol that preserve food | Yoghurt (lactic acid), wine (alcohol), sauerkraut, kimchi |
Prelims Tip: Pasteurisation is named after French microbiologist Louis Pasteur. The HTST (High Temperature Short Time) method heats milk to 72 °C for 15 seconds and then rapidly cools it. UHT (Ultra-High Temperature) processing heats milk to 135–150 °C for 2–5 seconds, allowing storage without refrigeration for months.
Key Distinction: Food irradiation does NOT make food radioactive. It uses gamma rays (from Cobalt-60 or Caesium-137), electron beams, or X-rays to destroy bacteria, parasites, and insects. India approved irradiation of onions, potatoes, and spices for the domestic market in 1994.
Frequently Asked Questions (Prelims Pattern)
| Question | Answer |
|---|---|
| Which vitamin deficiency causes scurvy? | Vitamin C (Ascorbic Acid) |
| Which vitamin deficiency causes night blindness? | Vitamin A (Retinol) |
| What is the "3 Ds" disease from B₃ deficiency? | Pellagra (Dermatitis, Diarrhoea, Dementia) |
| Which is the only water-soluble vitamin stored in the body? | Vitamin B₁₂ (Cyanocobalamin) |
| What is the most abundant organic compound on Earth? | Cellulose |
| What is denaturation of protein? | Loss of 3D structure due to heat, pH change, or chemicals |
| Which enzyme digests starch in the mouth? | Salivary amylase (ptyalin) |
| What is pasteurisation? | Heating milk to 72 °C for 15 seconds (HTST) to kill pathogens |
| What is lyophilisation? | Freeze-drying — preserving by freezing and vacuum sublimation |
| What is FSSAI's parent ministry? | Ministry of Health and Family Welfare |
| Which mineral deficiency causes goitre? | Iodine |
| What are trans fats? | Artificially hydrogenated unsaturated fats; most harmful to heart health |
| What did WHO say about aspartame in 2023? | IARC classified it as Group 2B (possibly carcinogenic — limited evidence); JECFA reaffirmed ADI of 40 mg/kg; no ban; FSSAI retained existing limits |
| What is the FSSAI +F logo? | Certification mark on fortified foods (rice, wheat flour, oil, milk, double-fortified salt); since March 2024, fortified rice supplied to all 80 crore PDS/PM POSHAN/ICDS beneficiaries |
| What are Shree Anna / Nutri-cereals? | Millets (sorghum, pearl millet, finger millet, foxtail millet); high fibre, iron, calcium; low glycaemic index; India led International Year of Millets 2023 |
Cross-paper relevance
- GS3 — General Science (primary) — Carbohydrates, proteins, lipids, vitamins (deficiency diseases), enzymes, food adulteration; Prelims factual domain bridging chemistry and health
- GS2 — Social Justice & Governance — FSSAI food safety standards, trans-fat elimination (FSSAI 2% limit from 2022), food fortification policy, PDS nutritional quality
- GS3 — Agriculture — Crop nutrient content, bio-fortification (iron-fortified rice, zinc wheat), food processing industry; millets/Shree Anna as nutritional and agricultural policy bridge; FSSAI fortified rice in PDS (80 crore beneficiaries)
- Essay — "Food security vs food safety: India's dual nutritional challenge"
Recent Developments (2024–2026)
ICMR-NIN Dietary Guidelines 2024 — Biochemistry of Optimal Nutrition
ICMR and the National Institute of Nutrition (NIN) released updated Dietary Guidelines for Indians in 2024 with 17 evidence-based recommendations. Key biochemistry connections: limit salt (NaCl) to under 5 g/day to reduce hypertension risk (sodium-potassium pump regulation); minimise ultra-processed foods high in trans-fatty acids (artificial trans-fats: partially hydrogenated vegetable oils — linked to cardiovascular disease); ensure adequate protein from diverse sources (complete vs incomplete amino acid profiles); and emphasise complex carbohydrates (lower glycaemic index — slower glucose release, better insulin response).
UPSC angle: ICMR-NIN 2024 guidelines connect biochemistry directly to India's nutrition policy — essential for both Prelims (specific vitamin deficiencies, recommended intakes) and Mains (food security, NCD prevention).
FSSAI Food Fortification — Fortified Rice Nationwide in PDS (Since March 2024)
FSSAI mandates food fortification under the Food Safety and Standards (Fortification of Foods) Regulations, 2018 for five staples: rice, wheat flour, edible oil, milk, and double-fortified salt (iron + iodine). The landmark milestone: since March 2024, fortified rice is supplied across the entire Public Distribution System (PDS), PM POSHAN (Mid-Day Meal), and ICDS — covering approximately 80 crore beneficiaries (the world's largest food fortification programme by reach). Fortified food packs carry the +F logo. An amendment to the regulation on tolerance limits for micronutrients in fortified foods was also published in 2024-25. New FSSAI labelling regulations (published 2025) will come into force from 1 July 2027.
UPSC angle: The March 2024 PDS fortified-rice universalisation (80 crore beneficiaries) is the most significant FSSAI food fortification update — connects food chemistry (micronutrient addition, bioavailability) to food security governance.
WHO Aspartame Classification — FSSAI Position (2023–2025)
In July 2023, IARC (WHO's cancer research arm) classified aspartame as possibly carcinogenic to humans (Group 2B) — based on limited evidence for hepatocellular carcinoma. However, JECFA (Joint FAO/WHO Expert Committee on Food Additives) reaffirmed the Acceptable Daily Intake (ADI) of 40 mg/kg body weight, finding it safe within normal consumption levels. India's FSSAI retained existing aspartame usage limits (no ban), consistent with JECFA's position. FSSAI noted: in the absence of substantive new safety evidence, existing limits are maintained; WHO guidelines on non-sugar sweeteners (NSS) guide public health education on reducing sugar intake. Mandatory warning labels are required on products containing aspartame (not suitable for children or pregnant women). There is no India-specific ban; the issue is one of consumer awareness, not prohibition.
UPSC angle: IARC Group 2B = "possibly carcinogenic" (limited evidence, not confirmed) — same category as aloe vera extract and pickled vegetables. JECFA vs IARC positions are a classic regulatory science conflict. FSSAI = retained limits; no ban. Good Prelims trap: WHO did NOT ban aspartame — it classified it as Group 2B only.
International Year of Millets 2023 — India's Millet Legacy (2024–2026)
India's leadership of the International Year of Millets 2023 (IYM 2023) left a lasting biochemistry-policy legacy. Key follow-on developments:
- Nutri-cereals / Millets (sorghum, pearl millet, finger millet, foxtail millet, etc.) are nutritionally dense — rich in dietary fibre, iron, calcium, zinc, and B-vitamins; low glycaemic index; relevant to diabetes and obesity management
- India continued millet promotion through the National Year of Millets 2023 legacy framework — FSSAI updated millet-based food product standards; millets included in PM POSHAN mid-day meal menus
- India exports millets to 140+ countries; Shree Anna branding was launched by PM Modi; National Mission on Edible Oils expanded to include millets as part of crop diversification
- FAO/G20 2023 commitments led to millet research networks in 50+ countries
UPSC angle: Millets (Shree Anna) biochemistry — high dietary fibre (helps gut health, lowers GI), iron (combats anaemia), calcium (bone health); GS3 Agriculture-Science bridge topic. Link to India's nutrition policy (POSHAN 2.0), NCD prevention (diabetes, obesity), and agricultural diversification (GS3 Economy).
India's Drug Discovery — Enmetazobactam FDA Approval (2024)
In early 2024, Indian pharmaceutical company Orchid made history as the first Indian firm to receive simultaneous FDA (USA) and EMA (Europe) approval for an indigenously discovered novel drug — enmetazobactam, a beta-lactamase inhibitor combating antimicrobial resistance. This demonstrates India's growing capability in original biochemical research and drug discovery, moving beyond generics. India's bioeconomy reached USD 165.7 billion in 2024.
UPSC angle: Orchid's enmetazobactam approval is India's first original FDA-approved drug discovery — connects biochemistry (enzyme inhibition, beta-lactamase mechanism) to India's pharmaceutical sector achievement.
Key Terms for Quick Revision
| Term | Meaning |
|---|---|
| Monosaccharide | Simplest sugar unit (e.g., glucose, fructose); cannot be hydrolysed further |
| Polysaccharide | Long chain of sugar units (e.g., starch, cellulose, glycogen) |
| Amino Acid | Building block of proteins; 20 standard types, 9 essential |
| Peptide Bond | Covalent bond linking two amino acids in a protein chain |
| Denaturation | Loss of protein's native 3D structure and biological function |
| Enzyme | Biological catalyst that speeds up reactions without being consumed |
| Substrate | The specific molecule on which an enzyme acts |
| Saturated Fat | Fat with no double bonds between carbon atoms; solid at room temperature |
| Trans Fat | Artificially hydrogenated fat; raises LDL and lowers HDL cholesterol |
| Vitamin | Organic compound required in small amounts for metabolic functions |
| FSSAI | Food Safety and Standards Authority of India; regulates food safety since 2011 |
| Pasteurisation | Heat treatment (72 °C, 15 s) to kill pathogens in milk and beverages |
| Lyophilisation | Freeze-drying; preservation by freezing followed by vacuum sublimation |
| Food Irradiation | Exposure to ionising radiation to kill microorganisms; does not make food radioactive |
| Nucleic Acid | DNA or RNA; polymers of nucleotides that carry genetic information |
Sources: Wikipedia; Britannica; FSSAI (fssai.gov.in); PMC (NCBI); PIB (pib.gov.in); PMF IAS; BYJU'S Biology.
