IV. Food Science

CSS GSA — Paper 7, Part-I, Section IV (Food Science)

This is the index for Food Science. Each sub-topic below has its own sub-page with full notes, MCQ traps, and self-test questions.

Past Paper Weightage

• Concept of Balanced Diet (esp. vitamin deficiency diseases) is the highest-yield topic in this section and appears nearly every year — start here.

Sub-topics

Weak areas

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Past paper practice

• Balanced diet / vitamin deficiency diseases and food preservatives vs antioxidants are asked almost every year — master these first

Past Paper Questions (FPSC GSA Paper 7, 2016–2025)

Each question gives a Full Answer (write this in the exam) and Quick Notes (bullets for fast revision).

2025 — Q5(a) [5] Food Contaminants vs Food Adulterants

Full Answer: Food contaminants are harmful substances that enter food unintentionally, at any stage from production to consumption, such as bacteria, pesticide residues, heavy metals, or industrial pollutants introduced through poor handling, storage, or environmental exposure. Food adulterants, by contrast, are substances intentionally added to food, usually for economic gain, to increase quantity, improve appearance, or reduce cost, such as adding chalk powder to flour, water to milk, or artificial colors to spices, often at the expense of the food's quality, nutritional value, or safety.

Quick Notes:

• Contaminant = unintentional (bacteria, pesticide residue, heavy metals)
• Adulterant = intentional, for profit (chalk in flour, water in milk, fake colors)

2025 — Q5(b) [5] Major Food Groups

Full Answer: Food is generally classified into major groups based on the nutrients they primarily provide: carbohydrates (cereals, grains, bread, rice — provide energy), proteins (meat, fish, eggs, pulses, dairy — provide growth and repair), fats and oils (butter, cooking oil, nuts — provide concentrated energy and essential fatty acids), fruits and vegetables (provide vitamins, minerals, and fiber), and dairy products (milk, cheese, yogurt — provide calcium and protein). A balanced diet includes appropriate proportions from each group to meet the body's energy and nutritional needs.

Quick Notes:

• Groups: Carbohydrates (energy), Proteins (growth/repair), Fats/Oils (concentrated energy), Fruits/Vegetables (vitamins/minerals/fiber), Dairy (calcium/protein)

2024 — Q4(a) [5] Role of Carbohydrates and Vitamins in the Body

Full Answer: Carbohydrates are the body's primary and most readily available source of energy; they are broken down into glucose, which fuels cellular respiration in every cell, and any excess is stored in the liver and muscles as glycogen for later use. Vitamins are organic compounds needed in small quantities that the body generally cannot synthesize on its own; they perform a wide range of regulatory roles such as supporting vision and immune function (Vitamin A), aiding calcium absorption and bone health (Vitamin D), acting as antioxidants (Vitamin C and E), and assisting metabolism and nerve function (the B-vitamin group). Deficiency of any vitamin leads to a specific, identifiable disease.

Quick Notes:

• Carbohydrates → main energy source → broken into glucose → excess stored as glycogen
• Vitamins → small-quantity organic regulators: A (vision/immunity), D (bone/calcium), C/E (antioxidants), B-group (metabolism/nerves)

2023 — Q5(a) [5] Antioxidants — Why Used in Food, Natural vs Synthetic

Full Answer: Antioxidants are substances added to food to prevent or slow oxidation, the chemical reaction between food components (especially fats) and oxygen that causes rancidity, spoilage, discoloration, and loss of nutritional value; by neutralizing free radicals produced during oxidation, antioxidants extend a food's shelf life and preserve its taste, color, and nutrients. Natural antioxidants include Vitamin C (ascorbic acid), Vitamin E (tocopherol), and plant-derived compounds found in fruits, vegetables, and spices. Synthetic antioxidants, manufactured chemically for wider or cheaper use in processed food, include BHA (butylated hydroxyanisole) and BHT (butylated hydroxytoluene), which are used in packaged snacks, oils, and cereals, though their long-term safety has drawn some regulatory scrutiny.

Quick Notes:

• Antioxidants prevent oxidation → stop rancidity/spoilage/discoloration, preserve nutrients
• Natural: Vitamin C, Vitamin E, plant compounds
• Synthetic: BHA, BHT — used in packaged/processed foods

2021 — Q4(d) [5] Food Contaminants vs Food Adulterants

Full Answer: (See 2025 Q5(a) above for the fuller model answer — same core distinction: contaminants enter food unintentionally, adulterants are added intentionally for profit.)

Quick Notes:

• Contaminant = unintentional; Adulterant = intentional, for economic gain

2021 — Q5(a) [5] Malnutrition — Causes and Consequences

Full Answer: Malnutrition is a condition resulting from an improper or insufficient diet, encompassing both undernutrition (deficiency of calories, protein, vitamins, or minerals) and overnutrition (excess intake leading to obesity). Its major causes include poverty and food insecurity, lack of access to a varied and balanced diet, poor maternal and child feeding practices, disease (which increases nutrient needs while reducing appetite/absorption), and lack of nutritional awareness. Consequences include stunted physical growth and low body weight in children, weakened immune function leading to more frequent illness, impaired cognitive development and learning ability, anemia and other deficiency diseases, and in severe cases, increased mortality; overnutrition-related malnutrition contributes to obesity, diabetes, and cardiovascular disease.

Quick Notes:

• Malnutrition = undernutrition (deficiency) or overnutrition (excess/obesity)
• Causes: poverty, poor diet access, poor feeding practices, disease, lack of awareness
• Consequences: stunted growth, weak immunity, impaired cognition, anemia, obesity/diabetes (if overnutrition)

2020 — Q3(b) [5] Carbohydrates — Classification with Examples

Full Answer: Carbohydrates are classified into three main types based on their molecular structure. Monosaccharides are the simplest form, single-sugar units that cannot be broken down further, such as glucose, fructose, and galactose. Disaccharides are formed from two monosaccharide units joined together, such as sucrose (table sugar, glucose + fructose), lactose (milk sugar, glucose + galactose), and maltose (glucose + glucose). Polysaccharides are large, complex chains of many monosaccharide units, such as starch (energy storage in plants), glycogen (energy storage in animals), and cellulose (structural fiber in plant cell walls, indigestible by humans).

Quick Notes:

• Monosaccharides: glucose, fructose, galactose (simplest)
• Disaccharides: sucrose, lactose, maltose (two units)
• Polysaccharides: starch, glycogen, cellulose (many units, complex)

2020 — Q3(c) [5] Food Preservation Methods

Full Answer: Food preservation methods slow or prevent spoilage caused by microorganisms, enzymes, and oxidation. Common methods include refrigeration and freezing (slowing microbial growth and enzyme activity through low temperature), canning (sealing food in airtight containers after heat-sterilizing it to kill microorganisms), drying/dehydration (removing moisture that microorganisms need to grow), salting and sugaring (drawing out moisture through osmosis and creating an environment hostile to microbes), pickling (using acidic vinegar/brine to inhibit microbial growth), and pasteurization (brief heating to kill pathogens, commonly used for milk and juices) along with the use of chemical preservatives and antioxidants to slow oxidation and microbial spoilage.

Quick Notes:

• Cold-based: refrigeration/freezing (slows microbes/enzymes)
• Heat-based: canning, pasteurization (kills microbes)
• Moisture-removal: drying, salting/sugaring (osmosis)
• Chemical: pickling (acid), preservatives/antioxidants

2019 — Q2(a) [5] Vitamin Deficiency Diseases (matching table)

Full Answer: (See the II. Biological Sciences page's 2019 Q2(a) entry for the complete matching table — same content: Vitamin A deficiency → night blindness; B1 → beriberi; B2 → cracked skin/lips; B3 → pellagra; B12 → pernicious anemia; C → scurvy; D → rickets/osteomalacia; K → poor blood clotting.)

Quick Notes:

• A→night blindness, B1→beriberi, B2→cracked skin, B3→pellagra, B12→anemia, C→scurvy, D→rickets, K→poor clotting

2018 — Q5(c) [5] Balanced Diet

Full Answer: A balanced diet is one that provides all the essential nutrients — carbohydrates, proteins, fats, vitamins, minerals, fiber, and water — in the correct proportions needed to maintain good health, support normal growth and development, and provide the energy required for daily activity, without excess or deficiency of any nutrient. It typically includes a variety of foods from all major food groups (grains, proteins, dairy, fruits and vegetables, and fats/oils) in moderate portions, tailored to an individual's age, sex, activity level, and health status. A balanced diet helps prevent both nutrient-deficiency diseases (like scurvy or anemia) and diet-related chronic diseases (like obesity, diabetes, and cardiovascular disease).

Quick Notes:

• Balanced diet = all essential nutrients (carbs, protein, fat, vitamins, minerals, fiber, water) in correct proportion
• Includes variety from all food groups, tailored to individual needs
• Prevents both deficiency diseases and diet-related chronic diseases

2016 — Q9(a) [5] Preservatives and Antioxidants

Full Answer: Preservatives are substances added to food to prevent or slow down spoilage caused by microorganisms such as bacteria, yeast, and mould, thereby extending shelf life — common examples include salt, sugar, vinegar, sodium benzoate, and sulphites. Antioxidants are substances added specifically to prevent oxidation, the chemical reaction with oxygen (especially affecting fats and oils) that causes rancidity, discoloration, and nutrient loss — common examples include Vitamin C, Vitamin E, BHA, and BHT. While both extend a food's usable life, preservatives target microbial spoilage while antioxidants target chemical/oxidative spoilage, and many processed foods use both together for maximum shelf-life extension.

Quick Notes:

• Preservatives: stop microbial spoilage (salt, sugar, vinegar, sodium benzoate, sulphites)
• Antioxidants: stop oxidative spoilage/rancidity (Vitamin C, E, BHA, BHT)
• Difference: microbial vs chemical/oxidative spoilage — often used together

2024 — Part-I MCQs (Food Science items)

Full Answer:

1. In fish liver oil there is: (D) Vitamin A and Vitamin D. Fish liver oil (e.g., cod liver oil) is a well-known natural source of the fat-soluble vitamins A and D together.
2. The minimum amount of vitamin stored in the human body is of: (B) Vitamin C. Vitamin C is water-soluble and not stored in significant amounts by the body (unlike fat-soluble vitamins A, D, E, K), so it must be replenished regularly through diet.

Quick Notes:

• Fish liver oil → Vitamin A + Vitamin D
• Least-stored vitamin in body → Vitamin C (water-soluble, not stored like A/D/E/K)

2025 — Part-I MCQs (Food Science items)

Full Answer:

1. Maximum amount of carbohydrates are obtained from: (C) Whole grain food. Whole grains (wheat, rice, oats, etc.) are composed largely of starch, making them the richest common dietary source of carbohydrates compared to nuts (mostly fat) or plant oil (pure fat, no carbohydrate).
2. The process of preserving meat by stewing in a covered earthenware jug is called: (B) Jugging. Jugging is a traditional preservation/cooking method where meat is slow-cooked in a sealed jug or pot, often with its own blood/juices, to extend its usable life and enhance flavour.
3. Which products can be prepared using raw guava: (C) Both Jam and Jelly. Raw (unripe) guava is naturally high in pectin, which sets well, making it suitable for both jam (using the pulp) and jelly (using the strained juice).
4. Which is used as a stabilizer in ice cream: (C) Gelatin. Gelatin is added to ice cream to stabilize the mixture, prevent large ice-crystal formation, and give a smoother, creamier texture during freezing.
5. The process of adding vitamins to milk is known as: (B) Fortification. Fortification is the deliberate addition of nutrients (commonly Vitamin D, sometimes A) that are not naturally present in sufficient amounts, to improve a food's nutritional value.

Quick Notes:

• Most carbs from: Whole grain food (starch-rich)
• Meat stewed/preserved in sealed jug = Jugging
• Raw guava (high pectin) → both jam and jelly
• Ice cream stabilizer = Gelatin
• Adding vitamins to milk = Fortification