Introduction to Food Technology & Food Composition

The science and engineering of what we eat. Learn what food technologists do, the food system from farm to fork, the major food components (water, carbohydrates, proteins, lipids, vitamins, minerals, fibre), proximate analysis, energy values with Atwater factors, wet and dry basis, food groups and processing levels, and careers in food industry, safety regulation and R&D — with Python computing the energy and macronutrient profile of a food.

Food technology applies chemistry, microbiology, engineering and nutrition to turn raw agricultural materials into safe, nutritious, tasty and convenient foods — and to keep them that way until they're eaten.

India's food processing sector is one of the largest manufacturing employers, spanning dairy, grains, edible oils, beverages, snacks, fruits and vegetables, meat and seafood. Every packet on a shop shelf has been designed, processed, packed and tested by food technologists.

An analogy

A food is like a building made from a few types of bricks — water, carbohydrates, proteins and fats — plus small amounts of 'fittings' (vitamins, minerals, flavours). Food technology decides how those bricks are arranged, protected and transformed.

Major food components

What foods are made of:

• Water — 5% (biscuits) to 95% (vegetables); controls texture, shelf life and microbial growth
• Carbohydrates — sugars, starch, fibre; energy, texture, sweetness, browning
• Proteins — amino acids; nutrition, structure (gluten, egg, meat), emulsification, foaming
• Lipids — fats and oils; energy, flavour, mouthfeel; prone to oxidation (rancidity)
• Micronutrients — vitamins and minerals; ash = total mineral content

The food system and processing levels

Farm production → post-harvest handling → primary processing (milling, dairy collection, slaughter) → secondary processing (bakery, snacks, beverages) → packaging → distribution and cold chain → retail → consumer. Processing ranges from minimal (washing, cutting) to extensive (extruded snacks, ready meals). Objectives: safety, preservation, convenience, nutrition, sensory quality and value addition.

Proximate analysis

Standard lab methods: moisture (oven drying), protein (Kjeldahl nitrogen × 6.25), fat (Soxhlet extraction), ash (muffle furnace at 550 °C), crude/dietary fibre (enzymatic-gravimetric), carbohydrate by difference. Rapid methods: NIR spectroscopy for moisture, protein and fat on production lines.

Careers and trends

Food technologists work in production, quality assurance, R&D, regulatory affairs (FSSAI, Codex), packaging, sensory science and supply chain. Trends: plant-based and alternative proteins, precision fermentation, clean labels, fortification, reduction of salt/sugar/fat, personalised nutrition, food waste valorisation and digital traceability.

Formulas

• Atwater energy: E (kcal) = 4P + 9F + 4C + 2·fibre
• Energy share: % energy from fat = 9F/E × 100
• Proximate analysis: moisture + protein + fat + carbohydrate + fibre + ash = 100
• Dry basis: x_db = x_wb/(1 − moisture)
• Carbohydrate by difference: C = 100 − (moisture + protein + fat + ash + fibre)

Worked example: Energy value

Given: P 7 g, F 30 g, C 55 g per 100 g

Find: kcal.

• 28 + 270 + 220

Answer: 518 kcal/100 g

Worked example: Carbohydrate by difference

Given: Moisture 12, protein 11, fat 1.5, ash 0.6, fibre 2

Find: C.

• 100 − 27.1

Answer: 72.9 g/100 g

Worked example: Dry basis

Given: Fat 3% in milk with 88% water

Find: Fat on dry basis.

• 3/12

Answer: 25% db

Energy and macronutrient profile

# Food composition: energy (Atwater factors) and dry-basis nutrients
food = {"protein": 8.0, "fat": 3.5, "carbohydrate": 12.0, "fibre": 2.0, "water": 73.5, "ash": 1.0}   # g per 100 g
energy_kcal = 4 * food["protein"] + 9 * food["fat"] + 4 * food["carbohydrate"] + 2 * food["fibre"]
print(f"total composition {sum(food.values()):.1f} g/100 g")
print(f"energy {energy_kcal:.1f} kcal/100 g = {energy_kcal*4.184:.0f} kJ/100 g")
for k in ("protein", "fat", "carbohydrate"):
    share = {"protein": 4, "fat": 9, "carbohydrate": 4}[k] * food[k] / energy_kcal * 100
    print(f"{k:12s} {share:5.1f}% of energy")
dry = 100 - food["water"]
print(f"protein on dry basis {food['protein']/dry*100:.1f}%")
# total composition 100.0 g/100 g
# energy 115.5 kcal/100 g = 483 kJ/100 g
# protein       27.7% of energy
# fat           27.3% of energy
# carbohydrate  41.6% of energy
# protein on dry basis 30.2%

This composition resembles a cooked dal (lentil) dish: mostly water, but 30% protein once water is removed. Atwater factors (4/9/4/2 kcal/g) are the basis of every nutrition label. Comparing on a dry basis removes the effect of water, making foods comparable.

Common mistakes

• Wrong: Comparing nutrients of wet and dry foods directly. — Right: Convert to dry basis or per serving.
• Wrong: Using 4 kcal/g for fat. — Right: Fat gives 9 kcal/g.
• Wrong: Ignoring fibre in carbohydrate energy. — Right: Fibre gives ~2 kcal/g, not 4.

Applications

• Nutrition labelling: Every packaged food declares energy and nutrients.
• Product formulation: Designing high-protein or low-fat foods.
• Quality control: Moisture and fat checks on production lines.
• Public health: Fortification programmes (iodised salt, fortified rice).

Key takeaways

• Water, carbs, proteins, fats + micronutrients.
• E = 4P + 9F + 4C (+2 fibre).
• Compare on dry basis or per serving.
• Food tech spans safety, processing, nutrition and R&D.

Going further

• NIR spectroscopy: Rapid in-line composition analysis.
• Food matrix effects: Digestibility depends on structure, not just composition.
• Alternative proteins: Plant, fungal and cultivated proteins.