Food Science, Nutrition, and Food Preparation
Domain 3, Food Science, Nutrition, and Food Preparation, tests nutrient function and digestion, dietary guidance, energy calculations, food safety and HACCP, the science behind cooking reactions, and recipe math. Many items combine a nutrition label or recipe with a calculation, so practice both halves.
Nutrient rules of thumb
- Energy: carbohydrate 4 kcal/g, protein 4 kcal/g, fat 9 kcal/g, alcohol 7 kcal/g.
- AMDR: carbohydrate 45–65%, fat 20–35%, protein 10–35% of calories. Fiber target is 14 g per 1,000 kcal. Added sugars under 10% of calories; sodium under 2,300 mg daily.
- Protein RDA for adults is 0.8 g/kg body weight, rising in pregnancy, lactation, and endurance training.
- Fat-soluble vitamins A, D, E, K; water-soluble B vitamins and vitamin C leach into cooking water and are destroyed by heat.
- DRI family: EAR, RDA, AI, UL. The UL is a ceiling, never a target.
Food safety
- Danger zone 41–135°F. Poultry and stuffed items to 165°F; ground meat and egg dishes to 155°F; whole muscle meat, pork, and fish to 145°F with a 3-minute rest.
- Two-stage cooling: 135°F to 70°F within 2 hours, then to 41°F within 4 more hours.
- HACCP: hazard analysis, critical control points, critical limits, monitoring, corrective action, verification, record keeping.
Food science
- Maillard browning needs protein plus a reducing sugar plus heat and low moisture; caramelization is sugar alone.
- Starch gelatinizes in hot liquid and sets as it cools. Fat shortens gluten strands and tenderizes; salt and acid strengthen gluten.
Worked example
A snack bar has 12 g fat, 30 g carbohydrate, and 20 g protein. What share of calories comes from fat? Reasoning: 12 × 9 = 108; 30 × 4 = 120; 20 × 4 = 80; total 308 kcal. Fat share = 108/308 = 35%, at the very top of the 20–35% AMDR band. Compute before judging; the protein contributes less energy than the carbohydrate despite the larger gram figure.
Traps that cost marks
- Using 9 kcal/g for protein or 4 kcal/g for fat.
- Reversing the two-stage cooling temperatures.
- Confusing gelatinization (starch) with gelation (gelatin).
- Reading percent daily value as a share of your own needs; it references a 2,000-kcal diet.