Post-Harvest Management, Processing and Value Addition
Domain 8 tests what happens between harvest and sale, and how processing adds value. Expect maturity indices, cooling, grading, storage and simple product calculations.
Core rules
- Harvest at the correct maturity. Maturity indices include colour, firmness, size, soluble solids and days after flowering.
- Remove field heat quickly. Precooling slows respiration and extends shelf life.
- Sort out damaged fruit, grade by size and quality, and avoid rough handling.
- Climacteric fruits such as banana and mango ripen after harvest with a respiration peak. Non-climacteric fruits such as citrus and grape do not ripen further after harvest.
- Ethylene can accelerate ripening; ventilation and separation prevent unwanted ripening.
- Processing includes drying, canning, freezing, jam, jelly, squash, pickle and juice. Hygiene and correct acidity or sugar levels are essential.
Worked example
A processor has 10 kg fruit pulp at 10% total soluble solids and wants jam at about 68% TSS. Let sugar added be x kg. Total solids = 10 × 0.10 + x = 1 + x. Total mass = 10 + x. For 68% TSS, 1 + x = 0.68(10 + x). This gives 0.32x = 5.8, so x = 18.1 kg sugar. The final batch is about 28.1 kg and tests near 68% TSS. Acid and pectin are adjusted separately.
Traps that cost marks
Do not treat all fruits as climacteric. Do not store mature ripe fruit with immature fruit without considering ethylene. Do not confuse jam with jelly. Do not cool hot processed jars slowly in a way that risks spoilage.