ICAR AIEEA-PG — Agricultural Engineering & Technology (Major Subject Group 10) · India · National Testing Agency for ICAR
Original practice questions written to the published syllabus · not past papersKeeping fruits and vegetables alive and saleable after harvest: cooling, handling, packhouses, controlled atmospheres and processing.
In the exams: GATE AG Section 6 (processing of fruits, vegetables and spices; CA/MA storage); ICAR AICE subject 41
ICAR AIEEA-PG — Agricultural Engineering & Technology
Unit VI (processing, storage, refrigeration, cold stores, plant layout) asks definitions and standard relations: respiration and RQ, Q10, precooling methods, CA/MA principles, blanching and dehydration pretreatments, juice extraction and clarification, pectin gels, canning divide at pH 4.6, and spice processing steps. Single-answer MCQs with negative marking reward exact recall.
How our questions for ICAR AIEEA-PG spread across the units of Post-Harvest Engineering of Horticultural Crops. Difficulty: 52 easy, 26 medium, 10 hard.
| Dehydration of fruits and vegetables | 13 | |
| Respiration and ripening physiology | 12 | |
| Value addition | 11 | |
| Pre-cooling: hydro, forced-air and vacuum cooling | 9 | |
| Juice extraction | 9 | |
| Processing of spices and plantation crops | 9 | |
| Washing, sorting and waxing | 6 | |
| Grading, including machine vision | 6 | |
| Packhouse design | 5 | |
| Controlled and modified atmosphere storage | 5 | |
| Minimal processing | 3 |
Choose an answer, then open the working. Each explanation says why the right answer is right and why the others are not.
When malic acid (C4H6O5) is the main respiratory substrate, the respiratory quotient is about
B. 1.33
C4H6O5 + 3 O2 -> 4 CO2 + 3 H2O, so RQ = 4/3 = 1.33. An RQ of 1.0 applies to hexose sugars and about 0.7 to fats, which need more oxygen per carbon. 0.75 inverts the ratio (O2/CO2 = 3/4).
Further reading: Kader (ed.), Postharvest Technology of Horticultural Crops (UC ANR 3311)
In chlorinated wash water, the pH is normally held near 6.5 to 7.5 mainly because
C. hypochlorous acid, the most effective form, dominates at slightly acidic to neutral pH
HOCl is a far stronger sanitiser than the hypochlorite ion, which dominates at high pH. Going much below pH 6.5 increases chlorine gas release and corrosion, so a slightly acidic to neutral band is used.
Further reading: Kader (ed.), Postharvest Technology of Horticultural Crops (UC ANR 3311)
The main hygienic principle in packhouse layout is that
D. produce flows one way from dirty to clean zones, never crossing incoming produce or waste
Cleaned and packed produce must never cross paths with incoming field produce, culls, waste or field bins, which carry soil and pathogens.
Further reading: Kader (ed.), Postharvest Technology of Horticultural Crops (UC ANR 3311)
If slice thickness is doubled, other conditions unchanged, the falling-rate drying time to a given moisture ratio (diffusion-controlled) becomes about
B. four times as long
In Fick's solution time appears as D t / L^2, so for the same moisture ratio t is proportional to L^2; doubling thickness quadruples the time.
Further reading: Sahay and Singh, Unit Operations of Agricultural Processing
Vegetables are blanched before dehydration mainly to
B. inactivate enzymes that cause off-flavour and discolouration in storage
Blanching inactivates enzymes such as peroxidase and catalase and removes tissue air; it reduces but does not eliminate microorganisms.
Further reading: Srivastava and Kumar, Fruit and Vegetable Preservation: Principles and Practices
10 g of dried vegetable pieces absorb water and weigh 55 g after rehydration. The rehydration ratio is
A. 5.5
Rehydration ratio = rehydrated mass / dried mass = 55/10 = 5.5. 4.5 is the water absorbed per gram, not the ratio. 0.18 inverts the ratio (10/55).
Further reading: Srivastava and Kumar, Fruit and Vegetable Preservation: Principles and Practices
A processor blends a 12 degBrix juice with a 65 degBrix concentrate to make 1 000 kg of a 20 degBrix base. The concentrate needed is about
A. 151 kg
Pearson square: juice parts = 65 - 20 = 45, concentrate parts = 20 - 12 = 8; concentrate = 1 000 x 8/53 = 151 kg. Check: 849.1 x 0.12 + 150.9 x 0.65 = 200 kg solids = 20%. 849 kg is the juice, not the concentrate. 178 kg divides the concentrate parts by the juice parts (1 000 x 8/45) instead of the total; 123 kg divides by 65.
Further reading: Fellows, Food Processing Technology
A ready-to-serve beverage is to contain 10% juice (juice at 12 degBrix) and 10% total soluble solids. Treating juice solids and added sugar as the only soluble solids, the sugar to add per 100 kg of beverage is
D. 8.8 kg
Juice = 10 kg contributing 10 x 0.12 = 1.2 kg solids. Sugar = 10 - 1.2 = 8.8 kg. Adding 10 kg ignores the juice solids; 1.2 kg is the juice's own contribution; 11.2 kg adds the juice solids instead of subtracting them.
Further reading: Srivastava and Kumar, Fruit and Vegetable Preservation: Principles and Practices
White pepper is produced by
A. retting ripe berries in water and removing the outer skin
White pepper is the seed after the outer pericarp has been removed by retting and washing or by mechanical decortication.
Further reading: Pruthi, Major Spices of India: Crop Management and Post-Harvest Technology
Parchment coffee is dried to about
D. 10 to 12% moisture before hulling
Parchment coffee is dried to roughly 10 to 12% moisture for safe storage and hulling; wetter beans mould, over-dried beans lose quality.
Further reading: Coffee processing literature
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