ASRB NET — Farm Machinery & Power / Land & Water Management Engineering / Agricultural Structures & Process Engineering · India · Agricultural Scientists Recruitment Board (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
ASRB NET — Agricultural Structures & Process Engineering
Post-harvest handling and processing of horticultural crops with emphasis on Indian practice: packhouses and collection centres, evaporative cool chambers, CA/MA storage, dehydration and osmotic drying, fruit products and their standards, and spice and plantation-crop processing (pepper, cardamom, turmeric, ginger, coffee, tea, cashew, coconut).
How our questions for ASRB NET spread across the units of Post-Harvest Engineering of Horticultural Crops. Difficulty: 46 easy, 46 medium, 8 hard.
| Processing of spices and plantation crops | 17 | |
| Value addition | 13 | |
| Washing, sorting and waxing | 10 | |
| Dehydration of fruits and vegetables | 10 | |
| Juice extraction | 10 | |
| Respiration and ripening physiology | 9 | |
| Controlled and modified atmosphere storage | 9 | |
| Minimal processing | 7 | |
| Grading, including machine vision | 6 | |
| Pre-cooling: hydro, forced-air and vacuum cooling | 5 | |
| Packhouse design | 4 |
Choose an answer, then open the working. Each explanation says why the right answer is right and why the others are not.
1-Methylcyclopropene (1-MCP) delays ripening of apples mainly by
D. binding ethylene receptors
1-MCP occupies the ethylene receptors in the tissue, blocking the ethylene response. Oxidation of ethylene is what catalytic scrubbers and permanganate do; they remove ethylene from the air but do not block its action inside the fruit.
Further reading: Kader (ed.), Postharvest Technology of Horticultural Crops (UC ANR 3311)
Compared with room cooling, forced-air cooling of the same packed produce is faster mainly because
C. a pressure difference forces cold air through the carton vents past each item
In room cooling air flows around stacks and heat must conduct out through packages; forced-air cooling pulls air through aligned carton vents so each item is swept by cold air. The air temperature is typically similar in both methods.
Further reading: Thompson et al., Commercial Cooling of Fruits, Vegetables, and Flowers (UC ANR 21567)
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)
Visible/near-infrared spectroscopy in a packhouse is used mainly to predict
D. soluble solids content and dry matter non-destructively
Vis-NIR spectra relate to absorbance by water, sugars and other constituents; after calibration against laboratory values they predict internal attributes such as soluble solids and dry matter. Diameter and mass are measured by cameras and load cells.
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)
A breather bag and pressure relief valve are fitted to a CA room to
D. protect the gas-tight room from pressure differences caused by temperature and gas changes
A sealed room would develop pressure differences as air cools, warms or CO2 is scrubbed; the breather bag absorbs small volume changes and relief valves protect against larger ones.
Further reading: Kader (ed.), Postharvest Technology of Horticultural Crops (UC ANR 3311)
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
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
Ten here, 100 in the app. The Laisha app has every practice question we have written to ASRB NET in this subject, marked as you go, with timed papers, a jump-to-unanswered list and a certificate when you pass at 70 per cent.
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