Mass and Energy Balances - Food Engineering - Life Sciences Previous Year Questions

1

2011 · Life Sciences · Food Engineering · Mass and Energy Balances

Life Sciences (XL) 2011

A continuous dryer was used to dry 12 kg/min of a blanched vegetable containing 50% moisture (wet weight basis) to give a product containing 10% moisture. As the dryer could handle feed material with moisture content not more than 25%, a part of dried material was recycled and mixed with the fresh feed. The evaporation rate in the dryer will be

A

2.08 kg/min

B

5.33 kg/min

C

3.33 kg/min

D

2.93 kg/min

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2

2012 · Life Sciences · Food Engineering · Mass and Energy Balances

Life Sciences (XL) 2012

100 kg tomato juice containing 5% Total Solids (w/w) is concentrated to 25% Total Solids (w/w). The total amount of water removed from tomato juice in kg is

A

65

B

70

C

75

D

80

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3

2013 · Life Sciences · Food Engineering · Mass and Energy Balances

Life Sciences (XL) 2013

How much skim milk (in kg) containing 0.1% fat should be added to 500 kg of cream containing 50% fat to produce standardized cream containing 36% fat?

A

140

B

165

C

195

D

210

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4

2014 · Life Sciences · Food Engineering · Mass and Energy Balances

Life Sciences (XL) 2014

Saturated steam at 100°C is injected at 0.2 kg s⁻¹ into air stream flowing at 3 kg s⁻¹ and 25°C. Air contains 0.012 kg moisture per kg dry air. If the atmospheric pressure is 101.1 kPa, absolute humidity of air will be ______ kg kg⁻¹.

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5

2014 · Life Sciences · Food Engineering · Mass and Energy Balances

Life Sciences (XL) 2014

In an evaporator, milk is concentrated from 9.8% TSS to 52% TSS. Assume the solutes in the milk are non-volatile. The amount of vapour produced for 100 kg feed will be ______ kg.

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6

2016 · Life Sciences · Food Engineering · Mass and Energy Balances

Life Sciences (XL) 2016

Fruit juice is being pasteurized in a tubular heat exchanger. The retention time in holding tube of 0.2 m² cross sectional area is 3 seconds. If the flow rate of juice is 0.4 m³ s⁻¹, the length of the holding tube in m, is ____ .

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7

2016 · Life Sciences · Food Engineering · Mass and Energy Balances

Life Sciences (XL) 2016

80 kg of wheat containing 10 kg of moisture has been dried to a moisture content of 8% wet basis in 3 hours under constant rate period of drying. The drying rate in kg h⁻¹ is _____

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8

2016 · Life Sciences · Food Engineering · Mass and Energy Balances

Life Sciences (XL) 2016

The amount of sugar to be added (kg) to 40 kg of mango pulp to increase its total soluble solids from 20% wt. to 65% wt. is ______

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9

2017 · Life Sciences · Food Engineering · Mass and Energy Balances

Life Sciences (XL) 2017

In an evaporation process, a compressor picks up 0.05 m³ air in each revolution and compresses 500 kg of air per minute. If the specific volume of air is 0.9 m³/kg, then the compressor speed is ______rpm.

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10

2017 · Life Sciences · Food Engineering · Mass and Energy Balances

Life Sciences (XL) 2017

For a soybean oil extraction system, solvent:soy ratio is maintained at 0.5:1 (w/w). Original seed contains 18% oil (w/w). If the meal (soy solid) after final desolventization has 0.01 kg oil per kg oil free meal, then the effectiveness of the solvent (kg oil/ kg solvent) in the extraction process is ______ .

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11

2019 · Life Sciences · Food Engineering · Mass and Energy Balances

Life Sciences (XL) 2019

An ice cream mix of 870 g L^-1 has been used to prepare ice cream which yielded a finished product of 490 g L^-1. The per cent over run is ________ (round off to 1 decimal place).

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12

2019 · Life Sciences · Food Engineering · Mass and Energy Balances

Life Sciences (XL) 2019

Potato slices have been dehydrated from an initial solid content of 12% to a final solid content of 94%. If the peeling and other losses are to the tune of 10%, final yield (per cent) of the dried chips per ton of fresh potato taken is ________ (round off to 2 decimal places).

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13

2019 · Life Sciences · Food Engineering · Mass and Energy Balances

Life Sciences (XL) 2019

Room air is at 40 °C with 60% relative humidity. Saturated vapour pressure of water at 40 °C is 7.375 kPa. Humid volume of air (m³ per kg of dry air) is ______ (round off to 3 decimal places).

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14

2022 · Life Sciences · Food Engineering · Mass and Energy Balances

Life Sciences (XL) 2022

One hundred kg paddy is dried from 18% wet basis to 13% wet basis moisture content. The amount of water removed (in kg) from the paddy is ______ (round off to one decimal place).

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15

2022 · Life Sciences · Food Engineering · Mass and Energy Balances

Life Sciences (XL) 2022

The dry bulb temperature and relative humidity of air inside a storage chamber are 37 °C and 50%, respectively. The saturation pressure of water vapour at 37 °C and barometric pressure are 6.28 kPa and 101.32 kPa, respectively. The humidity ratio of air inside the chamber is ______ kg water (kg dry air)⁻¹ (round off to three decimal places).
Given: Molecular weight of water vapour and dry air are 18.02 g mol⁻¹ and 28.97 g mol⁻¹, respectively.

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16

2023 · Life Sciences · Food Engineering · Mass and Energy Balances

Life Sciences (XL) 2023

Calculate the efficiency in percent (rounded off to 1 decimal place) of an oil expeller which yields 37 kg oil containing 5% solid impurities from 100 kg mustard seeds. The oil content of the mustard seed is 38%.

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17

2023 · Life Sciences · Food Engineering · Mass and Energy Balances

Life Sciences (XL) 2023

The weight of 10 kg dried cauliflower containing 5% moisture (wet basis) after rehydration is 60 kg. If the fresh cauliflower contained 87% moisture (wet basis), calculate the coefficient of rehydration (rounded off to 2 decimal places).

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18

2023 · Life Sciences · Food Engineering · Mass and Energy Balances

Life Sciences (XL) 2023

The average moisture binding energy of a textured protein product (TPP) at 8% moisture content (dry basis) is 3200 cal.mol⁻¹. If the water activity of the TPP at the above moisture content is 0.30 at 30 °C, the water activity of the sample at 45 °C is ______ (rounded off to 2 decimal places). The value of Gas constant R = 1.987 cal.mol⁻¹.K⁻¹.

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19

2024 · Life Sciences · Food Engineering · Mass and Energy Balances

Life Sciences (XL) 2024

A 10 kg tomato pulp is concentrated from an initial moisture content of 90% (wet weight basis) to 35% (wet weight basis). The weight of the concentrate in kg is ________ (round off to 2 decimal places).

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20

2025 · Life Sciences · Food Engineering · Mass and Energy Balances

Life Sciences (XL) 2025

The true density and bulk density of wheat grains are 1280 kg/m³ and 740 kg/m³, respectively. The porosity of the grains is ______. (rounded off to 2 decimal places)

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