Pune University BE Biotechnology Food Biotechnology Question Papers

B.E. (Biotechnology)

FOOD BIOTECHNOLOGY (2008 Pattern) (Elective – III) (Sem. – II)

Time: 3 Hours]                                                                                              [Max. Marks :100

Instructions to the candidates:

1)            Answer three questions from Section -1 and three questions from Section – II.

2)            Answers to the two sections should be written in separate answer books.

3)            Neat diagrams should be drawn wherever necessary.

4)            Figures to the right indicate full marks.


Q1) a) Discuss in detail the various intrinsic factors affecting food spoilage by micro-organisms.                                                                                                         [10]

b) What is meant by sensory characteristics of a food component? How does food spoilage affect these sensory characteristics?                                                    [6]


Q2) a) Discuss in brief the different factors which affect water activity requirement of micro-organisms.                                                                                        [8]

b) Describe the growth conditions suitable for the survival of different types of spoilage micro-organisms.                                                                                     [8]

Q3) a) Describe in detail the process of pasteurization.                              [8]

b) Write notes on the following :                                                                            [10]

i)              Microwave based treatment of food.

ii)           Freeze drying.


Q4) Write notes on the following :                                                               [18]

a)            Drying of food.

b)            Hydrostatic pressure cooking.

c)            Preservation using food additives.


Q5) a) In an incidence of spoilage, the isolated spoilage organism was found to have a D0 value of 1.35 minutes. It is desired that the probability of spoilage from this organism be 1 in 100,000. Initial spore loads were generally of the order 10/can. Calculate the required F0 for this process to achieve the desired probability of spoilage.                 [6]

b) Lettuce was vacuum-cooled and then loaded into a refrigerated car for shipment to a market. The trip will last 48 h. Calculate the total amount of heat removed and the peak refrigeration load (maximum heat removal rate) if the amount of lettuce loaded is 3000 kg, the temperature in the truck is 2°C, the temperature of lettuce when loaded is 5°C and will drop to 2°C in 2h, the heat capacity of lettuce is 4.02 kJ/kg°C, the area of the walls of the truck is 80 m2, the overall heat transfer coefficient for the walls is 0.3 W/m2°C, the outside air temperature is 20°C, and the heat of respiration of lettuce in the temperature range of 2 to 5°C is 35 x 10-3 W/kg.                                                              [10]


Q6) a) A liquid food (specific heat 4.0 kJ/kg°C) flows in the inner pipe of a double pipe heat exchanger. The liquid food enters the heat exchanger at 20°C and exits at 60°C. The flow rate of the liquid food is 0.5 kg/s. In the annular section, hot water at 90°C enters the heat exchanger and flows counter currently at a flow rate of 1kg/s. The average specific heat of water is 4.18 kJ/kg°C. Assume steady-state conditions. Calculate :

i)             Exit temperature of water.

ii)           Log-mean temperature difference.

iii)        If the average overall heat transfer coefficient is 2000 W/m2°C and the diameter of the inner pipe is 5 cm, calculate the length of the heat exchanger. [10]

b) Freshly harvested berries measuring 2 cm in diameter are chilled from 18°C to 7°C in a chiller at -2°C with a surface heat transfer coefficient of 16 W/m2K. Calculate the time required to cool the berries in the chiller. The thermal conductivity for the berries is 0.127 W/mK, specific heat capacity is 3778 J/kg K and density of the berries is 1050 kg/m3. Take F = Bi1/2.                                                                                                   [6]



Q7) a) Describe the industrial process for the production of agar derived from algae. Also enlist its food based applications.                                                                 [9]

b) What is solid state bioprocessing? Discuss any one application of solid state bioprocessing for functional food production.                                    [9]


Q8) a) What is solid state fermentation? Explain in detail the process for mushroom production using SSF.                                                                                         [9]

b) Write a note on milk based fermented products of the Indian subcontinent.            [9]

Q9) a) Discuss in detail the role of enzymes in fruit juice processing. [8] b) Discuss the application of enzymes in meat processing.                                                                        [8]


Q10)Elaborate on the methods of production of pectinases and describe their various applications pertaining to the food industry.                                                                      [16]

Q11)With the help of neat sketches, describe the various anaerobic processes for treatment of food processing wastes.                                                                                            [16]


Q12)Write notes on the following :                                                                       [16]

a)            Different types of wastes generated from the food industry.

b)            Chemical methods of treating food wastes.

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