Download GTU (Gujarat Technological University Ahmedabad) B.Tech/BE (Bachelor of Technology/ Bachelor of Engineering) 2020 Winter 5th Sem 3151408 Thermal And Non Thermal Processing Of Foods Previous Question Paper
Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE- SEMESTER?V (NEW) EXAMINATION ? WINTER 2020
Subject Code:3151408 Date:01/02/2021
Subject Name:Thermal and Non Thermal Processing of Foods
Time:10:30 AM TO 12:30 PM Total Marks: 56
Instructions:
1. Attempt any FOUR questions out of EIGHT questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1 (a) What are thermal processes? Give three examples.
03
(b) What are the industrial applications of microwave heating?
04
(c) Describe the concept of decimal reduction time and thermal death time. Draw 07
and explain thermal resistance curve.
Q.2 (a) What are advantages of blanching?
03
(b) What is hurdle technology? Give five examples of hurdles used to preserve 04
food.
(c) Derive the equation for first order reaction. Draw a typical plot of first-order 07
data as the concentration versus time.
Q.3 (a) Write one limitation of steam blanching and water blanching.
03
(b) Discuss the individual quick blanching method in brief.
04
(c) The Fo for Clostridium botulinum is 1.1 minutes for 99.999% inactivation. 07
What would be the Fo for a 12 D inactivation, if Z=18?F. What would be D
and F value at 275?F?
Q.4 (a) Write the purpose of pasteurization in low acid food and acid food.
03
(b) Explain with diagram the pasteurization of unpackaged liquid using a plate 04
heat exchanger.
(c) Describe the construction and working of batch retort with a neat diagram.
07
Q.5 (a) Differentiate between shallow and deep fat frying.
03
(b) What is extrusion? Describe principle of operation of twin-screw extruder.
04
(c) What is aseptic processing? Discuss direct and indirect sterilization of food 07
products.
Q.6 (a) Define: (a) Radappertisation (b) Radicidation (c) Radurisation
03
(b) Write the application of ohmic heating in food processing. Write two major 04
advantages of ohmic heating.
(c) How processing of food is achieved through ultrasound? Explain ultrasonic 07
probe and ultrasonic bath system.
Q.7 (a) Write the advantages of non-thermal methods over thermal methods of food 03
processing.
1
(b) Describe the mechanism of dipole rotation and ionic interaction for dielectric 04
heating of food.
(c) What is the principle of high pressure processing? What are the main 07
components of a high-pressure system? Write two commercial application of
HPP.
Q.8 (a) Write the procedure for the improved general method for process time 03
calculation.
(b) Describe the concept of Q value? Write the relationship between Q value and 04
shelf life of food products.
(c) Describe the concept of pulsed electric field processing. What are its 07
advantage and limitations?
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This post was last modified on 04 March 2021