JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD
JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech III DAIRY AND FOOD ENGINEERING Previous Question Paper (May - 2019 - R15)
Part A is compulsory which carries 25 marks. Answer all questions in Part A. Part B consists of 5 units. Answer any one full question from each unit. Each question carries 10 marks and may have a, b, c as sub questions.
Part A
Define milk. What are the thermal properties of milk?
Answer
Milk is defined as the normal mammary secretion of healthy milch animals, obtained by complete milking, excluding colostrum. Its key thermal properties include specific heat (approx. 3.85-3.93 kJ/kg·K), thermal conductivity (approx. 0.53-0.56 W/m·K), and density, which vary depending on its fat and solids-not-fat content.
Briefly explain the homogenisation in ice-cream.
Answer
Homogenisation in ice-cream involves breaking down fat globules into smaller, uniform sizes (typically under 2 microns) using high-pressure homogenisers. This process increases the surface area of fat, promotes the formation of a stable fat-protein membrane, and ensures a smooth, creamy texture while preventing fat separation during freezing.
Give a process flow chart for cheese making process.
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Write about the material of milk storage tank.
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List different methods of cooling of milk in a dairy plant.
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Name any eight machineries used in modern dairy industry.
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What is the general drying behaviour of milk?
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On what factors the rate of evaporation of milk depends?
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Give the ingredients of ice-cream.
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What are toned and double toned milk?
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Part B
Describe the changes undergone by the milk food components during the processing.
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What are the membrane separation processes? Describe the principles of ultrafiltration of milk.
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Explain the composition and proximate analysis of any two milk food products.
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What do you understand by homogenization and what are its benefits?
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Write merits and demerits of HTST method over LTHT method.
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Write an essay on “unit operations” of various dairy and food processing system.
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Explain batch autoclave for sterilization of food and dairy products.
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How is milk standardized? Explain the use of Pearson's square technique to arrive at the standard milk.
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List the basic steps in manufacturing of cultured milk.
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Explain the process of blending and pasteurization of ice cream mix in manufacturing of ice cream.
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Define thermal death time and explain the importance of thermal death time in food preservation.
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Define sterilization and explain briefly the advantages of UHT processing. For a sterilized product, what are the advantages gained by a manufacturer, retailer and a customer?
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List out the different types of food freezing systems, describe briefly the plate freezing system with a neat diagram.
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Write a short note on utilities and requirements of food industry.
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What are the factors to be considered for establishment of modern dairy plant.
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Draw a plan of modern dairy plant and explain different sections.
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Explain freezing point curve for food and water with a neat sketch. Write an expression for freezing time calculation by using Plank’s equation.
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Write a short note on single stage liquid-liquid extraction process.
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Write briefly about packing and marketing of milk powder. How is milk powder stored?
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Explain the composition and proximate analysis of any two milk food products.
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