JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD
JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech III DAIRY AND FOOD ENGINEEING Previous Question Paper (November/December - 2018 - 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.
Part A
What are ASTM standards?
Answer
ASTM standards are internationally recognized technical standards developed by the American Society for Testing and Materials (now known as ASTM International). These standards define the specifications, test methods, classifications, and practices for a wide range of materials, products, systems, and services used across various industries, including food processing and dairy engineering, to ensure quality, safety, and consistency.
Draw a process chart of pasteurized milk.
Answer
The process flow for the production of pasteurized milk involves the following sequential steps:
- Reception: Raw milk is collected and weighed.
- Filtration/Clarification: Removal of physical impurities using filters or centrifugal clarifiers.
- Chilling: Cooling the milk to 4°C or below to inhibit bacterial growth.
- Standardization: Adjusting the fat and solids-not-fat (SNF) content to meet legal requirements.
- Homogenization: Breaking down fat globules to prevent cream separation.
- Pasteurization: Heating the milk (e.g., HTST method at 72°C for 15 seconds) to destroy pathogens.
- Cooling: Rapidly cooling the pasteurized milk to 4°C.
- Packaging and Storage: Filling into sanitized containers and storing in cold storage until distribution.
Write the purpose of UHT process.
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Explain the influence of bacteria in milk.
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What is emulsifier? Give its role.
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What is flow plan?
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What is evaporation? Enlist the different types of evaporators.
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Write the heat and mass balance in evaporation.
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What is reaction kinetics? And discuss it.
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Write mechanism of ultra-filtration.
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Part B
What is Rheology? Enlist its properties. Discuss any five properties.
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Elaborate the Kelvin model with neat figure.
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Discuss the working principles of cyclone.
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Draw the flow diagram of sterilized milk.
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What is the time necessary to heat milk from 40°C to 85°C with steam at 100°C? Given: volume of milk = 3 m³, area (A) = 9.5 m², heat transfer coeff (hv) = 5000 kcal/m²h°C, (hm) = 860 kcal/m²h°C, wall thickness = 0.003 m, conductivity (k) = 13 kcal/mh°C, density = 1030 kg/m³, specific heat = 0.93 kcal/kg°C.
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Discuss the cleaning and disinfection in transport facilities.
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Write the effect of higher temperature on milk quality.
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Write the effect of sterilization in the packages.
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Discuss the making process of butter oil.
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Discuss the important factors for dairy plant design.
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What are carbohydrates? Give their classification and write about the lactose.
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Discuss the role of minerals found in raw milk.
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In a manufacturing process of sweetened condensed milk, the milk is mixed with sugar to give a mixture of 60 parts condensed milk to 40 parts sugar. The mixture is evaporated until solids are 72%. What yield of sweetened condensed milk can be expected from 500 kg milk (14% solids)? Find water evaporated and sugar added.
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Discuss the working principles of spray drying.
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What is drying and dehydration? Discuss about the grains dryers.
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Discuss the sorption isotherm and hysteresis effect.
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What is liquid-liquid extraction? Describe the working mechanism.
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What is filtration? Give in detail general considerations of filtration.
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Write about membrane separation techniques.
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What is leaching? Elaborate a formula meant for rate of leaching.
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