Unit Operation in Food Industries I

Daffodil International University Department of Nutrition and Food Engineering Faculty of Health and Life Sciences B.Sc. in Nutrition and Food Engineering Midterm Examination Fall 2026 Course Code: 0721-1203 Course Title: Unit Operation in Food Industries I Level and Term: L-1, T-2 Section: 262 All Course Teacher Initials: JR/ZF/MMM/NMIH Time: 1 hour 30 minutes Total Marks: 25 Maintaining the order of the questions are highly appreciated Marks 1. a) Why do you call pasteurization is an example of unit operation? Justify with suitable example. [CLO1,PLO2,C1] 2.5 b) Discuss magnetic cleaning with proper illustration. [CLO1,PLO2,C1] 2.5 2. a) Explain the second law of thermodynamics with an example. [CLO1, PLO2, C2] 2.5 b) Suppose you have milk sample having a density value of (520 +R) lb/ft^3. You have to convert the value to kg/mm^3. Apply the conversion formula to convert the value. (Where, R is the last one digit of your ID No.) [CLO1, PLO2, C2] 2.5 3. a) Bangladesh is one of the largest wheat producers in the world. As a Food Engineer, which cleaning method would you choose for raw wheat cleaning? Explain the most suitable method for cleaning wheat and provide justification for your choice. [CLO1, PLO2, C4] 2.5 b) Differentiate between exothermic and endothermic reaction with suitable diagram. [CLO1,PLO2,C4] 2.5 4. a) Describe the principle of mass conservation and draw a schematic block diagram representing the overall mass balance and component balance for a system with two inputs and three outputs. [CLO1,PLO2,C3] 2.5 b) Draw and label the symbol of rotary pump, evaporator, condenser, belt conveyor, and storage tank. [CLO1,PLO2,C3] 2.5 5. a) If 35,000kg of whole milk containing 4% fat is to be separated in a 6 hour period into skim milk with 0.45% fat and cream with 45% fat, what are the flow rates of the two output streams from a continuous centrifuge which accomplishes this separation? [CLO1,PLO2,C3] 2.5 b) Potatoes are dried in a dryer. Initial moisture content of raw potaotes14% and final moisture content after drying 7%. What is the Drying yield of potatoes from each 1000 kg of raw potatoes? Assume that 8% of the original potatoes is lost in peeling by weight. Drying yield of potatoes. [CLO1,PLO2,C3] 2.5