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This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.

1.

The first milk that a cow produces after calving is called ________(a) Cream(b) Butter(c) Colostrum(d) High fat milkThe question was asked in an online interview.Enquiry is from Physical Properties of Milk topic in portion Chemistry of Milk of Dairy Engineering

Answer»

Correct answer is (c) Colostrum

The explanation is: The first milk that a cow PRODUCES after CALVING is called Colostrum. Colostrum has brownish-yellow color, PECULIAR SMELL and a rather SALTY taste. The content of catalyzes and peroxidase is high.

2.

1.7 ml of N/10 NaOH is required for titration of a 10 ml sample of milk. Compute the titratable acidity.(a) .17 °Th(b) 170 °Th(c) 17 °Th(d) 10 °ThThis question was addressed to me during an interview.Question is from Physical Properties of Milk in section Chemistry of Milk of Dairy Engineering

Answer»

The correct option is (c) 17 °Th

To explain: 10 x 1.7 = 17 ML would THEREFORE be needed for 100 ml, and the acidity of the milk is consequently 17 °Th.

3.

Titratable acidity of milk cannot be expressed in which of the following degree?(a) ᵒSH(b) ᵒTh(c) ᵒD(d) ℃I have been asked this question in an interview for job.I want to ask this question from Physical Properties of Milk topic in division Chemistry of Milk of Dairy Engineering

Answer»

The correct OPTION is (d) ℃

The best explanation: °SH = Soxhlet Henkel degrees, °Th = Thörner degrees; °D = Dornic degrees, all three can be USED to EXPRESS titratable ACIDITY.

4.

In determining acidity, the solution in the burette is?(a) Hydrochloric acid(b) Potassium salt(c) Potash alum(d) Sodium Hydroxide solutionThis question was addressed to me by my college professor while I was bunking the class.The origin of the question is Physical Properties of Milk topic in section Chemistry of Milk of Dairy Engineering

Answer»

Right answer is (d) Sodium HYDROXIDE solution

The best EXPLANATION: The BLUE LIQUID present in the BURETTE in this picture is a NaOH solution. NaoH is a basic solution.

5.

pH of normal milk is _____ at 25℃.(a) 4(b) 4.3(c) 6.6(d) 9This question was addressed to me in an internship interview.My question comes from Physical Properties of Milk topic in portion Chemistry of Milk of Dairy Engineering

Answer»

The correct choice is (c) 6.6

The best explanation: Normal milk is a slightly ACID SOLUTION with a PH falling between 6.5 and 6.7 with 6.6 the most usual value. The TEMPERATURE of measurement NEAR 25°C.

6.

What does pH of the solution represent?(a) Solubility(b) Osmotic pressure(c) Hydronium ion concentration(d) Water contentI have been asked this question in quiz.My question is based upon Physical Properties of Milk topic in section Chemistry of Milk of Dairy Engineering

Answer»

The correct CHOICE is (c) HYDRONIUM ion concentration

The EXPLANATION: The pH represents the hydronium ion concentration of a solution and can mathematically be defined as the NEGATIVE logarithm of the hydronium ion [H+] concentration.

7.

The acidity of a solution is dependent on which of the following?(a) Water content(b) Fat content(c) Acid content(d) [H+] ionsThis question was addressed to me during an interview.Asked question is from Physical Properties of Milk topic in section Chemistry of Milk of Dairy Engineering

Answer»

Right ANSWER is (d) [H+] ions

The EXPLANATION: The acidity of a solution depends on the CONCENTRATION of HYDRONIUM ions [H+] in it. When the CONCENTRATIONS of [H+] and [OH–] (hydroxyl) ions are equal, the solution is called neutral.

8.

Freezing point helps to check which of the following adulteration in milk?(a) Sugar adulteration(b) Water adulteration(c) Gas adulteration(d) Color adulterationI have been asked this question in unit test.Question is from Physical Properties of Milk topic in division Chemistry of Milk of Dairy Engineering

Answer»

The correct choice is (b) WATER ADULTERATION

Best explanation: The FREEZING point of milk is the only reliable parameter to check for adulteration with water. The freezing point of milk from INDIVIDUAL cows has been FOUND to vary from –0.54 to –0.59°C.

9.

Define the temperature at which a liquid turns into a solid when cooled.(a) Boiling point(b) Melting point(c) Freezing point(d) Evaporation temperatureThis question was addressed to me in final exam.This intriguing question originated from Physical Properties of Milk in chapter Chemistry of Milk of Dairy Engineering

Answer»

The CORRECT answer is (c) FREEZING point

Easy explanation: The temperature at which a liquid turns into a SOLID when cooled is called freezing point. The Freezing point of milk is CLOSER to 0℃.

10.

Osmotic pressure is controlled by the number of molecules or particles, not the weight of solute.(a) True(b) FalseThe question was posed to me in a job interview.My query is from Physical Properties of Milk in portion Chemistry of Milk of Dairy Engineering

Answer»

The correct CHOICE is (a) True

The explanation: Osmotic pressure is controlled by the NUMBER of molecules or particles, not the weight of SOLUTE; THUS 100 molecules of size 10 will have 10 TIMES the osmotic pressure of 10 molecules of size 100.

11.

Milk is ______ with blood.(a) Hypertonic(b) Hypotonic(c) Isotonic(d) No pressureThis question was addressed to me in a national level competition.This key question is from Physical Properties of Milk in portion Chemistry of Milk of Dairy Engineering

Answer»

Correct ANSWER is (C) Isotonic

Explanation: MILK is isotonic with blood. Isotonic denoting or RELATING to a solution having the same osmotic pressure as some other solution, especially one in a cell or a body fluid.

12.

Calculate the density of milk at 15.5℃ having 3.2% fat and 8.5% SNF.(a) 2.03 g/cm^3(b) 1.03 g/cm^3(c) 4.03 g/cm^3(d) 5.03 g/cm^3The question was posed to me in homework.The question is from Physical Properties of Milk topic in division Chemistry of Milk of Dairy Engineering

Answer» CORRECT OPTION is (d) 5.03 g/cm^3

Best explanation: Density of milk at 15.5℃ having 3.2% fat and 8.5% SNF is 1.03 g/cm^3. It can be CALCULATED using the FORMULA.
13.

In an equation Fat%, SNF% and water determine‘d’. The‘d’ in this expression is?(a) Viscosity(b) Friction force(c) Density(d) AccelerationThe question was posed to me in examination.Asked question is from Physical Properties of Milk in chapter Chemistry of Milk of Dairy Engineering

Answer» CORRECT ANSWER is (d) Acceleration

The BEST I can explain: The d is the density of MILK at the temperature 15.5℃.Density is basically the degree of compactness of the substance.
14.

Yellowish tinge in milk can be attributed to which of the following?(a) Carotene(b) Water(c) Riboflavin(d) MetalinThe question was asked in examination.This intriguing question originated from Physical Properties of Milk in division Chemistry of Milk of Dairy Engineering

Answer» RIGHT option is (a) Carotene

The best I can explain: The color varies from WHITE to yellow according to the COLORATION (carotene content) of the FAT. This is also the main reason behind the yellow color of the BUTTER.
15.

Opacity in milk is due to which of the following reasons?(a) White color(b) Heat treatment(c) Additives(d) Suspended particles of fatThis question was posed to me in an interview.My query is from Physical Properties of Milk topic in section Chemistry of Milk of Dairy Engineering

Answer» RIGHT choice is (d) Suspended particles of fat

To explain I would say: The opacity of MILK is due to its content of suspended particles of fat, proteins and certain minerals. HEAT TREATMENT has no effect on opacity.
16.

Heat treatment on minerals results leads to ___________(a) Clumps formation(b) Bubble formation(c) Foul smell(d) Loss of cheese making characteristicsI had been asked this question in an online quiz.This intriguing question originated from Changes In Milk and its Constituents topic in chapter Chemistry of Milk of Dairy Engineering

Answer»

Correct option is (d) Loss of cheese making characteristics

The best EXPLANATION: When heated above 75°C the substance loses water. Loss of water leads to the formation of INSOLUBLE calcium orthophosphate; which impairs the cheese making PROPERTIES of the MILK.

17.

Which of the following mineral is affected by heat treatment in milk?(a) Calcium(b) Potassium(c) Hydroxyphosphate(d) ZincThe question was posed to me in examination.Enquiry is from Changes In Milk and its Constituents topic in chapter Chemistry of Milk of Dairy Engineering

Answer»

The correct choice is (C) Hydroxyphosphate

Explanation: Of the minerals in milk only the important calcium hydroxyphosphate in the CASEIN MICELLES is AFFECTED by heating. Rest has no EFFECT on heating.

18.

Effect of Pasteurization on Vitamins in Milk ___________(a) Great loss(b) Little or no loss(c) Denature(d) SublimeThe question was asked in an international level competition.My question is based upon Changes In Milk and its Constituents topic in division Chemistry of Milk of Dairy Engineering

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Correct option is (B) Little or no loss

Best explanation: Pasteurization in a plate heat exchanger can however, be accomplished with virtually no loss of VITAMIN C. The other vitamins in milk suffer little or no harm from MODERATE heating.

19.

Most Heat sensitive vitamin in milk is?(a) Vitamin A(b) Vitamin B(c) Vitamin C(d) Vitamin DI have been asked this question during an online exam.This intriguing question comes from Changes In Milk and its Constituents topic in portion Chemistry of Milk of Dairy Engineering

Answer»

Right choice is (c) VITAMIN C

The explanation: Vitamin C is the most HEAT sensitive vitamin in MILK among all others. Milk is a rich SOURCE of Vitamin A& D.

20.

The lactulose content ______ with increased intensity of the heat treatment.(a) Decrease(b) Increase(c) Remains same(d) First increase and then decreaseThe question was posed to me in homework.This interesting question is from Changes In Milk and its Constituents topic in portion Chemistry of Milk of Dairy Engineering

Answer» CORRECT choice is (b) Increase

For explanation I WOULD say: The lactulose content thus increases with the increased intensity of the heat treatment. It may LEAD to denaturation of proteins.
21.

Effect of Heat treatment (Temperature above 100℃) on Lactose:(a) Greenish color(b) Bluish color(c) Brownish color(d) Reddish colorI have been asked this question in an online quiz.The doubt is from Changes In Milk and its Constituents topic in portion Chemistry of Milk of Dairy Engineering

Answer»

The correct option is (C) BROWNISH color

Easy explanation: Lactose undergoes CHANGES more readily in milk than in the dry state. At temperatures above 100 °C a reaction TAKES place between lactose and protein, resulting in a brownish color.

22.

Denature Protein contributes to an improvement in the quality of which of the following products?(a) Cultured milk product(b) Milk(c) Ice cream(d) CreamThe question was posed to me in my homework.My doubt is from Changes In Milk and its Constituents in division Chemistry of Milk of Dairy Engineering

Answer»

The CORRECT answer is (a) Cultured MILK product

To elaborate: In milk intended for cultured milk products (yogurt, etc.), the whey protein DENATURATION and interaction with CASEIN obtained at 90 – 95°C for 3 – 5 minutes will contribute to improved quality in the form of reduced syneresis and improved VISCOSITY.

23.

What is the result of heat treatment on proteins?(a) Denaturation(b) Blanching(c) Spore formation(d) Froth formationThe question was asked in class test.My question is from Changes In Milk and its Constituents in division Chemistry of Milk of Dairy Engineering

Answer»
24.

________ is recommended in order to avoid cream plug formation.(a) Cooling(b) Freezing(c) Churning(d) HomogenizationI have been asked this question in my homework.This question is from Changes In Milk and its Constituents in division Chemistry of Milk of Dairy Engineering

Answer» CORRECT answer is (d) Homogenization

The EXPLANATION: Homogenization is PRACTICED to avoid cream plug FORMATION. Cream plug formation leads to BLOCKAGE in pipes and tubes.
25.

The fat globules in milk when heated to 74℃ show which of the following phenomenon?(a) Frothing(b) Evaporation(c) Cream plug formation(d) CondensationI have been asked this question during an interview.This intriguing question comes from Changes In Milk and its Constituents topic in chapter Chemistry of Milk of Dairy Engineering

Answer»

The correct answer is (C) Cream plug formation

Easiest EXPLANATION: It has been shown that when MILK is pasteurized at 70 – 80°C for 15 seconds, the cream plug PHENOMENON is already evident at 74°C.

26.

The purpose of heat treatment on milk is ___________(a) Kill pathogenic microorganism(b) Heat milk(c) Evaporation(d) Taste enhancementThe question was asked in examination.My question is based upon Changes In Milk and its Constituents topic in division Chemistry of Milk of Dairy Engineering

Answer»

The CORRECT OPTION is (a) Kill pathogenic microorganism

The EXPLANATION is: HEAT treatment on milk aims to kill pathogenic microorganism. Heat treatment of milk also ENHANCES its shelf life.

27.

Enzyme responsible for Lipolysis is ____________(a) Pepsin(b) Pectinase(c) Lipases(d) RenninThis question was posed to me at a job interview.This is a very interesting question from Changes In Milk and its Constituents in section Chemistry of Milk of Dairy Engineering

Answer»

Correct answer is (c) Lipases

The BEST I can EXPLAIN: LIPOLYSIS is caused by the action of lipases. Lipolysis is encouraged by high STORAGE temperatures.

28.

What is the process of breakdown of fat into glycerol and free fatty acid called?(a) Addition(b) Reduction(c) Oxidation(d) LipolysisI got this question in an interview for internship.My question is based upon Changes In Milk and its Constituents in portion Chemistry of Milk of Dairy Engineering

Answer» RIGHT answer is (a) Addition

To elaborate: The breakdown of fat into glycerol and free FATTY acids is called lipolysis. Lipolysed fat has a RANCID TASTE and smell, caused by the presence of low molecular free fatty acids.
29.

_______ is the principal contributor to sunlight flavor.(a) Methional(b) Ethane(c) Heptanes(d) AcidI had been asked this question in an online quiz.Question is from Changes In Milk and its Constituents in chapter Chemistry of Milk of Dairy Engineering

Answer» RIGHT choice is (a) Methional

Explanation: Methional or 3-mercapto-methylpropionaldehyde is the principal contributor to sunlight FLAVOR, as this particular flavor is called. It is a TYPICAL off-flavor FOUND in MILK.
30.

Which of the following does not accelerate the rate of oxidation of fat?(a) Presence of iron and copper salts(b) Presence of dissolved oxygen(c) Exposure to light(d) Presence of waterThis question was posed to me during a job interview.This intriguing question originated from Changes In Milk and its Constituents topic in chapter Chemistry of Milk of Dairy Engineering

Answer»

The CORRECT CHOICE is (d) Presence of water

For explanation: The presence of iron and copper salts accelerates the onset of auto-oxidation and development of metallic flavor, as does the presence of dissolved oxygen and exposure to LIGHT, especially direct SUNLIGHT or light from fluorescent tubes.

31.

Combination of glucose (C6H12O6) and galactose (C6H12O6) molecules result in:(a) Maltose(b) Galactose(c) Lactose(d) SucroseI have been asked this question at a job interview.I'd like to ask this question from Composition of Cow Milk topic in portion Chemistry of Milk of Dairy Engineering

Answer» CORRECT choice is (c) Lactose

The best I can explain: Glucose and GALACTOSE COMBINE to form lactose. Lactose is the primary milk sugar.
32.

Which of the following fat-soluble vitamins are present in milk?(a) A(b) D(c) A & D(d) BI had been asked this question in homework.My question is from Composition of Cow Milk in section Chemistry of Milk of Dairy Engineering

Answer»

Correct answer is (c) A & D

For explanation: MILK contains many VITAMINS. Among the best KNOWN are A, B1, B2, C and D. Vitamins A and D are soluble in fat, or fat solvents, while the others are soluble in water.

33.

Which of the following is/are whey protein?(a) α – lactalbumin(b) β – lactoglobulin(c) κ- lactis(d) α – lactalbumin andβ – lactoglobulinI got this question in an internship interview.This intriguing question originated from Composition of Cow Milk in portion Chemistry of Milk of Dairy Engineering

Answer»

Right choice is (d) α – lactalbumin andβ – lactoglobulin

Explanation: The whey proteins are: α-lactalbumin and β-lactoglobulin. Whey protein is a COMPOSITE of GLOBULAR proteins isolated from whey, the LIQUID MATERIAL created as a by-product of cheese production.

34.

Which of the following ways is not to make caseinate particles flocculate and coagulate?(a) Precipitation by acid(b) Precipitation by enzymes(c) Precipitation by water(d) None of the mentionedThis question was posed to me in an interview.The origin of the question is Composition of Cow Milk in division Chemistry of Milk of Dairy Engineering

Answer» RIGHT choice is (c) PRECIPITATION by water

For explanation: Precipitation by ACID and precipitation by enzymes are the WAYS to make CASEINATE particles flocculate and coagulate. A precipitate is a solid that forms out of liquid.
35.

Casein cannot be classified as _________(a) α- casein(b) β- casein(c) κ-casein(d) Delta- caseinThis question was posed to me in unit test.Origin of the question is Composition of Cow Milk in division Chemistry of Milk of Dairy Engineering

Answer» CORRECT choice is (d) Delta- CASEIN

For EXPLANATION I would say: Casein is a GROUP of proteins commonly found in mammalian milk. They can be classified α- casein; β- casein and κ-casein.
36.

Name the organic compounds which have amines and carboxyl functional group in them.(a) Amino acid(b) Alcohol(c) Carboxylic acid(d) AmineI had been asked this question in class test.The above asked question is from Composition of Cow Milk in section Chemistry of Milk of Dairy Engineering

Answer»

Correct option is (a) Amino ACID

The explanation: This refers to the STRUCTURE of amino acid. They are ORGANIC COMPOUNDS containing amines and carboxyl functional GROUP.

37.

Milk has all the essential amino acid.(a) True(b) FalseThis question was posed to me by my college professor while I was bunking the class.This interesting question is from Composition of Cow Milk in chapter Chemistry of Milk of Dairy Engineering

Answer»

The correct answer is (a) True

Easy explanation: An important fact with regard to nutrition is that eight (nine for infants) of the 20 amino acids cannot be SYNTHESIZED by the human organism. All of them are PRESENT in MILK PROTEIN.

38.

_________ Value states the % of iodine that the fat can bind.(a) Fractional(b) Iodine(c) Fatty acid(d) DistillationI have been asked this question in final exam.The question is from Composition of Cow Milk in chapter Chemistry of Milk of Dairy Engineering

Answer»

Correct option is (b) Iodine

The best I can EXPLAIN: Iodine value STATES the percentage of iodine that the FAT can bind. Iodine is taken up by the double bonds of the unsaturated fatty acids.

39.

Which of the following can be the method to compute fat crystallization in cow milk?(a) JMR(b) DMR(c) NMR(d) CMRI have been asked this question during an interview.This intriguing question comes from Composition of Cow Milk topic in division Chemistry of Milk of Dairy Engineering

Answer»

Right answer is (c) NMR

To elaborate: The NMR METHOD can also be utilized to FIND out the degree of FAT crystallization as a FUNCTION of the TIME of crystallization.

40.

Approximate size of fat globules in milk solution is ______________(a) 10^–2 to 10^–3(b) 10^–4 to 10^–5(c) 10^–5 to 10^–6(d) 10^–6 to 10^–7This question was posed to me during a job interview.This intriguing question originated from Composition of Cow Milk in division Chemistry of Milk of Dairy Engineering

Answer» RIGHT choice is (a) 10^–2 to 10^–3

To explain: Size of fat GLOBULES in milk solution is 10^–2 to 10^–3. Fat is bound in the globular form by PHOSPHOLIPIDS membranes, which are hydrophobic.
41.

In milk, the whey proteins are in _____ solution and the casein in colloidal suspension.(a) Water(b) Colloidal(c) Fat(d) GasI had been asked this question by my college director while I was bunking the class.This key question is from Composition of Cow Milk in chapter Chemistry of Milk of Dairy Engineering

Answer»

Right ANSWER is (b) Colloidal

To explain I would SAY: Colloidal suspension constitutes of casein and Colloidal SOLUTION constitutes of WHEY proteins. They together make up milk.

42.

Milk is an emulsion of _____ in water.(a) Oil(b) Water(c) Soap(d) DirtThe question was posed to me by my college director while I was bunking the class.I want to ask this question from Composition of Cow Milk in section Chemistry of Milk of Dairy Engineering

Answer»

Correct answer is (a) Oil

To elaborate: Milk is a SUSPENSION of droplets of ONE liquid in ANOTHER. Milk is an EMULSION of fat in water.

43.

What is the fat percentage of cow milk?(a) 9%(b) 10%(c) 15%(d) 4%I had been asked this question during an online exam.I would like to ask this question from Composition of Cow Milk in chapter Chemistry of Milk of Dairy Engineering

Answer»

Right choice is (d) 4%

Explanation: COW MILK has 4% FAT PERCENT. It has an SNF (Solid not Fat) 8.5-9%. Rest is water.

44.

What is the moisture content of cow milk?(a) 30%(b) 50%(c) 83%(d) 90%I have been asked this question in my homework.The question is from Composition of Cow Milk topic in section Chemistry of Milk of Dairy Engineering

Answer»

The correct option is (c) 83%

Easiest EXPLANATION: Cows’ milk consists of about 87% WATER and 13% dry substance. It is considered to have elements of a complete balanced diet.

45.

True about cow’s milk are all except:(a) Cow’s milk contains 80% whey protein not casein(b) Cow milk has less carbohydrate than mother’s milk(c) Has more K+ and Na+ than infant formula feeds(d) Has more protein than breast milkThis question was posed to me in class test.My query is from Composition of Cow Milk in chapter Chemistry of Milk of Dairy Engineering

Answer»

The correct answer is (a) Cow’s milk contains 80% WHEY PROTEIN not casein

Easy explanation: Cow milk has LESS carbohydrate than mother’s milk; cow milk has more K+ and Na+ than infant formula feeds and cow milk has more protein than breast milk are all false.

46.

Number of Protons and electrons in an atom are _______(a) Different(b) Same(c) Average(d) ConstantI have been asked this question in a national level competition.Origin of the question is Basic Chemical Concepts in division Chemistry of Milk of Dairy Engineering

Answer»
47.

An electric field deflects beams of _______(a) Protons(b) Electrons(c) Neutrons(d) Protons and electronsI had been asked this question in semester exam.I would like to ask this question from Basic Chemical Concepts in portion Chemistry of Milk of Dairy Engineering

Answer»

Right ANSWER is (d) Protons and ELECTRONS

The BEST I can explain: An electric field deflects the BEAMS of both positively charged protons and negatively charged electrons.

48.

Most part of the atom is _______(a) Empty(b) Filled(c) Charged(d) CoveredI got this question by my school teacher while I was bunking the class.The question is from Basic Chemical Concepts topic in portion Chemistry of Milk of Dairy Engineering

Answer»

The correct OPTION is (a) Empty

The explanation: Major part of the ATOM is void. Nucleus carries proton and NEUTRON responsible for most of the weight of the atom.

49.

Smaller particles in atom are called ________(a) Atomic Particles(b) Sub-atomic particles(c) Smaller Particles(d) Neutral ParticlesI got this question in an online quiz.My question is from Basic Chemical Concepts in division Chemistry of Milk of Dairy Engineering

Answer»

Correct ANSWER is (B) Sub-atomic particles

The explanation is: Sub atomic particles are any of numerous subatomic constituents of the physical world that interact with each other, INCLUDING electrons, NEUTRINOS, photons, and alpha particles.

50.

Chemical symbol is the representation of _______(a) Chemical formula(b) Molecular formula(c) Structural formula(d) Atomic FormulaI have been asked this question by my college director while I was bunking the class.Origin of the question is Basic Chemical Concepts topic in portion Chemistry of Milk of Dairy Engineering

Answer»

Correct choice is (a) Chemical FORMULA

The best explanation: Chemical Symbol represents a chemical formula. MOLECULAR formula is a chemical formula that gives the TOTAL number of atoms of each ELEMENT in each MOLECULE of a substance.