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Correct choice is (b) Vacuum type

The best EXPLANATION: Vacuum deaeration has been used SUCCESSFULLY to expel dissolved air and FINELY dispersed air bubbles from milk. Warm (Preheated) milk is fed into an expansion VESSEL in which the vacuum LEVEL is adjusted to a level equivalent to a boiling point.

The correct answer is (a) INCREASE

To elaborate: Solubility of GASES decrease with an increase in solution temperature and or decrease in PRESSURE. The solubility of GAS in a solution decreases as the temperature of the solution rises and approaches SATURATION temperature.

The correct answer is (d) Henry law

The best I can explain: According to William Henry in 1803 its state, that gas solubility in a solution decreases as the gas partial pressure above the solution decreases. The solubility of a gas dissolved in a liquid is DIRECTLY PROPORTIONAL to the partial pressure of the gas.

The correct option is (d) Dispersion of air

For EXPLANATION I would say: The deaeration system can be manually or automatically operated. In both cases, the efficiency of air elimination DEPENDS very MUCH on how finely DISPERSED the air is. The smallest air BUBBLES cannot be removed.

The correct option is (b) Lower

The best I can EXPLAIN: The INLET of the cylindrical vessel MUST be located at a lower level than the outlet pipe of the MILK tank(s) on the vehicle, as the milk should not be pumped into the vessel but transferred to it by GRAVITY.

The correct OPTION is (a) True

Easy explanation: It is not unusual for incoming milk to CONTAIN 10% AIR by volume or EVEN more. Finely and coarsely dispersed air predominates at this stage. Dispersed air causes problems.

Right CHOICE is (a) 4.5-6%

The best I can explain: The TOTAL volume of air in milk in the UDDER can be some 4.5 – 6 %, of which O2 constitutes about 0.1%, N2 (NITROGEN) about 1% and CO2 3.5 – 4.9%.

Correct ANSWER is (d) Crystal state

Best explanation: Air in milk OCCURS in three states NAMELY DISPERSED; Dissolved; and chemically bound.

Right choice is (a) Duhring’s RULE

The best explanation: Duhring’s rule states that a linear relationship exists between the TEMPERATURES at which two solutions exert the same vapour pressure. The rule is mostly USED to compare a pure LIQUID and a solution at a GIVEN concentration.

The correct ANSWER is (b) ECONOMY of evaporator

For explanation I would say: Capacity is defined as the number of kilograms of water vaporized per hour. Economy is the number of kilograms vaporized per kilogram of steam FED to the unit. In a single effect evaporator the economy is approximately always LESS than 1, but in multiple-effect equipment it may be CONSIDERABLY greater.

Correct choice is (a) MULTIPLE effect evaporator

Easiest explanation: Considerable SAVING in steam and water can be EFFECTED by using multiple effect evaporators. The vapors from ONE effect have considerable latent heat and may thus be used for heating SECOND effect and vapors from the second effect to heat the third effect and so on. Thus great economies of operation may be made in large installations with multiple- effect evaporator.

The correct option is (d) LONG residence TIME of LIQUID

For explanation I would say: The advantages CLAIMED for the falling film evaporator are short residence time of liquid, good performance with small TEMPERATURE difference across the heating surface. More effects can be used with falling film evaporator as it will operate with a lower temperature difference than climbing film evaporator.

The correct option is (a) Climbing film evaporator

To EXPLAIN I would say: Climbing Film Evaporator, in this type the liquid to be evaporated is fed at the lower end of the VERTICAL tubes, heated by the condensing steam on the outside of the TUBE. The liquid starts boiling at the BOTTOM; the vapor along with the liquid tends to rise further up the tube in the form of a thin film. As the film rises further evaporation occurs until they REACH the top of the tubes.

Right choice is (d) Vapor separator and foam BREAKER

To explain: DEFLECTOR PLACED above the tube. This deflector is effective both as a vapor separator and as a foam breaker. When the ratio of feed to evaporation is LOW, RECIRCULATION of liquid is provided.

Correct option is (a) Severe scale formation

The best explanation: The MAIN disadvantage of climbing film evaporator is that a comparatively large volume of liquid is present in the evaporator at ONE time and most of it located at the BOTTOM. Because of this, severe scale formation occurs more rapidly in this region.

Correct choice is (B) LONG tube vertical evaporator

For explanation: In Long tube vertical evaporator, the feed enters at the bottom of the tube, STARTS boiling as it moves up the tube and the mixture of liquid and VAPOR leaving at the top at high velocity STRIKES against a deflector placed above the tube.

Right option is (b) Vertical TUBE evaporator

For explanation: Forced Circulation Evaporator is a MODIFIED FORM of vertical tube evaporator. In this type a pumps is used to force the evaporating liquid through the tubes. This helps to further IMPROVE the evaporating capacity.

Correct option is (b) Circular type evaporator

The best explanation: Circulation evaporators can be used when a low degree of CONCENTRATION is required or when small quantities of product are processed. In YOGURT production, for example, evaporation is utilized to concentrate milk 1.1 to 1.25 times, or from 13% to 14.5% or 16.25% solids content respectively. This treatment SIMULTANEOUSLY de-aerates the product and RIDS it of off-flavors.

Correct choice is (d) INCREASE water activity in order to increase microbiological and chemical

The best explanation: There are several reasons for concentrating food liquids, e.g. to REDUCE the cost of drying, induce crystallization, reduce costs for storage and transportation, reduce water activity in order to increase microbiological and chemical stability and to recover by-products from waste STREAMS.

Correct CHOICE is (a) separating soluble SUBSTANCES in solution

The best explanation: Crystallization, evaporation and distillation are methods of separation of soluble substances in a solution.

The CORRECT choice is (d) concentration and crystallization

Easiest EXPLANATION: The SOLUTION turns blue because of diffusion. On heating the solution nothing will happen. Evaporation of solution of CUSO4 leads to its concentration and crystal formation.

Correct answer is (c) vapors will be of both LIQUIDS with a higher CONCENTRATION of liquid having LOW boiling point

To explain: Vapors will be of both liquids with a higher concentration of liquid having low boiling point as the heating starts in miscible SOLUTION.

Correct choice is (c) at SURFACE of a liquid

The BEST I can explain: Evaporation takes place at a surface and below the boiling point. The surface atoms or molecules GAINS energy from SURROUNDINGS and overcome the ATTRACTIONS of other molecules & get to vaporize.

Right OPTION is (b) humidity of surrounding air increases

Easiest EXPLANATION: Humidity is the amount of WATER VAPOR present in the air. The air around us cannot hold more than a definite amount of water vapor at a given temperature. If the amount of water in air is already high, the rate of evaporation DECREASES.

The correct option is (b) exposed surface area of LIQUID decreases

To explain: A substance that has a larger surface area will evaporate faster, as there are more surface MOLECULES per UNIT of VOLUME that are potentially able to ESCAPE.

Correct answer is (a) directly proportional to temperature of LIQUID

To EXPLAIN I would SAY: Evaporation depends directly on temperature of liquid. Higher the temperature of the substance the GREATER is the kinetic energy of the molecules at its surface and therefore the faster the RATE of their evaporation.

Right option is (b) Molecular weight

Easiest EXPLANATION: Membranes with a definite SEPARATION LIMIT separate everything with a definitely lower molecular weight, while membranes with a DIFFUSE limit let some MATERIAL with a higher molecular weight through and stop some with a lower molecular weight.

Right answer is (d) 50℃

Explanation: In most CASES, the processing temperature is about 50°C for dairy applications. Filtration plants are normally supplemented with a simple cooling system integrated into the INTERNAL circulation loop to COMPENSATE for the SLIGHT RISE in temperature that occurs during operation and maintain a constant processing temperature.

Correct option is (d) Membrane filtration

Easiest explanation: MF in DAIRY industry is basically used for reduction of BACTERIA in skim milk, whey and brine, but also for defatting whey INTENDED for whey PROTEIN concentrate (WPC) and for protein fractionation.

Right CHOICE is (c) Ultra filtration

Explanation: UF in DAIRY INDUSTRY is typically used for concentration of milk proteins in milk and whey and for protein standardization of milk intended for cheese, yoghurt and some other PRODUCTS.

The correct ANSWER is (d) Diafiltration

For explanation: Diafiltration is a technique that uses ultra filtration membranes to COMPLETELY remove, replace, or lower the concentration of SALTS or solvents from solutions CONTAINING proteins, peptides, nucleic ACIDS, and other biomolecules.

Correct OPTION is (c) Membrane fouling

To explain I would say: Membrane fouling is a process whereby a solution or a particle is deposited on a membrane SURFACE or in membrane pores in a process such as in a Membrane BIOREACTOR so that the membrane’s performance is DEGRADED. It is a major obstacle to the widespread use of this TECHNOLOGY.

Right answer is (a) Feed

Explanation: Inlet solution which has to be fractionated is called feed. Once feed is INJECTED the membrane FILTRATION PROCESS starts.