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MFN-008: Principles of Food Science

MFN-008: Principles of Food Science

IGNOU Solved Assignment Solution for 2022-23

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Assignment Code: MFN-008/AST-5/TMA-5/22-23

Course Code: MFN-008

Assignment Name: Principles of Food Science

Year: 2022-2023

Verification Status: Verified by Professor


Section A -Descriptive Questions (80 marks)


There are eight questions in this part. Answer all the questions


1. a) What is amylase and amylopectin? Enlist different properties of starch and its application in food industry. (4)

Ans) Amylose: The molecular weights of amylose molecules range from 104 to 206. Amylose can take on extended shapes (hydrodynamic radii of 7–22 nm), however it typically forms parallel left-handed double helical junction zones or a relatively stiff left-handed single helix. The hydroxyl groups are positioned on the outside of the coil, while the core of the helix is lipophilic and solely contains hydrogen atoms. Amylose makes up around 25% of most starches. The two commercially available high amylose corn starches have apparent amylose levels of between 52 and 75 percent.


Amylopectin: A chain of roughly 30 glucose units called amylopectin units forms between the branches. Typically a few more "outer" unbranched chains (also known as A-chains) than "inner" branched chains (also known as B-chains) (a). The lone reducing group is found in only one chain, known as the C-chain.


Each amylopectin molecule has a compact shape and may hold up to two million glucose residues. The molecule has a striped look due to the amylopectin's branching structure, which arranges its knotted branch points in a row with smooth chains separating them. Because of their size, these molecules look stripped under a light microscope, resembling "growth rings" in the starch grain.


Properties of Starch:

  1. Starch Gelatinisation

  2. Starch Retrogradation

Application of Starch in Food Industry:


In the food sector, starches are used as a thickener, a fat-sparing agent, an adhesive, a binder, an encapsulating agent, a film forming, a gelling agent, a water-binding agent, a texturizer, etc.


b) Discuss the role of modified starches in food and confectionery industries. (4)

Ans) Modified starches are an ingredient in a variety of goods, including instant desserts, jelly beans, salad dressings, tomato and pizza toppings, canned soups, etc. Many different items use modified starches. Various varieties are available, and they all serve distinct purposes based on how the starch has been altered.

c) What is agar? Write about its application in food industry. (2)

Ans) Agar is a polysaccharide that is unusual in that it is found in the cell walls of some red algae and contains sulfated galactose monomers. Because agar contains a heat-resistant gel, the baking industry has been the greatest agar usage. Agar is used to provide the necessary technical effects in confectionary items such agar jelly candies, marsh mallows, and sweet potato-sugar-agar confections at a concentration of 0.3 to 1.8 percent. Agar is another ingredient used in the production of canned meat, fish, and poultry products to protect the contents from deterioration during storage and transportation. Agar is used to improve the textures and stability of dairy products including Neufchatel process cheese, cream cheese, and fermented milk products. Agar has been compared favourably to gelatin in the fining of vinegar, juice, and wine.


2. a) What are the different deteriorative changes that occur in fats and oils? Describe briefly. (4)

Ans) Changes occurring in fats and oils causing deterioration as follows:




The primary process involved in the oxidative degradation of lipids is "autoxidation," which is the reaction with molecular oxygen via a self-catalytic mechanism. Three sections make up the autoxidation reaction:

  1. initiation.

  2. propagation.

  3. termination.


Factors Influencing Lipid Oxidation


Food lipids are made up of a range of fatty acids, each with unique chemical, physical, and oxidation susceptibility characteristics. Foods also contain a variety of non-lipid ingredients that could co-oxidize and/or interact with oxidising lipids and their oxidation products. The additional parameters affecting autoxidation include oxygen concentration, temperature, and moisture.




Lipolysis is the hydrolysis of ester linkages in lipids. Free fatty acids are released as a result of either enzyme activity or heat and moisture. The fat in living animal tissue is essentially devoid of free fatty acids. However, when the animal is died, they can be created by the activity of an enzyme. Since animal fats are typically not processed, quick conversion is especially crucial. The hydrolysis-causing enzymes can be inactivated by the temperatures frequently utilised in rendering. Unlike animal fats, mature oil seeds' oils may have undergone a large amount of hydrolysis by the time they were harvested, resulting in high levels of free fatty acids. Thus, after extraction, the majority of vegetable oils need to be neutralised with an alkali.


Thermal Decomposition


The chemical changes that are brought about by heating food can have a significant impact on its flavour, appearance, nutritional value, and toxicity. In addition to going through breakdown reactions, the various nutrients in food also interact with one another in a very complex manner to create a very large number of new molecules.


b) Describe the different biological functions of protein in our body. (4)

Ans) Proteins play a part in the morphology and functionality of organelles and cells. Following is a possible classification scheme for proteins:


Structural elements: Fibrous proteins make up structural proteins. The keratins, which make up the protective coating of all land vertebrates including skin, fur, hair, wool, claws, nails, hooves, horns, scales, beaks, and feathers, are perhaps the fibrous proteins that people are most familiar with.


Defensive Proteins: These proteins offer disease defence. A good example of a protective protein is an antibody. These fight against viruses and germs. Additionally, immunoglobulins, give the body defence against infectious diseases and invading organisms.


Contractile Proteins: Similar to the proteins present in muscles and other cells and tissues, these proteins play a role in contractile activities. These proteins take part in motile activity, localised contractile events in the cytoplasm, and cell aggregation phenomena in the latter.


Nutrient and Storage proteins: Amino acids are stored in these proteins. The egg white's ovaalbumin protein is utilised by the developing embryo as a source of amino acids. For young mammals, the primary source of amino acids is casein, a milk protein. Proteins are kept in plants' seeds.


Transport proteins in plasma: Toxic substances can be released into the environment or nutrients can be imported into cells thanks to transport proteins anchored in lipid membranes. Transport proteins are required to assist molecules cross membranes when diffusion is not possible.


Enzymatic Proteins: The proteins that have catalytic activity—the enzymes—are the most diverse and most specialised. Enzymes catalyse almost all of the chemical processes of organic biomolecules in cells. There are more than 2,000 recognised enzymes.


Hormonal proteins: The functions of the body are coordinated by hormone proteins. The information that controls cell permeability and metabolism is carried by a variety of peptide and protein hormones, including insulin and growth hormone.


Receptor Proteins: These are integrated into nerve cells' membranes and are used to monitor chemical signals given forth by other nerve cells.


c) What is tyndall effect? (2)

Ans) A powerful, focused beam of light is one of the greatest tools for telling a solution from a colloidal dispersion. The beam leaves a brilliant, clear path as it goes through a colloidal dispersion because light rays scatter or diffuse as a result of being redirected from colloidal particles' surfaces.


3. a) What is invert sugar ? Give an example. Explain its uses in food industry. (4)

Ans) Sucrose is an invert sugar that can be hydrolyzed to separate into its component sugars, fructose and glucose. It is known as "invert sugar" because the hydrolysis of sucrose results in a change in the rotation of polarised light in the solution, an effect known as "sucrose inversion." Either an enzyme or an acid is present, which causes this inversion to occur. The consumer sees syrup as being particularly sweet because the fructose and glucose mixture is significantly more soluble than the sucrose crystals.


From corn starch, high fructose corn syrup (HFCS) is produced. Acid or an enzyme hydrolyzes the maize starch, and the resulting glucose is subsequently "inverted" into fructose. The processing conditions can be adjusted to alter the inversion percentage. This is an additional food processing technique, particularly in the area of sweeteners.


Acid and enzymes hydrolyze and invert sugar molecules into their monosaccharide constituents in food systems. This has the consequence that any substance containing an acid component may cause the hydrolysis of sucrose into fructose and glucose. Especially if the product is heated, this is crucial. As reducing sugars (whereas sucrose is not), fructose and glucose promote browning. They are more hygroscopic and soluble than sucrose. Sugar crystallisation can be an issue in a number of items. For instance, in the confectionery sector.


b) What is Rheology of foods? What are the different textural parameters observed in foods? (4)

Ans) Rheology is the study of stress and strain, or, to put it another way, it is the study of how materials, both liquids and solids, flow and deform when subjected to stress and strain. Rheology primarily addresses the three properties of elasticity, plasticity, and viscosity.


A food's flow characteristics are actually fairly intricate. To the extent that it does, dough is elastic. For instance, if bread dough is stretched, but not too far, it will spring back. Elasticity is a crucial quality for baked goods as well. such as a bread crumb or a cake, particularly if they are fresh.


Unlike plastic deformation, elastic deformation can be reversed. When a minimum force is applied, a material that displays plastic flow resists shifting positions. This is a quality that cake icing should have. The frosting should be soft yet hold its shape and not run down the sides of the cake.


Solids do not flow, yet some can be forced to deform and then return to their original shape. This is elasticity, and elastomeric solids include gels made of pectin, gelatin, starch baked custard, etc. The stiffness of gels can be assessed objectively using a variety of methods. Plastic flow is irreversible, unlike elastic flow, which a material will resist until a force is applied.


c) Write about the different methods of pasteurization. (2)

Ans) Pasteurization is a heat treatment that typically uses temperatures below 100° C and kills some but not all of the microorganisms present. For instance, milk is frequently heated to 63 °C for 30 minutes, 71 °C for 15 seconds, or, in the case of UHT, 138 °C for 2-4 seconds. Examples include the routine pasteurisation of milk, wine, beer, fruit juices, and aerated waters. The products are immediately cooled after the heat treatment, which may involve the use of steam, hot water, dry heat, or electric currents. Other techniques are typically used in addition to pasteurisation to extend shelf life.


4. a) Briefly describe the role of irradiation and fermentation in food industry. (4)

Ans) Role of irradiation in food industry: One of the food processing methods accessible to the food business is food irradiation, which helps to both limit the organisms that cause food-borne illnesses and lower food losses from rotting and degradation. Irradiating food entails using radiation such as gamma rays, x-rays, electron beams, or radioactive substances. The radiation does not make the food radioactive; instead, it sterilises it, eradicates microorganisms, and regulates several aspects that lead to food degradation.


Technology for irradiating food also has some benefits over traditional methods. If irradiation offers a technically sound and cost-effective alternative to conventional processing techniques, each application should be assessed on its own merits.


Role of fermentation in food industry: People all throughout the world consume a variety of fermented foods, whether they are of plant or animal origin. As one starts to understand more about the eating customs of many cultures, what is so amazing is the range of substrates used as raw materials, ways of preparation, and sensory attributes of completed goods. Numerous indigenous or "traditional" fermented meals and drinks are still prepared as works of art in the home. Others are prepared on a huge industrial scale using biotechnological methods, like soy sauce, for example.


Bread fermented dairy products, vegetables and sauces, coffee, and cocoa are just a few of the fermented foods. These foods have been researched scientifically for many years, and our understanding of them keeps up with advances in modern science. This led to production techniques that reflect current technological advancements. The popular Japanese fermented foods shoyu (fermented soybean products), miso (fermented soybean products), natto (fermented soybean products prepared with microorganisms), and sake have all adopted this contemporary trend. Contrarily, many other fermented foods from Asian and African countries, such as emple, gari, kimchi, and others, have not even been partially examined by modern scientists and have just recently come to their attention. As a result, the majority of these meals are still made using age-old, less sophisticated techniques, with basic tools, either at home for personal use or on a small-scale in a hamlet.


b) Describe the alterations that occur in egg during processing and storage. (4)

Ans) The pace and conditions of handling, uncoated shells, storage durations and temperatures, and other factors all adversely affect the quality, flavour, composition, and functional qualities of eggs more quickly and to a greater extent.


Fresh eggs and eggs that have been frozen or dried retain basically the same nutritional value. Nutrient loss during the drying or freezing operations is negligible. Eggs that have been dried, frozen, and properly preserved show no further nutritional loss.


No method had an advantage in terms of thiamine content when hard-cooked and scrambled eggs were compared. However, riboflavin levels in scrambled eggs were roughly 20% lower than in hard-cooked eggs. Both cooking techniques resulted in a 0.22 percent loss of the amino acid threonine.


Eggs' nutritional value is not much lost when dried under typical circumstances. It has been shown that the amounts of vitamins A, B, thiamine, riboflavin, pantothenic acid, and nicotinic acid in dried whole eggs are nearly identical to those in fresh egg products. Dried eggs' protein content practically hasn't altered. Negative drying or storage conditions could erode nutritional qualities. Any egg product that doesn't have an awful flavour, however, will likely retain all of its nutritious benefits.


Whole egg and yolk products may lose solubility if drying conditions are too stringent or if storage conditions are unfavourable, and this loss of solubility will be accompanied by a loss of heat-coagulating characteristics. Increased viscosity upon reconstitution of the plain whole egg and plain yolk is one sign that too much heat was used to dry them. When compared to a dried plain whole egg, the dried plain yolk's viscosity changes more dramatically.


Dehydration has little impact on the density of egg products. A dried egg product has roughly the same density as the liquid it was dried from when it is reconstituted to its original solid state. Depending on the drying techniques and environmental factors, the dried egg product's bulk density might vary significantly. Products made from dried eggs are substantially bulkier than those made from spray-dried eggs. Bulk density is lowest in items made from freeze-dried eggs.


c) What are the factors that affect the quality of taste in food? (2)

Ans) Consumer approval, tasting panels, complicated changes in the physical and chemical structure of the food as influenced by various intrinsic and external elements, and appearance, texture, flavour, nutritional, sanitary, and keeping considerations. Quality standards.


5. a)What is atmospheric dehydration ? Enlist the different dryers used in the food industry. (4)

Ans) Atmospheric forced-air driers artificially dry fruits and vegetables by passing heated air with controlled relative humidity over the food to be dried, or by passing the food to be dried through the heated air, and is the most widely used method of fruit and vegetable dehydration. Apples, prunes, and a few vegetables are processed using atmospheric dehydration.


Types of Dryers in food industry:

  1. Air convection dryers

  2. Kiln

  3. Cabinet, tray or pan

  4. Tunnel

  5. Continuous conveyor belt

  6. Belt trough

  7. Air lift

  8. Fluidized bed

  9. Spray

  10. Drum or roller dryers

  11. Atmospheric

  12. Vacuum

  13. Vacuum dryers

  14. Vacuum shelf

  15. Vacuum belt

  16. Freeze dryers



b)Briefly discuss the primary processing of the following: (3+3)


i. Cereals

Ans) The several species of wheat, rice, maize or corn, jowar, barley, ragi, bajra, rye, and oats are all considered cereals or grains since they are the seeds of grasses. The largest portion, or around one-fifth of India's consumption expenditures, goes on cereal. They are primarily consumed in the form of first-stage products like paddy rice and wheat flour, such as atta. The four main grains farmed and eaten in the nation are rice, wheat, maize, and sorghum. According to FAO statistics for 2003, India produced approximately 102 million MT of rice, compared to the global production of 590 million MT. Cereal meals are consumed widely because of how easily they can be created and stored, how inexpensive they are to make, and how nutritionally beneficial they are.


ii. Pulses

Ans) Pulses are the edible fruit or seed of plants that produce pods, and they are widely grown around the world. Due to their high protein content, which ranges from 20 to 40%, they are significant as a major source of proteins in the diets of populations who depend predominantly on cereals as staple foods worldwide. They provide protein of a respectable quality for a far lesser cost than animal proteins. In most of the world, pulses are primarily consumed as soft-cooked dishes, either whole or in dehulled split form. The majority of pulses are grown in India. The following pulses are classified as important pulses based on their production and consumption: Red gramme (tur), Bengal gramme (chana), Black gramme (urad), Green gramme (mung), and others, including cow pea, cluster bean or guar, French bean or kidney bean, Indian bean or field bean, and soybean. In contrast, the poisonous substances contained in many pulses—such as moth or tepary bean, lentil, horsegram (kulthi), peas, and khesari dhal—are what are to blame for a variety of human illnesses. Harmful compounds can be eliminated by either heating them up or boiling them out.


6. a) Briefly discuss different phases of developing a new product. (6)

Ans) Three stages make up the process of creating a new product: formulation or recipe development; standardisation of processing techniques; and evaluation and testing of the final product's quality parameters. The following are the pertinent issues:

  1. In order to learn the optimised recipe.

  2. To develop efficient processing environments.

  3. To guarantee the high quality of food goods.

  4. To precisely forecast marketability


It is common knowledge that the majority of food products are made from a variety of ingredients and go through a number of processing procedures. Therefore, when developing a new product, it is necessary to determine whether the recipes and processing techniques can produce a product of sufficient quality or if they need to be altered in order to satisfy market demands. There are three stages in the development of a product, and that each stage is interdependent on the other two. As a result, planning the work becomes difficult. Therefore, the most straightforward approach to product development is to use the trial-and-error method, often known as the one factor at a time approach. It is a straightforward procedure in which only one ingredient can be altered at a time if modifications need to be made to the formulation. For instance, the materials used to make the sweet and spicy versions of fried snacks are flavourings, salt, and sugar. These are regarded as the factors that affect the product's quality. By altering the number of flavourings while keeping the levels of salt and sugar constant, the impact of flavourings is examined. The product of highest quality is chosen. The ideal levels of sugar and salt are then established in a comparable manner. Then, in order to create the sweet and sour fried snack with the best overall quality, the ideal amounts of flavourings, salt, and sugar are blended.


b) Discuss the functional role of sugars in foods. (4)

Ans) From the perspective of the customer, sugars are essentially connected to sweetness. Essentially, sweetness is a physiological sense. The sweetness of solutions at various concentrations is compared to that of regular sugar solutions until they appear to be the same, which is why it must be tested by human testers. The sweetness ratio is then determined by the ratio of concentrations.


Although sugar's primary function in food is to add sweetness, it also serves a variety of other functions in the food system. For instance, crystallisation typically plays a crucial structural function in the production of candies. Sugar in baked goods not only aids in the browning of the product but also has the potential to tenderise it due to its effects on the denaturation of protein and the gelatinization of starch. Sugars are crucial components in many diets because they provide a variety of additional purposes. Additionally to improving cooking with flavour and utility, they support a diverse and safe food supply. Many of the roles that sugars play in food cannot easily be replaced by other components.


Sweetness: The most well-known functional quality of sweeteners is sweetness. Our intrinsic predilection for sweetness becomes less pronounced as we get older and is visible soon after birth and before postnatal learning. Sweetness is linked to positive emotions like pleasure, gratitude, and reward, which adds to the allure of sweet foods. Confections have a sweet flavour and texture that are enhanced by the sugar and fat mix. Sucrose adds sweetness to beverages without changing their delicate flavours.


Texture: Sugars play a significant role in how food "mouthfeels," or how it feels in the mouth. For instance, glucose syrups give ice cream its perceived smoothness and substance. Lactose crystallisation, which results in the gritty or grainy texture often associated with frozen dairy products, can be avoided by adding sugar syrup. Controlling the rate and degree of sugar crystallisation throughout the candy-making process results in a huge variety of varied textures. These range from soft candies with minimal crystallisation, such fondants and fudge, to hard candies with desirable crystalline or grainy structures, like hard candies. Because honey doesn't crystallise, it can be used in confections to keep their soft, smooth consistency.


7. a) What are biocatalysts? Explain their role in food industry. (4)

Ans) As parts of living cells, after isolation, or in free or immobilised forms, enzymes can be utilised in business. They can all be thought of as biocatalysts. Because yeasts possess the enzymes needed to introduce desirable characteristics, they have long been used in the baking and brewing industries.


Baking Industry: Prior to baking bread, wheat flour (mostly carbohydrate and proteins) is combined with yeast, water, and other ingredients. The yeast may then break down the glucose and maltose, creating carbon dioxide, which disrupts the protein structure of the dough and makes it suitable for baking.


Brewing Industry: Malt, which is created by allowing barley seeds to sprout in damp conditions, serves as the primary beginning ingredient in this process. The amylase present breaks down the reserve starch to produce, among other things, glucose and maltose. The grains may next be roasted to stop further germination and to add flavour. Water is then used to remove the soluble material present to create the wort. The yeast then uses this to cause the alcoholic fermentation of the glucose and maltose to make ethanol.


C. Cheese Production: When making cheese, the milk protein k-casein is converted to paracasein through a controlled, limited hydrolysis that is catalysed by chymosin (rennin). Paracasein clots in the presence of Ca2+ and can be isolated from the whey; the clot is then given time to mature under carefully controlled conditions to make cheese.


b) Write in brief about foams and emulsions. (3)

Ans) Foams: A foaming agent must be present in the continuous phase before the gas disperses in order for a foam to form. To lower surface tension and create a distinct surface layer that prevents the coalescence of gas bubbles, the foaming agent must be absorbed at the surface. As a foaming agent, surface active lipids, glycosides, and proteins are employed. The two primary processes for creating foams are whipping and condensation.


Emulsions: If two liquids are mutually incompressible, a genuine emulsion is a colloidal dispersion of one liquid un another. Emulsions display the traits of colloidal systems, with the dispersed phase's particle size being roughly 0.1 mm. The continuous phase refers to the liquid in which the dispersion occurs.


Essentially, a food emulsion is a two-phase system made up of liquids like oil, wax, or essential oils and water. Dispersed phase, continuous phase, and/or emulsifier are the three components that make up an emulsion. The emulsifier is a surface active chemical that lowers interfacial tension and creates physical barriers around each droplet to prevent or present coalescence.


c) Explain different properties of solution which are important in food preparation. (3)

Ans) Properties of solution in food preparation:


Vapour Pressure: Vapour pressure is the force that the vapour places on top of the liquid when equilibrium is reached. The temperature affects the vapour pressure.


Boiling Point: One of the characteristics of solutions that has a direct relationship with vapour pressure is boiling point. This feature of water is helpful when preparing foods that are liquids at higher temperatures, such as jams, jellies, syrups, confectionery, etc.


Freezing Point: The temperature at which a substance turns from a liquid to a solid is known as the freezing point of that substance. When the vapour pressure of a liquid and its solid counterparts are equal, the liquid freezes. Water freezes at 0 degrees Celsius.


Viscosity: Internal friction tends to stop moving sections of fluids that are moving in relation to one another. This is determined by comparing it to a reference viscosity, usually that of water at 25 °C. The viscosity of a fluid can alter significantly due to a variety of circumstances, including temperature.


8. a) Explain different freezing systems used in food industry. (4)

Ans) The different freezing systems are summarized herewith:


Freezing by Contact with a Cooled Solid: Dish Freezing The product is sandwiched between two metal plates in this procedure, and pressure is typically used to ensure good contact. Plate freezers are only appropriate for materials or blocks that are regularly formed. Hot liquid is circulated to break the ice seal and thaw the product once it has frozen. To avoid the package being crushed or bulging during freezing, spacers are placed between the plates.


Freezing by Contact with a Cooled Liquid: Totally Freezing This method uses direct heat exchange to quickly lower the temperature of the meal by submerging it in low-temperature brine. Salt solutions (sodium chloride), sugar solutions, glycol and glycerol solutions, and alcohol solutions are the most often utilised fluids. Flexible membranes are utilised to completely cover the food while enabling quick heat transfer in order to prevent the food from coming into touch with liquid refrigerants.


Freezing by Contact with a Cooled Gas

There are several ways to freeze by coming into touch with chilled gas. These consist of:

  1. Cupboard Freezing.

  2. Air–Blast Freezing: Belt and tunnel freezing, as well as fluidized bed freezing.

  3. Using a Cryogenic System.


b) Discuss the role of sensory evaluation in food product development. (4)

Ans) A scientific field known as sensory assessment is used to elicit, measure, analyse, and interpret responses to food and material features as they are perceived by the senses of sight, smell, taste, touch, and hearing. In any case, the food sector strives to:

  1. Create new products by altering formulas already in use.

  2. Delve into new markets.

  3. More successfully compete in the current market.

  4. Maintain a high standard of quality.


Because of these compulsions, sensory evaluation is crucial. The most important feature of food is its quality, or, from the perspective of the consumer, its acceptability. In research on product development, quality assurance, market acceptability of food products, and evaluation of food services, the gathering of data on food acceptance is a critical step. A sensory panel is typically assembled to periodically evaluate the product's quality before consumer testing.


c) What is functional food? Explain by giving examples. (2)

Ans) A food that has a component integrated into it to provide a specific medical or physiological advantage, other than a strictly nutritional benefit, is referred to as a functional food. For instance:




Despite the fact that mustard seeds are typically used as a condiment, significant new food applications are constantly being discovered. Products made from mustard, such as mustard oil, mustard flour, prepared and crushed mustards, and mustard bran, are readily available in the marketplace. Due to its rheological and interfacial characteristics, mustard mucilage should have several uses in the food industry. Numerous mustard constituents have advantageous physiological benefits. These include the potential effects of isothiocyanates on the prevention of cancer and antimicrobial activity, the effects of viscous fibre on the metabolism of glucose and lipids, and the potential health advantages of phytates, dithiolthiones, and proteins.


Section B - OTQ (ObjectiveTypeQuestions) (20marks)


1. Explain the following briefly in 2 –3 lines: (5)


I. Monomeric enzymes

Ans) Enzymes that are monomeric, or made up of just one polypeptide chain, cannot be divided into smaller parts. There are very few monomeric enzymes that are known, and they all catalyse hydrolytic processes. They typically range from 13 kDa to 35 kDa in molecular weight and comprise 100 to 300 amino acid residues. Some, like carboxypeptidase A, are connected to a metal ion, but the majority function on their own without the aid of a cofactor.


II. Whey Protein Concentrate

Ans) A fantastic source of low fat dairy protein, whey protein concentrate (WPC) is a very nutritious ingredient made from fresh dairy whey and is spray dried. Many functional and processed foods, beverages, and health supplements use it as an ingredient of choice due to its beneficial qualities, including as high solubility and water retention capacity..


III. Antioxidants

Ans) Antioxidants are compounds that can prevent or delay the oxidation of materials that are susceptible to it. They offer defence against oxidative alterations in fats and oils as a result of this feature. They work by interacting with free radicals to stop the chain reaction from spreading.


IV. Class I and class II preservatives

Ans) The additional ingredients in food preservation can be divided into two categories. The first one is referred to as a class I preservative and is thought to be rather safe for people. It uses ingredients including sugar, salt, spices, acetic acid (vinegar), and alcohol. The use of class II preservatives, which include benzoic acid, sulphur dioxide, nitrates, nitrites, and a variety of neutralizers, firming agents, and bleaching agents, is included in the second group. These chemicals are generally considered safe for people when used in the permitted doses allowed by the food regulatory agencies because higher concentrations can be harmful to their health.


V. Minimally processed foods

Ans) Minimally processed foods include both traditional goods like pre-made salads and vegetables, pre-cut fruit, pre-cooked meat, heat-and-eat meals, and modern foods like fresh pasta and pasta sauces. When these goods are heated, substantially less heat is used than what is needed to heat the foods in cans.


2. Differentiate between the following: (10)


i) Caramelization and Maillard Reactions

Ans) Maillard reaction is a chemical reaction that takes place involving amino acids and reducing sugars in food. Therefore the reactants of this reaction are amino acids and reducing sugars. Moreover, it is a non-pyrolytic reaction. Here, the browning occurs via producing a mixture of poorly characterized molecules that is responsible for the aroma and flavor of browned food. Caramelization is a chemical reaction that takes place involving sugar in food. hence the reactants of Caramelization are sugars in food. It is a pyrolytic reaction. In addition to that, it forms three forms of polymers that are responsible for the brown color of food; caramelans, Caramelens and Caramelins.


ii) Protein Concentrate and Protein Isolate

Ans) There are several nutritional differences between whey isolate and concentrate. These differences are caused by the processing methods.


When the liquid whey is collected as a by-product of cheese or yogurt production, it undergoes several processing steps to increase its protein content .


After a sufficient protein concentration is achieved, the liquid can be dried to form whey concentrate powder that consists of up to 80% protein by weight. The remaining 20% of the whey concentrate powder contains carbohydrates and fats.


If different processing steps are used to reduce the fat and carbohydrate content of whey, a whey isolate powder containing 90% or more protein by weight can be produced.


Overall, the processing steps used in the production of whey isolate result in higher protein content and lower fat and carbohydrate content per serving.


However, the types of amino acids found in both forms of whey are virtually identical, since they are derived from the same proteins.


iii) Cellulose and Hemicellulose

Ans) Cellulose and hemicellulose are two types of natural polymers that are mainly found in the plant cell walls and are important components of natural lignocellulosic materials. But these two components are different in the chemical composition and the structure. The key difference between cellulose and hemicellulose is that cellulose is an organic polysaccharide molecule whereas hemicellulose is a matrix of polysaccharides. ellulose is an un-branched polymeric molecule and has 7,000–15,000 glucose molecules per polymer. Hemicellulose contains shorter chains of 500–3,000 sugar units and it is a branched polymer.


iv) Solar drying and Mechanical dehydrator

Ans) Fruits and vegetables can be dried using the sun and solar energy at a low cost because sunlight is used as the heat source. Compared to that, mechanical dehydration is more expensive since it requires a supply of heat, which can come from either steam or electricity.


The earliest method of food reserving, solar drying uses solar energy to preserve food products. It is still used today to preserve foods like raisins. The newest method of food drying also uses mechanical dehydration.


If the temperature is hot, moderately dry, and rain-free during and immediately after the typical harvesting time, the sun/solar drying process can be employed on a commercial basis in villages as well. Due to the expensive machinery required, mechanical dehydration can only be employed on a large scale commercially.


Dust, rain, and gloomy weather are the greatest obstacles to sun drying. But hygiene is crucial in the case of mechanical dehydration.


v) Pasteurization and canning

Ans) Pasteurization is a heat treatment that typically uses temperatures below 100° C and kills some but not all of the microorganisms present. Foods are cooked in hermetically sealed (airtight) jars or cans during the canning process to a temperature that kills microorganisms and inactivates enzymes that could be harmful to human health or cause the food to deteriorate.


The products are immediately cooled after the heat treatment, which may involve the use of steam, hot water, dry heat, electric currents, or any combination of these. No microorganisms can enter the product because of the vacuum seal that is created in the caning after heating and cooling.


Examples of products that are regularly pasteurised include milk, wine, beer, fruit juices, and aerated waters. All types of tinned foods, including soup, meat, beans, cereal grains, legumes, nuts, and other different dried food products, including fruit, coffee, milk, soups, fish, meat, and vegetables, are examples of food preserved through canning.


3. Match the following: (5)


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