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MFN-008: Principles of Food Science

MFN-008: Principles of Food Science

IGNOU Solved Assignment Solution for 2023-24

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Assignment Code: MFN-008/AST-5/TMA-5/23-24

Course Code: MFN-008

Assignment Name: Principles of Food Science

Year: 2023-2024

Verification Status: Verified by Professor

Section A -Descriptive Questions (80 marks)

Q1a) Explain in brief function of sugars in foods.

Ans) Sugars serve various functions in foods, contributing to flavour, texture, and preservation.

Some key functions of sugars in foods include:

a) Sweetness: Sugars are natural sweeteners that enhance the flavour of many foods and beverages. They provide a pleasant, sweet taste that is widely appreciated by consumers.

b) Flavour Enhancement: Besides sweetness, sugars can also enhance other flavours. They mask or balance out undesirable tastes and can improve the overall taste profile of a product.

c) Texture and Mouthfeel: Sugars can contribute to the texture and mouthfeel of foods. In products like baked goods, they help retain moisture, leading to a soft and tender texture. In candies, they can create a smooth, creamy, or chewy texture.

d) Color Development: Sugars can undergo Maillard reactions, caramelization, or browning reactions during food processing. These reactions lead to the development of desirable colors and flavours in various products.

e) Preservation: Sugars play a role in food preservation. They can reduce water activity in foods, which inhibits the growth of spoilage microorganisms and pathogens. Jams, jellies, and syrups are examples of sugar-preserved products.

f) Fermentation: In products like bread and alcoholic beverages, sugars serve as a fermentable substrate for yeast and other microorganisms, leading to the production of carbon dioxide (for leavening) and alcohol (in the case of beverages).

Q1b) How are melanin (brown pigments) formed during food processing? Explain.

Ans) Melanins are brown pigments that form as a result of complex chemical reactions involving sugars and amino acids, particularly through Maillard reactions and caramelization. The formation of melanins during food processing is a crucial aspect of color and flavour development.

Here's how melanins are formed:

a) Maillard Reactions: Maillard reactions occur when reducing sugars (e.g., glucose, fructose) react with amino acids (the building blocks of proteins) under heat. This reaction leads to the formation of brown pigments, including melanoidins. Melanoidins are responsible for the brown color of bread crust, roasted coffee beans, and the exterior of grilled meats.

b) Caramelization: Caramelization is a non-enzymatic browning reaction that involves the pyrolysis (thermal decomposition) of sugars. When sugars like sucrose are heated to high temperatures, they break down into simpler compounds and form brown pigments. This process is responsible for the brown color and flavour of caramel and toffees.

c) Polymerization: The products of Maillard reactions and caramelization can further react with each other or with other compounds to form larger, more complex molecules. These polymers contribute to the brown color of various foods.

d) Flavour Development: In addition to color, the formation of melanins during food processing contributes to the development of desirable roasted, toasted, or caramel flavours. This enhances the overall sensory profile of foods.

The extent and nature of melanin formation can vary depending on factors such as temperature, time, pH, and the specific sugars and amino acids present in the food. Food scientists and culinary experts leverage these reactions to achieve the desired color and flavour characteristics in a wide range of products.

Q2a) Discuss gelatinization and retrogradation of starches in brief.

Ans) Gelatinization and Retrogradation of Starches:

Gelatinization: Gelatinization is the process by which starch granules absorb water and swell, leading to the thickening and swelling of a starch-containing food product. This process occurs when starches are heated in the presence of water. During gelatinization, the starch granules absorb water, causing them to swell and eventually burst, releasing amylose and amylopectin into the surrounding liquid. This results in the thickening of the liquid, forming a gel-like structure. Common examples of gelatinized starches include the thickening of gravies, sauces, and custards.

Retrogradation: Retrogradation is the opposite process of gelatinization. After gelatinized starches have cooled and the products containing them are stored, the starch molecules realign and recrystallize. This can lead to the formation of a firmer and often gritty texture in products like refrigerated leftover rice or bread as it stales. Retrogradation can be undesirable in certain foods as it affects texture and quality. However, in some food applications, retrograded starch can be desirable, such as in the formation of resistant starch in certain processed foods, which has potential health benefits as a dietary fibre.

Q2b) What are food hydrocolloids? List its uses in food processing industry.

Ans) Food hydrocolloids are food ingredients derived from natural sources, such as plants and seaweeds, and are used to modify the texture, appearance, and stability of a wide range of food products. Hydrocolloids have the ability to form gels, thicken, stabilize emulsions, and control water migration in food systems.

They are vital components in many processed foods and serve various functions, including:

a) Thickening: Hydrocolloids are used to increase the viscosity of food products, making them thicker and more stable. They are often used in soups, sauces, and dressings.

b) Gel Formation: Some hydrocolloids can create gels, providing structure and texture to foods. Examples include gelling agents in fruit preserves and gummy candies.

c) Stabilization: Hydrocolloids are used to stabilize emulsions and prevent ingredients from separating. They are commonly found in salad dressings, mayonnaise, and ice cream.

d) Water Binding: Hydrocolloids can absorb and retain water, preventing syneresis (the separation of liquid from a gel) in products like yogurt and fruit fillings.

e) Texture Modification: They can influence the texture of foods, providing creaminess, chewiness, or elasticity to products like ice cream and bakery items.

Common examples of food hydrocolloids include agar-agar, carrageenan, xanthan gum, and pectin.

Q2c) What is extruded starch? Give example.

Ans) Extruded starch is starch that has been subjected to extrusion cooking, a process that uses heat, pressure, and mechanical shear to transform starchy ingredients into expanded, ready-to-eat products. A well-known example of extruded starch is expanded snacks like puffed corn or rice snacks. In this process, starchy ingredients are mixed with water and subjected to high temperature and pressure within an extruder. As the mixture exits the extrusion die, it undergoes rapid expansion due to the sudden drop in pressure, creating a puffed or expanded texture. Starches play a crucial role in providing the structural integrity of these snacks. The extrusion process gelatinizes and expands the starch, resulting in a light and crispy texture.

Q3a) Describe various factors which influence the process of deep fat frying.

Ans) Deep fat frying is a cooking method that involves submerging food in hot oil or fat. Several factors influence the process of deep fat frying:

a) Temperature: The frying temperature is critical. It affects the rate of heat transfer to the food and the final product's texture. Frying at too low a temperature can result in oily and greasy food, while frying at too high a temperature can led to burning or overcooking.

b) Oil Type: The type of oil used can impact the flavour, texture, and nutritional quality of the fried food. Oils with high smoke points, like vegetable oil and peanut oil, are preferred for deep frying due to their stability at high temperatures.

c) Food Moisture: The moisture content of the food being fried is crucial. Excess moisture can cause oil spattering and result in less crispy food. It's important to pat dry food items before frying.

d) Food Size and Shape: The size and shape of the food items can affect frying time and oil absorption. Smaller pieces tend to cook faster and absorb less oil compared to larger items.

e) Frying Time: The duration of frying should be sufficient to cook the food completely while achieving the desired level of crispiness. Overcooking can result in a dry or burnt product.

f) Oil Freshness: The quality and freshness of the frying oil play a crucial role. Reusing oil for multiple frying cycles can lead to oil degradation and undesirable flavours in the fried food.

g) Oil Filtration: Proper filtration of the frying oil can extend its useful life by removing food particles and contaminants. This helps maintain the oil's stability and quality.

h) Batter or Coating: The use of batter or coating on the food's surface can impact the texture and appearance of the fried product.

Q3b) Explain how autoxidation causes deterioration of fats and oils.

Ans) Autoxidation is a process that occurs when fats and oils are exposed to oxygen in the presence of heat, light, or metal catalysts. It can lead to the deterioration of fats and oils through several chemical reactions, including the formation of volatile compounds and off-flavours.

The key steps in autoxidation are:

a) Initiation: Oxygen reacts with unsaturated fatty acids in the oil to form free radicals. These free radicals are highly reactive and can initiate a chain reaction.

b) Propagation: Free radicals attack nearby unsaturated fatty acids, resulting in the formation of more free radicals. This chain reaction continues until terminated.

c) Termination: The chain reaction is terminated when two free radicals combine to form a non-radical compound.

d) The consequences of autoxidation in fats and oils include:

i) The development of rancid or off-flavours, which can make the oil or fat unsuitable for cooking.

ii) A decrease in the oil's smoke point, making it less stable at high temperatures.

iii) A reduction in the oil's nutritional quality, as essential fatty acids may become oxidized.

iv) The potential formation of harmful compounds, such as peroxides.

Q3c) Give examples of transport proteins in plasma.

Ans) Plasma, the liquid component of blood, contains various transport proteins that play essential roles in carrying and delivering substances throughout the body.

Some examples of transport proteins in plasma include:

a) Albumin: Albumin is the most abundant plasma protein and serves as a carrier for numerous small molecules, including fatty acids, bilirubin, calcium, and hormones. It helps maintain oncotic pressure and regulates the distribution of substances in the bloodstream.

b) Globulins: Globulins encompass a diverse group of proteins, including immunoglobulins (antibodies) that play a crucial role in the immune system. Other globulins act as transport proteins for specific substances such as iron (transferrin), cholesterol (high-density lipoprotein or HDL), and thyroid hormones (thyroxine-binding globulin or TBG).

c) Fibrinogen: Fibrinogen is involved in blood clotting and is converted to fibrin during the coagulation process.

d) Haptoglobin: Haptoglobin binds to free haemoglobin released from red blood cells, preventing its loss in urine and potential kidney damage.

e) Ceruloplasmin: Ceruloplasmin is involved in transporting and regulating copper levels in the body.

Q4a) Briefly describe advantages and disadvantages of using microorganisms as a source of protein.

Ans) Advantages and Disadvantages of Using Microorganisms as a Source of Protein:


a) High Protein Content: Microorganisms can be engineered to produce a high concentration of protein efficiently.

b) Rapid Growth: Microorganisms like bacteria and yeast have short generation times, allowing for quick protein production.

c) Sustainability: Microbial protein production can be more environmentally sustainable than traditional animal agriculture, as it requires fewer resources like land and water.

d) Precise Genetic Engineering: Genetic modification of microorganisms enables the production of specific proteins with desired properties.

e) Consistency: Microbial production can result in consistent product quality.

f) Reduced Food Safety Concerns: Microbial proteins are produced in controlled environments, reducing the risk of foodborne pathogens.


a) Consumer Acceptance: The acceptance of microbial-derived proteins in the human diet is an ongoing challenge.

b) Taste and Texture: Microbial proteins may differ in taste and texture compared to traditional animal or plant-based proteins.

c) Allergenicity: Some individuals may be allergic to proteins produced by specific microorganisms.

d) Regulatory Challenges: The regulation of microbial proteins in the food industry can be complex.

e) Environmental Impact: The environmental impact of the fermentation process used for microbial protein production, including energy use and waste management, needs to be considered.

Q4b) What is WPC? Write its uses and functional properties.

Ans) WPC is a protein product derived from whey, the liquid byproduct of cheese production. It is created by removing most of the non-protein components of whey, resulting in a protein-rich powder.

WPC has several uses and functional properties:


a) Dietary Supplement: WPC is widely used as a dietary supplement for athletes and individuals looking to increase their protein intake.

b) Functional Food Ingredient: It is used as an ingredient in various food products, including protein bars, shakes, and baked goods.

c) Beverages: WPC can be added to beverages to improve their protein content and provide a creamy texture.

d) Infant Formulas: It is used in the production of infant formulas due to its high-quality protein content.

e) Bakery Products: WPC can enhance the protein content and texture of baked goods like bread and muffins.

Functional Properties

a) Protein Content: WPC is rich in high-quality proteins, making it a valuable protein source.

b) Solubility: It has excellent solubility in both cold and hot water, making it suitable for a wide range of applications.

c) Emulsification: WPC can form stable emulsions, which is beneficial in salad dressings, creamers, and other emulsified products.

d) Gelling: It can contribute to the gelling properties of certain food products, such as gel desserts and custards.

e) Water-Binding: WPC has water-binding capabilities, helping products retain moisture and improve texture.

f) Foaming: It can create stable foams, useful in applications like whipped toppings.

Q5a) Give nutritional and functional role of following:

i. Copper

Ans) Nutritional Role: Copper is an essential trace mineral involved in various physiological processes, including the formation of red blood cells, maintenance of healthy bones and nerves, and support of the immune system.

Functional Role: In food, copper is not typically added as a nutrient but can interact with other components. It can catalyze oxidation reactions and influence food color, especially in acidic or alkaline environments. Copper cookware is valued for its heat conductivity, which affects the cooking process.

ii. Iron

Ans) Nutritional Role: Iron is a vital mineral for the formation of haemoglobin, which carries oxygen in the blood. It also plays a role in energy metabolism and immune function.

Functional Role: In food, iron can serve as a fortification, especially in cereals and other products to prevent iron-deficiency anaemia. Iron cookware can influence the taste and color of certain foods, and it can also act as a leavening agent in bread-making.

iii. Biotin

Ans) Nutritional Role: Biotin, a B-vitamin, is essential for various metabolic processes, particularly fatty acid synthesis and the metabolism of amino acids and glucose.

Functional Role: Biotin has limited direct functional use in food processing. However, it plays a role in maintaining the quality of fresh produce by supporting proper metabolism and preventing spoilage.

iv. Cyanocobalamin

Ans) Nutritional Role: Vitamin B12 is vital for nerve function, red blood cell formation, and DNA synthesis. It is crucial for maintaining overall health.

Functional Role: Cyanocobalamin is not typically used for its functional properties in food processing. It is, however, essential in nutritional supplements and fortified foods to address vitamin B12 deficiencies in populations.

Q5b) Write about microbial and animal sources of natural colours used in foods.

Ans) Microbial and Animal Sources of Natural Colors:

Microbial Sources

a) Monascus spp.: Monascus species of fungi produce a natural red color, often referred to as "red yeast rice." This natural color is used in the food industry to provide red and pink hues to various products, including sauces, tofu, and rice wine.

b) Spirulina: Spirulina, a blue-green microalga, contains phycocyanin, a natural blue pigment. It is used to impart blue and green shades to foods and beverages.

c) Beet Juice Concentrate: Beet juice extracted from beetroots is used as a natural colorant, providing shades of red to pink.

Animal Sources

a) Carmine (Cochineal Extract): Carmine is a natural red color obtained from the dried bodies of the female cochineal insect. It is used in various food and beverage products, including yogurt and candies.

b) Shellac (Confectioner's Glaze): Shellac, derived from the secretions of the lac beetle, is used as a glazing agent in confectionery products, providing a shiny finish.

c) Guanine (Pearl Essence): Guanine, sourced from fish scales or guano (bird excrement), is used in cosmetics and foods to create a pearly or iridescent effect.

Q6a) Differentiate between sols, gels, and suspension by giving their properties

Ans) Comparison between sols, gels, and suspension:

Q6b) Explain Dash Pot Model for measuring rheology parameters.

Ans) The Dash Pot model is a simple mechanical model used in rheology to understand the behaviour of materials under stress and strain. It consists of a piston (dash pot) moving through a viscous medium. The resistance to the motion of the piston represents the dash pot's viscosity. The model is used to measure rheological parameters, such as viscosity and viscoelasticity. Here's how it works:

a) Components of the Model:

1) Dash Pot: Represents a fluid or viscous medium with a known viscosity.

2) Piston: Represents the material or substance being tested.

3) Force: Applied to the piston to move it through the dash pot.

b) Procedure:

1) The piston is placed in the dash pot filled with a viscous fluid.

2) An external force is applied to the piston to push it through the viscous medium.

c) Measurements:

1) The velocity of the piston's movement is measured over time.

2) The force required to move the piston at a constant velocity is also recorded.

d) Analysis:

a) The recorded data (force vs. velocity) is used to determine the viscosity of the fluid in the dash pot.

b) The model can also be used to assess the viscoelastic behaviour of materials. For instance, if the force is applied suddenly and then released, the material's elastic response can be observed.

In the Dash Pot model, the viscosity of the fluid represents the dash pot's damping effect. This model helps in characterizing the flow and deformation properties of materials, making it valuable in various fields, including food science, polymer engineering, and materials science.

Q7a) Briefly describe advantages of food irradiation over conventional process of preservation.

Ans) Advantages of Food Irradiation:

a) Extended Shelf Life: Food irradiation can significantly extend the shelf life of various food products by reducing or eliminating microorganisms responsible for spoilage.

b) Pathogen Control: It effectively kills harmful bacteria, parasites, and pathogens like E. coli and Salmonella, enhancing food safety.

c) Preservation of Nutrients: Food irradiation can preserve the nutritional value of foods better than other preservation methods like canning or heat treatment.

d) Reduced Chemical Use: It reduces the need for chemical preservatives and additives, contributing to cleaner and more natural food products.

e) Insect Control: Food irradiation can eliminate insect pests in stored grains and dried foods, reducing the need for chemical pesticides.

f) Reduced Food Waste: By extending the shelf life and preventing spoilage, food irradiation helps reduce food waste.

Q7b) Describe alterations occurring in milk and milk products while processing.

Ans) Alterations in Milk and Milk Products during Processing:

a) Pasteurization: Pasteurization, a common process for milk, involves heating to kill harmful bacteria. While it enhances safety, it can affect the flavour and nutrient content of milk.

b) Homogenization: Homogenization reduces the size of fat globules in milk, preventing cream separation. It results in a smoother texture but does not affect nutrient content.

c) Fermentation: In the production of yogurt and cheese, lactic acid bacteria are added to milk to ferment lactose, producing lactic acid. This thickens the product and changes its flavour.

d) Ultra-High Temperature (UHT) Treatment: UHT treatment involves heating milk to a high temperature for a short time, extending shelf life. It can alter the flavour slightly.

e) Evaporation: Evaporating milk to create condensed milk or evaporated milk removes water, increasing the concentration of nutrients, but it may alter the texture.

f) Cheese Making: Cheese production involves curdling milk with enzymes or acid, separating curds from whey. Different cheese types result from variations in processing and aging, leading to various textures and flavours.

Q8a) Explain the following methods of food processing:

i. Smoking

Ans) Smoking is a food preservation method that involves exposing foods, typically meat and fish, to the smoke from burning wood or other materials. The smoke contains chemicals and antimicrobial compounds that help preserve the food, enhance flavour, and impart a smoky aroma. The process involves both drying and the application of antimicrobial agents through the smoke. Smoking is commonly used for items like smoked salmon and smoked sausages.

ii. Pickling

Ans) Pickling is a preservation method that uses brine or vinegar to preserve or ferment foods, such as vegetables (e.g., cucumbers for pickles), fruits, and even eggs. The high acidity of vinegar and the salt in the brine create an environment that inhibits the growth of spoilage microorganisms. This method also imparts a distinct sour or tangy taste to the food.

iii. Fermentation

Ans) Fermentation is a natural preservation method that relies on the action of beneficial microorganisms like lactic acid bacteria and yeast to convert sugars into organic acids (e.g., lactic acid) and alcohol. This process lowers the pH, creating an environment hostile to harmful bacteria. Fermented foods include yogurt, sauerkraut, kimchi, and sourdough bread.

iv. Irradiation

Ans) Food irradiation uses ionizing radiation to destroy bacteria, parasites, and other pathogens. It can extend shelf life and improve food safety. The process does not significantly raise the temperature of the food and does not make it radioactive. Irradiation is used for items like spices, dried fruits, and some meat products.

Q8b) Briefly explain process of Canning of different foods.

Ans) Canning is a preservation method that involves sealing food in airtight containers and then subjecting it to heat treatment to kill microorganisms.

The key steps in the canning process include:

a) Preparation: Food is cleaned, peeled, and cut into appropriate sizes.

b) Packing: The prepared food is placed into cans or jars. For fruits, vegetables, or acidic foods, a hot syrup or liquid is added. For low-acid foods, the food is typically packed in its natural juices or oil.

c) Sealing: Lids or caps are secured onto the containers to create an airtight seal.

d) Heat Processing: The sealed containers are subjected to heat treatment, which varies depending on the type of food. This can involve boiling, pressure cooking, or steam processing.

e) Cooling: After heat processing, the cans or jars are allowed to cool. As the contents cool, a vacuum is formed, creating a strong seal.

f) Storage: Once cooled and sealed, the canned food is ready for storage and has an extended shelf life.

Q9a) What do you understand by microwave heating? Give its application in food processing.

Ans) Microwave heating is a method of cooking and heating food that utilizes microwave radiation. Microwaves are a form of electromagnetic radiation with frequencies between 300 MHz (megahertz) and 300 GHz (gigahertz). When microwaves interact with food, they cause water molecules to vibrate, generating heat. This internal heat generation is the reason microwave ovens can quickly and efficiently cook or heat food.

Applications in Food Processing

Microwave heating is widely used in food processing for various applications, including:

a) Cooking: Microwave ovens are commonly used for reheating cooked food, defrosting frozen items, and quickly cooking a wide range of dishes.

b) Blanching: Microwave blanching is used to deactivate enzymes in vegetables before freezing. It helps preserve the color, texture, and flavour of the vegetables.

c) Pasteurization: Microwaves can be used to pasteurize certain liquid foods, such as milk and fruit juices, by heating them to a temperature that kills harmful microorganisms while preserving the nutritional quality.

d) Drying: Microwave drying is a rapid and efficient method for removing moisture from various food products like fruits, vegetables, and herbs, helping extend their shelf life.

e) Roasting and Baking: Some microwave ovens are equipped with convection features that combine microwave and convection heating, allowing for roasting and baking.

Q9b) Discuss various bacterial fermented foods and their characteristics.

Ans) Bacterial fermentation is a traditional method of food preservation and flavour enhancement. Various foods are created through the action of beneficial bacteria. Some common bacterial fermented foods and their characteristics include:

a) Yogurt: Yogurt is produced by fermenting milk with lactic acid bacteria, mainly Lactobacillus and Streptococcus strains. It has a tangy flavour, creamy texture, and is a good source of probiotics, which are beneficial for gut health.

b) Cheese: Cheese is made from milk using bacteria (Lactobacillus and others) and enzymes (rennet). The type of bacteria, processing, and aging result in various cheese flavours and textures, from soft, mild cheeses to hard, aged varieties.

c) Sauerkraut: Sauerkraut is fermented cabbage, typically using lactic acid bacteria. The fermentation process creates a sour flavour, and sauerkraut is often used as a condiment.

d) Kimchi: Kimchi is a Korean side dish made from fermented vegetables, primarily Napa cabbage. It is known for its spicy and pungent taste and is rich in vitamins and probiotics.

e) Sourdough Bread: Sourdough bread is leavened using a sourdough starter containing lactobacilli and wild yeast. The fermentation process gives the bread its characteristic sour taste and chewy texture.

f) Kefir: Kefir is a fermented milk product made using kefir grains, which contain lactic acid bacteria and yeast. It has a slightly effervescent, tangy flavour and is a probiotic beverage.

g) Fermented Soy Products: Fermented soy products like miso, tempeh, and natto are made through the action of specific bacteria and fungi. They are rich in protein and have distinct flavours.

Q10a) Explain term ‘Minimally Processed Fresh Foods’. Also give advantages of these products.

Ans) Minimally Processed Fresh Foods: Minimally processed fresh foods are food products that have undergone minimal processing and retain much of their natural, fresh characteristics. This processing approach aims to preserve the sensory and nutritional qualities of the food while ensuring convenience and extended shelf life. Minimally processed fresh foods typically include fruits, vegetables, and other perishable items that have been cleaned, cut, or peeled to some extent, without significant alterations. Examples include pre-cut vegetables, bagged salads, and pre-sliced fruits.

Advantages of Minimally Processed Fresh Foods

a) Convenience: Minimally processed fresh foods save consumers time and effort in meal preparation. They are ready to use, reducing the need for washing, peeling, or chopping.

b) Extended Shelf Life: While not as long-lasting as heavily processed foods, minimally processed fresh foods have a longer shelf life compared to whole, unprocessed items. This can help reduce food waste.

c) Nutrient Retention: Minimal processing preserves the natural nutrients, flavours, and textures of the food. This makes it a healthier choice compared to heavily processed foods with added preservatives and artificial ingredients.

d) Increased Consumption of Fresh Produce: Minimally processed fresh foods can encourage individuals to consume more fruits and vegetables, contributing to a healthier diet.

e) Reduced Exposure to Additives: These foods typically contain fewer additives and preservatives compared to highly processed alternatives, which is beneficial for health-conscious consumers.

f) Customization: Minimally processed fresh foods provide a balance between convenience and customization. Consumers can further prepare or season the food to suit their preferences.

Q10b) Discuss physical, chemical, and microbiological changes that occur during food storage and distribution.

Ans) During food storage and distribution, various physical, chemical, and microbiological changes can occur, affecting the quality and safety of the products. Some of these changes include:

a) Physical Changes:

1) Moisture Loss: Foods may lose moisture during storage, leading to changes in texture, such as staling in baked goods or wilting in vegetables.

2) Texture Changes: The texture of some foods can change due to factors like freezing, thawing, or mechanical damage during handling and transportation.

3) Color Changes: Exposure to light, oxygen, or temperature variations can cause color changes in certain foods, leading to loss of appeal.

b) Chemical Changes:

1) Lipid Oxidation: Fats and oils in foods are susceptible to oxidation, which can lead to off-flavours, rancidity, and decreased nutritional quality.

2) Maillard Reaction: This reaction can occur in foods like bread and coffee, resulting in browning and the development of characteristic flavours.

3) Nutrient Degradation: Vitamins, especially sensitive to heat and light, may degrade during storage, affecting the nutritional value of foods.

c) Microbiological Changes:

1) Microbial Growth: Foods can become contaminated by bacteria, moulds, and yeast, leading to spoilage or potential health risks.

2) Pathogen Growth: If proper temperature and sanitation measures are not maintained, harmful pathogens can multiply, increasing the risk of foodborne illnesses.

Section B - OTQ (Objective Type Questions) (20marks)

Q1) Explain the following briefly in 2 –3 lines:

I. Product development

Ans) Product development refers to the process of creating new food products or improving existing ones. It involves research, formulation, testing, and marketing to meet consumer demands and preferences.

II. HTST pasteurization

Ans) HTST (High-Temperature Short-Time) pasteurization is a method of heat treatment used to kill harmful microorganisms in liquid foods like milk and juices. It involves heating the product to a high temperature for a short duration, followed by rapid cooling to maintain quality.

III. Emulsions

Ans) Emulsions are stable mixtures of immiscible liquids, such as oil and water, achieved through the use of emulsifiers. Common examples include mayonnaise, salad dressings, and vinaigrettes.

IV. Cryogenic Freezing

Ans) Cryogenic freezing is a freezing technique that uses extremely low temperatures, often with the help of liquid nitrogen or carbon dioxide, to quickly freeze food products. This method preserves food quality by minimizing the formation of large ice crystals.

V. Marinating

Ans) Marinating involves soaking food, typically meat, poultry, or vegetables, in a seasoned liquid mixture to enhance flavour, tenderness, and sometimes preservation. Marinating can be done for a short period or several hours, depending on the desired results.

Q2) Differentiate between the following:

i) Primary processing and Secondary processing of cereals

Ans) Comparison between Primary processing and Secondary processing of cereals:

ii) Preservation and Fermentation

Ans) Comparison between Preservation and Fermentation:

iii) Guar gum and Gellan gum

Ans) Comparison between Guar gum and Gellan gum:

iv) Autoxidation and lipolysis

Ans) Comparison between Autoxidation and lipolysis:

v) Spray drying and Roller drying

Ans) Comparison between Spray drying and Roller drying:

Q3) Match the following:


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