‭Unit 1‬

‭Processing of milk products:‬

‭1) Cream‬
‭### **1. Definition and Composition of Cream**‬
‭- **‬‭Definition‬‭**: Cream is the portion of milk rich in fat, typically‬
‭separated mechanically or by gravity.‬
‭- **‬‭Composition‬‭**: Cream contains milk fat (10%–70%), water,‬
‭proteins, carbohydrates, and minerals, with fat as the principal‬
‭component.‬
‭### **2. Methods of Cream Separation**‬
‭Cream is separated from milk using the following methods:‬
‭#### **a) Gravity Separation**:‬
‭- Milk is allowed to stand, and cream rises to the surface due to the‬
‭lower density of fat.‬
‭- **‬‭Limitations‬‭**: Slow process, not suitable for large-scale‬
‭production.‬

‭#### **b) Mechanical Separation (Centrifugal Cream‬

‭Separator)**:‬
‭- Milk is fed into a cream separator where centrifugal force‬
‭separates cream from skim milk.‬
‭- The separator has a bowl with disks that help divide the milk into‬
‭cream and skim milk streams.‬
‭- **Advantages**: Quick, efficient, and widely used in the dairy‬
‭industry.‬
‭### **3. Standardization of Cream**‬
‭- Cream is standardized to achieve a desired fat content (e.g.,‬
‭25%–30% for table cream, 35%–40% for whipping cream).‬
‭- **Fat Adjustment**: Skim milk is added or removed to standardize‬
‭fat content.‬

‭### **4. Pasteurization of Cream**‬

‭- Cream is pasteurized to destroy pathogens and increase shelf life.‬
‭- **Temperature and Time**: Pasteurization is carried out at higher‬
‭temperatures than milk due to the higher fat content, which‬
‭insulates bacteria. Typical conditions are:‬
‭- **High-temperature short-time (HTST)**: 85°C for 15 seconds.‬
‭- **Batch pasteurization**: 63°C–65°C for 30 minutes.‬
‭### **5. Homogenization (Optional)**‬
‭- Cream may be homogenized to improve texture and prevent fat‬
‭separation during storage.‬
‭- Homogenization breaks down fat globules into smaller sizes,‬
‭resulting in a stable emulsion.‬
‭### **6. Cooling and Storage**‬
‭- After pasteurization, cream is rapidly cooled to 5°C or below to‬
‭prevent microbial growth and maintain quality.‬
‭- Stored in sanitized tanks or containers under refrigeration.‬
‭### **7. Packaging**‬
‭- Cream is packaged in suitable containers such as bottles, pouches,‬
‭or cartons under hygienic conditions.‬
‭- **Considerations**: Packaging should prevent contamination and‬
‭oxidation of fat.‬
‭### **8. Types of Cream Products**‬
‭- **Table Cream**: Used in beverages and as a topping.‬
‭- **Whipping Cream**: Contains a higher fat percentage for‬
‭stability during whipping.‬
‭- **Heavy Cream**: Contains 36%–40% fat, used in rich desserts‬
‭and sauces.‬
‭- **Sour Cream**: Fermented cream with a tangy flavor‬
‭### **9. Quality Control**‬
‭- Regular testing for fat content, microbial quality, and sensory‬
‭attributes is essential.‬
‭- **Parameters**: Fat percentage, acidity, taste, and consistency.‬
‭### **Applications of Cream**‬
‭- Used in culinary products (e.g., soups, sauces, desserts).‬
‭- As a base for butter and other dairy items.‬

‭2) Butter‬
‭Butter is a high-fat dairy product widely used for culinary and‬
‭commercial purposes.‬
‭### **Processing of Butter**‬
‭The butter-making process can be divided into the following stages:‬
‭### **1. Collection and Separation of Cream**‬
‭- **Milk Collection**: High-quality, fresh milk is collected.‬
‭- **Cream Separation**: Cream is separated from milk using‬
‭centrifugal cream separators. The cream's fat content is‬
‭standardized to about 30–40%.‬
‭### **2. Pasteurization of Cream**‬
‭- The separated cream is pasteurized at **85–90°C for 15–30‬
‭seconds** to destroy harmful microorganisms and deactivate‬
‭enzymes.‬
‭- Pasteurization also improves the keeping quality and flavor of the‬
‭butter.‬
‭### **3. Cooling and Ripening**‬
‭- **Cooling**: After pasteurization, the cream is cooled to‬
‭**4–7°C** to encourage crystallization of fat.‬
‭- **Ripening**: Lactic acid bacteria may be added to the cream for‬
‭controlled fermentation. This step enhances the flavor and aroma of‬
‭the butter.‬
‭### **4. Churning**‬
‭- The ripened cream is churned in a **butter churn** to separate‬
‭fat from the buttermilk.‬
‭- During churning:‬
‭- Fat globules coalesce into larger masses.‬
‭- The buttermilk is drained off, leaving a butter mass.‬
‭### **5. Washing**‬
‭- The butter is washed with chilled water to remove residual‬
‭buttermilk and impurities, which improves its shelf life.‬
‭### **6. Working of Butter**‬
‭- The butter is kneaded or worked to improve its texture, distribute‬
‭moisture evenly, and expel excess water.‬
‭- Salt may be added during this stage for flavor and preservation.‬
‭- Unsalted butter is also produced based on market demand.‬
‭### **7. Molding and Packaging**‬
‭- The butter is molded into desired shapes or blocks.‬
‭- It is packaged in parchment paper, plastic wraps, or other‬
‭materials to prevent oxidation and maintain freshness.‬
‭### **8. Storage and Distribution**‬
‭- Butter is stored at **refrigerated temperatures (below 10°C)** to‬
‭prevent spoilage.‬
‭- Proper storage conditions are critical to maintaining its quality,‬
‭especially for unsalted or lightly salted butter.‬
‭### **Chemical Composition of Butter**‬
‭Butter typically contains:‬
‭- **Fat**: 80–85%.‬
‭- **Water**: 12–16%.‬
‭- **Proteins and Salts**: 1–2%.‬
‭- **Lactose**: Minimal amount.‬
‭### **Types of Butter**‬
‭- **Salted Butter**: Contains added salt.‬
‭- **Unsalted Butter**: Pure butterfat without salt.‬
‭- **Cultured Butter**: Made from fermented cream, offering a‬
‭tangy flavor.‬
‭- **Clarified Butter (Ghee)**: Butter with water and milk solids‬
‭removed.‬
‭### **Quality Control**‬
‭Key factors in butter production include:‬
‭- Proper pasteurization of cream.‬
‭- Hygienic conditions during processing.‬
‭- Accurate fat content standardization.‬
‭- Prevention of rancidity and spoilage.‬

‭3) Ice cream‬

‭**Processing Steps**:‬
‭- **‬‭Milk‬‭Selection‬‭**: High-quality milk or cream is used, often‬
‭blended with other ingredients like sugar, stabilizers, and flavorings.‬
‭- **‬‭Pasteurization‬‭**: The mixture is pasteurized at 82°C for 20-30‬
‭minutes to destroy pathogenic microorganisms.‬
‭- **‬‭Homogenization‬‭**: This step reduces the size of fat globules‬
‭and ensures smooth texture.‬
‭- **‬‭Cooling‬‭**: After pasteurization and homogenization, the mixture‬
‭is rapidly cooled to 4°C.‬
‭- **‬‭Aging‬‭**: The cooled mixture is left to age for 4-6 hours,‬
‭improving texture and flavor.‬
‭- **‬‭Freezing‬‭**: The mixture is churned in a freezing machine,‬
‭incorporating air (overrun), which gives ice cream its light, airy‬
‭texture.‬
‭- **‬‭Storage‬‭**: Finally, the ice cream is hardened at -18°C to‬
‭maintain its consistency and flavor.‬
‭4. Evaporated Milk‬
‭**Processing Steps**:‬
‭- **‬‭Milk‬‭Pre‬‭-‬‭treatment‬‭**: Fresh milk is filtered and pasteurized to‬
‭remove bacteria and enzymes.‬
‭- **‬‭Concentration‬‭**: The milk is heated under reduced pressure in‬
‭an evaporator to remove about 60% of the water content,‬
‭concentrating the milk.‬
‭- **‬‭Homogenization‬‭**: This step is carried out to ensure uniformity‬
‭in fat distribution and prevent cream separation.‬
‭- **‬‭Sterilization‬‭**: The concentrated milk is sterilized at 115-120°C‬
‭for about 15-20 minutes to kill any remaining microorganisms.‬
‭- **‬‭Cooling‬‭and Packaging‬‭**: After sterilization, the evaporated milk‬
‭is cooled and packaged in cans or tetra packs for long shelf life.‬

‭5. Condensed Milk‬

‭**Processing Steps**:‬
‭- **‬‭Milk‬‭Pre‬‭-‬‭treatment‬‭**: Like evaporated milk, fresh milk is‬
‭pasteurized and filtered.‬
‭- **‬‭Sugar‬‭Addition‬‭**: Sugar (usually 40-45%) is added to the milk,‬
‭which not only sweetens but also acts as a preservative.‬
‭- **‬‭Concentration‬‭**: The milk-sugar mixture is evaporated to‬
‭remove 60% of the water content.‬
‭- **‬‭Homogenization‬‭**: This ensures the milk and sugar are well‬
‭mixed and the fat content is evenly distributed.‬
‭- **‬‭Sterilization‬‭**: The condensed milk is then sterilized to prevent‬
‭microbial growth.‬
‭- **‬‭Cooling‬‭and‬‭Packaging‬‭**: After sterilization, the condensed milk‬
‭is cooled and packaged in sealed containers.‬
‭6. Dried Milk and Dehydrated Milk‬
‭**Processing Steps**:‬
‭- **‬‭Milk‬‭Pre‬‭-‬‭treatment‬‭**: Fresh milk is filtered, pasteurized, and‬
‭standardized to achieve the desired fat content.‬
‭- **‬‭Concentration‬‭**: The milk is concentrated by evaporation,‬
‭removing around 50% of its water content.‬
‭- **‬‭Spray‬‭Drying‬‭**: In the case of dried milk (such as skimmed milk‬
‭powder or whole milk powder), the concentrated milk is sprayed into‬
‭a hot air chamber. The water evaporates quickly, leaving behind fine‬
‭milk powder.‬
‭- **‬‭Roller‬‭Drying‬‭**: An alternative drying method where the‬
‭concentrated milk is spread onto heated rollers, and the resulting‬
‭dried film is scraped off.‬
‭- **‬‭Packaging‬‭**: The dried milk is packaged in moisture-proof‬
‭containers to prevent spoilage.‬

‭5. Fermented Milk Products (e.g., Yoghurt)‬

‭**Processing Steps**:‬
‭- **‬‭Milk‬‭Selection‬‭and‬‭Pasteurization‬‭**: High-quality milk is‬
‭selected, pasteurized at 85°C for 30 minutes, and cooled to‬
‭43-45°C.‬
‭- **‬‭Inoculation‬‭with‬‭Starter Culture‬‭**: Starter cultures containing‬
‭*Lactobacillus bulgaricus* and *Streptococcus thermophilus* are‬
‭added. These bacteria ferment lactose to lactic acid, which gives‬
‭yogurt its characteristic flavor and texture.‬
‭- **‬‭Fermentation‬‭**: The milk is incubated at 43-45°C for 4-6 hours,‬
‭during which the bacteria produce lactic acid, curdling the milk and‬
‭thickening it.‬
‭- **‬‭Cooling‬‭and‬‭Storage‬‭**: After fermentation, the yogurt is cooled‬
‭rapidly to 4°C to stop the fermentation process and then packaged.‬
‭- **‬‭Additional‬‭Flavors‬‭**: Sometimes, flavors, sweeteners, or fruits‬
‭are added after fermentation.‬

‭Processing of cheese cheddar, mozzarella, cottage and processed‬

‭cheese‬
‭1. Cheddar Cheese‬
‭Cheddar cheese is a popular hard cheese known for its firm texture‬
‭and sharp taste. The processing of cheddar involves several steps,‬
‭including curdling, cooking, pressing, and aging.‬

‭**Process of Cheddar Cheese**:‬

‭1. **Milk Preparation**:‬
‭- Fresh cow's milk is pasteurized to kill bacteria and enzymes that‬
‭may spoil the milk.‬
‭2. **Acidification and Coagulation**:‬
‭- **Starter cultures** (lactic acid bacteria) are added to milk to‬
‭lower the pH, followed by the addition of rennet to coagulate the‬
‭milk.‬
‭3. **Cutting the Curd**:‬
‭- The coagulated milk is cut into small curds to promote whey‬
‭expulsion.‬
‭4. **Cooking and Stirring**:‬
‭- The curds are heated and stirred to further expel whey and‬
‭improve the texture.‬
‭5. **Whey Draining**:‬
‭- The whey is drained off, and the curds are further cooked to‬
‭increase their acidity and firmness.‬
‭6. **Cheddaring**:‬
‭- The curds are stacked and turned to allow further whey drainage‬
‭and texture development.‬
‭7. **Salting**:‬
 ‭- Salt is added to the curd to enhance flavor, inhibit microbial‬
‭growth, and aid in moisture retention.‬
‭8. **Pressing**:‬
‭- The curds are pressed into molds to form a solid block.‬
‭9. **Aging (Maturation)**:‬
‭- The cheese is aged for a period (usually several months) to‬
‭develop flavor and texture. The aging process gives cheddar its‬
‭characteristic sharp taste.‬

‭2. Mozzarella Cheese**‬

‭Mozzarella is a soft, elastic cheese with a mild flavor, traditionally‬
‭made from water buffalo milk, though cow's milk is commonly used‬
‭today.‬
‭**Process of Mozzarella Cheese**:‬
‭1. **Milk Preparation**:‬
‭- Fresh milk is pasteurized, and a lactic acid starter culture is‬
‭added to acidify the milk.‬
‭2. **Coagulation**:‬
‭- Rennet is added to coagulate the milk, forming curds.‬
‭3. **Curd Cutting**:‬
‭- The curds are cut into small pieces, and the whey is drained off.‬
‭4. **Cooking and Stretching**:‬
‭- The curds are heated in hot water or whey (around 80-90°C)‬
‭until they soften and become elastic.‬
‭- The curds are kneaded and stretched (called **pasta filata**) to‬
‭develop the characteristic smooth texture of mozzarella.‬
‭5. **Shaping**:‬
‭- The cheese is shaped into balls or other forms and then cooled in‬
‭cold water or brine.‬
‭6. **Storage**:‬
 ‭- Mozzarella is typically stored in brine or whey, which helps‬
‭preserve its moisture content and fresh texture.‬

‭3. Cottage Cheese**‬

‭Cottage cheese is a soft, creamy cheese made from curds with a‬
‭mild flavor. It is less processed and has a higher moisture content‬
‭compared to other cheeses.‬
‭**Process of Cottage Cheese**:‬
‭1. **Milk Preparation**:‬
‭- Milk is pasteurized to ensure safety and remove spoilage-causing‬
‭bacteria.‬
‭2. **Acidification**:‬
‭- A starter culture is added to sour the milk slightly, lowering the‬
‭pH and aiding coagulation.‬
‭3. **Coagulation**:‬
‭- Rennet is added to form curds. The curd is cut into small pieces‬
‭to facilitate whey expulsion.‬
‭4. **Whey Drainage**:‬
‭- The curds are separated from the whey and lightly cooked, if‬
‭necessary, to further expel the whey.‬
‭5. **Washing**:‬
‭- The curds are washed with cool water to reduce acidity and‬
‭improve texture.‬
‭6. **Salting**:‬
‭- Salt is added to the curds for flavor and preservation.‬
‭7. **Packaging**:‬
‭- The curds are packed in containers, often with some whey, to‬
‭maintain moisture content.‬
‭### **4. Processed Cheese**‬
‭Processed cheese is made by blending natural cheese with‬
‭emulsifiers, heat, and other ingredients to create a smooth,‬
‭homogeneous product.‬
‭**Process of Processed Cheese**:‬
‭1. **Blending**:‬
‭- Natural cheese (often cheddar, mozzarella, or other varieties) is‬
‭finely ground and blended with emulsifiers (such as sodium citrate or‬
‭phosphate salts), milk, and sometimes other ingredients like butter‬
‭or cream.‬
‭2. **Heating**:‬
‭- The mixture is heated to a high temperature to melt the cheese‬
‭and emulsifiers, creating a smooth, consistent texture.‬
‭3. **Forming**:‬
‭- The processed cheese is then formed into blocks, slices, or‬
‭spreadable forms.‬
‭4. **Cooling and Packaging**:‬
‭- The cheese is cooled and packaged for storage and sale. It has a‬
‭longer shelf life than natural cheese due to its processing and‬
‭additional ingredients.‬
‭**processing of dairy by-products**‬
‭is an important aspect of dairy production. Dairy by-products are‬
‭the secondary products generated during the manufacture of‬
‭milk-based products like butter, cheese, yogurt, and cream. These‬
‭by-products can be valuable and often provide economic benefits by‬
‭being further processed into usable items.‬
‭### **1. Types of Dairy By-Products**‬
‭Dairy by-products can be classified into two broad categories:‬
‭- **Liquid by-products** (such as whey and buttermilk).‬
‭- **Solid by-products** (such as cream, curd, and lactose).‬
‭### **2. Whey**‬
‭- **Production**: Whey is a liquid by-product obtained from the‬
‭curdling of milk during cheese production. It remains after the milk‬
‭has been coagulated and separated into curds and whey.‬

‭- **Composition**: Whey contains proteins (like **whey protein**),‬

‭lactose, vitamins, minerals, and trace elements. However, it is low in‬
‭fat content.‬

‭- **Processing**: Whey is processed into several products:‬

‭- **Whey powder**: The liquid is concentrated and dried to form a‬
‭powder that can be used in infant foods, bakery products, and as a‬
‭protein supplement.‬
‭- **Whey protein concentrate**: This is obtained by removing most‬
‭of the lactose and minerals, leaving behind a concentrated form of‬
‭whey protein.‬
‭- **Lactose**: The lactose in whey is often extracted and‬
‭crystallized for use in pharmaceuticals, dairy products, and as a food‬
‭additive.‬

‭### **3. Buttermilk**‬

‭- **Production**: Buttermilk is a liquid by-product that forms when‬
‭cream is churned to make butter. It is the residual liquid left after‬
‭butter has been separated from the milk or cream.‬

‭- **Composition**: Buttermilk is low in fat but rich in proteins,‬

‭particularly casein, along with minerals like calcium.‬

‭- **Processing**: Buttermilk can be processed into:‬

 ‭- **Fermented buttermilk**: It is cultured with lactic acid‬
‭bacteria for enhanced taste and preservation, making it a popular‬
‭drink in many cultures.‬
‭- **Dried buttermilk powder**: By evaporating the moisture,‬
‭buttermilk can be converted into a powder used in food applications,‬
‭such as in baking, sauces, and soups.‬

‭### **4. Cream**‬

‭- **Production**: Cream is the fatty portion of milk that is‬
‭separated either by gravity or through centrifugation. It is primarily‬
‭used to produce butter.‬

‭- **Processing**: The cream can be further processed into:‬

‭- **Butter**: Cream is churned to separate butterfat from the‬
‭water phase. Butter can be processed into varieties like salted,‬
‭unsalted, or clarified butter (ghee).‬
‭- **Ice Cream**: Cream is a primary ingredient in ice cream and‬
‭can be mixed with milk, sugar, and other flavoring agents.‬
‭- **Butter Oil**: Clarified butter or milk fat is used in high-value‬
‭dairy products, particularly in the pharmaceutical and cosmetic‬
‭industries.‬
‭### **5. Casein and Caseinate Products**‬
‭- **Production**: Casein is the principal protein in milk and can be‬
‭separated from whey during cheese production. It can also be‬
‭extracted from skim milk.‬

‭- **Processing**: Casein can be further processed into:‬

‭- **Caseinates**: By neutralizing casein with an alkali, caseinates‬
‭are produced, which are used in the food industry as emulsifiers,‬
‭stabilizers, and thickeners.‬
 ‭- **Casein-based plastics**: Casein is sometimes used in industrial‬
‭applications, such as the manufacture of adhesives and plastics.‬

‭### **6. Lactose**‬

‭- **Production**: Lactose is a natural sugar found in milk and is‬
‭present in whey after cheese production.‬

‭- **Processing**: Lactose can be processed into:‬

‭- **Lactose crystals**: The extraction of lactose from whey‬
‭results in a white, crystalline form that is used as a food ingredient‬
‭and in pharmaceutical formulations.‬
‭- **Lactose-free products**: Lactose is removed from milk‬
‭products for people with lactose intolerance, leading to products like‬
‭lactose-free milk and dairy-based products.‬

‭**Introduction to functional milk products**‬

‭### **Overview of Functional Milk Products**‬

‭1. **Definition**:‬
‭Functional milk products are dairy products that have been‬
‭modified or enhanced to provide health benefits over and above the‬
‭basic nutritional value. These benefits can be due to the presence of‬
‭bioactive compounds such as probiotics, prebiotics, functional lipids,‬
‭or other bioactive ingredients like antioxidants, vitamins, or‬
‭minerals.‬
‭2. **Types of Functional Milk Products**:‬
‭The following are some common types of functional milk products,‬
‭as discussed in *Dairy Technology*:‬
‭- **Probiotic Milk Products**:‬
‭These include fermented milk products such as **yogurt, kefir,‬
‭and cultured buttermilk**, which contain beneficial microorganisms‬
‭(probiotics) like *Lactobacillus* and *Bifidobacterium*. These‬
‭probiotics support gut health, aid in digestion, and enhance immunity.‬

‭- **Prebiotic-enriched Products**:‬
‭Prebiotics are non-digestible food components that stimulate the‬
‭growth and activity of beneficial bacteria in the gut. Milk can be‬
‭fortified with prebiotics like **oligosaccharides** (e.g.,‬
‭fructooligosaccharides or galactooligosaccharides) to improve gut‬
‭health.‬

‭- **Fortified Milk**:‬
‭Functional milk can be fortified with additional vitamins, minerals,‬
‭or nutrients. Common examples include **vitamin D-fortified milk**‬
‭and **calcium-enriched milk**, aimed at improving bone health and‬
‭preventing deficiencies.‬

‭- **Functional Butter and Cheese**:‬

‭These dairy products may be enriched with specific fatty acids,‬
‭such as **omega-3 fatty acids**, or other bioactive compounds like‬
‭conjugated linoleic acid (CLA), which are associated with health‬
‭benefits, including improved cardiovascular health and weight‬
‭management.‬

‭- **Milk with Antioxidants**:‬

‭Functional milk products can be enriched with antioxidants, such‬
‭as **vitamin E, selenium, or polyphenols**, which can help combat‬
‭oxidative stress and reduce the risk of chronic diseases like cancer‬
‭and heart disease.‬
‭3. **Health Benefits of Functional Milk Products**:‬
‭Functional milk products are beneficial for various health‬
‭conditions, including:‬
 ‭- **Digestive Health**: Probiotics improve the gut flora, which‬
‭aids in digestion, absorption of nutrients, and the prevention of‬
‭gastrointestinal disorders like irritable bowel syndrome (IBS).‬
‭- **Immunity Boost**: Probiotic and prebiotic products enhance‬
‭immune function, helping the body fight off infections and diseases.‬
‭- **Bone Health**: Fortified milk products, especially those‬
‭enriched with **calcium** and **vitamin D**, support bone density‬
‭and reduce the risk of osteoporosis.‬

‭4. **Market Trends and Consumer Demand**:‬

‭- There is increasing consumer demand for dairy products that‬
‭contribute to **well-being** and **preventive health**, not just‬
‭nutrition. This shift has led to significant innovation in the dairy‬
‭industry, as manufacturers develop new functional milk products.‬
‭- The popularity of functional milk products is particularly high in‬
‭markets like **Europe**, **North America**, and parts of **Asia**.‬

‭5. **Production and Technology**:‬

‭The development of functional milk products involves **advanced‬
‭dairy processing techniques** that ensure the preservation of‬
‭bioactive compounds and maintain the desired health benefits. This‬
‭may include fermentation, fortification, and the incorporation of‬
‭functional ingredients in milk.‬

‭Effects of processing on the physicochemical and nutritional‬

‭quality of milk.‬

‭1. **Heat Treatment (Pasteurization & Sterilization)**:‬

‭- **Pasteurization**: This process involves heating milk to a‬
‭specific temperature (typically between 63°C and 72°C for 15‬
‭seconds) and then rapidly cooling it. The main goal is to kill harmful‬
‭microorganisms without significantly altering the milk's quality.‬
‭However, **heat treatment** can cause some changes:‬
‭- **Protein Denaturation**: Heat can cause proteins like casein‬
‭and whey to denature, but this generally does not reduce the‬
‭nutritional value significantly.‬
‭- **Changes in Enzyme Activity**: Pasteurization inactivates‬
‭enzymes, such as lipase, which prevents rancidity in milk.‬
‭- **Fat Separation**: Some fat globules may break up or‬
‭coalesce, leading to slight changes in the texture or consistency of‬
‭milk.‬

‭- **Sterilization**: Milk is heated to a much higher temperature‬

‭(usually 115°C to 130°C for 20-30 minutes) to achieve longer‬
‭shelf-life. While sterilization destroys more microorganisms than‬
‭pasteurization, it can cause:‬
‭- **Color Changes**: Milk may develop a yellowish or brownish‬
‭tint due to Maillard reactions between sugars and amino acids.‬
‭- **Loss of Vitamins**: Heat-sensitive vitamins like Vitamin C and‬
‭some B vitamins are reduced.‬
‭- **Fat Oxidation**: The higher heat can also result in some‬
‭oxidation of fats, which can affect flavor.‬

‭2. **Homogenization**:‬
‭- **Fat Emulsification**: Homogenization is a mechanical process‬
‭where milk is forced through a fine nozzle under high pressure,‬
‭breaking down fat globules into smaller particles. This increases‬
‭milk's stability and prevents the cream from separating.‬
‭- **Texture & Mouthfeel**: Homogenization results in a smoother‬
‭texture and better mouthfeel, as the milk becomes more uniformly‬
‭dispersed.‬
 ‭- **Digestibility**: Smaller fat globules in homogenized milk may‬
‭be more easily digestible.‬

‭3. **Fermentation**:‬
‭- Fermentation, such as in the production of yogurt and kefir,‬
‭introduces beneficial bacteria that can enhance the **probiotic‬
‭content** of milk products.‬
‭- **Acidity**: Fermentation increases the acidity of milk products,‬
‭affecting the taste and texture (e.g., thicker consistency in yogurt).‬
‭- **Nutritional Content**: Fermented dairy products may have‬
‭improved bioavailability of nutrients, such as calcium and magnesium.‬

‭### **Effect of Processing on Nutritional Quality**‬

‭1. **Proteins**:‬
‭- Heat treatments like pasteurization and sterilization can cause‬
‭some denaturation of milk proteins, particularly the **whey‬
‭proteins** (such as lactalbumin and lactoglobulin). However, these‬
‭changes are generally reversible and do not significantly affect the‬
‭nutritional value, though it might reduce the digestibility or‬
‭bioavailability of certain amino acids.‬
‭- **Fermentation** can increase the digestibility of milk proteins‬
‭by breaking down lactose and casein into more easily absorbable‬
‭forms.‬

‭2. **Vitamins and Minerals**:‬

‭- **Vitamins**: Certain **heat-sensitive vitamins** (especially‬
‭Vitamin C and some B vitamins) are reduced during processing,‬
‭particularly during **sterilization**. However, other vitamins like‬
‭**Vitamin A** and **D** are more stable. **Fortification** of milk‬
‭after processing is often used to restore or enhance vitamin levels.‬
 ‭- **Minerals**: The mineral content of milk, particularly calcium‬
‭and phosphorus, remains relatively stable through heat treatment.‬
‭However, **processing methods like ultra-filtration** or‬
‭**dehydration** might concentrate or slightly reduce some minerals‬
‭depending on the process.‬

‭3. **Fat**:‬
‭- Homogenization increases the surface area of fat molecules,‬
‭leading to a more uniform distribution of fat in milk, but the‬
‭**fat-soluble vitamins** (A, D, E, K) remain largely unaffected by‬
‭homogenization.‬
‭- **Fat loss** can occur during **skimming** (removal of cream),‬
‭but this reduces the total fat content and can be used to produce‬
‭low-fat milk products.‬

‭4. **Lactose**:‬
‭- The lactose content in milk is generally stable through most‬
‭processing methods. However, in **fermented milk products**The‬
‭lactose is partially converted into lactic acid, making it easier to‬
‭digest for those who are lactose intolerant.‬
‭- **Ultra-high temperature (UHT)** processing can also affect‬
‭lactose breakdown slightly, but this is not significant enough to make‬
‭milk suitable for people with lactose intolerance unless specifically‬
‭treated.‬

‭5. **Taste and Flavor**:‬

‭- Processing methods like pasteurization, homogenization, and‬
‭sterilization can **alter the flavor** of milk. For example,‬
‭**pasteurized milk** has a cooked flavor, while **sterilized milk**‬
‭may develop a more pronounced, sometimes unpleasant taste due to‬
‭the higher temperatures used.‬
 ‭- **Fermentation** and aging processes can significantly change‬
‭the taste and flavor profile of dairy products (e.g., cheese, yogurt).‬

‭Common defects of milk products and their remedial measures‬

‭### **Common Defects of Milk Products and Their Remedial‬

‭Measures**‬

‭### 1. **Off-flavors in Milk and Dairy Products**‬

‭- **Cause**:‬
‭- **Bacterial contamination** (e.g., *Pseudomonas*, *Lactobacillus*‬
‭species) that produce volatile compounds.‬
‭- **Feed contamination** (e.g., rancid feed or certain plants like‬
‭clover can cause "cow odor").‬
‭- **Improper storage** (exposure to light, high temperatures).‬
‭- **Oxidation** of fats, leading to **rancidity**.‬

‭- **Remedial Measures**:‬
‭- Use **clean equipment** and **sanitation practices** to avoid‬
‭bacterial contamination.‬
‭- Ensure proper **storage conditions** (low temperature, dark‬
‭environment).‬
‭- Improve **feed quality** and avoid certain plants that affect‬
‭milk flavor.‬
‭- **Add antioxidants** to milk products to prevent fat oxidation.‬

‭### 2. **Acidification or Sourness**‬

‭- **Cause**:‬
‭- **Bacterial activity** (e.g., *Lactic acid bacteria* like‬
‭*Streptococcus* and *Lactobacillus*) that ferment lactose into‬
‭lactic acid.‬
 ‭- **Delay in cooling** or improper handling of milk.‬
‭- **Improper pasteurization** or storage at too high a‬
‭temperature.‬

‭- **Remedial Measures**:‬
‭- **Pasteurize milk** to destroy harmful bacteria.‬
‭- Maintain **proper refrigeration** and avoid delay in cooling.‬
‭- Store milk at **appropriate temperatures** (below 4°C).‬
‭- Use **preservatives** like potassium sorbate in some products to‬
‭extend shelf life.‬

‭### 3. **Clotting or Coagulation**‬

‭- **Cause**:‬
‭- **Excessive acidity** or overripe milk.‬
‭- Contamination with **foreign enzymes** (e.g., rennet or bacterial‬
‭proteases).‬
‭- **Improper pasteurization** or **storage**.‬

‭- **Remedial Measures**:‬
‭- Ensure **proper pasteurization** to deactivate any unwanted‬
‭enzymes.‬
‭- **Monitor milk pH** closely and ensure it’s within the required‬
‭range (around 6.6–6.8).‬
‭- Regular **quality control** of milk before processing.‬

‭### 4. **Fat Separation or Creaming**‬

‭- **Cause**:‬
‭- **Improper homogenization**, leading to the separation of milk‬
‭fat.‬
‭- **Temperature fluctuations** during storage, causing fat‬
‭globules to separate.‬
‭- **Remedial Measures**:‬
‭- Ensure **proper homogenization** during milk processing.‬
‭- **Store milk at a consistent, low temperature** (around 4°C).‬
‭- **Use stabilizers** or emulsifiers in certain products to prevent‬
‭fat separation.‬

‭Organic Milk and Products‬

‭### **Organic Milk and Products: Definition and Characteristics**‬

‭1. **Definition of Organic Milk**:‬

‭Organic milk is produced from dairy animals raised without the use‬
‭of synthetic hormones, antibiotics, or genetically modified feed. The‬
‭farming practices ensure the use of organic fertilizers,‬
‭chemical-free grazing pastures, and humane treatment of animals.‬

‭2. **Certification**:‬
‭Organic milk and its products must comply with regulations set by‬
‭certifying bodies (e.g., USDA Organic, EU Organic Certification).‬
‭These certifications ensure adherence to organic farming and‬
‭processing standards.‬

‭3. **Characteristics**:‬
‭- Free from synthetic additives and chemicals.‬
‭- Richer in omega-3 fatty acids due to pasture-based feeding.‬
‭- Free from antibiotic residues or pesticide contamination.‬

‭### **Processing of Organic Milk Products**‬

‭1. **Milk Handling and Processing**:‬
 ‭Organic milk undergoes minimal processing to retain its natural‬
‭quality. Pasteurization and homogenization are common, but‬
‭practices such as **ultra-pasteurization** may be used to extend‬
‭shelf life without preservatives.‬

‭2. **Product Range**:‬

‭Organic dairy products include:‬
‭- **Fluid Milk**: Pasteurized whole, skim, and flavored milk‬
‭varieties.‬
‭- **Yogurt**: Organic milk is fermented using live bacterial‬
‭cultures without synthetic thickeners.‬
‭- **Cheese**: Made using organic rennet and cultures, often aged‬
‭for natural flavor development.‬
‭- **Butter and Ghee**: Processed from cream collected under‬
‭organic standards.‬
‭- **Ice Cream**: Contains organic milk, cream, and natural flavors.‬
‭- **Milk Powders**: Spray-dried without artificial additives.‬

‭### **Nutritional and Health Benefits**‬

‭1. **Higher Nutritional Value**:‬

‭Organic milk often has a higher content of beneficial nutrients like‬
‭omega-3 fatty acids, antioxidants, and vitamins (e.g., Vitamin E,‬
‭beta-carotene).‬
‭2. **Healthier for Consumers**:‬
‭It is free from harmful residues, appealing to those concerned‬
‭about long-term health risks associated with conventional milk‬
‭additives.‬
‭3. **Environmental and Ethical Considerations**:‬
‭Organic dairy farming promotes biodiversity, soil health, and‬
‭humane treatment of animals, contributing to sustainable practices.‬
‭Manufacturing of indigenous milk products viz. paneer, channa,‬
‭khoa, ghee, dahi, rasgulla, gulabjamun and shrikhand‬

‭Indigenous milk products are traditional dairy-based foods that have‬

‭been developed and consumed in specific cultural or regional‬
‭contexts over centuries.‬

‭### **1. Paneer**‬

‭**Paneer** is a fresh, acid-coagulated, non-fermented milk product.‬
‭- **Process**:‬
‭1. Milk is heated to **85°C** for 5–10 minutes.‬
‭2. It is cooled to **70°C** and coagulated using food-grade acids‬
‭like **citric acid** or **lactic acid**.‬
‭3. The curd is separated from the whey, pressed under weight, and‬
‭cooled.‬
‭- **Uses**: Popular in culinary applications like curries and snacks.‬

‭### **2. Channa**‬

‭**Channa** is similar to paneer but has a softer texture and is not‬
‭pressed.‬
‭- **Process**:‬
‭1. Milk is boiled and coagulated using **citric acid**, **lemon‬
‭juice**, or **vinegar**.‬
‭2. The curd is gently separated and drained of whey without‬
‭pressing.‬
‭- **Uses**: Used as a base for making sweets like **rasgulla** and‬
‭**sandesh**.‬

‭### **3. Khoa**‬

‭**Khoa** is a concentrated milk product made by heat desiccation.‬
‭- **Process**:‬
 ‭1. Milk is boiled in a wide, shallow pan over medium heat with‬
‭continuous stirring.‬
‭2. Heating continues until most of the water evaporates, and the‬
‭product reaches a semi-solid consistency.‬
‭3. Different types of khoa (e.g., **pindi**, **danedar**, or‬
‭**dhap**) are made by controlling the final moisture content.‬
‭- **Uses**: Used as a base for sweets like **gulabjamun**,‬
‭**burfi**, and **pedha**.‬

‭### **4. Ghee**‬

‭**Ghee** is clarified butter with a rich, nutty flavor.‬
‭- **Process**:‬
‭1. Cream or butter is heated to remove moisture.‬
‭2. The fat is separated from milk solids, which caramelize during‬
‭the process, giving ghee its characteristic flavor.‬
‭3. The clarified fat is filtered and stored.‬
‭- **Uses**: Widely used in cooking, frying, and as a flavor enhancer.‬

‭### **5. Dahi (Curd)**‬

‭**Dahi** is a fermented milk product prepared by bacterial‬
‭fermentation.‬
‭- **Process**:‬
‭1. Milk is heated to **90°C** to kill pathogens and denature‬
‭proteins.‬
‭2. It is cooled to **42°C** and inoculated with a starter culture‬
‭(e.g., **Lactococcus lactis**, **Lactobacillus bulgaricus**).‬
‭3. The inoculated milk is incubated until coagulation occurs.‬
‭- **Uses**: Consumed as is or used in preparations like **raita** and‬
‭**lassi**.‬
‭### **6. Rasgulla**‬
‭**Rasgulla** is a spongy, syrupy sweet made from channa.‬
‭- **Process**:‬
‭1. Fresh **channa** is kneaded into a smooth dough and shaped‬
‭into small balls.‬
‭2. These balls are boiled in a sugar syrup under pressure for 10–15‬
‭minutes.‬
‭3. They are soaked in syrup to absorb sweetness.‬
‭- **Uses**: Served as a dessert.‬

‭### **7. Gulabjamun**‬

‭**Gulabjamun** is a deep-fried sweet made from khoa.‬
‭- **Process**:‬
‭1. **Khoa** is kneaded into a dough with a small amount of flour.‬
‭2. The dough is shaped into balls and deep-fried in ghee or oil at‬
‭low heat until golden brown.‬
‭3. The fried balls are soaked in warm sugar syrup flavored with‬
‭cardamom or rose water.‬
‭- **Uses**: Popular desserts served warm or cold.‬

‭### **8. Shrikhand**‬

‭**Shrikhand** is a creamy, sweetened yogurt-based dessert.‬
‭- **Process**:‬
‭1. Dahi is hung in a muslin cloth to remove whey, forming‬
‭**chakka** (strained curd).‬
‭2. The chakka is blended with sugar and flavorings like cardamom,‬
‭saffron, or nuts.‬
‭3. The mixture is chilled and served.‬
‭- **Uses**: Served as a dessert or accompaniment to meals.‬