Value addition in milk (all milk products & by products etc.)


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Dr. Waqas Nawaz
PMAS Arid Agriculture University Rawalpindi Pakistan

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Value addition in milk (all milk products & by products etc.)

  1. 1. SUBMITTED TO: Dr. Muhammad Fiaz SUBMITTED BY: 11-arid-961 Muhammad Zohaib Hameed 11-arid-962 Muzammal Tariq 11-arid-969 Shafqat Shabeer 11-arid-975 Waqas Nawaz 11-arid-985 Ayesha Azad
  2. 2. OUTLINE Unit 1: Unit 2: Unit 3: Unit 4: Introduction 1.1 Milk 1.2 Milk Products 1.3 Milk by-Products 1.4 Ranking wise milk production 1.5 Composition of milk (Different species) Value Addition to Milk 2.1 Value addition to milk 2.2 Why process the Milk? 2.3 Processing of milk 2.3.1 Raw milk storage 2.3.2 Cleaning & De-creaming 2.3.3 Homogenization 2.3.4 Pasteurization 2.3.5 Ultra Heat Treatment (UHT) 2.3.6 Sterilization 2.3.7 Vitamin fortification 2.3.8 Cooling 2.3.9 Storage, Filling & Packaging Milk Product 3.1 Milk 3.1.1 Whole milk 3.1.2 Cultured milk 3.1.3 Half & Half 3.1.4 Evaporated milk 3.1.5 Sweetened condensed milk 3.1.6 Non-fat dairy milk 3.2 Cream 3.2.1 Light cream 3.2.2 Light whipping cream 3.2.3 Heavy cream 3.2.4 Sour Cream 3.3 Cheese 3.3.1 Dry curd cottage cheese 3.3.2 Cottage cheese 3.4 Yogurt 3.4.1 Low fat yogurt 3.4.2 Non-fat yogurt 3.5 Butter 3.6 Ghee 3.7 Koa Milk by-Products 4.1 Whey 4.2 Skimmed Milk 4.3 Butter Milk 4.4 Ghee residue
  3. 3. Unit.1: Introduction 1.1 Milk: "The lacteal secretion, practically free from colostrums, obtained by the complete milking of one or more healthy cows, which contains not less than 3.25% of milk-fat and not less than 8.25% milk-solids-not-fat.” 1.2 Milk Products: “A dairy product is food produced from the milk of mammals. Dairy products are usually high energy-yielding food products. A production plant for the processing of milk is called a dairy or a dairy factory.” 1.3 Milk by-Products: “A dairy by-product may be defined as a product of commercial value produced during the manufacture of a main product. The newly acquired economic importance of a by-product will make it a main product in the future” 1.4 Ranking Wise Milk Production: 1. India 2. USA 3. Pakistan 4. China 5. Brazil 6. Germany 7. Russian Federation 8. France 9. New Zealand 10. UK *WORLD: 721.4 Million Ton ECM 137.5 Million Ton ECM 84.3 Million Ton ECM 41.6 Million Ton ECM (2nd buffalo milk producing) 33.9 Million Ton ECM 32.0 Million Ton ECM 31.1 Million Ton ECM 30.1 Million Ton ECM 25.2 Million Ton ECM 21.3 Million Ton ECM 14.1 Million Ton ECM **ECM (Energy Correct Milk) Ref: IFCN 2012 dairy report
  4. 4. 1.5 Composition of Milk: Unit.2: Value Addition in Milk 2.1 VALUE ADDITION TO MILK: Dairy farmers have the opportunity to add value to raw milk by producing a wide variety of processed products, to increase the return above the base price of raw milk. These include:  Heat-treated liquid drinking milk, such as pasteurizing, or ultra high treatment, then adding flavors or incorporating it into other drinks  Separating the milk fat from other milk solids to produce butter and ghee, and also skim milk  Fermenting milk to produce yoghurt, which is also called curds in some countries  Fermenting milk to produce cheese with its major by-product, whey  Using the by-products, skim milk and whey, to produce ice cream, cheese and whey based drinks  Adding ingredients to heated milk to produce a variety of sweets such as caramel.  Further processing, such as adding acids to coagulate the milk, produces different kinds of sweets  Using cheese in cooking to produce high-value products such as cheesecakes. Adding value to raw milk can be undertaken on an individual farm or a group of farms, using a larger, and often more reliable, supply of the raw product. Developing such as cottage industries has several requirements that need to be considered. These include:  A regular supply of quality milk that can be further economically processed  Infrastructure to support the processing at the farmer, village and regional levels  Organizational support for farmers and farming communities to develop the processing skills  Infrastructure for marketing the final products.
  5. 5. 2.2 Why Process the MILK?? There are many reasons to process milk into dairy products, such as the following:  Many dairy products can be kept longer than fresh milk therefore the milk does not have to be consumed immediately.  The demand for fresh milk may be limited, and there may be more interest in dairy products.  If the daily amount of fresh milk for sale is limited, it may be more economical to process the milk into less perishable products, store them, and sell them later in greater quantities.  There may be no market for fresh milk close by, and only preserved products can be sold at markets at a greater distance.  Greater financial gain may be obtained.
  6. 6. 2.3 Processing of Milk: Processing of milk involves following steps; 2.3.1 Raw Milk Storage: The whole milk should be stored at 4ºC or less in a refrigerator within two hour after milking. Storage time at plant is maximum 72 hours. Longer holding time allows growth of the psychrophilic bacteria which can secrete heat resistant proteases & lipases. One temperature treatment that is used to control bacterial numbers is Thermization. Milk is heated at 57-68 ºC for 15 seconds. This is only effective if milk is cooled at 4 ºC after treatment. This is applied to raw milk that is to be stored for several days prior to use. Its purpose is to reduce the gram-negative psychrotrophic spoilage organisms. (Enzyme production) 2.3.2 Cleaning & De-creaming (Separator/Filtration): Once the milk has been collected, cooled, and transported to the processing plant, it is first clarified and that means all particulate matter is removed. This takes advantage of the different densities of the particulates and the milk matrix; essentially a decanting process. It can be quiescent (settling out) or removal by centrifugation. Centrifugal force is used to remove bacteria and their spores. Clarification: Removal of small particles …straw, hair etc. from milk; 2 lb/2,642 is based on density Bactofugation: Centrifugal separation of microorganisms from milk: Bacteria and particularly spores have higher density than milk. Two-stage centrifugation can reduce spore loads up to >99%. Optimal temperature for clarification is 55-60ºC Microfiltration: Micro-filter membranes of 1.4 mm or less can lead to reduction of bacteria and spores up to 99.5-99.99% 2.3.3 Homogenization: Definition: “Treatment of milk or a milk product to insure breakup of fat globules such that no visible cream separation occurs after 48 h at 40ºF (4.4ºC)” Homogenization breaks up the oil droplets in milk and prevents the cream from separating out and forming a layer. This is of particular importance for sterilized milk which has a long shelf-life and when the formation of a cream layer is not desired. Additional changes include increased viscosity and a richer taste. Homogenizers are more usually designed for industrial-scale production. Homogenization is a mechanical process where milk is forced through a small passage at high velocity. Effects of homogenization:   No cream line formation due to smaller fat globules Whiter color & more full-bodied flavor, better mouth-feel
  7. 7. Process requirements:  Homogenization most efficient when fat phase is in a liquid state  Cream >12% fat cannot be homogenized at normal pressure, high pressure homogenization process is necessary 2.3.4 Pasteurization: Pasteurization is a relatively mild heat treatment, (usually performed below 100°C) which is used to extend the shelf-life of milk for several days. It preserves the milk by the inactivation of enzymes and destruction of heat-sensitive micro-organisms, but causes minimal changes to the nutritive value or sensory characteristics of a food. Some heat-resistant bacteria survive to spoil the milk after a few days, but these bacteria do not cause food poisoning. The time and temperature combination needed to destroy 'target' microorganisms will vary according to a number of complex inter-related factors. For milk, the heating time and temperature is either 63°C for 30 minutes or alternatively 72°C for 15 seconds. Only the former combination is possible on a small scale and for this the simplest equipment required is an open boiling pan. Better control is achieved using a steam jacketed pan, and this can be fitted with a stirrer to improve the efficiency of heating. Both of these are batch processes which are suited to small-scale operation. A higher production rate may be possible using a tubular-coil pasteurizer. This equipment has been tested and has been successful for some fruit products but it is presently still at a developmental stage. 2.3.5 Ultra Heat Treatment (UHT): Milk is heated to a higher temperature than pasteurized milk, stays fresher longer, have longer shelf life (up to 3 months) & no bacterial growth because milk is packaged in sterilized, air free packaging. 2.3.6 Sterilization: Sterilization is a more severe heat treatment designed to destroy all contaminating bacteria. The milk is sterilized at a temperature of 121°C maintained for 15-20 minutes. This can be achieved using a retort or pressure cooker. Unlike pasteurization, this process causes substantial changes to the nutritional and sensory quality of the milk. In some countries, flavored milk has become a very popular product. However, sterilization is not recommended for small-scale production for the following reasons:  The cost of a retort and ancillary equipment is high for the small-scale processor.  It is essential that the correct heating conditions are carefully established and maintained for every batch of milk that is processed. If the milk is overheated, the
  8. 8. quality is reduced, and it may have a rather burnt taste and aroma.  If the milk is not heated sufficiently, there is a risk that micro-organisms will survive and grow inside the bottle. In low-acid foods such as milk, many types of bacteria including Clostridium botulinum can grow and cause severe food poisoning.  Due to the potential dangers from food poisoning, the skills of a qualified food technologist/microbiologist are required in order to routinely examine samples of sterilized milk that have been subjected to accelerated storage conditions. This requires a supply of microbiological media and equipment. In summary, the process of sterilization requires a considerable capital investment, the need for trained and experienced staff, regular maintenance of sophisticated equipment, and a comparatively high operating expenditure. 2.3.7 Vitamin Fortification: 78% of milk sold in the PAKISTAN is fortified with Vitamins A and D. Some milk is also fortified with extra protein and extra calcium. 2.3.8 Cooling: Pasteurization does not destroy all of the microorganisms therefore the milk has to be cooled rapidly to prevent the growth of surviving bacteria. Cooling can be achieved on a small scale by using a bottle-cooling system. 2.3.9 Storage, Filling & Packaging: Pasteurized milk has a shelf-life of 2-3 days if kept at 4°C. Maintaining this low temperature causes a substantial increase to the cost of transportation and distribution and is therefore a major disadvantage to the development of a small-scale pasteurized milk business. If packaged in sealed bottles and stored at room temperature, sterilized milk should have a shelf-life in excess of six months.  Functions of packaging:  Enable efficient food distribution  Maintain product hygiene  Protect nutrients and flavor  Reduce food spoilage  Convey product information  Different containers:  Glass bottles (translucent vs. dark): can be reusable or recyclable  Plastic containers  Cartons  Plastic bags
  9. 9. Unit 3: Milk Products: 3.1 Milk: 3.1.1 Whole Milk: Contains not less than 3.25% milk fat (fat solids) and 8.25% non-fat solids. Addition of vitamins A and D is optional, but if added, vitamin A must be present at a level of not less than 2,000 International Units (I.U.) per quart. If added, vitamin D must be present at 400 I.U. per quart. 3.1.2 Cultured Milk: Contains not less than 3.25 percent milk fat (fat solids) and 8.25% non-fat solids. Culturing any of the following milk products alone or in combination produces it: cream, milk, partially 3.1.3 Half and Half: Consists of a mixture of milk and cream containing not less that 10.5% milk fat, but less than 18% milk fat. 3.1.4 Evaporated Milk: Evaporated milk is made by removing about 60% of milk’s water. It contains not less than 6.5% milk fat, not less than16.5% non-fat solid; and not less than 23% by weight of total milk solids. Evaporated milk is a heat-sterilized product with an extended shelf life with a yellowish color and cooked flavor. 3.1.5 Sweetened Condensed Milk: This product results from the removal of about 60% of the water from a mixture of milk (whole and nonfat pasteurized, homogenized milks) and carbohydrate sweeteners such as sucrose. This product contains not less than 8% milk fat and not less than 28% total milk solids. It is obtained by removal of water
  10. 10. only from pasteurized skim milk (unless otherwise indicated). 3.1.6 Non-fat Dry Milk: Nonfat dry milk is made by removing water from pasteurized skim (non-fat or fat free) milk. The product contains not more than 5% by weight of moisture, and not more than 1.5% by weight of milk fat (unless otherwise indicated). 3.2 Cream: After leaving milk to stand for about 24 hours at as low a temperature as possible (4-12°C), the cream can be skimmed off using a spoon or saucer. This method makes use of the fact that cream rises and then stays on top of the milk. It contains most of the milk fat. Only cow milk readily produces cream this way; other kinds of milk need a hand creamer (centrifugal milk separator) to separate cream and milk. 3.2.1 Light Cream: It contains not less than 18% milk fat, but less than 30%. Light creamy also be called “coffee cream” or “table cream.” 3.2.2 Light Whipping Cream: Contains not less than 30% milk fat, but less than 36% milk fat. It may also be called “whipping cream.” 3.2.3 Heavy Cream: Contains not less than 36% milk fat. Heavy creamy also be called “heavy whipping cream.” 3.2.4 Sour Cream: The product resulting from the addition of lactic acid-producing bacteria to pasteurized cream containing not less than 18% milk fat. Sour creamy also be call “cultured sour cream.”
  11. 11. 3.3 Cheese: 3.3.1 Dry Curd Cottage Cheese: A soft, un-ripened cheese made from skim milk and/or reconstituted nonfat dry milk. The cheese curd is formed by the addition of either lactic acid-producing bacteria (cultured) or acidifiers (directly adding lactic acid). The latter process is called direct acidification. Rennet and/or other suitable enzymes may be used to assist curd formation. Dry curd cottage cheese contains less than .5% milk fat and not more than 80% moisture. The product may also be called “cottage cheese dry curd.” 3.3.2 Cottage Cheese: The product resulting from the addition of a creaming mixture (dressing) to dry curd cottage cheese. Cottage cheese contains not less than 4% milk fat and not more than 80% moisture. 3.4 Yogurt: Yoghurt is produced when milk is soured by certain lactic acid bacteria, which prefer growing temperatures far above room temperature: 37 – 45°C. The milk should first be heated to 85°C or higher. A high pasteurization temperature (above 72°C) gives a better consistency (thickness) to the final product. After the milk has been soured, the resulting yoghurt can be used to make more fresh yoghurt by adding it to fresh milk. Yogurt: The product resulting from the culturing of a mixture of milk and cream products with lactic acid-producing bacteria, Lactobacillus bulgaricus and Streptococcus thermophilus. Yogurt contains not less than 3.25% milk fat and 8.25 percent non-fat solids. 3.4.1 Low fat Yogurt: Similar in composition to yogurt except that it contains not less than .5% milk fat and no more than 2% milk fat. 3.4.2 Non-fat Yogurt: Similar in composition to yogurt except that it contains less than .5% milk fat. 3.5 Butter: During churning the cream, sour cream or sour milk will be mixed intensively with air. This process causes fat globules to flocculate (or stick together), producing butter and buttermilk. The simplest way to make butter from small quantities of milk is by using a bottle or a jar that can be covered with a well-closing lid or a simple bowl with beaters. If large quantities of milk or cream are available, you should consider acquiring a real churn. There are several types available. The churn tub is a simple method, which is often used in the tropics. A cheap and practical domestic churn is a glass pot with a paddle attached to a screw top. The paddle can be turned manually. This churn is difficult to clean. It is best to rinse it with water before use, in order to prevent the butter from sticking to the sides. Churns should not be filled more than one third with soured milk or sour cream. Churn with a regular up and down or sideways movement. Stop churning when the butter particles reach the size of rice grains or peas and the buttermilk looks rather liquid. If, after 30 minutes, no grains have yet been formed, you can change the
  12. 12. temperature by adding a little clean cold or warm water. See also the remarks at the end of this chapter. The amount of added water should never be more than 25% of the total amount of churned cream or milk. The butter particles will float to the top of the buttermilk, because butter is lighter than buttermilk. This makes it easier to separate the two products by pouring off the buttermilk through a coarse sieve. Never add too much water, otherwise the buttermilk will become too watery. 3.6 Ghee: To make ghee, you will need: • butter • a heat source • a pan • a metal spoon. Heat the butter until water and fat form separate layers; the fat will float on top. There are two ways to remove the water:  It can be removed by further heating. The water present will evaporate.  It is possible to remove the layer of fat with a spoon. This fat should then be heated again. The scum, which will form, has to be skimmed off regularly, preferably with a skimmer. The color of ghee can vary from almost white to dark brown. A rancid flavor is acceptable, but if it tastes burnt it should be discarded.
  13. 13. 3.7 Koa (Khoa): Koa or khoa is a type of concentrated milk. You will need: • fresh (un-boiled) whole or skimmed milk • a heat source • a shallow, clean, wide, iron pan with a thick, flat bottom • a flat, clean metal utensil to stir with (e.g. a flat pancake spatula). Fill the pan with the milk up to 30 to 50% of its capacity. Bring the milk to boiling, stirring continuously. The water will evaporate and after some time the milk will reach a certain viscosity this means the milk will thicken. Take great care to scrape the sides of the pan during stirring. Once the milk has reached a dough-like consistency and stirring does not prevent the mass from sticking to the side of the pan, you can remove it from the heat source and lower the temperature by at least 20°C. At this point the water content should have been reduced to about 40% of what it was. Take the lump of koa out of the pan, put it on a cold surface and flatten it. After cooling, the koa will be firm and can be cut into squares. It will have a sweet, nutty flavor. Koa can be kept only for about 2 - 5 days because of possible re-infection. The preparation of koa requires much time (a few hours) and fuel, on top of which 1 liter of milk produces only 0.4 liters of koa. Unit 4: Milk By-Products: During the manufacture of different dairy products, the inevitable problem of utilization of by-products is encountered. Because of their unique and important nutrients available in the by-products, they have to be utilized in a proper manner considering the welfare of the general masses.
  14. 14. Conversion of edible nutrients into non edible substances will not augur well given the rampant malnutrition staring at the face of the impoverished developing countries. The profitability of the dairying can be greatly improved by economically utilizing the dairy by-products and it can be considered as a prerequisite to profitable dairy business. With the advancement in technology, the scope is wide open for creating newer channels of utilization of the by-products arising from dairy processing. 4.1 whey watery part of milk produced when raw milk sours and coagulates. It has low solid & high lactose. 4.1.1 Acid whey: drained from cheese curd acidified to 4.6 by cultures (or acid). E.g. Cottage cheese 4.1.2 Sweet whey: drained from curd formed by rennet coagulation. E.g. Cheddar 4.2 Skimmed milk or skim milk. Culturing normally involves the addition of certain charactering ingredients and lactic-acid producing bacteria. An example of cultured milk is buttermilk. Sr. No 1 3 4 By Product Skim milk Butter Buttermilk Cheese, Casein Channa, Paneer 2 Main Product cream Whey Ghee Ghee residue Processing method Pasteurization Sterilization Fermentation Fermentation ,Concentration Concentration Drying Products Made Flavored milk Sterilized flavored milk Cultured Buttermilk Concentrated sour skim milk Plain and Sweetened Condensed skim milk Dried skim milk or Skim milk powder or Non Fat Dry Milk NFDM) Coagulation Cottage cheese, edible casein Fermentation ,Concentration Condensed buttermilk Concentration, drying Dried buttermilk Coagulation Soft cheese Fermentation Whey beverage, Yeast whey Concentration Plain and sweetened condensed whey, whey protein concentrate, whey paste, lactose Drying Dried whey Coagulation Ricotta cheese Processing Sweetmeat, Toffee, Sweet paste