Download to read offline
dairyprocessing-180708173002-1.pdf
- 2. BANARAS HINDU BANARAS HINDU UNIVERSITY UNIVERSITY Centreof Food Science & Centre of Food Science & Technology Technology
- 3. MILK MILK PROCESSING PROCESSING SUBMITTED TO: Dr. R.C. Pradhan Asst. Professor Dept. of Agricultural Farm Engineering SUBMITTED BY: SUBMITTED BY: Sukhveer Singh Sukhveer Singh Prabal Pratap Singh Prabal Pratap Singh Uday Pratap Singh Uday Pratap Singh
- 5. -:INTRODUCTION:- Milk is aunique in that it is both consumed, as fluid milk with minimal processing and it is the raw material used to manufacture a wide variety of product. Definition Milk may be defined as the whole, fresh, clean, lacteal secretion obtained by the complete milking of one or more healthy milch animals, excluding that obtained within 15 day before or 15 days after calving or such periods as may be necessary to render the milk practically colostrums-free and containing the minimum prescribed percentages of milk fat and milk-solid-not-fat.
- 6. -:MILK AND ITSCOMPOSITION:- Milk Water Total solid Fat Solid not fat (SNF) True fat Associates substance Phospholipids Cholestrol Carotene Vitamin (A, D, E, K) Lactose Nitrogeneous Mineral Other Substance Constituents Non Protein Protein Casein Lactalbumin Lactoglobulin Protease-peptone Pigments Dissolved gases Vitamin (B,C) Enzymes bacteria
- 7. WATER WATER Largest fraction ofmilk & ranges from 80-90%. Largest fraction of milk & ranges from 80-90%. Serves as carrier for other constituents of milk. Serves as carrier for other constituents of milk. MILK FAT MILK FAT The Milk fat exists in the form of small globules, which The Milk fat exists in the form of small globules, which averages approximately 2-5 microns in size. averages approximately 2-5 microns in size. Milk fat is rich source of energy & good source of vit. Milk fat is rich source of energy & good source of vit. A & D. A & D. % of milk fat varies in different animals & their % of milk fat varies in different animals & their varities. varities. It may ranges from 1-13%. It may ranges from 1-13%.
- 8. MILK PROTIEN MILK PROTIEN Milknormally contains about 0.5% of nitrogen of Milk normally contains about 0.5% of nitrogen of which 95% constituents milk protein & 5% non which 95% constituents milk protein & 5% non protein nitrogen. protein nitrogen. Casein is phosphoprotien, accounts for 80% of Casein is phosphoprotien, accounts for 80% of total protein content. total protein content. The viscosity & white colour of milk are largely The viscosity & white colour of milk are largely because of casein. because of casein. MILK SUGAR OR LACTOSE MILK SUGAR OR LACTOSE It occurs exclusively in mammalian milk. It occurs exclusively in mammalian milk. The average lactose content of cow & buffalo milk The average lactose content of cow & buffalo milk is 4.5 & 4.8% respectively. is 4.5 & 4.8% respectively.
- 9. ENZYMES ENZYMES A number ofenzymes present in milk. More than A number of enzymes present in milk. More than 25 enzymes have been identified in cow milk. 25 enzymes have been identified in cow milk. The milk enzymes are of considerable importance The milk enzymes are of considerable importance in certain aspects of milk technology. For example in certain aspects of milk technology. For example lipase is responsible for the development of rancid lipase is responsible for the development of rancid flavours in milk. flavours in milk. VITAMINS VITAMINS Milk is good source of fat soluble (Vitamins A,D,E Milk is good source of fat soluble (Vitamins A,D,E & K) & water soluble vitamins (B). & K) & water soluble vitamins (B). Milk is good source of Vitamin A but it is poor Milk is good source of Vitamin A but it is poor source of Vitamin C. source of Vitamin C. MINELRALS MINELRALS Milk is an important source of calcium, potassium, Milk is an important source of calcium, potassium, phosphorous & magnesium. phosphorous & magnesium.
- 10. Properties of Milk Propertiesof Milk 1. Physical state of Milk: 1. Physical state of Milk: The Milk constituents exists The Milk constituents exists partially as a solution & partially in colloidal state. partially as a solution & partially in colloidal state. 2. Acidity of Milk: 2. Acidity of Milk: The titratable acidity of milk is usually The titratable acidity of milk is usually expressed as lactic acid equivalent per 100 ml. of milk & it expressed as lactic acid equivalent per 100 ml. of milk & it may range from 0.13 – 0.21%. may range from 0.13 – 0.21%. 3. pH of Milk: 3. pH of Milk: Milk is slightly acidic in nature & its ph Milk is slightly acidic in nature & its ph value varies from 6.5 – 6.7. value varies from 6.5 – 6.7. 4. Colour of Milk: 4. Colour of Milk: Milk ranges in colour from yellowish Milk ranges in colour from yellowish creamy to creamy white. The larger the fat globules & the creamy to creamy white. The larger the fat globules & the higher the fat percentage , the greater intensity of the yellow higher the fat percentage , the greater intensity of the yellow colour. colour.
- 11. 5. Flavour: 5. Flavour:This is composed of smell (odour) & taste. This is composed of smell (odour) & taste. Milk is sweet in taste. The chlorides & lactose are Milk is sweet in taste. The chlorides & lactose are mainly responsible for taste. mainly responsible for taste. 6. Specific gravity: 6. Specific gravity: The specific gravity of milk is The specific gravity of milk is determined by using a plunger of special shape & determined by using a plunger of special shape & volume called lactometer. volume called lactometer. 7. Viscosity: 7. Viscosity: The viscosity of milk is always higher The viscosity of milk is always higher than viscosity of water due to presence of dissolved than viscosity of water due to presence of dissolved solids in milk. At normal temperature viscosity from 1.5– solids in milk. At normal temperature viscosity from 1.5– 2. 2. 8. Boiling point of milk: 8. Boiling point of milk: The Boiling point of milk The Boiling point of milk varies from 100.17 - 101°c. This is slightly higher than varies from 100.17 - 101°c. This is slightly higher than that of water due to dissolved substances in milk. that of water due to dissolved substances in milk.
- 12. 9. Freezing pointof Milk: 9. Freezing point of Milk: Milk freezes at an Milk freezes at an average temperature of -0.55°c (range -0.5°c to -0.61°c), average temperature of -0.55°c (range -0.5°c to -0.61°c), which is slightly lower than that of pure water (0°c). which is slightly lower than that of pure water (0°c). 10. Electrical conductivity: 10. Electrical conductivity: Electrical conductivity is Electrical conductivity is a measure of the ability of solution to carry electrical a measure of the ability of solution to carry electrical current. Value of electrical conductivity for normal milk current. Value of electrical conductivity for normal milk range from 0.003-0.005 mhos/min. range from 0.003-0.005 mhos/min. 11. Thermal conductivity: 11. Thermal conductivity: It is important because it It is important because it determines how fast milk is heated or cooled. At 20°c, determines how fast milk is heated or cooled. At 20°c, thermal conductivity of milk is 0.50-0.53 W/mK. thermal conductivity of milk is 0.50-0.53 W/mK. 12. Heat stability of Milk: 12. Heat stability of Milk: It is defined as the length It is defined as the length of time required to induced coagulation at a given of time required to induced coagulation at a given temperature or temperature required to induce coagulation temperature or temperature required to induce coagulation in a given time. in a given time.
- 13. Milk Milk Proce Processing Operations: ssingOperations: Once th milk has been received at the milk Once th milk has been received at the milk processing centre, or dairy, it should be processing centre, or dairy, it should be immediately strained, cooled & processed so as to immediately strained, cooled & processed so as to prevent any bacteriall growth. prevent any bacteriall growth.
- 14.
- 15. PASTEURIZATION Pasteurization is theprocess and applied to market milk today. Milk are heating at least 630 C for 30 minutes, or 72°C for 15 second. After pasteurization ,the milk is immediately cooled to 5°C or below.
- 16. History of pasteurization 1.Pasteurization term is first time used by Louis Pasteur in 20 April 1862.and eliminate bacteria in wines 2. The pasteurization of milk was adopted in 1895.
- 17. Method of Pasteurization 1.Low temperature long time (LTLT) 2. High temperature short time (HTST) 3. Ultra high temperature (UHT)
- 18. 1. LTLT: Lowtemperature long time this method commonly know as Batch or Holding method of pasteurization and ideal temperature is 63C for 30 minute(Milk) 2. HTST: High temperature short time. This method is know as continuous process of pasteurization and is 72C for 15 second. 3. UHT: Ultra high temperature. This process was developed in 1950.and temperature are provide 135C to 150 C for one second
- 19. HOMOGENIZATION HOMOGENIZATION Breakdown of milkfat globules is called Breakdown of milk fat globules is called Homogenization and fat globules Homogenization and fat globules subdivision to 2 microns or less in diameter. subdivision to 2 microns or less in diameter.
- 20. Effect of homogenization onmilk 1. 1. Increased the viscosity of Milk. Increased the viscosity of Milk. 2. 2. Reduced the milk curd tension. Reduced the milk curd tension. 3. 3. More creamier structure, bland flavor. More creamier structure, bland flavor.
- 21. Merits & Demeritsof Homogenization Merits: 1. No formation of cream layer 2. Produces soft curd and better digested 3. More palatable to brighter appearance Demerits: 1. Increased cost of production 2. Greater tendency for milk 3. Curdling in cookery
- 22. CREAM SEPRATION CREAM SEPRATION Thebasic principle of cream sepration is The basic principle of cream sepration is based on the fact that density of fat (930 based on the fact that density of fat (930 kg/m kg/m3 3 ) ) is lower than milk average 1036 is lower than milk average 1036 kg/m kg/m3 3 ). Hence when mlik which may be ). Hence when mlik which may be considered to be a mixture of fat (as considered to be a mixture of fat (as cream) & skim milk, is subjected to either cream) & skim milk, is subjected to either gravity or a centrifugal force the two gravity or a centrifugal force the two components, viz. cream & skim milk by components, viz. cream & skim milk by virtue of their differing densities, stratify virtue of their differing densities, stratify from one another. from one another.
- 23. Gravity Seperation Method GravitySeperation Method
- 24. Centrifugal separation method Centrifugalseparation method
- 25. STANDARDIZATION STANDARDIZATION Standrdization refers tothe adujestment Standrdization refers to the adujestment ( i.e. raising or lowerin the fat and/ or solid – ( i.e. raising or lowerin the fat and/ or solid – not-fat %). Of milk to desired value, So as to not-fat %). Of milk to desired value, So as to confirm to some lefgal or others confirm to some lefgal or others requirement. requirement.
- 26. MIXING OF INSGREDIENTS MIXINGOF INSGREDIENTS Ice cream contains numbers of ingredients Ice cream contains numbers of ingredients obtained from various source. The obtained from various source. The ingredients used in the manufacture of ice ingredients used in the manufacture of ice cream include dairy (like whole milk, skim cream include dairy (like whole milk, skim milk, cream, frozen cream, butter, butter oil milk, cream, frozen cream, butter, butter oil condensed milk products,dried milk product, condensed milk products,dried milk product, and non dairy product like sugar, stabilizer and non dairy product like sugar, stabilizer and emulsifiers. and emulsifiers.