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Technology of milk products Dry Milk powder presentation

Power point on various dry milk products and their technologies involved.

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Technology of milk products Dry Milk powder presentation

  2. 2. HISTORY  Marco Polo in the 13th century reported that soldiers of Kublai Khan carried sun-dried milk on their expeditions.  Scriptures from the early Bhuddhist and Jain period have documented sweet made from Heat desiccated milk such as sihakesara and morandeka Which was used as Desserts to be eaten at the end of Meal.  The first commercial production of dried milk was organized by the Russian chemist M. Dirchoff in 1832. In 1855, T.S. Grimwade took a patent on a dried milk procedure  Roller drying was the main means of producing milk powders until the 1960s when spray drying took over.
  3. 3. Composition of Milk Water: 87-88% Carbohydrate: (approx. 5% ) • mainly Lactose→ Lactic acid by bacterial fermentation • In heated milk products, e.g., in condensed milk, there is also lactulose which is a little sweeter’ Fat: 3-4% in whole milk; • contains fat soluble vitamins, pigment carotene & Xanthophylls; contains cholesterol & phospholipids but is primarily TGs(95%) • The fat in milk occurs in the form of droplets or globules, surrounded by a membrane and emulsified in the milk serum part (the whey part or the watery part). • Milk is an o/w emulsion which is not naturally physically stable that is why creaming occurs if it is left to stand.
  4. 4. Protein: (3-4%) Casein (80% of milk protein) • The casein is arranged in super-structures called micelles, which consist of protein together with phosphate, citrate and calcium. • The caseins are actually a group of similar proteins, which can be separated from the other milk proteins by acidification to a pH of 4.6 (Ip) • The casein micelles also may be coagulated by addition of the enzyme rennin. Whey proteins (20% of milk protein) • lactalbumin, lactoglobulin & immunoglobulin • Whey proteins are more hydrated than casein and are denatured and precipitated by heat rather than by acid. Other protein components • include enzymes such as lipase, protease, & alkaline phosphatase, which hydrolyses TGs, proteins, & phosphate esters, respectively. Themilk proteins are of high BV & are readily used by the body
  5. 5. Vitamins & Minerals: • Vitamins A, B6, B12, C, D, K, E, thiamine, niacin, biotin, riboflavin, folates, and pantothenic acid. • Vitamin A is naturally in the fat component of whole milk and more may be added prior to sale. • whole milk is generally (98%) fortified with vitamin D because it is naturally present only in small amounts. • Low-fat and non-fat milk are fortified with both of these fat-soluble vitamins because milk fat is reduced or absent. Minerals • Ca & P approx. 1% of milk • Ca is present as calcium caseinate, calcium phosphate & calcium citrate. • Other minerals present are chloride, magnesium, potassium, sodium, and sulfur.
  6. 6. INTRODUCTION  The heat processing of milk causes the following  Reduction in water activity.  Substantial destruction of pathogenic and spoilage microorganisms.  Inactivation of enzymes.  Heat induced chemical interactions leading to reduction of Redox potential.  All these help to extend the shelf life of under the ambient temperature
  7. 7. DRIED MILK PRODUCTS  Dry milk: made with whole milk or skimmed milk dehydrated to about 97% by spray drying & vaccum drying. Good shelf life. Highly hygroscopic & can be reconstituted to fluid milk.  Skim milk powder: Skim Milk Powder is obtained by removing water from pasteurized skim milk. It contains 5% or less moisture (by weight) and 1.5% or less milkfat (by weight) and a minimum milk protein content of 34%.  Khoa: semi-solid obtained from milk by evaporating in open pans with continuous stirring in circular motion. Yield is about 20% of weight of milk used.  Whey powder : is a mixture of globular proteins isolated from whey, the liquid material created as a by-product of cheese production. Whey protein is commonly marketed as a dietary supplement, and various health claims have been attributed to it in the alternative medicine community.
  8. 8. Flow chart diagram of Whole Milk powder production
  9. 9. MILK POWDER  Milk powder manufacture is a process now carried out on a large scale.  It involves removal of water at the lowest possible cost under stringent hygiene conditions while retaining all the desirable natural properties of the milk - colour, flavour, solubility, nutritional value.  During milk powder manufacture water is removed by boiling the milk under reduced pressure at low temperature.  The resulting concentrated milk is then sprayed in a fine mist into hot air to remove further moisture and so give a powder.  Whole (full cream) milk contains, typically, about 87% water and skim milk contains about 91% water.  Approximately 13 kg of whole milk powder (WMP) or 9 kg of skim milk powder (SMP) can be made from 100 L of whole milk.
  10. 10. RECEIVING AND SELECTION  Milk should be of high chemical, bacteriological and organoleptic quality.  Acidity higher than 0.15% reduces the solubility.  Antibiotic and pesticides reduce quality.  Clarification by centrifugation or filtration is needed.  Cooling to 4 degree C.  Standardization: to adjust the ratio of fat and Total Solids.
  11. 11. PREHEATING  Standardised milk is heated to temperatures between 75 and 120 C and held for a specified time from a few seconds up to several minutes (cf. pasteurisation: 72 C for 15 s).  Preheating causes a controlled denaturation of the whey proteins in the milk and it destroys bacteria, inactivates enzymes, generates natural antioxidants and imparts heat stability.  The exact heating/holding regime depends on the type of product and its intended end-use.  High preheats in Whole Milk Powder is associated with improved keeping quality but reduced solubility.  Preheating methods are indirect (via heat exchangers), or direct (via steam injection or infusion into the product), or a mixture of the two
  12. 12. Different pasteurisation methods 1 • Low-temperature-longer time(LTLT) • 65oC for 30 minutes, called the Holding or Batch method 2 • High-Temperature-Short-Time (HTST) • heat treatment of 72oC for 15 seconds is applied, followed by rapid cooling to below 10oC. Also called the continuous system or flash pasteurisation. 3 • Ultra High Temperature (UHT) • 149.5oC for 1 second or 93.4oC for 3 sec.
  13. 13. Contd.. Heat treatment: Higher than pasteurization (88-95 C/15- 30sec) 1. Destroy all pathogens. 2. Inactivate enzymes (especially lipase). 3. Activate SH groups (antioxidant). HTST produces better powder quality. De-aeration of milk before heating protects vitamin C
  14. 14. EVAPORATION  The preheated milk gets concentrated in stages from around 9.0% total solids content for skim milk and 13% for whole milk, up to 45-52% total solids.  This is achieved by boiling the milk under a vacuum at temperatures below 72 C in a falling film on the inside of vertical tubes, and removing the water as vapour.  This vapour, which may be mechanically or thermally compressed, is then used to heat the milk in the next effect of the evaporator which may be operated at a lower pressure and temperature than the preceding effect.  More than 85% of the water in the milk may be removed in the evaporator. Evaporators are extremely noisy because of the large quantity of water vapour travelling at very high speeds inside the tubes.
  15. 15. EVAPORATION  In spray drying, milk is concentrated to 40-50% and for roller drying, to only 33- 35%.  Highly concentrated milk will form a thick layer on the roller. which inhibits further drying.  Highly concentrated milk is viscous and causes difficulties during atomization.
  16. 16. HOMOGENIZATION  Function : to prevent creaming, or the rising of fat to the top of the container of milk.  The process of homogenization permanently emulsifies the fine fat globules by a method that pumps milk under high pressure [2000–2500 lb/in2 (psi)] through small mesh orifices of a homogenizer.  Homogenization mechanically increases the number & reduces the size of the fat globules. The size is reduced to 1/10 of their original size.  Resulting in the milk that maintains more uniform composition with improved body and texture, a whiter appearance, richer flavor, & more digestible curd.  Homogenization of highly concentrated milk (more than 3:1) destabilizes protein and decreases powder solubility.
  18. 18. WORKING PRINCIPLE When the product enters the valve area under high pressure and with low velocity it must pass the adjustable gap between the valve and seat. Creates a rapid increase in velocity with a corresponding pressure drop. The very high energy release causes turbulence, this in combination with powerful cavitation will tear apart particles to a submicron size. The high velocity collision of the product on the impact ring will further contribute to this action.
  19. 19. DRYING  Atomizing the concentrated milk into a hot air stream (180-200C).  Controlling the air temp., air flow, and size of droplets, water could be removed from droplets exposed to relatively low heat.  Spray drying: excellent solubility, flavor and color.  Powder leaves the two or three-stage dryer and enters cooling systems.
  20. 20. EFFECTS OF HEAT  Coagulation of protein (lactalbumin & lactoglobulin) at 66°C.  Increasing temperatures and length of heating may break the fat emulsion if the protein film around the fat globules breaks. Thus the fat will coalesce.  High heat also forms greater amounts of coagulum at the bottom of the pan than low heat.  Maillard reaction or Non-enzymatic browning or“carbonyl-amine browning” reaction between the free carbonyl group of a reducing sugar and the free amino group of protein. Max. effect is with lysine followed by tryptophan & arginine.  Scum formation  Destruction of microorganisms at higher temperatures.  Scorching of milk: heating over hot water stirring can prevent it.  Colour, flavour & digestibility.
  21. 21. DIFFERENT TYPES OF DRYING Spray Drying • Pasteurized milk is first concentrated in an evaporator to approximately 50% milk solids. The resulting concentrated milk is then sprayed into a heated chamber where the water almost instantly evaporates, leaving fine particles of powdered milk solids. Drum Drying •Milk is applied as a thin film to the surface of a heated drum, and the dried milk solids are then scraped off. However, powdered milk made this way tends to have a cooked flavor, due to caramelization caused by greater heat exposure. Freeze Drying • Same as drum drying but involves freezing which retains more amount of nutrition.
  22. 22. SPRAY DRYING  Spray drying involves atomising the milk concentrate from the evaporator into fine droplets.  Done inside a large drying chamber in a flow of hot air (up to 200 degree C) using either a spinning disk atomiser or a series of high pressure nozzles.  The milk droplets are cooled by evaporation and they never reach the temperature of the air.  The concentrate may be heated prior to atomisation to reduce its viscosity and to increase the energy available for drying.  The remaining water is evaporated in the drying chamber, leaving a fine powder of around 6% moisture content with a mean particle size typically of < 0.1 mm diameter.  Secondary drying takes place in a fluid bed, or in a series of such beds, in which hot air is blown through a layer of fluidised powder removing water to give product with a moisture content of 2-4%.
  24. 24. SPRAY DRYING spray drier nozzle Atomization of concentrated milk
  25. 25. DRUM DRYING
  26. 26. FREEZE DRYING  Technically known as lyophilisation, or cryodesiccation—is a dehydration process typically used to preserve a perishable material or make the material more convenient for transport.  The food material is placed in a vacuum chamber and frozen until the water crystallizes. The air pressure is lowered, creating a partial vacuum, forcing air out of the chamber; next heat is applied, sublimating the ice; finally a freezing coil traps the vaporized water.  Freeze drying, which preserves many nutrients in milk, compared to drum drying Freeze dried ice cream
  27. 27. Freeze dryer production type Loading a freeze dryer
  28. 28. PACKAGING AND STORAGE The powder passes through a sieve with 0.7 mm diameter openings. Important to retain the proper quality during storage. Container should protect the powder from moisture, air, light and contamination substances. Can be Tin cans, Retort pouches, etc.
  29. 29.  Multilayer boxes or bags with a polyethylene layer inside.  Cans covered with aluminum foil on the contact surface.  Long storage should be in an atmosphere of inert gas such as nitrogen or in partial vacuum.  High moisture content of the powder increases lactose crystallization.  High relative humidity of the environment is dangerous.
  30. 30. QUALITY AND PROCESS CONTROL: CHEMICAL COMPOSITION OF MILK POWDER (%) Water 3.4 Protein 25.2 Fat 26.2 Carbohydrates 38.1 Ash 7.0
  31. 31. QUALITY CONTROL  Microbiological and organoleptic control.  Water, fat, free fat, proteins, mineral, Total Ash, solubility, flowability, bulk density and particle size distribution.
  32. 32. QUALITY DEPEND ON  Manufacturing techniques and parameters (evaporation,preheating, homogenization)  Drying techniques and conditions.  Storage conditions.
  33. 33. EFFECT OF THE DRYING TECHNIQUE ON POWDER STRUCTURE AND BULK DENSITY (g/cm3): Roller drying gives compact structure with irregular shape. Very low bulk density. Spray drying gives spherical particles with smooth surface. Higher bulk density. High inlet air forms Wrinkles. Nozzle atomizer gives higher density (more regular shape).
  34. 34. POWDER SOLUBILITY  More protein denaturation = less solubility.  Heat treatment increases stability. Lower inlet and outlet temperatures.  Milk quality (acidity is important).  Too low outlet air temperature or high feeding flow rate will increase moisture.  Formation of lumps: lactose will absorb water from  atmosphere and form lumps.
  35. 35. TO IMPROVE FLOW ABILITY (ABILITY TO FLOW FREE) WITHOUT FORMING LUMPS 1. Silicates, 2. calcium phosphates, 3. silica oxide can be added to cover the surface and decrease adhesion among particles.
  36. 36. FAT OXIDATION Oxidation is enhanced in the presence of oxygen, light and ions. Packing in a partial vacuum or replace oxygen with inert gases like nitrogen. BROWNING Maillard reaction. (too high temperature during drying or too high storage temperature).
  37. 37. SKIM MILK POWDER PRODUCTON  Skim Milk Powder is obtained by removing water from pasteurized skim milk.  It contains 5% or less moisture (by weight) and 1.5% or less milk fat (by weight) and a minimum milk protein content of 34%.  Skim Milk Powder is classified for use as an ingredient according to the heat treatment used in their manufacture.  There are three main classifications: high-heat (least soluble), medium-heat, and low-heat (most soluble).  Spray-dried Skim Milk Powder is available in two forms: ordinary or non- agglomerated (non-instant) and agglomerated (instant).
  38. 38. Flow chart of Skim milk preparation
  39. 39. SKIM MILK POWDER PREPARATION 1. Receiving and selecting milk, Clarification, Cooling and storing at temperature below 7 degree C. 2. Separation to 0.05-.1% fat. 3. Pasteurization: Usually 72 C for 15 sec is used. 4. Heat treatment: Skim milk powder differs from whole milk powder by the heat treatment given to skim before evaporation. a. Low heat skim milk: only pasteurization. b. High heat skim milk: 85-88 C for 15-30 min. Extent of heat treatment is measured by whey protein index (WPNI): mg N/g powder. Highest with low heat.
  40. 40. EVAPORATION AND DRYING. Two-part moisture removal: a. Evaporation: To increase the TS to 40-50%. Energy used in multiple effect evaporator is 10 times lower than in spray drying. Also evaporation produces large powder particles with less occluded air and longer life. b. Drying: atomizing the concentrated milk into a hot air stream (180-200C). Controlling the air temp., air flow, and size of droplets, water could be removed fro droplets exposed to relatively low heat.
  41. 41. PACKAGING AND STORAGE Non Fat Dry Milk Powder (Skim Milk Powder) can be stored at ambient temperature with no risk of oxidative changes as fat is removed.
  42. 42. MALTED MILK  It is a powdered gruel made from a mixture of malted barley, wheat flour, and whole milk, which is evaporated until it forms a powder.  Malt powder comes in two forms:  Diastatic malt contains enzymes that break down starch into sugar; this is the form bakers add to bread dough to help the dough rise and create a good crust.  Nondiastatic malt has no active enzymes and is used primarily for flavor, mostly in beverages. It sometimes contains sugar, coloring agents, and other additives.
  43. 43. WHEY PROTEINS  Whey protein is the collection of globular proteins isolated from whey.  The protein in cow's milk is 20% whey protein and 80% casein protein,  The protein fraction in whey constitutes approximately 10% of the total dry solids in whey. This protein is typically a mixture of beta-lactoglobulin (~65%), alpha-lactalbumin (~25%), bovine serum albumin (~8%)  The amino acid cysteine in whey protein is a substrate for the synthesis of glutathione in the body which is an ubiquitous cellular antioxidant; laboratory experiments have suggested that whey protein and its components might reduce the risk of cancer in animals, suggesting an avenue for future medical research
  44. 44. DRY BUTTERMILK  The product is obtained by drying liquid buttermilk that was derived from the churning of butter and pasteurized prior to condensing. Dry buttermilk product shall have a protein content of less than 30%. It may not contain, or be derived from, NDM, dry whey or products other than buttermilk and contains no added preservative, neutralizing agent or other chemical.  The Product should be stored and shipped in a cool, dry environment with temperatures below 80ºF and relative humidity below 65%.  Applications include bakery products, frozen desserts, dry mixes, beverages, dairy products, frozen foods, salad dressings and snack foods.
  45. 45. MILK PERMEATE POWDER  Milk Permeate is a by-product of the Milk Protein Concentrate (MPC) production process, formed after ultrafiltration of milk to extract protein and fat.  The product is then dried using advanced spray drying techniques. Milk permeate powder is characterized by a clean, slightly salty taste and uniform particle size. It consists of lactose, water, vitamins and minerals. Milk Permeate Powder can be used to standardize Skim Milk Powder (SMP) and is a natural food ingredient with excellent functional and nutritional characteristics. It is suitable for a wide range of applications including beverages, seasonings, confectionery, soups, sauces, desserts, bakery and dairy.
  46. 46. COMPOSITION  Lactose(minimum 75%), 80% protein 3%, ash 8.5% fat trace amount moisture 1.5%
  47. 47. FREEZE-DRIED ICE CREAM  Ice cream that has had most of the water removed from it by a freeze-drying process, sealed in a pouch, and requires no refrigeration.  It is also known as astronaut ice cream or space ice cream, typically a slab of ready-to-eat dehydrated ice cream. Compared to regular ice cream, it can be kept at room temperature without melting and is more brittle and rigid but still soft when bitten into.  It was developed by Whirlpool Corporation under contract to NASA for the Apollo missions. However, it was never used on any Apollo mission.
  48. 48. REFERENCES  https://www.adpi.org/DairyProducts/DryMilks/MilkPermeatePowder/tabid/356/Default.aspx.  www.wikipedia.com  http://www.ifst.org/learninghome/  Hand book of Milk processing Dairy products and Packaging technology by EIRI board of consultants & Engineers .Engineers India Research institute.  Vaclavik,V.A., Christian,E.W., Essentials of Food Science, Third Edition, Springer.