Fermentated milk products


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Fermented milk products, also known as cultured dairy foods, cultured dairy products, or cultured milk products, are dairy foods that have been fermented with lactic acid bacteria.
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Fermentated milk products

  1. 1. PRODUCTS -Saugat Bhattacharjee ABBS
  2. 2. INTRODUCTION  Milk is a whitish liquid containing proteins, fats, lactose , various vitamins and minerals that is produced by the mamary glands of all mature female  the milk of cows, goats and other animals used as food b humans  mik is extremely perishable and many ways have been developed to preserve it The earliest method which have been used for many thousands of years is fermentation Fermentation is a metabolic process in which an organism convert a carbohydrate such as starch and sugar into an alcohol or an acid Example yeast perform fermentationto obtain energy by converting sugar into alcohol Bacteria perform fermentation by converting carbohydrates into lactic acid
  3. 3. HISTORY OF FRMENETATION It is a natural process People applied fermentation to make products such as wine ,cheese ,beer etc. In 1850s and1860s Louis Paster became the first scientist to study fermentation when he demonstrated fermentation was caused by living cells He showed that lactic acid fermentation is caused by living organism In 1860 he demonstrated that bacteria cause souring in milk a process formely thought to be merely chemical change and his work in identifying the role of microorganism in food spoilage lead to the process of pasteurization
  4. 4. Fermented milk product Yoghurt Cultured butter milk cheese
  5. 5. Cheese
  6. 6. TYPES OF CHEESE I. Soft cheese II. Semi soft cheese III. Semi hard cheese IV. Hard cheese V. Fresh cheese VI. Blue cheese VII.Processed cheese
  7. 7. SOFT CHEESE Examples of soft cheese are camembert, feta, celtic etc. This type of cheese does not undergo any heating or presseing A penicillium fungus gives it furry white rind Not usually used in cooking soft cheese are used to spread on bread or crackers Wine to serve is beaujolous The organisms found is streptococcus cremoris , penicillium camemberti found in camembert Celtic cheese
  8. 8. Streptococcus cremoris Penicillium camemberti
  9. 9. SEMI SOFT CHEESE Examples are gouda, port soft, muenster This type of cheese does not undergo any heating or pressing The rind is rinsed and brshed with a solution of salt water enriched with a specific bacteria , which encourages orange coloured fungi to appear Ideal for snacking or deserts, some semi soft cheese may be used for cooking if they stand up to heat well enough Wine to serve is red bordeaux The organisms found are lactococcus lactis found in gouda, brevibacterium linens found in muenster
  10. 10. HARD CHEESE Examples aged manchego, mimolette, tuscano, pelorina etc A hard cheese needs to have less water content (30% to 48% ) in the end product than a soft cheese ( which has 50% to 70%) Packed into moulds , firmly pressed and stored for long periods ( up to two years ) they bocome hard and more pungent over time Wine to serve them red wine as burguncly
  11. 11. SEMI HARD CHEESE Examples are cheddar ,edam , emmental, cantal etc These cheese onces transformed into curds are heated , pressed, moulded and left to ferment . This is how the famous holes appear in cheese that is stored in cellars ( such as emmental ) They are very rich in calcium Maturing can take from three to nine months or even longer Wine serve full bodied red wines such as rioja The organism found are lactobacillus casei, streptococcus cremoris found in cheddar
  12. 12. Streptococcus cremoris
  13. 13. BLUE CHEESE Examples are roquefort , gorgonzola , stilton The production of this cheese involves inoculating it with fine long skewers containing penicillium cultures which allow mould to develop in the cheese This is what produce the green or blue veins Wine to serve is sweet wines , loupiac sauternes The organisms found are penicillium roqueforti and lactococcus lastis in roquefort
  14. 14. Penicillium roquefort
  15. 15. FRESH CHEESE Examples are cottage , mozzarella and fromage frains COTTAGE CHEESE This is fresh cheese with 80% water content Milk is curdled an drained but little other processing takes place and there is no ageing Cattage cheese is typically eaten with fruits or in salad MOZZARELLA This cheese is obtained through kneading and stretching the curd until it reaches the desired consistency Mozzaella is often used in pizza and lesagine FROMAGE FRAINS This cheese is hardly drained or matured Its milk proteins simply coagulate under the effect of lactic ferments It can be eaten on its own or with added flavouring
  16. 16. Cottage cheese
  17. 17. PROCESSED CHEESE This cheese is made up of a mixture of cheese , butter, cream and milk that is heated and emulsified Some varieties are flavoured or spiced The shelf life is generally very long Cheese are also classified as unriped if produced by single step fermentation or ripened if addition growth is required during maturation of cheese to achive the desired taste , texture and aroma Ripening involves additional enzymatic transformations after the formation of cheese curd Various fungi are also used in the ripening of different cheese The unriped cheese is inoculated with fungal spores
  18. 18. PRODUCTION OF CHEESE Basic stages involved in cheese making are as follows : Standardization; this is done to adjust fat or to have balanced ratio of fat to casein or increasing fat through cream for making cream cheese Clarification; effective alternative to filtration for the removal of extraneous matter, leucocytes and some bacteria , it is carried out at 32c to 35c centrifugally Bacterofugation; if centrifuged milk is passed through the unit a seond time about 90% of the remaing 10% is removed, thus total 99% bacteria can be removed Homogenization; milk is homogenized at low pressure to reduce whey exudation from the coagulum, to make cheese white and promote fat hydrolysis Thermization ; the raw milk is stored for few days before using it for cheese making, it is subjected to heat treatment at 63C for 10 to 15 seconds and cooled at 5C
  19. 19. Ultrafiltration; by membrane filtration under low pressure milk can be sepaated into retentate with fats , casein, whey proteins Ripening of milk; this is achieved by heating the milk to 30 to 33C and adding starter bacteria eg. Lactococcus lactis , which has the effect of speeding up the natural process of milk souring Rennetting; after increase in acidity of milk created by startee rennet extract is added to milk and uniformly distributed to efffect coagulation of milk eg of coagulating enzyme is bacillus sutilis or mucor meihei Cutting the coagulum; this has a great effect it release a large volume of whey,establishes the size of the curd particle Scalding; in high scalding the temperature may be 52 to 58 C , in medium scald 30 to 42C and in low scald is 30 to 35C . During combined action of stirring and heat , lactic acid in curd particles is formed by the starter organism Draining the whey; the cud is allowed to settle, acidity is measured untill it reaches the desired level Milling; milling of the texturized matted curd is done at 0.6 to 0.7C acidity helps in distribution of salt which act as preservative
  20. 20. Pressing; the curd is filled in moulds and pressed, the degree varies with the type of cheese Dressing and package ; the green cheese is packed in heat shrink barrier film
  21. 21. YOGHURT
  22. 22. Yoghurt is produced by the controlled fermentation of milk by two species of bacteria Lactobacillus bulgaricus and L actotococcus thermophilus (streptococcus thermophilus) The sugar in milk is called lactose which is fermented to acid ( lactic acid) and it is the one which cause he characteristic curd to form Streptococcus thermophilus bring the pH of the milk down to 5.5 Lactobacillus bulgaricus convert lactose to lactic acid Proteolytic enzymes from L . bulgaricus break down milk protein into peptide s These peptides stimulate the growth of L . themophilus which in turn produces formic acid and carbondioxide These are the growth stimulants for the L . Bulgaricus
  23. 23. Lactobacillus bulgaricus Streptococcus thermophilus
  24. 24. TYPES OF YOGHURT I. II. III. IV. V. VI. Set yoghurt Stirred yoghurt Drinking yoghurt Flavored yoghurt Concentrated yoghurt Frozen yoghurt
  25. 25. Set yoghurt A solid set where by the yoghurt firms in a container and not disturbed, its incubated and cooled in the final package . The firm is jelly like texture
  26. 26. Stirred yoghurt Made in large container then stirred or otherwise dispensed into secondary serving containers . The consistency of the set is broken and the texture is less firm than set yoghurt
  27. 27. Drinking yoghurt Stirred yoghurt to which addition milk and flavours are mixed in. a fruit or fruit syrups is added mixed in milk to achieve the desired thickness. The shelf life of this product is 4 to 10 days , since the pH is raised by fresh milk addition. Commericialproducts recommend a thoroughly shafe before consumption
  28. 28. Flavored yoghurt Fruits , fruits syrups or pie filling can be added to the yoghurt just before poured into pots , it usually contain about 50% sugar
  29. 29. Concentrated yoghurt Incubated like stirred yoghurt after coagulation is broken some water is boiled off producing a rough and grlty textures
  30. 30. Frozen yoghurt Incubated like stirred yoghurt , cooling is achieved by pumping through a freezer like ice cream, it has a texture like ice cream
  31. 31. PRODUCTION OF YOGHURT Raw milk is taken which have low count of organisms and substances which suppress the development of starter microbes eg. Streptococcus thermophilus Standardization of fats; this involves the removal of fat content of milk , mixing full cream milk with skim milk or by using standardizing centrifuge Homogenization; is done by first pre treating it to 60 to 65C and passing it through an homogenizer at 100 to 200 kg/cm2 to stabilize the product and provide smooth texture Heat treat; this involves heating the milk at 90 to 95 for 5mins to improve the texture of yoghurt Cooling ; after heating the substrate is cooled to incubation temperature 42 to 45 C The culture contain two strains of microorganism streptococcus salivarius and lactobacillus delbrueckii
  32. 32. BUTTER MILK
  33. 33. BUTTER MILK It is a fermented milk product made by using mesophilic starters Different products are produced by using different stains of lactic acid bacteria as starter cultures and different fractious of whole milk as the starting substrate Sour cream uses streptococcus cremoris or S. lactis for producing lactic acid and leuconostoc cremoris for characteristic flavour Cream is starting substrate , butter is normally made by churning cream that has been soured by lacctic accid bacteria Streptococcus cremoris or S.lactis is used to produce lactic acid rapidly and leuconostoc citrovorum produce necessary flavors
  34. 34. PRODUCTION OF BUTTER MILK Fresh or skim milk is taken and standardise making it free from antibiotics and detergents Milk is homogenized at 200 kg/cm2 at 15C then heat treated at 90C for 13 mins to get satisfactory end product Then it is cooled to 23C and inoculated wit a mixed culture having lactococcus lactis and leuconostoc citrovorum as primary produces of aroma and flavour The inoculation may range from 1 to 2% When acidity reaches 0.9% the product is gently mixed , cooled bottled and stored at 5C The fermentation time may be around 16 to 20 hrs The final product is a viscous drink with pleasing aroma and flavour