Cheese production

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<ul><li> 1. CHEESE PRODUCTION </li> <li> 2. INTRODUCTION-ETYMOLOGY Word cheese Latin casues, meaning to ferment/become sour HOW OLD IS THE CHESE YOU ENJOY? Gorgonzola 879 AD. Roquefort 1070 Grana 1200 Cheddar 1500 Gouda 1697 Gloucester 1697 Stilton 1785 Camembert 1791 </li> <li> 3. INTRODUCTION Ultimately a milk product Widely used all over the world as food product Purely a product of microbial fermentation Flavor and aroma changes depending upon the microorganism being used. Before long, people learned that curds can be aged for over weeks and months and then pressed together to form large cakes of cheese. The art of cheese making have traveled from Asia to the Europe and then spread all over the world CHEDDAR CHEESE </li> <li> 4. DISCOVERY Though it is not certain that who made the first cheese but it is certain that it was accidental. Nomadic tribes of Central Asia are considered to be the legends who discovered cheese. Carried milk in saddlebags that made from animal skin probably from the stomach, which contains the coagulating enzyme known as rennin Fermentation and curdling would have happened due to the galloping motion of the horse Effective separation of milk into curds and whey. Whey had been used as an energy drink and curd was drained in perforated earthenware bowls and slightly salted to have a highly proteinaceous food. </li> <li> 5. Saddlebags Earthenware bowl </li> <li> 6. Valued for portability, long life, and high content of fat, protein, calcium, and phosphorus. More compact than milk- longer the shelf life. Hard cheeses last more than soft cheeses Eg: Cheddar cheese Made from raw milk. Since it is not pasteurized, higher vitamin contents. Salmonella, Mycobacterium and Brucella are the pathogens that might have seen in raw milk. U.S Federal Law- the cheese made from raw milk should be aged for over 60 days to prevent the development of pathogens. </li> <li> 7. DIFFERENT TYPES Roquefort Cheese Camembert Cheese Brie Swiss cheese </li> <li> 8. Gorgonzola Gouda Stilton Grana Gloucester </li> <li> 9. Cheese is completely a milk product. Whole milk- compressed, processed and stored to produce cheese. Wide range of cheese can be produced in countries where milk is legally allowed to process without pasteurization. In most of the countries the range of cheeses is smaller because of this reason Whey is a byproduct of cheese production Like most of other fermented food products such as beer, wine, etc. cheese also can be stored for longer periods, say years. </li> <li> 10. PRINCIPLES OF CHEESE PRODUCTION Cheese a way of storing milk over years Nowhere near as big as the market for cows milk cheese, considerable amount of cheese is made from other milk such as goat and sheep. Cheese by coagulating milk (separating curd and whey) Both raw milk and pasteurized milk can be used for cheese making. Needs more rennet (up to twice) for homogenized milk than the raw milk. This milk produces a curd that is smoother and less firm than that of raw milk, so most people add calcium chloride to the cheese </li> <li> 11. CHEESE MANUFACTURE The manufacture of most cheeses involves the following Pasteurization Kills nearly all microorganisms including pathogens that cause diseases and other undesirable organisms such as yeasts and coliforms (may alter the characteristics by producing CO2z and undesirable proteolysis) Regular HTST pasteurization at 72-730C for 15-20 seconds is commonly applied. Spore forming bacteria Clostridium tyrobutyricum can survive pasteurization and produces butyric acid and large volumes of hydrogen gas by fermenting lactic acid, which will destroy the structure of cheese. Chemical inhibitors such as NaNO3 or H2O2 can be used but in several countries, it has been banned and mechanical modes have been preferred. </li> <li> 12. Bactofugation Process in which a specially designed centrifuge- bactofuge is been used to separate the bacteria and spores that present in milk. Efficient way of reducing the number of spores in milk since their specific gravity is lesser than that of milk. Normally separate milk into a fraction which is more or less free from bacteria and a concentrate which contains both spores and bacteria. Example- spore load in cream by Bacillus cereus is reduced. Typically 60-630C is the temperature applied in Bactofugation </li> <li> 13. BACTOFUGE </li> <li> 14. Microfiltration A membrane filter with a pore size of approximately 0.2 micron can filter bacteria from a water solution Most of the fat globules and some of the proteins are as large as, or larger than, the bacteria. This results in the filter fouling very quickly when membranes of such a small pore size are chosen. In practice, membranes of a pore size of 0.8 to 1.4 micron are chosen to lower the concentration of protein. </li> <li> 15. In addition, the protein forms a dynamic membrane that contributes to the retention of micro-organisms. Provides an indirect sterilization Due to the high bacteria-reducing efficiency, microfiltration allows production of hard and semi-hard cheese without any need for chemicals to inhibit growth of Clostridia spores. </li> <li> 16. Additives in cheese milk The essential additives in the cheese making process are the starter culture and the rennet Under certain conditions it may also be necessary to supply other components such as calcium chloride (CaCl2) and saltpetre (KNO3 or NaNO3) An enzyme, lysozyme, has also been introduced as a substitute for saltpetre as an inhibitor of Clostridia organisms </li> <li> 17. Starter Two principal types of culture are used in cheese making: Mesophilic cultures with a temperature optimum between 20 and 40C Thermophilic cultures which develop at up to 45C. The most frequently used cultures are mixed strain cultures, in which two or more strains of both mesophilic and thermophilic bacteria exist in symbiosis These cultures not only produce lactic acid but also aroma components and CO2. Carbon dioxide is essential for creating the eyes in round- eyed and granular types of cheese </li> <li> 18. Three characteristics of starter cultures are of primary importance in cheese making 1. ability to produce lactic acid 2. ability to break down the protein 3. ability to produce carbon dioxide (CO2). Calcium chloride (CaCl2 ) If the milk is of poor quality for cheese making, the coagulum will be soft. This results in heavy losses of fines (casein) and fat as well as poor syneresis during cheese making. 5 20 grams of calcium chloride per 100 kg of milk is normally enough to achieve a constant coagulation time and result in sufficient firmness of the coagulum. </li> <li> 19. For production of low-fat cheese, and if legally permitted, disodium phosphate (Na2PO4), usually 10 20 g/kg, can sometimes be added to the milk before the calcium chloride is added. This increases the elasticity of the coagulum due to formation of colloidal calcium phosphate, which will have almost the same effect as the milk fat globules entrapped in the curd. </li> <li> 20. Carbon dioxide (CO2 ) Addition of CO2 is one method of improving the quality of cheese milk. Carbon dioxide occurs naturally in milk, but most of it is lost in the course of processing Adding carbon dioxide by artificial means lowers the pH of the milk: the original pH is normally reduced by 0.1 to 0.3 units. This will then result in shorter coagulation time. The effect can be utilized to obtain the same coagulation time with a smaller amount of rennet </li> <li> 21. Rennet All cheese manufacture depends upon formation of curd by the action of rennet or similar enzymes except in cottage cheeses. Coagulation of casein is the fundamental process in cheese making. It is generally done with rennet, but other proteolytic enzymes can also be used. The active principle in rennet is an enzyme called chymosin, and coagulation takes place shortly after the rennet is added to the milk. </li> <li> 22. The two major processes occurs after the addition of rennet are 1. Transformation of casein to paracasein under the influence of rennet 2. Precipitation of paracasein in the presence of calcium ions The whole process is governed by the temperature, acidity, and calcium content of the milk as well as other factors The optimum temperature for rennet is in the region of 40C, but lower temperatures are normally used in the practice, basically to avoid excessive hardness of the coagulum </li> <li> 23. Rennet is extracted from the stomachs of young calves and marketed in form of a solution with a strength of 1:10000 to 1:15 000, which means that one part of rennet can coagulate 10000 15000 parts of milk in 40 minutes at 35C. Bovine and porcine rennet are also used, often in combination with calf rennet (50:50, 30:70, etc.). Rennet in powder form is normally 10 times as strong as liquid rennet. </li> <li> 24. Diagram showing the action of rennet on the casein micelle. The enzyme in rennet cleaves the casein releasing a large peptide. The surface of the micelle changes from being hydrophilic and negatively charged to hydrophobic and neutral. As a consequence, the micelles aggregate to trap fat globules and microorganisms in developing curd. </li> <li> 25. Substitutes for animal rennet Found substitutes for animal rennet about 50 years ago, concerning the vegetarians in India, Israel and the Middle East who refused to accept the cheese with animal rennet. Use of porcine rennet is out of the question in Muslim world, also was a reason to find substitute for animal rennet. In recent years the quality of the animal rennet is a concern which also is a reason. There are two main types of substitute coagulants </li> <li> 26. 1. Coagulating enzymes from plants and, 2. Coagulating enzymes from microorganisms Coagulation ability is best shown by plant enzymes, but the cheese will be having a bitter taste during storage. Enzymes from thistle or cynara are used in some traditional cheese production in the Mediterranean Phytic acid, derived from unfermented soybeans, or Fermentation-Produced Chymosin (FPC) may also be used Today, the most widely used Fermentation-Produced Chymosin (FPC) is produced either by the fungus Aspergillus niger or Kluyveromyces lactis </li> <li> 27. Acid coagulation Any soft cheeses are produced without use of rennet, by coagulating milk with acid, such as citric acid or vinegar, or the lactic acid produced by soured milk. Cream cheese, paneer, and rubing are traditionally made this way The acidification can also come from bacterial fermentation such as in cultured milk </li> <li> 28. CHEESEMAKING A: vat during stirring B: vat during cutting C: vat during whey drainage D: vat during pressing </li> <li> 29. Disturbances in cultures Slow rate of production of lactic acid or failure to produce lactic acid. Antibiotics used to cure udder diseases. Bacteriophages, thermo-tolerant viruses found in the air and soil. Detergents and sterilising agents used in the dairy. </li> <li> 30. Acidification Important for the proper release of curd from whey, and to co...</li></ul>

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