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Institut de Tehnologie du Cambodge Génie Chimique et Alimentaire

Institut de Tehnologie du Cambodge Génie Chimique et Alimentaire. Lecturer: Dr. HUL Seingheng Group 7: PENG Chanthol PHEAP Kanika PHEAP Theavy PHOEURN Vuthamry POENG Huykheng. TOPIC: YEAST PRODUCTION. INTRODUCTION. Yeast Unicellular-Fungi Eukaryotic

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Institut de Tehnologie du Cambodge Génie Chimique et Alimentaire

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  1. Institut de Tehnologie du CambodgeGénieChimique et Alimentaire Lecturer: Dr. HUL Seingheng Group 7: PENG Chanthol PHEAP Kanika PHEAP Theavy PHOEURN Vuthamry POENG Huykheng

  2. TOPIC: YEAST PRODUCTION

  3. INTRODUCTION Yeast Unicellular-Fungi Eukaryotic Facultative anaerobes Capable of forming colonies on solid culture media Classification of Bakery’s yeast Kingdom: Fungi Phylum: Ascomycota Subphylum: Saccharomycotina Class: Saccharomycetes Order:Saccharomycetales Family: Saccharomycetaceae Genus: Saccharomyces Species: S. cerevisiae

  4. INTRODUCTION

  5. INTRODUCTION • Baker’s yeast is manufactured by six major companies in the United States. Those are Universal Foods (Red Star Yeast), Fleischmanns, Gist-Brocades, Lallemand (American Yeast), Minn- dak, and Columbia.

  6. PRODUCTION OF BAKER’S YEAST • As a result of grain shortages resulting from World War I a shift was made from the use of grain to the use of beet molasses, supplemented by ammonia and phosphate. • There are two major steps in the development of baker’s yeast technology: • Vienna process • Classical batch method and Zulaut method.

  7. PRODUCTION OF BAKER’S YEAST • Yeast Strain Used • Nowadays, the most common baker’s yeast strain is Saccharomycescerevisiae. • Yeast strains used for the modern fast-rising dough have been developed with the following properties: • Ability to grow rapidly at about T= 20-25oc • Ability to produce large amount of CO2, rather than alcohol • Good keeping qualities

  8. PRODUCTION OF BAKER’S YEAST • High invertase and other enzyme activity to hydrolyse the higher glucofructans rapidly • Ability to grow and synthesize enzyme and coenzymes under the anaerobic conditions of the dough • Ability to resist the osmotic effect of salts and sugars in the dough

  9. PRODUCTION OF BAKER’S YEAST • Substrate • The substrate usually used for baker’s yeast production is molasses. • When 2 types of molasses are simultaneously available, they are then mixed in equal amounts so that the nutritional deficiency of one type is made up by the other. • When only 1 type of molasses is available deficiencies are made up by adding appropriate nutrients.

  10. PRODUCTION OF BAKER’S YEAST • The molasses is: • Clarified : to impart undesirable color to the yeast and to reduce foaming. • Sterilized (is achieved by heating at 100oc-110oc for about 1h) after pH adjusted (by adjusting to pH 6-8) to prevent caramelization of the sugar. • P, NH4 , Mg, K, Zn, thiamin are added for maximum productivity to be mixed molasses.

  11. Fermentor processes1lb dry wt. of yeast required 4.3lb of molasses, 0.9lb of NH3, 0.3lb of NH4H2PO4 , 1.1lb of (NH4)2 SO4 and 60lb of air. Steam sterilized fermentor

  12. PRODUCTION OF BAKER’S YEAST Harvesting the yeast The period of fermentation varies from 10 to 20hr. Process: The fermentation broth is cooled Storing cell in centrifugal separator Including water Centrifugation until they are lighter in color

  13. PRODUCTION OF BAKER’S YEAST • Adding before filtration 0.2-0.6% sodium chloride • Passing over a rotary vacuum filter or through a filter press • Excess salt is removed during filtration by spraying water over the filtered yeast • Yeast production

  14. PRODUCTION OF BAKER’S YEAST • Packaging • The yeast is packaged as compressed yeast or active dry yeast. • Compressed yeast: is mixed with fine particles of ice, starch, vegetable oils which all help to stabilize it. • It is then compressed into blocks of small (1-5 Ib) blocks for household use or large (up to 50 Ib) for factory bakery operations. • Store at – 7 to 0°C and transported in refrigerated vans.

  15. PRODUCTION OF BAKER’S YEAST • Active dry yeast: is more stable in that it can be used in areas or countries where refrigeration is not available. Compressed yeast Active dry yeast

  16. FOOD YEASTS • Important : to provide protein; to impart flavor and to supply vitamins especially B-vitamins. • Food yeasts have several synonyms: dried yeast, inactive dried yeast, dry yeast, dry inactive yeast, dried torula yeast, Saccaromycessiccum, sulfite yeast, wood sugar yeast, and xylose yeast. • Yeasts used as food yeasts: • Saccharomycescerevisiae, • Saccharomycescarlbergiensis, • Saccharomycesfragilis* • Candida tropicalis

  17. FOOD YEASTS Ethanol: Substrate for food yeasts production that is used only by: Saccharomycesfragilis Candida tropicalis**. Note: * can utilize lactose for fermentation of whey. ** most widely used in food yeast preparation. *** using in U.S is the preference.

  18. FOOD YEASTS • Substrate most commonly used for food yeast production are: • molasses: the fed batch method. • sulphite liquor: the continuous • using Candidautilis fermentation. • wood hydrolysate • and whey. Using saccharomyceslactis, Kluyveromyces***, • Other unconventional sources have been developed such as: hydrocarbons, alcohol and wastes of various types. But only the most commonly substrate will be discussed.

  19. FEED YEAST Feed yeasts is used to produceanimal food. Several thousands tons of yeasts are recovered from breweries around the world annually. Cells are recovered by centrifugation and spray or drum-dried

  20. ALCOHOL YEASTS • Alcohol yeasts are those to be used in beer brewing, wineries and distilleries for spirits of industrial alcohol. • The production of alcohol yeasts, the aim is cell production • The yeasts used are specially selected strains of the following: • Brewing:Saccaromycescerevisiae, SaccharomycesuvarumcarlbergensisS.uvarum. • Wine: Saccharomycescerevisiae, Sacch.bayanus, Sacch.beticus, Sacch.elipsoides • Distillery yeasts: Saccharomycescerevisiae

  21. ALCOHOL YEASTS • The medium used in the multiplication of the yeast is made of materials to be found in the final fermentation. • Alcohol yeasts are usually recovered and reused for several rounds of fermentation before being discarded.

  22. YEAST PRODUCTS • Yeasts are used in the various products like: • Food • pharmaceutical and related industries. • Yeast extracts are used in the preparation of soups, sausages, gravies, to which they impart a meaty flavor. • The extracts may be obtained by autolysing the yeast and thereafter spray-drying or drum-drying with or without extracting soluble materials from the autolysate. • Yeast extracts are consumed for dietary purposes on pharmaceutical grounds as a source of vitamins, mainly vitamin B12.

  23. CONCLUSION • The important of yeast in industrial food for human and animal. • How yeast is produced involving substrate, fermentor processes, harvesting and packaging.

  24. Thank For Your Attentive Listening! Welcome for questions

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