Importance of yeast

1. Importance of Importance of
YeastYeast
The yeasts have a lot of economic The yeasts have a lot of economic
value to the mankind. They have value to the mankind. They have
certain beneficial as well as harmful certain beneficial as well as harmful
activities.activities.

2.  Bread Making:Bread Making: For the manufacture of bread, For the manufacture of bread,
yeast is mixed with white flour, . The process of yeast is mixed with white flour, . The process of
fermentation starts .The bread swells up and fermentation starts .The bread swells up and
becomes spongy due to the pressure exerted by becomes spongy due to the pressure exerted by
accumulated carbon dioxide accumulated carbon dioxide
Beneficial uses:
1) Food Industry

3. Flavor and quality of bread is Flavor and quality of bread is
attained by selecting different attained by selecting different
strains of yeaststrains of yeast

4. Production of alcohol:Production of alcohol:
Ethyl alcohol is manufactured by the Ethyl alcohol is manufactured by the
fermentation of potatoes, cereals, molasses etc.fermentation of potatoes, cereals, molasses etc.
CC66HH12120066 + Yeast  + Yeast zymasezymase > 2C > 2C22HH55OH + OH +
2C02C022
(Glucose) Fermentation (ethyl alcohol) + (Glucose) Fermentation (ethyl alcohol) +
(carbon dioxide)(carbon dioxide)

5. Fermentation:Fermentation:
Breakdown of starch and sugar by Breakdown of starch and sugar by
yeast into carbon dioxide and ethyl yeast into carbon dioxide and ethyl
alcohol in the absence of oxygen is alcohol in the absence of oxygen is
called alcoholic fermentation. The called alcoholic fermentation. The
alcohol is the major ingredient in alcohol is the major ingredient in
brewing industry.brewing industry.

6. Yeast as a source of food:Yeast as a source of food:
Yeast contains nutritive substances and proteins Yeast contains nutritive substances and proteins
in sufficient quantities. in sufficient quantities.
Dried yeast cells contain 40 - 50% of protein. Dried yeast cells contain 40 - 50% of protein.
Some strains of yeast have considerable amount Some strains of yeast have considerable amount
of fat.of fat.

7. As Food SupplementsAs Food Supplements
Yeast as a source of VitaminsYeast as a source of Vitamins
with ultra-violet rays, they produce Vitamin - D with ultra-violet rays, they produce Vitamin - D
Yeast is used in the preparation of Vitamin - B Yeast is used in the preparation of Vitamin - B
complex tablets. When yeast cells are irradiatedcomplex tablets. When yeast cells are irradiated

8. 2) Use in Brewing Industry2) Use in Brewing Industry
Beer:Beer: Yeast is added to  Yeast is added to malted grainsmalted grains and  and
allowed to ferment .allowed to ferment .
The type of yeast used will affect the type and The type of yeast used will affect the type and
flavor of beer produced. flavor of beer produced.
Commonly used Yeast is Commonly used Yeast is S. CerevisiaeS. Cerevisiae, also , also
known as a “top fermenting” or “top cropping” known as a “top fermenting” or “top cropping”
yeast.yeast.

9. Use in Brewing IndustryUse in Brewing Industry
Wine:Wine: Yeast is naturally present on the skins of  Yeast is naturally present on the skins of
grapes and can be used to naturally ferment grapes and can be used to naturally ferment
grape juice into wine. grape juice into wine.
There are many different strains of There are many different strains of S. CerevisiaeS. Cerevisiae
and each will produce a unique flavor and each will produce a unique flavor
characteristic in a finished wine.characteristic in a finished wine.

10. 3) Nutrition:3) Nutrition:  
Yeast is a good source of protein, B vitamins, Yeast is a good source of protein, B vitamins,
and minerals. and minerals.
Yeast intended as a nutritional supplement is Yeast intended as a nutritional supplement is
often sold as “nutritional yeast” or “yeast often sold as “nutritional yeast” or “yeast
extract.”extract.”

11. 4) Use in Medicine4) Use in Medicine
Lowering high cholesterolLowering high cholesterol..
Research showed that taking a specific Research showed that taking a specific
red yeast product for two to three months could red yeast product for two to three months could
significantly lower total and “bad cholesterol” significantly lower total and “bad cholesterol”
(low-density lipoprotein (LDL)(low-density lipoprotein (LDL)
They are also utilized in medicine as a source of They are also utilized in medicine as a source of
enzymesenzymes

12. Medical UseMedical Use
·Yeast causes Lowering of high cholesterol Yeast causes Lowering of high cholesterol
and triglyceride levels caused by human and triglyceride levels caused by human
immunodeficiency virus (HIV) disease immunodeficiency virus (HIV) disease
(AIDS)(AIDS)..

13. 5) Yeast and biotechnology:5) Yeast and biotechnology:
Yeast belongs to Yeast belongs to traditional biotechnologytraditional biotechnology
In the industry of In the industry of fermentationfermentation, yeast is used , yeast is used
not only in food industries to make bread, wine not only in food industries to make bread, wine
and beer, but also in non-food industries, such and beer, but also in non-food industries, such
as the Biofuel industry, to produce ethanol.as the Biofuel industry, to produce ethanol.

14. 6) Use in Molecular Genetics6) Use in Molecular Genetics
Yeasts are Model organisms in genetics.Yeasts are Model organisms in genetics.
Used as Synthetic pathways for antibiotics or Used as Synthetic pathways for antibiotics or
other molecules of interest .other molecules of interest .
Used in Gene TherapyUsed in Gene Therapy

15. 7) Cleansing of Environment7) Cleansing of Environment
Yeast protects and cleans the environment by Yeast protects and cleans the environment by
following ways:following ways:
1)1)Pollution cleanupPollution cleanup
2)2)Waste recyclingWaste recycling
3)3)Crop protection Crop protection
4)4)Many Yeasts live symbiotically in organisms. Many Yeasts live symbiotically in organisms.
5)5)BioremediationBioremediation

16. Disadvantages:Disadvantages:
1) YEAST & WEIGHT LOSS1) YEAST & WEIGHT LOSS
Yeast infections can range in severity from Yeast infections can range in severity from
minor discomfort to a life-threatening ailment, minor discomfort to a life-threatening ailment,
depending on your immune system, the type of depending on your immune system, the type of
yeast, the location of the yeast and the way you yeast, the location of the yeast and the way you
combat it combat it

17. 2 ) HAIR LOSS DUE TO RED 2 ) HAIR LOSS DUE TO RED
YEAST RICEYEAST RICE
Red yeast rice is a culture of the yeast, grown on Red yeast rice is a culture of the yeast, grown on
rice and consumed as food, may cause hair lossrice and consumed as food, may cause hair loss

18. 3) Food spoilage3) Food spoilage
  During their growth, yeasts metabolize some During their growth, yeasts metabolize some
food components ( sucrose, ethanol, acetic acid) food components ( sucrose, ethanol, acetic acid)
and produce metabolic end products. This and produce metabolic end products. This
causes the physical, chemical, and sensible causes the physical, chemical, and sensible
properties of a food to change, and the food is properties of a food to change, and the food is
spoiled spoiled

19. 4) Intoxication4) Intoxication
Yeasts cause Intoxication of food and imbibed Yeasts cause Intoxication of food and imbibed
drinks drinks

20. 5) Resistant5) Resistant
Yeasts can tolerate very high temperature, hence Yeasts can tolerate very high temperature, hence
difficult to check their reproductiondifficult to check their reproduction

21. 6) Plant Pathogens6) Plant Pathogens
Certain species of Yeast are plant pathogens and Certain species of Yeast are plant pathogens and
decrease crop productiondecrease crop production

22. 7) Animal Diseases7) Animal Diseases
Some species cause skin, hair and nail infections Some species cause skin, hair and nail infections
in humans e.g. Candida Albicansin humans e.g. Candida Albicans
Yeasts cause respiratory diseases in humans Yeasts cause respiratory diseases in humans
e.g.Aspergilus e.g.Aspergilus

23. ReferencesReferences
http://foodreference.about.com/od/Ingredients_Basics/a/What-Is-Yeast.htmhttp://foodreference.about.com/od/Ingredients_Basics/a/What-Is-Yeast.htm
  
http://wiki.answers.com/Q/What_is_the_economic_importance_of_yeast#ixzz26GjuRCFnhttp://wiki.answers.com/Q/What_is_the_economic_importance_of_yeast#ixzz26GjuRCFn

http://www.ehow.com/about_5366675_role-http://www.ehow.com/about_5366675_role-
yeast-breadmaking.htmlyeast-breadmaking.html
http://www.livestrong.com/article/286403-http://www.livestrong.com/article/286403-
yeast-weight-loss/ yeast-weight-loss/

24. ReferencesReferences
http://www.lesaffrehumancare.com/about-http://www.lesaffrehumancare.com/about-
lesaffre-human-care/yeasts-and-lesaffre-human-care/yeasts-and-
biotechnology/biotechnology-fields-of-biotechnology/biotechnology-fields-of-
application.htmlapplication.html
http://www.marketsandmarkets.com/Market-http://www.marketsandmarkets.com/Market-
Reports/yeast-industry-268.htmlReports/yeast-industry-268.html
www.wikipedia.org.comwww.wikipedia.org.com
www.Google.comwww.Google.com

25. Prepared ByPrepared By
Syed Imran Abbas Shah.Syed Imran Abbas Shah.
Punjab,PakistanPunjab,Pakistan