1. FERMENTATION: INDUSTRIAL ASPECTS
GULPREET KAUR
Department of Biological Sciences
Florida Institute of Technology, FL 32901

2. OBJECTIVES
• Describe the chemistry of Fermentation
• List at least five fermented food products
• Describe the process of industrial production of
one fermented food product

4. FERMENTATION?
Chemical changes in Organic substrates
through the activity of living microbes

5. EXAMPLES?

7. INDUSTRIAL ALCOHOL PRODUCTION
C6H12O6 C2H5OH + CO2
Sugar Ethanol
Yeast
Fermentation
NO OXYGEN!

8. Yeast
• Eukaryotic
• 3-4 µm in size
• Mostly anaerobic
• Grow on organic
compounds
Saccharomyces cerevisae

9. Wine Production

10. PROCESS OUTLINE
• Picking, handling, crushing Grapes
• Pre-treatment
• Fermentation
• Post-fermentation
• Racking
• Storage and Ageing
• Clarification
• Packing

11. Grape Processing
Good varieties of Grapes -
Zinfandel, Merlot, Blue
Portuguese, Refosco
Picked at Maturity –
Balling Degree of 21 to 23⁰
Crushed in Machines -
• Machine could be made of
Stainless Steel or Nickel
• Should not be made of
Iron, Steel, Tin or Copper

12. Pre-treatment
• Sterilization - to kill undesired microbes
• SO2 or sulphites are used
• ̴2-6 oz. Potassium Bisulphite added per tonne of
grapes

13. Fermentation
• Saccharomyces ellipsoideus used
• Starter culture prepared
▫ To facilitate quick growth
 Large supply of oxygen
 Stirring
▫ No alcohol produced!

14. • Fermentation in Tank
▫ Starter culture added to Grape Juice
▫ Time: 3-5 days
▫ Temperature: 70-90⁰F
▫ No oxygen added
▫ Stirring twice a day
▫ Initial Sugar concentration: 22 ⁰ Balling
Final concentration of alcohol = Balling reading × 0.575
At the end of this step:
• Sugar concentration : 0-4⁰ Balling
• Lots of CO2 has accumulated in the tank

15. Post- Fermentation Processing
• Kept in Closed Storage tanks with bungs
▫ 7-10 days
▫ Excess CO2 released
▫ No sugar left – Yeast dies off!
• Racking
• Storage and Ageing
• Packaging

16. QUESTIONS?

17. ASSESSMENT 1
• What is a starter culture? What is its purpose?

18. ASSESSMENT 2
• What do you think would happen if an alcohol
fermentation tank was not closed properly while
processing ?

19. ASSESSMENT 3
From the list given below, write an ‘F’ in front of
the foods that you think are fermented and an ‘N’
for foods that are not.
• __ Coca Cola
• __ Yoghurt
• __ Bread
• __ Hamburger
• __ Whisky
• __ Pizza