FERMENTATION: INDUSTRIAL ASPECTS

GULPREET KAURDepartment of Biological SciencesFlorida Institute of Technology, FL 32901

OBJECTIVES

•Describe the chemistry of Fermentation

•List at least five fermented food products

•Describe the process of industrial

production of one fermented food product

FERMENTATION?

Chemical changes in Organic substrates through the activity of living microbes

EXAMPLES?

INDUSTRIAL ALCOHOL PRODUCTION

C6H12O6 C2H5OH + CO2

Sugar Ethanol

Yeast

Fermentation

NO OXYGEN!

Yeast

•Eukaryotic•3-4 µm in size

•Mostly anaerobic•Grow on organic

compounds

Saccharomyces cerevisae

Wine Production

PROCESS OUTLINE

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

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

Pre-treatment

•Sterilization - to kill undesired microbes•SO2 or sulphites are used

• '2-6 oz. Potassium Bisulphite added per tonne of grapes

Fermentation

•Saccharomyces ellipsoideus used

•Starter culture prepared▫To facilitate quick growth

Large supply of oxygen Stirring

▫No alcohol produced!

•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

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

QUESTIONS?

ASSESSMENT 1

•What is a starter culture? What is its purpose?

ASSESSMENT 2

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

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