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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