Food Fermentation Technology Flashcards
Fermentation
Any process involving the production of organic products by the mass culture of a microorganism
Microorganism, grown on large scale, able to produce valuable commercial products or to carry out important chemical transformation
Zymology
The art of studying fermentation
Fermentation Technology
Discipline of biotechnology which involves he development of new fermentation processes & the improvement of the current process
What is fermentation in biochemistry?
1) A metabolic process of deriving energy fro organic compounds.
2) The common group of microb involved is Bacteria, Yeasts, and Molds
3) Fermentation allows the production of a small amount of ATP in anaerobic conditions
Primary fermentation processes
1) Lactic Acid Fermentation
2) Alcohol Fermentation
How does lactic acid fermentation happens in human?
1) Happens in many cells including human muscle cell during rapid exercise
2) Muscles are not getting enough O2 to produce all the ATP they need, so lactic acid fermentation was used
3) This process regenerates NAD+ so that glycolysis can continue to make small amounts of ATP
Lactic Acid Fermentation in Food
Lactic acid fermentation is a metabolic process by
which glucose and other six-sugars are converted into cellular energy and the metabolite lactate, which is lactic acid in solution
Examples of the products that were produced by LAB
1) Fermented Vegetables = Pickles
2) Fermented Dairy Product = Yogurts, Cheese
3) Fermented Cereal = Idli, Dosa
4) Fermented Meat = Salami
LAB
1) Major group
- Lactobacillus
- Lactococcuss
- Pediococcus
- Streptococcus
2) LAB are mesophiles (10 - 40 oC)
3) pH rang from 4 - 8
4) They grow readily in most food substrates and lower the pH rapidly to a point where competing organisms are no longer able to grow.
What is homolactic fermentation?
- Homolactic fermentation is a type of fermentation where microorganisms, such as certain bacteria, convert sugars into lactic acid.
- In homolactic fermentation, the microorganisms only produce lactic acid as the main end product.
- This process does not produce any gas or other byproducts.
What is heterolactic fermentation?
- Heterolactic fermentation is a type of fermentation where microorganisms convert sugars into a combination of lactic acid, ethanol (alcohol), and carbon dioxide gas.
- In heterolactic fermentation, the microorganisms produce lactic acid as well as other byproducts.
LAB (Gram-positive bact)
Lactic acid bacteria (LAB) are gram-positive bacteria, including Lactobacillus, Leuconostoc, and Streptococcus, that play a vital role in food production.
In products like buttermilk, yogurt, and cottage cheese, Lactobacillus bacteria produce acid through fermentation, which helps eliminate competing bacteria.
This acid also benefits humans who consume these foods. During the production of yogurt and cheese, the lactic acid fermentation creates a highly acidic environment that causes proteins in milk to solidify, resulting in the formation of curds.
Advantages of brining and lactic acid fermentation
• low cost
• have low energy requirements for both processing and preparing foods for consumption
• high yield acceptable
• diversified flavors.
• microbial spoilage
• toxin development
The use of salts in fermentation
Depending on the salt concentration, salting directs the subsequent course of the fermentation, limiting the amount of pectinolytic and proteolytic hydrolysis that occurs, thereby controlling softening and preventing putrefaction (decay process).
ALCOHOL FERMENTATION
A biological process in which sugars such as glucose, fructose, and sucrose are converted into cellular energy and thereby produce ethanol and carbon dioxide as metabolic waste products.
Alcohol fermentation is done by yeast and some kind of bacteria
Yeast were used to break down complex carbohydrates to simple sugars
The process of alcohol fermentation
1) Begins after glucose enters the cells
2) The glucose is broken down into pyruvic acid
3) Pyruvic acid is then converted to CO2+Ethanol+Energy
4) Takes place in anaerobic conditions
Etahnol is used as
• Solvent - Resins, Cosmetics, Pharmaceutical
• Chemical intermediate - Petroleum derived chemicals
• Fuel - Used as a biofuel
Bacteria for ethanol production
1) Many bact can produce ethanol
2) Many of them produce end products such as;
- Other alcohols
- Organic acids
- Polyols
- Ketone gases
3) Bacteria that metabolize EMP pathway;
- Clostridium sp
- Streptococcus sp
Yeast for ethanol production
Primary interest are Saccharomyces sp
How does the organism for the ethanol production were selectedd?
1) Low pH
2) High temperature
3) High growth & fermentation rate
4) Osmotolerance
What are the raw materials for the ethanol production?
1) Saccharine
2) Starch
3) Cellulose materials
Saccharine
1) Glucose, Fructose, Maltose
Molasses
1) Contain 52-55% fermentable sugars
2) Molasses with above 15-20% sugar contents will need to be dilute
Cane Sorghum
1) 14% fermentable sugar contents
2) Extraction requires heavy duty
3) Acidification is necessary
Sugar Beet
1) Mostly preferred
2) 15% sugar, 82% water, small amount of starch
3) Juice is extracted by crushing
4) Enzymes improve the alcohol yield
Sugar Corn Waste
1) Sugar is extracted same with sorghum
2) Back slopping in the range of 20-25%
3) Acidification is necessary
Grains
1) Must be milled, diluted, cooked, and fermented
2) Conttain large amounts of fermentable materials
3) Alcohol yield is dependent on converted starch
Jerusalem Artichokes
1) Abundant source of alcohol (16-18%) fermentable materials
2) Materials should be crushed to pulp and cooke for 2-3 hours
3) Dilution is not necessary
Potato
1) Cooked with steam under pressure
2) After cooking, mash is cooled to conversion for 15-20 minutes
3) Once converted, pH should be adjusted mash is fermented
Sweet Potato
1) Similar manner to potatoes
2) Dilution is necessary
Starchy materials are of 2 categories
• Encased by grain hulls
• Starch is readily available
Malting
1) Seeds are moistened & allowed to sprout
2) The seeds are powdered, and the powder is called malt
Miling
1) Grains are milled to expose he starch
2) Material is ground as fine as possible
Cooking
1) Starch is liquefied by boiling under pressure
2) TO dissolve the water soluble starches
3) Done with steam under pressure at 100oC
4) Use less water during cooking
5) Water may be added to dilute the mash
6) So cooling time may be saved
7) The cooked malt is called mash
Conversion of starch
1) Conversion starch to fermentable sugar by certain enzymes in the malt or by acid hydrolysis
Enzyme Extracts
1) Commercially available
2) 3 basic types;
- Alpha amylase = Produce dextrose
- Beta amylase = Prooduce maltose
- Gluco amylase = Reduce the remaining starch
Acid hydrolysis
1) Requires acid proof equipment and high temperature
2) Dilute mineral acids is added to grain slurry
3) Then immediately neutralized with calcium hydroxide
Mash Cooling
1) Done after conversion and pH is checked
2) Cooling coils are used for cooling
Product recovery
1) Cell biomass is separated by centrifugation/sendimentation
2) Desired microorganism aggregated, readily separated from broth by sendimentation
Separation of cell biomass
1) Flocculation
2) Filtration
3) Flotation
4) Centrifugation
Flocculation
1) Flocculation agents is added;
- Hydrocolloids
- Inorganic salts
2) Produce large aggregate which still settle more readily
Filtration
1) Bacterials cultures - Absolute filters
2) Filamentous fungi - Depth filters
Flotation
1) By introducing gas into liquid
2) Cells gets adsorbed to the gas bubbles and rise to the foam layer at the top of vessels
Distillation
1) Separation for a mixture of liquids
2) It relies on differences in boiling points of the components liquids to be separated
3) The mixture to be separated is added to the distilled pot and is heated
4) Low boiling point will vaporize first
5) This vapors passes into distilling head and then into condenser
What is ethanol boiling point
78.5
Purification
1) HPLC
2) GLC
Applications of ethanol
1) Used as antiseptic
2) Used as a biofuel
3) As a disinfectant
4) In many medicines and drugs
Byproduct
1) Distiller dried grain with soluble (DDGS)
2) CO2 - Preparation of soft drinks
3) Yeast biomass
