Transcript Fermentation of Tea - Lectures For UG-5

Fermentation of Tea
Group - F
Simra Khattak
Saif Ullah Khan
Maryam jadoon
Aqib javed
Ammarah Khan
Nawal daud
Afifa Maryam
A night before exam
Yes, your guess is right
After taking tea
What is tea?

Aromatic beverage commonly prepared by pouring
boiling water over leaves of plant, Camellia sinensis.

Tu in Chinese, Cha in Bengali, Chai in Urdu.

tea plants are native to Asia

Highest density in border of Burma and Western
China.
Types of tea
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Hundreds of types of tea,
based upon different recipes.

Tea processing methods are different.
Basic difference

All kind of tea, are prepared by from plant, Camellia sinensis.

3 major classes, based upon extent of fermentation

Green, yellow, Black.

Least fermented- mildly fermented- highly fermented.
Why fermentation is required.

Preservation:
Antimicrobial agents

Taste:
Astringency is removed

Flavor:
Polyphenol

Aroma:
Volatile organic compounds
Biochemistry of Tea
Health and therapeutic advantages

Anti- oxidant activity of flavonoids (Ryan and Sutherland, 2011)

Reduces oxidative damage (khan et al, 2005)

Anti-cancer properties( Shukla and Taneja 2002)

Reduces atherosclerosis. (Vinson et al, 2004)

Anti-inflammatory properties (Nag Chaudhuri et al. 2005)

Maintenance of dental health. (Simpson et al. 2001)

Maintenance of bone health ( Hegarty et al, 2001)
Generalized process flow diagram
Hand picking
Compressing
Sorting
Steaming
heating/burning
Rolling
fermentation
withering
Spontaneo
us
oxidation
Slow oxidation
Final product
Optimum conditions
Types of teas actually vary from different fermentation procedures, each of
which having its own optimal conditions.
1.Green tea: (Fairley and Swaine, 1975)
Ph: 4.3-5.6
Temperature: 5°-30°C
Initiating Agent: H2O2 suspension.
2.Black tea: (Robert and Woods)
PH: 5-6
Temperature: 25°C
Fermentation, Supreme step of process

All the hundred different types of tea have common steps of tea processing,
but they only differ in FERMENTATION step.

Fermentation gives tea, its characteristic features.
•
Quality (type)
•
Aroma
•
Taste
•
Flavor
Selected types of tea

Kombucha tea

Pu-erh tea
Microbes being used in fermentation
Aspergillus Niger (Pu-erh tea)
Saccharomyces cerevisiae (kombucha
tea)
1.
2.
3.
4.
• the budding yeast commonly known as
brewing yeast
• used to make bread, wine, beer and
kombucha tea
• Favors aerobic fermentation in high
concentrations of sugar ,tolerate high
concentrations of ethanol.
Filamentous fungi
Pu-erh tea
Approved by FDA; GRAS
Toxicity is rare ,carefully treated in to
prevent spore formation
Kombucha, brief description

Effervescent fermented tea.

Can be black or green.
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It has many health benefits
Kombucha

Ingredients:

A starter culture which is kombucha (already brewed) or
vinegar.

scoby (kombucha mushroom)

Tea, green or black.

Organic sugars such as molasses
process
kombucha

Biochemical process
1.
• Alcohol formation from
sugar
2.
• acid formation from
nutrients and alcohol.
Pu-erh tea, brief description

Pu-erh is a microbially fermented tea.

Pu-erh undergoes solid-state fermentation
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The key organism found and responsible for almost all pu-erh fermentation
is Aspergillus niger.
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Longer the aging, more expensive and flavoursome.
Pu-erh tea

Process:
Take tea
leaves
packaging
Heat and Dry
compressing
Secondary
oxidation/fermentation
Endo-oxidation(tea leaf
enzymes)
Aging
Exo-oxidation(
catalyzed by microbes)
mainly Aspergillus niger
SIGNIFICANCE IN FOOD INDUSTRY
(PARTICULARLY IN PAKISTAN) AND
STATISTIC VALUES:

Beverages like tea and coffee serves to be second most famous beverage around the
world, right after water.

They are the second largest planted crops after wheat.

Pakistan serves to have around 170 units operating in this very sector.

Contributing towards growth in upstream and downstream industries
 Considering data from food and agriculture organization, FAO for tea production across
global market
 While considering data from Federal Bureau of statistics, Government of
Pakistan, average import of tea in recent last years is around as follows.
In the recent years, along with tea, coffee consumption has been
markedly increased. This can be visualized from following statistic
data from ICO.