Tea processing is the method in which the leaves from the tea plant Camellia sinensis are transformed into the dried leaves for brewing tea.

1. By : Chirantan Sandip Saigaonkar
Fts/2020/41
Shramshakti college of food technology , maldad , sangamner
chirantansaigaonkar2032@gmail.com
TEA
PROCESSING

2.  The word “Chai” is derived from a Cantonese word “茶” (cha) which means tea.
 Tea belongs to the genus Camellia and family Theaceae.
 It is one of the most popular beverages in the world.
• Its sensory properties
• Relatively low retail price
• Apparent health benefits
 It is a capital earning industry: Valuable source of income to many tea producer countries.
 Have been used in India for more than 160 years.
 Varieties of tea viz.
1. Chinese variety (C. sinensis var. sinensis) and
2. Assamese variety (C. sinensis var. assamica)
INTRODUCTION AND CLASSIFICATION
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3. Origin &
Distribution
 Centre of origin Southeast China.
 Principle tea producing countries:
 China, India, Sri Lanka, Indonesia and Kenya.
 India (1239150 tons) is the 2nd largest producer
next to China (2350000 million tons)
 The major tea-producing states in India are:
 Assam (52%), West Bengal, Tamil Nadu, Kerala,
Tripura, Arunachal Pradesh, Himachal Pradesh,
Karnataka, Sikkim, Nagaland, Uttarakhand,
Manipur, Mizoram, Meghalaya, Bihar, Orissa.
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4. CHEMICAL COMPOSITION
Healthy Beverage: owing to its chemical constituents
Fresh tea composes of water (75–78%)
and dry matter (22–25%).
From therapeutic point of view:
polyphenols, caffeine, vitamins and
minerals are pivotal.
Polyphenols, Caffeine and Essential Oils Flavour
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5. POLYPHENOLS:
Total polyphenols
Flavanols
i. (-)- Epicatechin
ii. (-)- Epicatechin gallate
iii. (-)- Epigallocatechin
iv. (-)- Epigallocatechin gallate
v. (+)- Catechin
vi. (+)- Gallocatechin
vii. Converted cathechin
a. Theaflavins (orange or orange–red color to tea)
b. Thearubigins (red–brown or dark-brown pigments in black
tea)
• high antioxidant properties
• can act as scavengers to ROS and
• prevent damages to cellular
macromolecules
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6. Alkaloids: Caffeine
• Trimethylxanthine
• Methylation of purine necleotides.
• Present in 63 species.
• Generally consumed through tea (12%).
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7. Vitamins
Vitamins in tea:
Vitamin B (riboflavin, nicotinic acid,
pantothenic acid and thiamine)
Vitamin C
Vitamin E
Most of them are lost during the processing of
fresh green tea leaves to black tea and oolong
tea.
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8. Minerals
 The various minerals and trace elements known to be present
in tea leaves include
fluorine, sodium, potassium, calcium, aluminum,
phosphorus, cobalt, iron, copper, iodine,
selenium, nickel and strontium
 Fluorine (3–200 ppm) in leaves could prevent dental decay.
 Potassium (9000–34000 ppm) could have a supplementary
effect in diets lacking potassium
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9. Free amino acids
Imparting colour to the tea liquor.
Free amino acids in tea include:
theanine, asparitic acid, threonine,
glutamic acid, glycine, α-alanine, valine,
methionine, isoleucine, leucine,
tyrosine, phenylalanine, lysine,
histidine, arginine, glutamine,
asparagines and tryptophan.
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10. Pigments
Tea pigments: Chlorophyll a and b and carotenoids
(lutein, β-carotene, neoxanthine and violaxanthine)
Have considerable medicinal properties particularly
beneficial in cardiac diseases.
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11. Types
of
Tea
Conventional:
Black tea
Oolong tea
White tea
Green tea
Yellow tea
Non-conventional
tea products
Instant tea (cold-
and hot-soluble),
Flavored tea, and
Decaffeinated
tea.
Others
canned or bottled
teas,
soluble tea mixes,
tea beverages,
frozen tea liquid,
and
tea tablets
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13. HARVESTING
 Interval of 7-14 days throughout the year.
 Terminal young tender portions of peripheral
shoots.
 Two leaves and a bud
 Quality of final product deteriorates with an
increase in mature leaf content.
 Two methods:
1. Plucking by hand (generally preferred)
2. Plucking by machine: modified hedge trimmers and
motorized machine pluckers.
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14. WITHERING
 Leaves spread (20-45 cm) on trays/ loft/
rooms.
 Cross flow of ambient or slightly heated
air (raised to 3-5 oC) is maintained for 12 -
14 hr
 Reduce moisture content from 75–85%
moisture to 50–70% .
 Changes in cell membrane permeability
 preconditions the leaf for maceration or
rolling.
 Gentle handling is a must to reduce
chances of oxidation during the process.
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15. Rolling/ maceration/ leaf distortion
 To disrupt the cells of tea leaves
 to mix the substrates (e.g., polyphenols) with the enzymes (e.g., polyphenol
oxidase)
 triggering the fermentation process.
 Two methods: Orthodox and CTC
 Others: Rotorvane, Legg-cut.
Orthodox method
Orthodox grades are long particles or whole leaf
type
Traditional method: rolling the withered tea
leaves in rollers
It diffuses slowly, breaks into smaller particles
easily while packing and most of all, it brews
less cups per kilogram
More costly to produce.
Retain delicate flavour inherent in plucked tea. 13-08-2022
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16. CTC (Crush-tear-curl) method
CTC grades are mostly granulated in
appearance
Crushing, tearing and curling the tea leaves
in between twin metal cylinders with
serrated surfaces
Quick brewer and yielding more cups per kg
Cost of manufacture is less due to less
waste and less caution needed in plucking.
In India today, over 80% of tea production is
of the CTC type, amounting approximately
to a staggering 650 million kg/year
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17. FERMENTATION
 Enzymatic oxidation process.
 Polyphenols in the leaf get oxidized
by PPO.
 Formation of theaflavins: Responsible for
briskness and brightness of tea.
 Formation of Thearubigins: Responsible for
colour and strength of tea.
 Breakdown in chlorophyll and changes
in carotenoids.
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18. FERMENTATION
 Spread in thin layers 5–8 cm deep on
the factory floor or on troughs or
racked trays in a fermentation room
(0.75 to 3 hrs).
 Temperature, oxygen and humidity:
important factors.
 Temperature varies between 24°C and
27°C and is controlled by using
humidifiers or cool air (90-95 %RH)
 The liquor characteristics of black tea can be
determined by control of temperature and time
of fermentation (chemical transformation). 13-08-2022
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19. FERMENTATION
 Fermentation is continued
 till the colour of leaf mass turns coppery red development of a pleasant
characteristic aroma (1-2 hours).
 Theaflavin: Thearubigin::1:10.
 Declination in tannin (20 % to 10-12%)
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20. Firing/ Drying
 To arrest fermentation (deactivation of enzymes): Hot air (90-120oC).
 To reduce moisture content (3-4 %).
 There are many approaches to drying: from simple batch dryers to very
sophisticated fluidized bed designs.
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21. Sorting and grading
 Final step:
 classification of leaf according to the size
and
 removal of stalk and fibre particles.
 Tea is often winnowed to remove the
stalky material.
 Grading and sorting: mechanically
oscillatory sieves fitted with meshes of
many different sizes.
 The major grades, in descending order of
size are whole, broken, fannings and
dusts.
Whol
e
Fanni
ngs
Broke
n
Dust
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23. Storage
 Chemical changes take place during the storage of finished tea products,
 Tend to lose all residual greenness and harshness within a few weeks.
 Tea remains sound and full of flavor for more than 1 year, if kept in a cool
place and protected from moisture and oxygen.
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24. Green Tea
Plucking
Japanese method (Steamed)
Steaming in revolving cylinder with agitator
for few minutes to soften the leaves.
Chinese method (Pan fried)
Placed on metal pan over hot flame for few minutes to render
leaves soft and pliable
Rolling
Traditionally using palm and fingers. Nowadays modern
machineries are available (10-15 mins). Sometimes, half
rolled leaves are partially dried rolled again.
Firing/ Drying (6 % MC)
Sorting/ Grading/ Packing
No Fermentation
The tannin,
chlorophyll, Vitamin C
and organic acids
reduced only slightly
due to enzyme
inactivation.
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25. Oolong Tea
Plucking
Withering
(spread on bamboo mats, exposed to sunlight and the leaves are turned 2–3
times. Leaves become soft; 10-20 % moisture loss)
Rotating
Indoors: 20–25°C and 75–85% RH for 6-8 hrs. 5-6 times. Leaf cells disrupted and
fermentation takes place. Edges turn red spreading to inner parts of leaves.
Fixing
Pan heating to 180-220oC for 3-7 minutes to arrest
fermentation.
Sorting/ Grading/ Packing
• Partial fermentation
• Red
• Intermediate between black
and green;
• Being closer to black
Rolling (Less breakage. Can be brewed
repeated)
Drying (2 stages)
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26. Yellow Tea
Plucking
Withering
(spread on bamboo mats, exposed to sunlight and the leaves are turned 2–3
times. Leaves become soft; 10-20 % moisture loss)
Roasting
166–176°C for 2–3 min with continuous stirring. Cool for 30-60 mins.
Rolling
50–60 min.
Sorting/ Grading/ Packing
• No fermentation
• Intermediate between black
and green;
• Being closer to green tea
Firing (4-5% MC)
tannins, volatile compounds
and other constituents
undergo chemical
transformations: Yellow tea
darker than green tea.
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27. White Tea
Plucking
Withering
(spread on bamboo mats, exposed to sunlight for several hours and moved indoors. Repeat for
2-3 days. Then continue withering indoors (29-30oC & 65-70% RH) till buds reach 30% MC/
leaves about 13 %.
Rolling
Before temperature drops. 2-3 times with suitable pressure.
Firing
Bud tea: 40–45°C for 20–30 minutes,
Leaf tea is fired at a temperature of 70–80°C for 10–15 min.
• No fermentation
• Bud white tea group and Leaf
white tea group.
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28. Specialty Tea: Value addition to tea.
1. Flavoured tea
 Blended with flower
petals, spices, herbs,
lemon, bergamot,
chocolate, rose, to
impart scent to tea.
 In India cardamom,
ginger, lemon,
bergamot and mint are
popular flavoured teas.
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29. Specialty Tea: Value addition to tea.
2. Brick Tea/ Compressed tea
 Black or green
 Compressed in the form
of bricks or cakes.
 Portions of bricks are
broken off for use and
are sometimes cooked
with butter or other
fats.
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30. 3. Herbal Tea (Tisanes)
 This type of tea can be made by
blending herbs and spices.
 Possess numerous medicinal
properties
 Boost energy
 Induce relaxation.
 E.g. cinnamon tea, ginger tea,
ginseng tea, peppermint tea
etc.
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31. Decaffeinated Tea
 Promoted on health grounds.
 Benefits of Caffeine:
 Stimulate the central nervous system,
 Increase vigilance,
 Alleviate mood,
 Promote psychomotor and cognitive performance of humans
 Over consumption causes
addiction, anxiety, insomnia,
gastrointestinal disturbances, increased blood pressure,
affect respiratory reproductive health..
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32.  Therefore, manufacture of decaffeinated tea is highly desirable in
order to regulate the levels of caffeine intake.
 It is produced by the removal of 60-90% of caffeine from black tea by
the process of solvent extraction (Chloroform or methylene chloride).
 Decaffeination using supercritical carbon dioxide is effective and
leaves no solvent residues, but it needs expensive equipment.
 Sawdust lingo-cellulose columns can be used to separate caffeine from
tea extracts.
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33. Tea Concentrates
 Tea leaves are extracted with hot water at 80°C–90°C.
 Citric acid and sodium bicarbonate are the additives
which help in better extraction.
 The extract is concentrated either by evaporation or
through freeze-concentration method.
 Other ingredients:
sugar, stabilizers (xanthan, CMC, or carrageen),
emulsifiers preservatives
flavorings (lemon oil or orange oil)
 Shelf life of the same is 6 months at 60°F without
deterioration and is then used for the formulation of
liquid tea based beverage.
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34. Tea Beverages
 Ready-to-Serve Tea Beverages: Instant Tea (liquid or powder), Brew tea,
Brewed tea extract, etc.
 Carbonated Tea Beverages: e.g. Sparkling lemonade Tea
 Kombucha
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35. Instant Tea
 It is the water soluble extract of tea leaf, usually
marketed as a powder, flake or granule, either
pure or as a part of flavoured mixes.
 Cold or hot soluble. Extensively used in machines.
 Manufactured by spray/freeze drying/ vacuum
drying of the concentrated brew.
 hygroscopic and consequently requires appropriate
packaging.
 Most Instant tea is made from black tea, but some
is made from green tea. These are produced
especially in USA and UK. Iced lemon teas are very
popular.
 Different forms present in market are, flavored
instant teas, decaffeinated soluble tea either plain
or with added flavors. 13-08-2022
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36. Ready-to-drink (RTD) tea
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38. Carbonated Tea Beverages
Black tea or decaffeinated black tea is extracted with water
Filtration through fine filters
Sugar syrup, preservative
and acidulant.
Filtrate
(tea solids (0.3-0.4%), sugar (10%), citric acid (0.1-0.5%)
Carbonated
Final Product 13-08-2022
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39. Kombucha
 China or Japan
 Traditional fermented tea is
known as tea cider.
 Medicinal properties.
 Tea fungus (Scoby): atleast 3
microorganism:
 Bacteria (Acetobacter
xylinum)
 Yeast (Zygosaccharomyces
rouxii and Candida sp.)
 It contains <0.5% alcohol.
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40. Kombucha
 Benefits:
 detoxifying and energizing
properties
 aids in curing gastric problems
 treatment of insomnia, arthritis,
hemorrhoids, heart diseases,
respiratory problems (allergies,
asthama)
 Prevention of cancer.
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