1. Beverages : Tea, Coffee (Morphology,
Processing & Uses)
By
N. Sannigrahi, Associate Professor
Department of Botany
Nistarini College, Purulia ( W.B) India
2. WATER BALANCE IN HUMAN BODY
Humans maintain their water balance by consuming an
equal amount of water to that which is excreted. The body keep
water in a balanced state by controlling intake and excretion.
However, the body can suffer from either a negative
positive water balance. Negative water balance, dehydration, is
defined as a reduction of water and salt in varying proportions
compared with the normal state, which may be caused failure
to replace obligatory water losses or failure of the regulatory
mechanism. Dehydration leads to hypernatremia, which can be
caused by one or more of the following: water loss in excess of
sodium chloride, inadequate water intake, addition of sodium
chloride (salt poisoning), osmotic diuresis (with glucosuria),
and diuretic therapy when free water intake is inadequate .
When the body loses salt to a greater extent than that of water,
hyponatremic dehydration occurs.
3. DRINKS
to drink fluid in order to preserve body fluid homeostasis and
survive. A minimum of 1.44 L of water is needed per day
to cover the water lost and to maintain the water balance .
Beverages could contribute to the human requirements of
water. Troiano et al. reported that 20-24% of energy intake
came from beverages. In addition to fulfilling a basic need,
drinks form part of the culture of human society. Types of
beverages consumed affect the composition of modern diet.
The word beverage has always been defined as not referring to
water. Furthermore, it has been reported that these beverages
are in the top ten contributing foods for several nutrients. Milk
contributes to energy, protein, fat, calcium and vitamin A
intake, while fruit juices contributes to energy, calcium, iron,
vitamin C, vitamin A, and fiber intake, and soft drinks
contributes in energy and vitamin C (in fortified fruit drinks)
intake.
4. TYPE OF DRINKS
According to Roethenbaugh, there are four primary sectors
of the global commercial beverage market (Figure 1): hot
drinks , milk drinks, soft drinks and alcoholic drinks. Hot
drinks, include tea and coffee. Soft drinks have five main
subcategories: bottled water; carbonated soft drinks; dilutables,
(squash, powders , cordials and syrups); fruit juices (100% fruit
juice and nectars(25–99% juice content); still drinks, including
ready-to-drink(RTD) teas, sports drinks and other
noncarbonated products with less than 25% fruit juice).
Alcoholic drinks, including beer, wine , spirits, cider, sake and
flavored alcoholic beverages. Amongst the
different types of beverages, milk, soft drinks, and fruit juices
are the most important and they are consumed in high amounts
.Beverages could be also classified into alcoholic and non
alcoholic drinks. An alcoholic beverage is a drink that contains
.
5. TEA-USES, CHEMICALS
ethanol. A non-alcoholic beverage is a drink that contains little
or no alcohol. This category includes low-alcohol beer, non-
alcoholic wine, and apple cider if they contain less than
0.5%alcohol by volume and they are called soft drinks
Camellia sinensis (L). O. Kuntze (Syn. Thea sinensis L.)
Family: Theaceae
USES
1. It is the most common non-alcoholic beverage, used by more
than one-half of the world’s population.
2. It is obtained from the dried leaves of Camellia sinensis, a
native of Assam or China.
A volatile oil, tannin (13 to 18%), and an alkaloid theine (2-
5%), are present in tea.
6. TEA-USES, CHEMICALS
5. Tea leaves, when infused in hot water, dissolve their alkaloid
and oil, and the beverage thus resulted has a stimulating effect.
If boiled for a longer period, tannin dissolves making the
beverage less beneficial.
6. India is a leading tea-exporting country.
7. For preparing green tea, the leaves are steamed and dried
without fermenting, while for black tea the leaves are withered,
rolled, fermented and dried.
8. Tannins of tea waste are used in plywood industry.
CHEMICAL COMPONENTS : Fresh tea leaf mainly rich in
flavones group of polyphenols known as catechins which
consists of 30% of the dry weight of the leaf. Other
polyphenols include glycosides, Chlorogenic acid,
Coumarylquinic acid 3-galloylquinic acid.
8. MORPHOLOGY OF TEA PLANT
Tea, Camelia sinensis belongs to the family Rubiaceae of
dicotyledonous is a large size shrub, 1-2 mt tall , straight or
slender stem arising from the base; leaf is hard, thick and
leathery; blade elliptic with obtuse apex; margin bluntly
serrulate with more or less incurved teeth; glabrous above and
villose below; petiole short, 3-7mm long; purple in color.
Flowers borne singly or pairs in the cataphyllary axils; pedicel
6-10 mm long with caducous bracteoles; bisexual, complete
with 5-6 sepals, imbricate, persistent, leathery; Petals 7-8, pink;
stamens numerous arranged in two whorls; ovary densely
hair,3 locules with 3-5 ovules in each locule in axil
placentation; fruit capsule either 1 or 2 or 3;spherical seeds
with 10-15 mm in diameter. The other species almost share
same type of taxonomic features except in some specified
cases.
10. TEA PROCESSING
The processing of tea consists of number of steps as follows:
Plucking-It takes place over 7-14 days and the deft fingers of
the expert pluckers can gather as much as 60 lb of leaf in one
day to make 15 lb of processed tea. Only two small leaves and
bud is collected from each shoot. In India, plucking is carried
throughout the year but two big flushing periods from April to
May when near about 25% and during September to December,
near about 40% annual crop is mostly harvested. The rest is
collected throughout the year round.
The most of this plucking activities are done by the women
labor due to chief and other benefits as enjoyed by the different
tea estates located in the different tea processing units.
Commercially, tea of three types- Black, Green and Oolong.
The Black tea is processed by the following events.
11. PROCESSING OF BLACK TEA
Withering- About 70% or more of the fresh weight of the leaf
contain water. Nearly 50% of the water must be removed
before rolling without break up. The leaf is generally spread
over withering racks arranged one above the other horizontally
and allow to remain 12-018 hours to loss its undesired
moisture. The leaf slowly and evenly becomes soft and flaccid
like soft leather and get ready for rolling.
Rolling- It imparts the characteristic twist to the leaf, breaks the
leaf cells and exposes the water content to the air to undergo
fermentation. After half an hour’s rolling, the leaf is removed
in aluminum trolleys to a sifter and ball breaker. The movement
of the specially designed roller causes the broken leaf and fine
particles to fall below and the rest is taken out after sieving.
The latter is again rolled for the second time with little bit
increased pressure. After the second roll, more or less green
and quite flaccid removed to the fermenting room.
12. PROCESSING OF BLACK TEA
Fermentation- During fermentation, the tannin in tea is partially
oxidized and the leaf changes color and turns bright coppery-
red. The rolled leaf is spread on aluminum sheets and the
oxidation which has commenced during rolling continues, the
leaf coming into contact with air. The period of fermentation
exceeds to 3 hours , but this includes rolling time as well. It is
generally thought that the shorter the fermentation, the more
pungent the liquor and longer the fermentation, the liquor
become softer and deeper in color.
Drying- After the leaf has changed its color, comes the final
operation. During drying or firing, the oxidation process is
arrested and most of the moisture of the leaf is dried up and
only 3-5% moisture is retained. The entire operation takes
place in two or three cycles before the finishing product
obtained.
13. PROCESSING OF BLACK TEA
Basically three types of made tea are processed..
Black tea : It is also called fermented tea. The fundamental
process in processing black tea consists of a series of oxidation
and condensations of certain substances present in the green
leaves mainly the polyphenols. During the process of black tea
manufacture, the polyphenols are oxidized to form two
coloring products, the aflavins (TF) and the arubigins
(TR).These along with the caffeine present in tea leaves give
the characteristic properties of black tea. There are two types of
black tea manufacture-Orthodox and
CTC. In orthodox manufacture, the green leaves are withered,
lightly rolled in rolling machine for initiating fermentation
(oxidization) and then dried. In CTC manufacture, the rolling is
more severe and the leaves are passed through the CTC
machine to cut the leaf mass into small bits.
14. GREEN TEA
Most of the tea made in China & Japan are of this nature. A
small quantity is made in North India but mainly for sale in
Afghanistan, Iran and some of the American market. The green
tea is not an oxidized (fermented) product
and bears little similarity to black tea. The chief feature in the
manufacture of green tea is that the polyphenol oxidase, the
enzyme that oxidizes the polyphenols, is deactivated by
steaming the green leaves. The color of green tea liquor is
greenish or lemon yellow, with no trace of red or brown color.
A green tea infusion delivers up its caffeine more quickly than
one of black tea, and it contains more
polyphenolic bodies than a black tea infusion, but these
substances are colorless and unoxidise.
15. OOLONG TEA
Oolong tea : It can be described as the cross between black and
green tea. It is also called semi-fermented tea with a unique
flavor. In preparing oolong tea, the green leaves are given a
brief wither in the sun for an hour or so; then after cooling, the
leaves are lightly manipulated by hands till they turn red and
develop a slight fragrance. After a short fermentation the
process is stopped by roasting it in a
hot iron pan. The Oolongs which have enjoyed a special market
in America , are now exclusively manufactured in Formosa.
LEAF GRADES: Leaf Grades
There are three grades in leaf grades-Orange Pekoe(OP), Pekoe
(P)and Poekoe Souchong(PS).
16. DIFFERENT TEA GRADES
Orange Pekoe(OP)-Long, thin weary leaves containing tip or
bud le4af, mainly the finer portions of shoot . The liquors are
generally light or pale in color with flavor.
Pekoe(P)- Leaves are slightly shorter and not wiry to that O.P,
buds are present, the liquors are however more in color and the
grade is quicker brewing than O.P
Pekoe Souchong (PS)- A bold and round leaf with pale liquors.
BROKEN GRADES: Consists of four main grades-
Broken Orange Pekoe ( B.O.P)-much smaller than any leaf
grades, contains tips, good color and strength made it
attractive.
Broken Pekoe(B.P)- Slightly larger than B.O.P but tips absent,
paler and less color, mainly used as filters.
17. DIFFERENT TEA GRADES
Broken Pekoe Souchong (B.P.S)-little larger and bolder than
B.P, lighter in the cup but useful as ‘filters’.
Fanning or Pekoe Fanning- these are much smaller than B.P.S
and are quick brewing and give good color liquor.
DUSTS: The smallest particles excluding fluff and stalk are
graded as Dusts; useful in quick brewing, liquors produce both
strength and color, good demand for catering purposes.
CTC- These are Crushing, Tearing & Curling process as done
by the machine as named as CTC tea. The leaf after withering
is slightly rolled without any pressure. The fine leaf is
separated and coarse leaf is fed into machine two or three even
four times to prepare the CTC leaf which is made available in
the market.
18. COFFEA
Coffea arabica (Arabian Coffee); C. canepbora syn. C. robusta
(Congo Coffee); C. liberica (Liberian Coffee).
Family: Rubiaceae
1.Coffee beans are roasted for developing the aroma, flavor and
color and finally ground before they reach to the consumer.
2. “Beans” contain caffeine (0.75 to 1.5%), a volatile oil,
glucose, dextrin, proteins and a fatty oil.
3.Caffeine provide stimulating effect while the volatile oil
(caffeole) is responsible for aroma and flavor.
4. Leaves and fruits of Coffee also contain some alkaloids.
5. In India, C. arabica is grown in Nilgiris and Kamataka.
6. Seeds of C. canepbora (syn. C. robusta), a robust evergreen
shrub, are used in making “instant coffee”.
20. MORPHOLOGY
Evergreen shrub of about 5 ft tall when unpruned, open
branching stem ; leaves opposite, dark green , glossy, elliptical,
acuminate with short petiole; flowers bisexual, white in
axillaries clusters; sepal small, cup shaped; corolla tubular;
fruits drupe in color on ripening but dark brown after maturity;
fruit ellipsoidal with two locules, each locule having single
seed; inner surface of the seed is deeply grooved, seed contains
corneous endosperm with small embryo; seeds 8.5-12 cm long
; self pollinating maintains the uniform nature of the seeds;
generally takes at least seven years to attain in maturity to
produce seeds; mostly cultivated at high elevation up to 1500
mt. in height or more; average 15℃-24 ℃ is good for
cultivation without frost; the plant is endemic to Africa but now
it is cultivated almost all continents in different forms
21. CONSTITUENTS OF COFFEA
Coffea contains a diverse of chemical constituents and these
chemicals play a very crucial role for its aroma and odor and
commercially make it as one of the non-alcoholic beverages in
the world. Caffeine is the main chemical constituent of coffee
present in coffee bean. Other chemical constituents are tannins,
fixed oils and proteins are also present in coffee bean. The
amount of caffeine present in coffee bean is 2-3 % .Amount of
tannin is 3-5%.13% proteins and 10-15% fixed oils are present
in coffee bean. The coffee contain sugars in the form of dextrin,
glucose and chlorogenic or caffeotannic acid.
The seed contain caffeine as the salt of chlorogenic acid and
combined with potassium. It also contain nicotinic acid. The
agreeable smell of coffee seed during roasting is due to caffeol
oil. It also contain pentosans. It also contain phenol ,pyridine
and valerianic acid.
22. PROCESSING OF COFFEA
Processing of Coffea is consisting of almost 8-10 steps before
marketing in available forms. They are as follows: Planting-
From nursery to the plantation site is usually done during the
wet season.
Harvesting the cherries- Generally after 3-4 years, the coffee
cherries are collected by labor intensive process and make it
ready for future steps.
Processing the cherries- Both dry and wet methods are used in
this regard. After this process , it beans are passed through
large fermented channels. Then the beans are rinsed after
fermentation and ready for drying
Drying the beans- The beans are dried retaining 11% moisture.
After sun drying, the parchment coffee are warehoused in jute
for further processing.
23. PROCESSING OF COFFEA
Milling the beans- Hulling, polishing, grading and sorting are
done sequentially. During, hulling, the fruit coat- exocarp,
mesocarp and endocarp are removed, the polishing is done to
silver color interior part over the beans.
Exporting the beans-Now the milled coffee called green coffee
are sent for further processing.
Tasting the coffee-Cupping is done to evaluate the aroma of the
beans.
Roasting the coffee- At about 200℃ it begins to brown in color
and caffeol is released from the beans called pyrolysis and
beans are immediately cooled down.
Grinding the coffee- Proper grinding is done for making it a
right ingredients of drink through proper analysis.
Brewing the coffee is done by the users.
24. THANKS FOR YOUR TIME
This presentation has been made without any financial interest,
to enrich open source of information. The presenter
acknowledges the followings to develop this PPT.
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