Standards of Tea for Ensuring
Market Requirement
Nimal Punyasiri
Biochemistry Division
Te a R e s e a r c h I n s t i t u t e o f S r i L a n k a
Standards of Tea
Related to:
Black Tea
Green Tea
White Tea
TRI recommendations on Pesticides
(Issue of MRLs)
Adulterations
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ISO Standards
Definition for Black Tea
Tea derived solely and exclusively, and
produced by acceptable processes, notably
withering, leaf maceration, aeration and
drying, from the tender shoots of varieties of
the species Camellia sinensis (Linnaeus) O.
Kuntze known to be suitable for making tea
for consumption as a beverage.
ISO 3720:2011
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ISO Standards
Definition for Green Tea
Tea derived solely and exclusively, and
produced by acceptable processes, notably
enzyme inactivation and commonly rolling or
comminution, followed by drying, from the
tender leaves, buds and shoots of varieties
the species Camellia sinensis (Linnaeus)
O.Kuntze, known to be suitable for making
Tea for consumption as a beverage.
ISO 11287:2011
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Chemical Composition – Fresh Tea Leaf
Constituent % by dry weight
Flavanols (Catechins) 17-30
Flavonols and flavonol glycosides 3-4
Leucoanthoyanins/Proanthocyanins 2-3
Phenolic acid and depsides ~5
Caffeine 3-4
Amino acids ~4
Simple carbohydrates ~4
Organic acids ~0.5
Polysaccharides ~13
Proteins ~15
Ash ~5
Cellulose ~7
Lignin ~6
Lipids ~3
Pigments ~ 0.5
Volatile substances 0.01 -0.02
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Total Polyphenol Content
in tea leaves
35.8% (Bud)
Ideal for
35 % (1st Leaf)
Manufacture
27.9 (2nd Leaf) of Black Tea
23.1% (3rd Leaf)
15.0% (Stem)
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Polyphenol Composition
Fresh Tea Leaf
Component g/100 g dry weight T
O
T T
Epigallocatechin gallate (EGCG) O 9 - 13 A
Epigallocatechin (EGC) T
A
3-6 L
Epicatechin gallate (ECG) L 3-6 P
Epicatechin (EC) C 1-3 O
A L
Gallocatechin (GC) T 1-2 Y
Catechin (C) S 1–2 P
H
Flavonols and their glycosides 3–4 E
Leucoanthocyanins/Proanthocyanidins 2–4 N
O
Phenolic acids 4 L
Total polyphenols 27 – 40 S
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ISO Standards for Black Tea / Green Tea
Parameter Test
TestMethod
Method Requirement
Requirement
Black Tea
Black Tea Green Tea
Water Extract % ISO 9768 32 min.
Water Extract % ISO 9768 32 min. 32 min.
Total ash % ISO 1575 4-8
Total ash % ISO 1575 4-8 4-8
Water soluble ash % ISO 1576 45
Water soluble ash % ISO 1576 45 45
Alkalinity of total ash % ISO 1578 1-3
Alkalinity of total ash % ISO 1578 1-3 1-3
Acid soluble ash % ISO 1577 1.0 max.
Acid soluble ash % ISO 1577 1.0 max. 1.0 max.
Crude fibre % ISO 5498 16.5 max.
Crude fibre % ISO 5498 16.5 max. 16.5 max.
Total Polyphenol % ISO 14502-1 9 min.
Total Polyphenol % ISO 14502-1 9 min. 11 min.
Total Catechins % ISO 14502-2 - 7 min.
Ratio of TC/TP - 0.5 min.
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Pathway to ISO Standards
ISO appoints special committee
ISO collects the data from all producers
Worldwide inter-laboratory testing
TRI already contributed the data and ideas
The process of formulating a standard –
approx. 15 years
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Contribution of the TRI
Parameters Standard Technique
Total Polyphenols ISO 14502-1 Spectrophotometry
Individual catechins ISO 14502-2 HPLC
Water extract (TS) ISO 9768 Gravimetry
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%
0
10
20
30
40
50
60
70
SLGT –…
SLGT –…
SLGT –…
SLGT –…
SLGT –…
SLGT –…
SLGT –…
SLGT –…
SLGT –…
SLGT –…
SLGT –…
SLGT –…
SLGT –…
SLGT –…
SLGT –…
SLGT –…
SLGT –…
SLGT –…
SLGT –…
SLGT –…
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SLGT –…
SLGT –…
SLGT –…
SLGT –…
SLGT –…
SLGT –…
SLGT –…
SLGT –…
SLGT –…
SLGT –…
SLGT –…
SLGT –…
SLGT –…
Water Extract in SL Green Tea
SLGT –…
SLGT –…
SLGT –…
11
32%
%
10
12
14
16
18
20
0
2
4
6
8
SLGT – 01
SLGT – 02
SLGT – 03
SLGT – 04
SLGT – 05
SLGT – 06
SLGT – 07
SLGT – 08
SLGT – 09
SLGT – 10
SLGT – 11
SLGT – 12
SLGT – 13
SLGT – 14
SLGT – 15
SLGT – 16
SLGT – 17
SLGT – 18
SLGT – 19
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SLGT – 20
SLGT – 21
SLGT – 22
SLGT – 23
Total Catechins
SLGT – 24
SLGT – 25
SLGT – 26
SLGT – 27
SLGT – 28
SLGT – 29
SLGT – 30
SLGT – 31
SLGT – 32
SLGT – 33
SLGT – 34
SLGT – 35
7%
12
Total Polyphenols
25
20
15
% 10
11 %
5
0
SLGT – SLGT – SLGT – SLGT – SLGT – SLGT – SLGT – SLGT – SLGT – SLGT – SLGT – SLGT – SLGT – SLGT – SLGT – SLGT – SLGT – SLGT –
01 03 05 07 09 11 13 15 17 19 21 23 25 27 29 31 33 35
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Ratio
TC/TPP
0.2
0.4
0.6
0.8
1.2
0
1
SLGT – 01
SLGT – 02
SLGT – 03
SLGT – 04
SLGT – 05
SLGT – 06
SLGT – 07
SLGT – 08
SLGT – 09
SLGT – 10
SLGT – 11
SLGT – 12
SLGT – 13
SLGT – 14
SLGT – 15
SLGT – 16
SLGT – 17
SLGT – 18
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SLGT – 19
SLGT – 20
SLGT – 21
SLGT – 22
SLGT – 23
Ratio of TC / TPP
SLGT – 24
SLGT – 25
SLGT – 26
SLGT – 27
SLGT – 28
SLGT – 29
SLGT – 30
SLGT – 31
SLGT – 32
SLGT – 33
SLGT – 34
SLGT – 35
14
0.5
New parameter to be added
L-Theanine
TRI has already established the levels in
Sri Lankan GT and BT
The L-theanine content in Sri Lankan black tea
ranged from 0.91 – 1.29 %
and
in green tea ranged from 0.26 – 1.49 % on dry
weight basis
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Theanine
(gamma –ethyl amino L-glutamic acid)
This unique Amino Acid was discovered in 1949 by
Sakato from tea leaves. (latest research shows that
Theanine (Thea) is found in 21 spp from theaceae
family, Ashihara et al., 2010)
It is known to be a neurotransmitter in the brain and
Imparts mind relaxation-inducing effect in humans
Improved memory
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Brain Waves
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ISO Standards
DEFINITION
Tea derived solely and exclusively, and
produced by acceptable processes, by
harvesting and a single withering/drying
stage from the bud and tender shoots or 1-2
leaves of varieties of the species Camellia
sinensis (Linnaeus) O. Kuntze known to be
suitable for making tea for consumption as a
beverage
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Sri Lanka - Proposal to ISO
The above definition would exclude teas such as
Ceylon silver Tips, silver needles from the
classification “ White Tea “.
Sri Lanka has proposed ISO to include Ceylon
Silver Tips into a separate category and treat as
Special Tea
This would pave the way to protect the unique
identity of silver tips and produce a new type of
tea in Sri Lanka “ White Tea”
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TRI Recommended Pesticides and their
MRLs
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MRL….
CODEX Maximum Limit for Pesticide Residues (MRL)
is the maximum concentration of a pesticide residue
(expressed as mg/kg), recommended by the CODEX
Alimentarius Commission to be legally permitted in
or on food commodities and animal feeds. MRLs are
based on GAP data and foods derived from
commodities that comply with the respective MRLs
are intended to be toxicologically acceptable
Codex website at: http://www.codexalimentarius.net
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MRL
0.05 mg/kg Japan
0.01 mg/kg
1 mg/kg
MRLs
0.1 mg/kg
5 mg/kg
?
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MRLs of TRI Recommended Pesticides (mg/kg)
Pesticide Japanese MRL EU MRL
2,4-D 0.01 0.1
Azadirachtin Exempted 0.01
Bitertanol 0.1 0.1
Carbofuran 0.2 0.05
Carbosulfan 0.1 0.1
Chlorfluazuron 10 Exempted
Copper salts Exempted 40 as Cu
Dazomet 0.1 0.02
Diazinon 0.1 0.02
Diuron 1 0.1
Fenthion 0.01 0.05
Glufosinate am. 0.5 0.1
Glyphosate 1.0 2.0
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MRLs of TRI Recommended Pesticides (mg/kg) contd.
Pesticide Japanese MRL EU MRL
Hexaconazole 0.05 0.05
Imidachlorprid 10 0.05
MCPA 0.01 0.1
Metam Sodium 0.1 0.02
Oxyfluorfen 0.01 0.05
Paraquat 0.3 0.05
Phenamiphos 0.05 0.05
Propargite 5.0 5.0
Propiconazole 0.1 0.1
Sulfur Exempted Exempted
Tebuconazole 30 0.05
Tebufenozide 25 0.1
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JMPR/GAP/FAO
Supervised field trials for 17 pesticides used in
tea have been already carried out.
When the MRLs are not achievable. TRI files
application to EU/JAPAN with experimental
evidence
Analysis is done only by an accredited lab in
Germany
Expensive exercise
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Analytical Contribution of TRI
Methods developed by TRI
1. Hexaconazole
2. Propiconazole GC-MS
3. Bitertanol
4. Tebuconazole
5. Pyraclostrobin (to be recommended)
6.MCPA Derivatization followed by GCMS
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Heavy Metals – SLTB Standard
Heavy Metal Accepted Limit Test Method
mg/kg
Iron max 500 AOAC:975:03
Copper max 100 AOAC:971:20
Lead max 2 AOAC: 972:25
Zinc max 100 AOAC:969:32
Cadmium max 0.2 AOAC:973:34
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Microbiological Requirements
SLTB Standard
Standard Accepted Limit Test Method
Aerobic Plate Count Max . 10,000 cfu/g ISO 4833:2003
Yeast & mould Max. 1000 cfu/g ISO 21527-2-2008
Total Coliforms Max. 10 MPN/g ISO 4831:2006
E.coli Absent/g ISO 7251:2005
Salmonella Absent/25 g ISO 6579:2002
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Food Adulteration
A substance has been added or
mixed or packed with it to increase
its bulk or weight, or reduce its
quality or strength, or make it
appear better or of greater value
than it is.
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Classic Examples of Food Adulteration
Black Pepper Papaya seeds
Chili powder Powdered bricks /Sudan dye
Coconut oil Palm oil
Milk fat Animal fat
Milk protein Melamine
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Importance of Prevention of Adulteration
Authentication of food products is of primary
importance for both consumers and industries, at all
levels of the production process, from raw materials
to finished products.
From the legislative point of view, quality standards
have been established through the requirement of
quality labels that specify the chemical composition
of each product.
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Detected Adulterations
28 Suspensions/Compounding of the offence
/ Cancellation – 2011 (up to May)
Made by SLTB*
* Source – Tea Commissioner
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Ultimate Goal
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© 2011, Tea Research Institute of Sri Lanka
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