TEA QUALITY PARAMETERS

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QUALITY PARAMETERS

The major quality parameters that are tested in made tea include Theaflavins (TF), Thearubigins (TR), High polymerized substances (HPS), Total liquor color (TLC) and Total soluble solids (Water extract). TF has a direct correlation with quality and price realization. TF contribute towards the briskness and brightness of tea liquor. During the course of fermentation, TF progressively increases till an optimum fermentation time, the period at which maximum quality is observed. In addition to having maximum value for TF, there has to be proper balancing of the liquor parameters for which the guide line stating the value of TR to be ten to twelve times as that of TF can be followed. TR are complex condensation products of oxidized catechins with TF. Together with HPS, TR increases the color, mouth feel and body of the tea liquor. Very high levels of TR indicate over fermentation. Similarly, very high levels of HPS and TLC also imply over fermentation. Low levels of TR indicate under fermentation and the liquor tastes harsh.

PROPERTIES OF CAFFEINE

Parameters such as caffeine and catechin play an important role on the quality of tea and require minimum stipulation. Caffeine is relatively a stable molecule and is a direct stimulant of the Central Nervous System. Together with TF it imparts briskness to the tea liquor. Caffeine level increases during processing and high levels of caffeine indicate a good leaf standard (caffeine decreases with the maturity of the crop shoots). Water extract or TSS has a direct influence on the cuppage. Higher values of TSS indicate a better quality of the raw material.

BRISKNESS AND COLOR INDICES

In addition to the above quality parameters briskness and color indices developed at UPASI TRI, correlate well with quality of made tea. Briskness index is given as percent ratio of TF to TF+CAF and the normal range for south Indian CTC tea is above 23. The color index is given as percent ratio of TF to TR+HPS and the normal range for south Indian CTC teas is from 5 to 11. Teas having maximum TF and a balanced TR/TF ratio (10 to 12) with optimum level of briskness and color indices will definitely have a better quality.

QUALITY PARAMETERS OF BLACK TEA Though the PFA (Preventive of Food Adulteration) Act requirements specify limits for tea and to great extent restricts adulteration, the various parameters listed under PFA requirements cannot be solely taken as quality standards for various teas. The problem of setting quality standards to made tea arises due to multitude of factors affecting the quality starting from the raw material to the variations in manufacturing conditions.

STANDARDS AS PER PFA ACT Tea means the tea derived solely and exclusively and produced by acceptable process notably formation and drying, from the leaves, buds and tender stems of the species of cultivated “Camellia”, known to be suitable for making tea for consumption as a beverage. Tea shall also comply with requirements specified in the following table in which all the requirements are expressed on the basis of the material oven dried at 103o C (+ or -2oC) by the method described in IS 3852.

CHEMICAL REQUIREMENTS FOR TEA
Characteristic Requirement Method of Test Ref. No.
Water extract, percent by mass, Min 32.0 IS 13862
Total ash, percent by mass 4.0 – 8.0 IS 13854
Water soluble ash, water of total ash, percent by mass, Min 4.0 IS 13855
Alkalinity of water soluble ash (as K2O), percent by mass 1.0 – 2.2 IS 13856
Acid insoluble ash, percent by mass, Max 1.0 IS 13857
Crude fibre, percent by mass, Max 17.0 IS 10226 (Pt 1)
Lead, mg / kg, Max 10.0 IS 12074 32.0 IS 13862
Copper , mg / kg, Max 150.0 IS 11123 32.0 IS 13862

PESTICIDE RESIDUE LIMITS FOR TEA (See also pesticide residues)
1 Dicofol, mg / kg, Max 5.0 IS 14629
2 Ethion, mg / kg, Max 5.0 IS 11773
3 Quinolphos, mg / kg, Max 0.01 IS 14437

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  • News letter June 2020

    News Letter -2020 June

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  • Publications

    Radhakrishnan,B., K. K. Srikumar, Smitha, K. B. Suresh. 2018. Evaluation of Sulfoxaflor 50%WG against Tea mosquito bug, Helopeltistheivora Waterhouse (Hemiptera: Miridae). Pestology. 42 (3), 31-36. Radhakrishnan, B. 2018. Recent issues on pesticide residues and other contaminants in Tea. Planters chronicle. 114(1): 4-11. Radhakrishnan B. and…

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  • Latest

    12/12/12

    The principal landmark in the history of tea research in south India, was the establishment of a Tea Experimental Station in Gudalur in 1926. During the last seven and half decades, this research organisation. Now known as the UPASI Tea Research Foundation (UPASI TRF), had…

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  • Publications and Library

    01/02/05

    Annual Report is the one among the major publications of UPASI TRF. Annual report of each year is released by September of the following year. Other publications include Research Highlights and half yearly Newsletters. The Bulletin of UPASI TRF is an occasional publication. The Handbook…

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Conferences Seminars

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  • National Symposium Announcement

    DATE:  22nd Jannuary, 2021

    PLACE:  

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  • PLACROSYM XXI

    DATE:  10-12 December 2014

    PLACE:  Kozhikode

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  • Research Extension Meeting

    DATE:  06-08 May 2013

    PLACE:  Valparai

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  • JOINT AREA SCIENTIFIC SYMPOSIA (JASS)

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  • INTERNATIONAL TEA CONVENTION

    DATE:  

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  • TGLIA

    DATE:   2013

    PLACE:  

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  • Dr.C.S. Venkata Ram Annual Tea Colloquium

    DATE:  1 August 2013

    PLACE:  VALPARAI

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  • INTERACTIVE SESSIONS / WORKSHOPS

    DATE:  28/04/2012

    PLACE:  VALPARAI

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  • PLATINUM JUBILEE SYMPOSIUM

    DATE:  2001

    PLACE:  Chennai

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  • PLANTATION CROPS SYMPOSIUM 2014

    DATE:  2014

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Research Activities

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  • Newsletter – Dec 2019

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  • Pesticide Residue

    Of late, considering the constant usage of pesticides and to monitor the residues in the final produce, a well equipped test facility was established at UPASI TRI in 1994. The pesticide residue laboratory is accredited by National Accreditation Board for testing and calibration Laboratories (NABL)…

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  • Botany

    The Tea Research Institute at Valparai has seven divisions namely Botany, Soil Chemistry, Entomology, Pesticide Residue, Plant Pathology & Microbiology, Plant Physiology & Biotechnology and Tea Technology. Botany Research activities of Botany Division include plant improvement, cultivation practices and weed research. Plant improvement programme was…

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  • Soil Chemistry

    Chemistry Division is involved in research pertaining to soil-plant nutrients of tea besides extending analytical service to the industry. The research activities include investigations on physico-chemical properties of soil, soil-plant interactions, response of tea to major, secondary and micronutrients and their interactions. The research work…

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  • Entomology

    Entomology Division involve in basic and applied aspects of insect pests, particularly, biology, ecology and evolving control measures. The division evolved and recommended physical, chemical and biological method of tea pests control. In the past, extensive studies on bioecology, crop loss due to major pests…

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  • Pathology & Microbiology

    In the division of Plant Pathology & Microbiology, research is carried out on diseases of tea and biofertilizers. Among the tea diseases, blister blight is the most important leaf disease caused by the pathogen, Exobasidium vexans affecting the tender harvestable shoots of tea resulting in…

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  • Physiology & Biotechnology

    Plant Physiology Division was established in 1980 which has been primarily concentrated on crop productivity. The division strives for excellence in applied research in tea productivity and bush health besides biotechnological studies. The research undertaken extends over a wide range of research programmes having collaborative…

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