Tea quality indicators. To assess the quality of tea, conduct examinations and in-depth study of its properties, various laboratory research methods are used (chemical and luminescent analyses, gas chromatography and spectrometry, etc.).

However, organoleptic studies of tea are still decisive in assessing its quality.

The organoleptic properties of tea are determined by specialists in the field of tasting assessment - tea testers, using a 10-point system (see Table 7). According to this system, the lowest-grade varieties of tea (domestic and foreign) are rated at only 1.5 points, and the highest quality - at 5.5 points and above. A rating of 8-10 points for tea is still considered unattainable. The highest quality teas, called Unique (for example, the best sizes Indian Darjeeling tea or Ceylon Nur-Eli), very rarely receive a rating of up to 7 points for their unique aromatic and taste properties. The assessment of ordinary premium grades is much lower. Thus, the highest grade I category of factory-made tea can have a score of 6.25-8.00, the highest grade II category (B-2) - 5.25-6.0, and the 1st grade - 4.75-5, 0.

The organoleptic method for assessing tea is so far the only express method that allows one to determine the entire set of properties of tea within 1-2 minutes.

According to GOST, the organoleptic assessment of tea is carried out according to the following indicators: aroma and taste, transparency and intensity of the infusion, color of the boiled leaf, appearance (cleaning) of dry tea.

To study the quality, 3 g of tea is poured into a tea tester with 130 ml of freshly boiling water with a pH of 6-7 and closed with a lid. After 5 minutes of infusion (brick tea is infused for 7 minutes), the extract without tea leaves is poured into a special white porcelain cup and the color and intensity of the infusion is determined. The color of the infusion gives an idea of the type of tea (black, green, yellow, red) and its varieties (brick and tile differ from long tea in the specific color of the infusion). When assessing the color of the infusion, attention is paid to its correspondence to the type of tea, thickness, intensity, and brightness. Bright color and the transparency that always accompanies it are a reliable sign of high quality tea, which cannot be said about color. Pressed teas do not give a bright infusion due to the large number of suspended particles in them. A dark, densely colored, but dull, opaque infusion is a sign of low quality tea. In an alkaline environment, the brightness and transparency of the tea infusion disappears and a brown color appears.

To determine the taste, sip a little tea from a cup and, without swallowing, roll it around in your mouth, assessing the taste sensations. The astringency and fullness of taste of the infusion are signs of high extract content of teas and their high P-vitamin activity. If the astringency is not sufficiently expressed, the tea has an “empty”, “flat” taste, characteristic of over-fermented teas.

The most important indicator of the quality of the infusion is its aroma, which is formed in the first one and a half to two minutes after brewing. Aromatic substances are concentrated in foam on the surface of the infusion. Due to the volatility of tea essential oil, the aroma of the infusion should be determined no later than 5 minutes from the moment of brewing, i.e. immediately after draining the infusion. To do this, a teapot with the boiled leaf remaining in it is brought to the nose and, drawing in air strongly, the smell is assessed. In tea testing practice, special terminology has been adopted to determine the aroma of good-quality tea: rose, almond, honey, citrus, a mixture of strawberry, geranium and black currant aroma, etc. Organoleptically, undesirable odors are also detected in the aroma of tea, which are the result of a violation of technology or improper storage: smokiness, roastiness, herbaceous smell, the smell of dampness, mustiness, mold, acid and various foreign odors.

A reliable idea of the quality of tea is given by assessing the color of the boiled leaf. To do this, turn the teapot over onto the lid and, after squeezing the remaining infusion from the boiled leaf, determine the color of the leaves and the uniformity of their color. High-quality black long tea has a boiled leaf with a bright copper color. Dark brown, green and dull shades of the color of the boiled leaf are assessed as defects.

To assess the appearance, average samples are poured onto clean sheets of paper and visually determined by the group of may (leaf or small), uniformity of color and degree of twisting of tea leaves, the presence of tips (golden tips - flush buds), indicating high quality tea, the presence of stems and tea dust , characteristic of low grades of tea from raw materials harvested in late autumn.

When assessing the quality of tea according to the current standard, humidity, the mass fraction of water-soluble extractive substances, and metal impurities are also determined. For a more complete characterization, in addition to standard indicators, ash content, caffeine, tannin and other components are determined.

The main quality indicators of green tea are:

Aroma and taste of tea;

Appearance;

Infusion color;

Indicator name	GOST requirements	Sample No. 1	Sample No. 2	Sample No. 3
Aroma and taste	Full bouquet, delicate delicate aroma, pleasant astringent taste	Rough aroma, slightly perceptible tart taste	Pleasant subtle and delicate aroma, pleasant strongly tart taste	Pleasant aroma, slightly noticeable taste.	Rough aroma, slightly perceptible tart and bitter taste.
Infusion	Transparent, light green, with a yellowish tint	Dark yellow with a reddish tint, cloudy	Transparent light green with a yellowish tint	Dark yellow. Cloudy with sediment	Dark yellow, cloudy.
Color of boiled leaf	Homogeneous, with a greenish tint	Heterogeneous, dark yellow	Homogeneous with a greenish tint	Heterogeneous, dark yellow	Heterogeneous, dark yellow.
Appearance	Smooth, uniform, well curled	Uneven, poorly twisted tea leaves	Smooth, homogeneous, twisted, without foreign impurities	Uneven, there are impurities: sticks, branches.	Leafy, uneven, poorly twisted tea leaves with foreign impurities

Requirements for organoleptic characteristics of green tea according to GOST

Appearance of tea infusion: -leaf and granulated; -pressed;	Light yellow or light green, transparent or cloudy; Red-yellow
Aroma and taste of tea infusion: -leaf and granulated; -pressed	Delicate aroma, pleasant tart taste; Characteristics of pressed green tea
Color of boiled tea leaf: -leaf and granulated; -pressed	Uniform, with a yellowish and greenish tint Dark green with a dark brown tint
Appearance of tea: -leaf -granulated; -pressed	Homogeneous, flat, curled Fairly flat, spherical or oblong Compressed tiles dark green, smooth surface, even edges

Sampling and quality assessment

Sample No. 1. Long green tea Greenfield, bouquet variety, large-leaf, net weight 100g, manufacturer: Orimi Trade LLC.

Sample No. 2. Tess lime. Green long tea with citrus zest, flower petals and lime aroma in bags. Ingredients: green tea, lemongrass, rose hips, citrus zest, calendula petals, natural lime flavor. Manufacturer: NEP LLC.

Sample No. 3. Green long tea flavored LIPTON.

Ingredients: long green tea, osmanthus and pear flavoring. Manufacturer: Unilever Rus LLC

Marking	GOST requirements	Actually	Correspondence
Sample No. 1.	Name Variety Date of manufacture Composition Net weight Standard designation Shelf life	+ + + + + + +	This sample meets all the requirements of GOST
Sample No. 2	Name Variety Date of manufacture Shelf life Composition Net weight Standard designation Shelf life	+ - + + + + + +	This sample does not comply with GOST for one indicator (the grade is not indicated on the packaging)
Sample No. 3	Name Variety Date of manufacture Shelf life Composition Net weight Standard designation Shelf life	+ - + + + + + +	This sample does not comply with GOST for one indicator (the grade is not indicated on the packaging)

Conclusion: Samples No. 2 and No. 3 do not indicate the type of tea. Sample No. 1 corresponds to GOST in all respects, No. 2 and No. 3 also correspond to GOST and belong to the third grade.

Conclusion

Green tea, which until recently was considered an oriental exotic, is becoming increasingly popular among tea lovers. In Russia back in the 17th-18th centuries. green tea, brought from China, was quite common, but was then replaced by black tea.

Green and black tea are made from the same tea leaves, but the difference in their production technology determines their different biological value and taste. To obtain green tea, the raw materials are subjected to heat treatment, which kills the enzymes of the tea leaf, which allows the substances contained in the tea leaf to be preserved from oxidation. Therefore, in terms of chemical composition, green tea is closer to “natural” tea leaves. It does not form dark-colored phenolic compounds. Green tea is very rich in vitamins . In my coursework, I studied the assortment of green tea in the Magnit and Dixie chain stores and learned that these stores have a fairly wide assortment of green tea. I found out that the main manufacturers on the market are: Orimi Trade LLC; Uniliver Rus LLC; NEP LLC; SDS-FOODS LLC; LLC "Baltic resource" Then I studied the main indicators of green tea and selected samples from the main manufacturers for comparative characteristics. I also studied the organoleptic characteristics of the green samples I selected, and I can draw the following conclusion: samples No. 2 and No. 3 do not indicate the type of tea. Sample No. 1 corresponds to GOST in all respects, No. 2 and No. 3 also correspond to GOST and belong to the third grade. Having studied the assortment of tea, I found out that a huge number of tea producers are competing on the world market, and the assortment of commercial tea varieties is constantly updated and expanded.

INTERSTATE COUNCIL FOR STANDARDIZATION, METROLOGY AND CERTIFICATION

INTERSTATE

STANDARD

Organoleptic analysis

Official publication

Standardinform

Preface

The goals, basic principles and basic procedure for carrying out work on interstate standardization are established by GOST 1.0-92 “Interstate standardization system. Basic provisions" and GOST 1.2-2009 "Interstate standardization system. Interstate standards, rules and recommendations for interstate standardization. Rules for development, acceptance, application, updating and cancellation"

Standard information

1 DEVELOPED by the non-profit organization "Russian Association of Tea and Coffee Producers "ROSCHAIKOFE" (Association "ROSCHAIKOFE")

2 INTRODUCED by the Federal Agency for Technical Regulation and Metrology (TK 451)

3 ADOPTED by the Interstate Council for Standardization, Metrology and Certification (Protocol No. 62-P dated December 3, 2013)

4 By Order of the Federal Agency for Technical Regulation and Metrology dated March 19, 2014 No. 189-st, the interstate standard GOST 32572-2013 was put into effect as a national standard of the Russian Federation on July 1, 2015.

Information about changes to this standard is published in the annual information index “National Standards”, and a list of changes and amendments is published in the monthly information index “National Standards”. In case of revision (replacement) or cancellation of this standard, the corresponding notice will be published in the monthly information index “National Standards”. Relevant information, notifications and texts are also posted in the public information system - on the official website of the Federal Agency for Technical Regulation and Metrology on the Internet

©Standardinform, 2014

In the Russian Federation, this standard cannot be reproduced in whole or in part. replicated and distributed as an official publication without permission from the Federal Agency for Technical Regulation and Metrology


(throughout the text of the standard)
First page of the standard	Date of introduction - 01/07/2014	Date of introduction - 01/07/2015

(IMS No. 2 2015)

INTERSTATE STANDARD

Organoleptic analysis Sensory tests

Date of introduction - 01/07/2014

1 area of use

This standard specifies a method for performing organoleptic analysis.

This standard uses normative references to the following interstate standards:

4 Essence of the method

The method is based on a visual assessment of the appearance and color of the tea leaf, on the olfactory and gustatory sensations of a specialist taster (titester), caused by volatile substances contained in the analyzed tea infusion. and components of tea infusion. on visual assessment of the color and color intensity of the boiled tea leaf.

5 Measuring instruments and utensils

5.1 Liquid glass thermometer with a temperature measurement range from 0 °C to 100 °C with a permissible error limit of ±1 °C according to GOST 28498.

6 Sampling

7 Requirements for specialist tasters

Organoleptic analysis is carried out by tea testers who have special knowledge and experience in assessing the organoleptic characteristics of tea.

8 Premises requirements

The room for organoleptic analysis should be well lit (without direct sunlight on the examination table), clean, isolated from extraneous noise. The walls of the room should be painted in light colors. The room temperature should be (22 ± 2)°C.

9 Preparing for analysis

The infusion for determining organoleptic characteristics is prepared according to GOST ISO 3103.

To determine the aroma and taste, the infusion is cooled to a temperature of (55 ± 5) * C.

10 Determination of organoleptic indicators

10.1 General provisions

10.1.1 Organoleptic analysis is carried out in the following sequence: determination of the appearance of the tea leaf, determination of the color of the infusion, determination of the aroma of the infusion, determination of the taste of the infusion, determination of the appearance of the boiled tea leaf.

10.2 Determining the appearance of tea leaves

The method is based on visual assessment of the appearance and color of the tea leaf. To determine the appearance of tea, a portion of the combined product sample is placed on a sheet of white paper. Particle shape. The uniformity and color of tea is determined visually in diffuse daylight or bright artificial lighting.

10.3 Determination of the color of the infusion

When visually assessing the main color of the infusion, its saturation, hue and additional tones are noted.

10.4 Determination of the aroma of the infusion

When assessing the aroma of the infusion, its richness and shades are noted.

10.5 Determination of the taste of the infusion

To assess taste, use the contents of the bowl after assessing the aroma. Taste sensations are assessed by the nature and fullness of taste, the severity of its shades, as well as the presence of aftertaste.

10.6 Determining the appearance of boiled tea leaves

For evaluation, boiled tea leaves remaining after preparing the tea infusion. placed on the inverted lid of the brewing vessel. Determine the basic color and saturation of the brewed tea leaf.

10.7 If there are disagreements in assessing the organoleptic characteristics of tea, the dissenting party forms a tasting commission with the participation of a third party, the composition of which ensures parity of stakeholders and independent experts.

The tasting commission conducts organoleptic analysis of tea samples. the results of which are binding on all interested parties.

11 Organoleptic analysis protocol

The test report must contain:

Information necessary to identify the sample;

Information about the sampling method;

Information about circumstances that could affect the results of the analysis;

Analysis results.

UDC 663.95:006.354 MKS 67.140.10

Key words: tea. organoleptic analysis, specialist taster (titester), appearance of the tea leaf, color of the infusion, aroma of the infusion, taste of the infusion, appearance of the boiled tea leaf

Signed for printing 02.10.2014 Format 60x84V e.

Uel print l 0.93 Circulation 62 copies Zak 4166 Prepared on the basis of the electronic version provided by the developer of the standard

FSUE "STANDARTINFORM". 123995 Moscow, Granatny lane, 4 www.gostinfo.ru info@gostinfo gi

THEORETICAL BASIS

Tea is obtained by special processing of the upper parts of the shoots (fleshes) of the evergreen tea plant of the tea family. The main value of tea is due to the content of the alkaloid caffeine and tannins. One of the important indicators of the quality of the finished tea is the content of water-soluble extractive substances in it, which turn into an infusion when brewed. Their quantity depends on the type and grade of tea: the higher the grade, the greater their content (28-40%).

Depending on the raw materials and processing technology, tea is produced in the following types and types:

Long leaf (loose) – (black, green, red, yellow, white), which is divided into leaf and small;

Trade varieties are finished products that are manufactured in tea-packing factories.

Natural coffee is the seeds (beans) of coffee plants from the genus Coffea Linney, growing in tropical countries. The physiological value of coffee is due to the presence of the alkaloid caffeine, aromatic substances and chlorogenic acid.

The industry produces the following types of natural coffee:

Natural roasted coffee (beans, ground, Turkish ground and ground with chicory);

Natural instant coffee (powdered, granulated, sublimated).

The quality of tea and coffee is determined by organoleptic, physico-chemical, microbiological and safety indicators.

When assessing the quality of tea organoleptically, the aroma, taste, intensity of the infusion and the color of the boiled leaf are determined.

Organoleptic assessment of the quality of coffee is carried out by appearance, taste and aroma, and for instant coffee, also by color.

The physical and chemical indicators of tea quality include the following: mass fraction of moisture, water-soluble extractive substances, metallomagnetic impurities, total ash, water-soluble ash, crude fiber and mass fraction of fines.

Physico-chemical indicators of coffee quality include the following: mass fraction of moisture, water-soluble extractive substances, caffeine, metal and foreign impurities, total ash and ash insoluble in hydrochloric acid, grinding size (for roasted ground coffee), complete solubility in hot and cold water, mass fraction of glucose and xylose (for instant coffee).

Microbiological indicators for tea and coffee indicate the presence of mold.

Among the safety indicators in tea and coffee, the content of toxic elements (lead, arsenic, cadmium, copper), aflatoxin B 1, radionuclides (cesium-137 and strontium-90) is standardized.

EXPERIMENTAL PART

Goal of the work: study the regulatory documentation for tea and coffee; master organoleptic methods for determining the quality of tea and coffee provided for by the standards.

Equipment, materials, reagents:

laboratory scales

Tea tasting kit

Determination technique

Organoleptic evaluation of tea.

When organoleptically assessing the quality of tea, the appearance (harvesting) of dry tea is first determined, and then its infusion is prepared, in which the aroma, taste, color intensity and color of the brewed leaf are determined.

For rate appearance average samples are poured onto clean sheets of paper and visually determined:

Tea group (leaf, fine or granulated);

Uniformity of color and degree of curling of tea leaves;

Availability of tips;

The presence of stems and tea dust, characteristic of low grades of tea and raw materials collected in late autumn;

Contamination with cuttings, coarse leaves, fibers and other impurities due to insufficient cleaning and sorting.

Analysis of this indicator gives an idea of what raw materials the products are made from and whether the technological conditions are followed, especially in the processes of rolling and sorting tea.

For preparing the infusion Weigh 3 g of tea and pour it into a tester teapot. Pour 125 ml of freshly boiling water, close the lid and leave for 5 minutes. Then the infusion is poured into a special white porcelain cup so that the boiled tea leaves do not get into the infusion.

When assessing colors the infusion pays attention to its suitability to the type of tea, thickness, intensity, brightness.

The determination of taste and aroma does not begin immediately after pouring the infusion, but after 1-1.5 minutes. For determining aroma When drinking tea, quickly open the lid of the teapot, bring it to your nose and, drawing in air strongly, evaluate the smell.

In tea tester practice, special terminology has been adopted to determine the aroma of good-quality tea:

Rosey;

Almond;

Honey;

Citrus;

A mixture of scents of strawberries, geraniums and black currants, etc.

Tea can have a full bouquet, subtle, delicate, pleasant or weak, coarse aroma, depending on the variety.

Unwanted odors:

Smokeiness;

Roastiness;

Herbaceous smell;

various foreign odors.

For determining taste They sip a little tea from the cup and, without swallowing, roll it around in their mouth, assessing the taste sensations.

The astringency and fullness of taste of the infusion are a sign of the high extract content of teas and their high P-vitamin activity. If the astringency is not sufficiently expressed, the tea has an empty “flat” taste, characteristic of over-fermented teas. Unfermented tea always has a bitter taste.

Tea with an insufficiently astringent taste is called “lifeless” tea. The reasons for this phenomenon may be the following: absorption of excess moisture by tea, high temperature and steaming of tea during drying.

The tea infusion obtained through proper fermentation, drying and storage of tea is characterized as “vital” or “alive”.

Grade the color of the boiled leaf gives a reliable idea of the quality of tea.

The boiled leaf is transferred from the teapot to its lid, squeezed with two fingers, and the color of the leaves and the uniformity of their color are determined.

High-quality black long tea has a boiled leaf with a bright copper color. Dark brown, green and dull shades of color are considered defects.

Good black long tea has a light brown color; green - from greenish-yellow to dark yellow.

Dark color occurs when the tea leaves are over-fermented or over-withered; green color - with insufficient fermentation.

When determining the color of a boiled leaf, pay attention to its uniformity: the lower the grade, the less uniform the color.

Enter the results of organoleptic assessment of tea quality in Table 1

A.S.Kucher

Mogilev 2012

1) Purpose of the work: Carry out quality control of drinks.

2) Instruments and equipment: Electric stove in accordance with GOST 306, FE, sieve, laboratory electric drying cabinet with thermostat in accordance with GOST 7365, VNIIHP HF apparatus, laboratory lever scales in accordance with GOST 19491, desiccator in accordance with GOST 6371, porcelain evaporation cups with a diameter of 6 - 8 cm in accordance with GOST 9147 (or cups (bulks)) according to GOST 7148.

Work order

Assessment of organoleptic and physicochemical parameters of tea

1.1 Organoleptic evaluation carried out at an infusion (infusion) temperature of 65 0, comparing it with the control. A control infusion is prepared from tea of the appropriate variety, which is brewed in an amount of 10 (20) g per 500 cm 3 of water, infused for 10 minutes and filtered.

The aroma and taste of the drink (subject to compliance with the laying standards and brewing rules) are characteristic of each type of tea. Properly brewed tea is clear. If the infusion is cloudy or its color is dull brown, it means that the tea was brewed incorrectly or has been infused for a long time.

Organoleptic characteristics of the test sample:

Color– transparent, orange-yellow hue.

Aroma and taste- characteristic of this type of tea.

Table 1 – Tea-infuser No. 1002

Table 3 – Dry matter content in tea

m dry V= 20.35 g

Table 4 – Organoleptic indicators of tea quality

1.2 Determining the freshness of the infusion. Boiling the tea infusion leads to loss of aroma, transparency and deterioration of color: from orange-yellow it becomes dirty brown. Tea that has been boiled is removed from sale and is not subject to further analysis.

Prepare a control infusion (infusion) according to recipe 1008. The test and control infusions are cooled to room temperature and filtered through a paper filter.

To determine the freshness of the infusion, 1 cm 3 of filtered infusion, test and control, is poured into two test tubes. To the samples add 2 cm 3 of a 1% solution of potassium iron sulfide and a 40% solution of sodium hydroxide. The contents of the tubes are shaken and left for 5-10 minutes. When the infusion is boiled or dry tea is not added to it, the liquid in the test tube turns light yellow; when the tea is brewed a second time, it turns lemon-colored; The liquid in the control tube is golden in color.

Table 5 - Determination of tea freshness

Continuation of table 5

1.3 Detection of burnt sugar in tea leaves. Burnt sugar enhances the color of the tea infusion, thereby masking the lack of dry tea. Detection of burnt sugar is based on the fact that tannins in tea (unlike burnt sugar) form a precipitate with a solution of copper acetate.

5 cm 3 of tea infusion is poured into a dry test tube, 2 cm 3 of a saturated solution of copper acetate is added and the contents of the test tube are thoroughly mixed and left for 15-20 minutes.

Based on the color of the liquid and the presence or absence of sediment, a conclusion is made about the presence of burnt sugar in the infusion (Table 6).

Table 6 - Characteristics of the strength of tea infusion according to standards

Tea infusions containing burnt sugar will be removed from sale.

The experimental results are shown in Table 7.

Table 7 - Determination of burnt sugar in samples

Conclusion: during the experiment, it was discovered that sample No. 1 contained burnt sugar.

1.4Detection of baking soda in tea leaves. In an alkaline environment, the color intensity of the tea leaves increases. Therefore, by adding baking soda to the tea leaves, you can mask the lack of dry tea or the use of stale tea.

The tea brew is cooled to room temperature. A drop of tea leaves is applied to a strip of universal indicator paper. Tea leaves with the addition of soda will turn the indicator paper green. In the absence of soda in the tea leaves, the yellow color of the paper will not change.

Table 8- Content of baking soda in tea

Conclusion: during the experiment it was discovered that sample No. 2 contained soda.

Related information.