Some standard content:
National Standard of the People's Republic of China
Grades of basket-fired green tea for scenting GB/T9172-88
This standard refers to and adopts international standards ISO1572-1980 "Tea-Preparation of ground samples of known dry matter content", IS01573-1980 "Tea-Determination of mass loss at 103℃", ISO1574-1980 "Tea-Determination of water extract", and IS01575-1980 "Tea-Determination of total ash". Subject content and scope of application
This standard specifies the technical requirements, test methods, inspection rules and packaging, storage and transportation requirements for unified graded scented tea. This standard applies to all grades of scented tea made from roasted green tea as raw material, which is refined and processed for cellar-made scented tea. 2 Reference standards
GB8302
Tea sampling
GB8303
GB8304
GB8305
GB8306
GB8310
GB8311
GB8313
Preparation of ground samples and determination of their substance content Determination of moisture
No leaching Determination of total ash content
Determination of crude fiber
Determination of powder and broken tea content
Determination of tea polyphenols
GB8314
3 Technical requirements
3.1 Grading and physical samples
3.1.1 Grading
Determination of total free amino acids
Grading of flower tea is divided into six grades according to quality, namely grade one to grade six. 3.1.2 Physical samples
Grading of flower tea: A standard physical sample is set for each grade. The physical sample is the lowest limit of each grade and is replaced every four years. 3.2 Quality indicators
3.2.1 Basic requirements
Grading of flower tea must be of normal quality, without deterioration, odor, and must not be mixed with non-tea inclusions. 3.2.2 Sensory indexes
3.2.2.1 The sensory quality of each grade of flower tea must conform to the standard sample. 3.2.2.2 The sensory quality indexes of each grade of flower tea are shown in Table 1: The terms used in the table refer to the Appendix B of the "Tunwu Suishu Hangwen Ping 7 Sets of Rough Roasted Green Tea Standards" of the Ministry of Commerce of the People's Republic of China HG016-84, which contains the common quality standard terms, nouns and function words for sensory evaluation.
【Thin, tight, even, straight, green and moist
tender, even
Grade丨Front seedlings
【Tight and straight
green and bright
Grade丨There are front seedlings
【Tight and straight
tender, even and green
Grade 31
"Still tight, slightly flat
Spread out, uneven
Grade 4!
Hooked, green and bright
Luster|Clean
"Hooked
"Flat||t t||【The green is still moist
The green is still moist
"Yellow-green
"The shape is still neat丨Still clean
"Flat
【The shape
丨Fragrant丨Soup
"Tender and fragrant丨Yellow-green and clear
丨Fragrant丨Yellow-green and bright
【With slightly tender stems】
"With tender stems
Still even｜With tendons
【Slightly loose, flat】Yellow-green is slightly dark丨Still even and thick Yellow-green is slightly dark
Five-level strips, round pieces!
"Loose, flat and light" "Yellow, slightly dry and oak丨Uneven
Stalks slightly yellow and dark
Grade 6丨
3.2.3 Physical and chemical indicators
Scented tea grade type bad Physical and chemical indicators of each level are shown in Table 2. 1 Stem and simple
Taste one leaf
|Rich, fresh and refreshing
1 Rich
【Fresh and refreshing
丨Fragrant yellow-green and bright丨Rich
丨Pure丨Bright yellow-green
"Peaceful" Slightly darker yellow-green
"Stalks are more rustic and coarse Yellow-green is darker
Peaceful
■Bland
Moisture, %(m/m) maximum limit
Ash, %(m/m) maximum limit
Broken tea, %(m/m) maximum limit
Powder, %(m/m) maximum limit
Water extract, %(m/m) maximum Lower limit
Crude fiber,
%(m/m)Maximum limit
Total flavor score
140.80140.20139.5038.00
111.4012.00
13.00【15.00
Note: Water extract, crude fiber and total flavor score are reference indicators. 3.3 Hygiene indicators
According to G Bn144 "Green Tea, Black Tea Hygiene Standard" 4 Test methods, inspection rules
4.1 Sampling method is implemented in accordance with GB8302. 4.2 Sensory inspection method is implemented in accordance with Appendix A. 4.3 Physical and chemical test methods
4.3.1 Moisture test method is implemented in accordance with GB8304. 4.3.2
Ash test method is implemented in accordance with GB8306. Broken tea, powder The test method shall be implemented in accordance with GB8311. 4.3.3
The test method for water extract shall be implemented in accordance with GB8305. The test method for crude fiber shall be implemented in accordance with GB8310. 4.3.5
The test method for total flavor shall be implemented in accordance with Appendix B. 4.3.6
4.4 The test method for hygiene indicators shall be implemented in accordance with GB5009.57 "Analysis Methods for Hygiene Standards for Tea". 4.5 Re-inspection rules
If there is a dispute over the inspection results, the retained samples shall be re-tested or double the samples shall be taken from the same batch of products in accordance with GB8302, and the unqualified items shall be re-inspected, and the re-inspection results shall prevail. 5 Marking, packaging, transportation, storage
5.1 Marking
The outer packaging of tea leaving the factory should be labeled with the product name, grade, trademark, net weight, batch number, factory name, packaging date, and indicate "moisture-proof" and other signs. The text should be simple and concise, the pattern should be eye-catching and clear, and the words should be neat. 5.2 Packaging
5.2.1 Tea from the same batch can only be packaged in the same way, and the net weight must be the same. 5.2.2 The packaging container is made of materials that do not affect the quality of the tea. 5.2.3
Packaging is divided into outer packaging and inner and outer packaging.
5.2.3.1 Outer packaging
Three wooden boxes , plywood box or carton, specifications: wooden box 460×460×500mm**3;
plywood box 440×440×450mm**3; carton 355×355×190mm**3;
5.2.3.2 Inner Packing
Inner packing uses odorless kraft paper or kraft paper with aluminum foil or non-toxic plastic film as moisture-proof inner bag, bonded or heat-sealed with non-toxic adhesive.
5.3 Transportation
All kinds of transportation vehicles must be clean, sanitary, dry, odorless and pollution-free; they must be protected from rain, moisture and sun exposure during transportation; they must be placed and unloaded gently during loading and unloading, and must not be thrown or collided; it is strictly forbidden to mix and transport with toxic, harmful, odorous and easily contaminated items.
5.4 Storage
Tea must be stored in a clean, moisture-proof, odor-free warehouse with a relative temperature below 70%. It is strictly forbidden to mix it with toxic, harmful, odorous, and easily contaminated items. Pay attention to keeping it ventilated and dry. Appendix A
Sensory inspection method
(Supplement)
A1 Principle
According to the method of this standard, use the discrimination ability of human sensory organs (vision, smell, taste, touch) to evaluate the quality of tea.
A2 Conditions
A2.1 Lighting
The light is bright, soft, and the brightness is consistent. The review room is required to have natural light from the north, and lighting equipment can also be used. A2.2 Room temperature
The room temperature should be maintained at 20~25℃.
A2.3 Indoor atmosphere
The indoor environment must be clean and dry, with fresh air circulation. There must be no volatile gases with peculiar smells. Smoking is prohibited indoors. A3 Evaluation tools
A3.1 Evaluation tea tray
Made of plywood or non-toxic plastic, white, 230mm long and wide, 30mm high, with a notch in one corner of the tray. A3.2 Evaluation tea cups and bowls
Made of pure white porcelain, the thickness, size and color must be consistent. A3.2.1 Evaluation tea cups
The cup is 65-2mm high, 66-2mm in outer diameter, and 62-2mm in inner diameter. The capacity is 150mL, there is a small hole on the lid, and there is a small moon-shaped notch on the cup mouth opposite to the handle. A3.2.2 Evaluation tea bowls
The bowl is 55mm high, with an outer diameter of 95mm at the top and an inner diameter of 92mm, and a capacity of 150mL. A3.3-leaf bottom plate
Small black square wooden plate, 95mm long and wide, 15mm high. A3.4 Net spoon
Made of copper wire mesh, round bottom.
A3.5 Tea spit bucket
Made of iron sheet, 800mm high, 350mm upper and lower diameters, 200mm waist diameter. A3.6 Other utensils
a. Balance: sensitivity 0.1g;
Clock or sand timer;wwW.bzxz.Net
Teaspoon;
d. Boiling water shell;
e. Electric stove or electric kettle.
A4 Evaluation method
Compare the appearance and internal quality of the sample with the standard sample of bad grade of scented tea. A4.1 Appearance Evaluation
Take 110-140g of the thoroughly mixed sample and place it on a tea evaluation tray. After rotating the tea evaluation tray several times, inspect its appearance and evaluate the four quality factors of the tea leaves: strands, wholeness, purity, and color. A4.2 Internal Quality Evaluation
Take 3g of the mixed sample from the tea evaluation tray and place it in a tea evaluation cup. Fill it with boiling water, cover it, and soak it for 5 minutes. Then drain the tea soup into the tea evaluation bowl. Evaluate the three factors of soup color, aroma, and taste in turn. Finally, move the tea residue in the cup to the leaf bottom tray and inspect the leaf bottom.
A4.3 Scoring
Compare with the standard sample and score the various factors of the appearance and internal quality of the tea according to the following regulations. Comparison with standard samples
A4.4 Result evaluation
A4.4.1 The appearance and internal quality of the tea are scored separately according to each quality factor. The levels of the internal quality and appearance must be in the same grade to be rated as a product of that grade.
A4.4.2 If there is one "low" (-3 points) or one "lower" (-2 points) and one "slightly lower" (-1 point) or three "slightly lower" (-3 points) scores for each quality factor, they are all rated as lower than the standard of that grade. A4.4.3 If there is one "lower" score for each quality factor, it is rated as lower than the standard of that grade. Appendix B
Chemical identification method for tea flavor
(Supplement)
This appendix refers to GB8313 and GB8314. B1 Principle
Tea polyphenols and amino acids are the main flavor components of green tea. Tea polyphenols are measured by ferric tartrate colorimetry to obtain flavor concentration; amino acids are measured by triketone colorimetry to obtain flavor freshness; the ratio of amino acids to tea polyphenols is used to obtain flavor alcohol, which decreases with the taste.
B2 Instruments and appliances
Use routine laboratory instruments and the following items: B2.1 Constant temperature water bath
B2.2 Analytical balance: sensitivity 0.0001g
B2.3 Spectrophotometer.
B3 Reagents
The reagents used should be analytical grade (AR), and the water should be distilled water. B3.1
Ferric tartrate solution: weigh 1g ferrous sulfate (FeS047H2O) and 5g potassium sodium tartrate (C14H406KNa·4H20)
Add water to dissolve, and dilute to 1L (should be kept away from light and refrigerated, with a validity period of one month). B3.21/15M disodium hydrogen phosphate solution: weigh 23.877g disodium hydrogen phosphate (Na2HPO4·12H2O), dissolve in water, and dilute to 1L.
B3.31/15M potassium dihydrogen phosphate solution: weigh 9.078g potassium dihydrogen phosphate, dissolve in water, and dilute to 1L.
pH7.5 phosphate buffer: aspirate 85mL1/15M disodium hydrogen phosphate solution and 15mL1/15M potassium dihydrogen phosphate and mix evenly.
pH8.0 phosphate buffer: aspirate 95mL1/15M sodium dihydrogen phosphate solution and 5mL1/15M potassium dihydrogen phosphateB3.5
mix evenly.
B3.62% triketone solution: weigh 2g hydrated triketone, add 50mL water, add 80mg stannous chloride (SnCL2 · 2H2O),
dissolve, filter, and add water to make up to 100mL. B4
Operation method
B4.1 Sampling
Follow the provisions of GB8302.
B4.2 Sample preparation
Follow the provisions of Appendix CGB83032.3.2. B4.3 Determination steps
B4.3.1 Preparation of test solution
Follow the provisions of Appendix CGB8305.
B4.3.2 Concentration determination
Accurately draw 1mL of the test solution and inject it into a 25mL volumetric flask, add 4mL of water and 5mL of tartaric acid iron solution, mix thoroughly, and then add
pH7.5 phosphate buffer to the scale. Use a 10mm colorimetric cup to measure the absorbance (A1) at a wavelength of 540nm, using the reagent blank solution as a reference.
B4.3.3 Freshness determination
Accurately draw 1mL of the test solution and inject it into a 25mL volumetric flask, add 0.5mL of pH8.0 phosphate buffer and 0.5mL of 2% tri
ketone solution, and heat in a boiling water bath for 15min. After cooling, add water to the scale. Let it stand for 10min, and use a 5mm colorimetric cup to measure the absorbance (A2) at
570nm, using the reagent blank solution as a reference. B4.4 Calculation of results
B4.4.1 Calculation method and formula
Concentration is calculated by formula (B1):
Concentration=A1×100
Freshness is calculated by formula (B2):
Freshness=A2×100
Mellowness is calculated by formula (B3):
Total flavor score is calculated by formula (B4):
Total flavor score=concentration+freshness+mellowness·
If the requirements of reproducibility are met, the arithmetic mean of the two measurements is taken as the result. B4.4.2 Repeatability
When the same sample is measured twice, the difference in the absorbance values of freshness and depth shall not exceed 0.01. Appendix C
Rapid method for determination of moisture and ash content in tea
(reference)
C1 Rapid method for determination of moisture content in tea
C1.1 Apparatus and utensils
Follow the provisions of Chapter 2 of GB8304.
C1.2 Operation method
C1.2.1 Sampling
Follow the provisions of GB8302.
C1.2.2 Preparation of aluminum baking powder
Follow the provisions of 3.3 of GB8304.
C1.2.3 Determination steps
In the dry baking powder of known weight, weigh 10g of the thoroughly mixed sample (accurate to 0.001g), shake it gently to flatten the sample, and place it in an oven preheated to 140℃, with the powder cover tilted on the powder edge. Keep a proper distance between each powder. When the oven temperature rises back to 130℃, bake for 27 minutes. Cover and take out the dried blood, place in a desiccator and cool to room temperature. Weigh accurately to 0.001g. Note: This determination method can obtain the same results as GB8304, but in each case, the analyst needs to perform
verification.
C1.3 Result calculation
C1.3.2 Calculation method and formula
The mass percentage of moisture in tea is calculated according to formula (C1): G1-G2
Moisture (%)
Where: G1——Sample and dried blood after baking, g: G2-
Sample and dried blood after baking, g:
Sample mass, g.
If the requirements of repeatability (C1.3.2) are met, take the arithmetic mean of the two determinations as the result. C1.3.2 Repeatability
According to GB8304.
C2 Rapid method for determination of total ash content in tea
C2.1 Apparatus and equipment
According to 2.3, 2.4, 2.5 of GB8306. The upper diameter of the porcelain boat is 600mm×30mm and the height is 15mm. C2.2 Operation method
C2.2.1 Sampling
According to GB8302.
C2.2.2 Sample preparation
According to GB8303.
C2.2.3 Preparation of porcelain boat
Place the clean porcelain boat in a high-temperature furnace at 700±25℃ and burn for 20min. When the furnace temperature drops to about 300℃, take out the porcelain boat, cool it to room temperature in a desiccator, and weigh it (accurate to 0.001g). C2.2.4 Determination steps
Weigh 2g of the mixed ground sample (accurate to 0.001g) and place it in a porcelain boat of known weight. Slowly heat it on a hot plate until the sample is fully carbonized until there is no smoke. Move the porcelain boat into a high-temperature electric furnace and burn it at 700±25℃ for 20min. When the furnace temperature drops to about 300℃, take out the porcelain boat, cover it with a clean small glass slide, cool it to room temperature in a desiccator, and weigh it to an accuracy of 0.001g.
C2.3 Result calculation
C2.3.1 Calculation method and formula
The dry mass percentage of total ash in tea is calculated according to formula C2: G1-G2
Total ash (%)=
-mass of sample and porcelain boat after burning, g: Where: G1-
G2-mass of porcelain boat, g;
G-mass of sample, g;
Percentage of dry matter content of sample.
If the requirements of repeatability (C2.3.2) are met, the arithmetic mean of the two measurements shall be taken as the result. C2.3.2 Repeatability
According to the provisions of 4.2 of GB8306.
Additional remarks:
This standard was proposed by the Tea and Livestock Bureau of the Ministry of Commerce.
This standard was drafted by the Hangzhou Tea Processing Research Institute of the Ministry of Commerce. The main drafters of this standard are Zhong Luo, Xiao Juqin, Guo Wenwen, Zhou Weilong and Pu Hejuan. Approved by the Ministry of Commerce of the People's Republic of China on April 30, 1988 (C2)
Implemented on July 1, 1988
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