Some standard content:
National Standard of the People's Republic of China
1 Subject content and scope of application
Raw sugar
GB/T15108--94
This standard specifies the technical requirements, test methods and inspection rules for raw sugar, as well as the requirements for marking, packaging, transportation and storage. This standard applies to raw sugar that is not directly edible and is made from purified sugarcane juice. 2 Technical requirements
2.1 Sensory indicators
2.1.1 The crystals are uniform and loose.
2.1.2 The surface of the crystals has a thin layer of raw molasses. 2.1.3 There should be no obvious impurities such as sand and stone in the sugar. 2.2 Physical and chemical indicators
The physical and chemical indicators must comply with the provisions of Table 1.
Project name
Sugar content, %
Loss on drying, %
Conductivity ash, %
Color value, IU
Insoluble impurities in water, mg/kg
3Test method
3.1 Determination of sensory index: qualitative determination by visual measurement. 3.2 Determination of sugar content
3.2.1 Instruments and equipment
3.2.1.1 Balance: accuracy ±0.002g. 3.2.1.2 Volumetric flask: 100.00±0.02mL. 3.2.1.3 Filtration equipment: glass stemless funnel, beaker, medium-speed quantitative filter paper.
3.2.1.4 Sugar detector, should have international sugar scale, according to sugar scale Z, the accuracy of automatic sugar detector is 0.05Z, the accuracy of visual sugar detector is 0.1.
Note: If using sugar detector with old sugar scale S, the reading S must be multiplied by a coefficient of 0.99971 to convert into Z. 3.2.1.5 Observation tube: length 200.00±0.02mm. 3.2.2 Reagents
3.2.2.1 Basic lead acetate solution: Weigh 340g basic lead acetate powder and dissolve it in about 1000mL freshly boiled distilled water, and adjust the concentration to 54.3°Bx (1.24±0.01g/cm2). The prepared solution should be prevented from contacting with carbon dioxide in the air. 3.2.2.2 Distilled water. www.bzxz.net
3.2.3 Determination steps
3.2.3.1 Calibration of the sugar meter
The reading of the sugar meter should be calibrated with a standard quartz plate. It cannot be calibrated with sucrose solution. For sugar detectors without quartz wedge compensators, the temperature should be measured when reading the optical rotation of the quartz plate, and the accuracy should be 0.2℃. If the temperature is more than ±0.5℃ different from 20℃, the temperature correction of the optical rotation of the quartz plate should be performed using formula (1), and the correction value should be used to calibrate the reading of the sugar detector.
α, = α2e[1 + 0.000 14(t — 20) Where: t is the temperature when reading the optical rotation of the quartz plate, ℃; α20 is the optical rotation of the quartz plate at 20℃, Z; α, is the optical rotation of the quartz plate at t℃, Z. 3.2.3.2 Determination of sugar content
Weigh 26.000 ± 0.002g of sugar sample into a clean small beaker, dissolve it with 40-50mL of distilled water, and transfer it to a 100mL volumetric flask. Rinse the beaker with a small amount of distilled water 3-5 times, and pour the rinse water into the volumetric flask. Add distilled water to make the volume reach 60-70mL, then add 1.00±0.05mL of basic lead acetate solution, shake slowly to mix the solution, continue shaking and add distilled water until the spherical part of the volumetric flask is filled, and let it stand for at least 10 minutes to reach room temperature. Then add distilled water to about 1mm below the mark of the volumetric flask, make sure the neck of the volumetric flask has been cleaned, and be careful not to let the solution entrain air bubbles. If there are bubbles, use one or two drops of ether to eliminate them. Then hold the top of the neck of the volumetric flask vertically, so that the mark of the volumetric flask is level with the operator's eyes, observe against a bright background, and add water with a long dropper until the lower edge of the meniscus is tangent to the mark. Use clean filter paper to absorb the inner wall of the volumetric flask above the mark, plug the stopper tightly, and shake it thoroughly. Let the solution stand for at least 5 minutes to allow the precipitate to fall, and then filter it with filter paper. Discard the first 10mL of filtrate and collect about 50-60mL of the subsequent filtrate. When filtering, the funnel must be covered with a watch glass. Rinse the observation tube with the filtrate for 2-3 times and fill it up. Be careful not to allow air bubbles to be trapped in the observation tube. Place the observation tube in the sugar detector and visually measure the sugar detector 5 times. Take the reading below 0.05Z. If an automatic sugar detector is used, there should be enough time for the instrument to stabilize before measurement. After measuring the reading, immediately measure the temperature of the solution in the observation tube and be accurate to 0.1℃.
3.2.3.3 Calculation and result expression
The temperature for measuring sugar content should be as close to 20℃ as possible, generally in the range of 15-25℃. If the sugar content is not measured at 20.0±0.2℃, it should be corrected to 20℃.
Sugar content X is calculated according to formula (2) and formula (3) and expressed as a percentage. The calculation result is rounded to three significant digits. Sugar meter with quartz compensator:
X, = P,[1 + 0. 000 32(t -- 20)J Sugar meter without quartz wedge compensator:
XP[1 + 0. 000 19(t - 20)J
Where: P,--observed sugar content of raw sugar sample, 2; When measuring P,, the temperature of sugar solution, ℃.
3.3 Determination of loss on drying
3.3.1 Instruments and equipment
3.3.1.1 Electric thermostatic box: During the measurement, the temperature at 2.5 ± 0.5 cm above the drying tube III should be maintained at 105 ± 1°C. 3.3.1.2 Desiccator with color-changing silica gel. 3.3.1.3 Weighing bottle: 6 cm in diameter and 3 cm in height. 3.3.2 Determination steps
3.3.2.1 Drying
(2)
(3)
Preheat the drying oven to 105℃. Place the empty weighing bottle with the lid open in the drying oven and dry for at least 30 minutes. 629
GB/T 15108—94
Then take the weighing bottle out of the drying oven, cover it, and place it in a desiccator to cool to room temperature (maximum 2 () above room temperature). Weigh as quickly as possible, with an accuracy of 0.1 mg.
Put 9.5~10.5g of sample in the weighing bottle as quickly as possible, cover it, and weigh it accurately to 0.1mg. The thickness of the sugar layer in the weighing bottle should not exceed 1cm
Remove the cover and put it into a drying oven together with the weighing bottle. Dry it accurately at 105℃ for 3h. Cover the weighing bottle and move it into a desiccator to cool to room temperature (up to 2℃ higher than room temperature). Weigh it as quickly as possible, accurately to 0.1mg. 3.3.2.2 Calculation and result expression
Loss on drying X. Calculate according to formula (4) and express it as a percentage. The result should be two decimal places. w. W×100||tt| |Where: w, the mass of a weighing bottle
W. The mass of the weighing bottle and the sample before drying, gW. The mass of the weighing bottle and the sample after drying. 3.4 Determination of conductivity ash
3.4.1 Instruments and equipment
3.4.1.1 Conductivity meter: measuring range 0~500μS/cm, the measurement accuracy should not be greater than 1.5% of the full scale. 3.4.1.2 Volumetric flask: 100±0.05mL. 3.4.2 Reagents
3.42.1 Pure water: the conductivity is lower than 15uS/cm, and it should be actually measured. (4)
3.4. 2.2 0.01mol/L potassium chloride solution: Take potassium chloride (analytical grade) and heat it to 500℃ (dark red hot), dehydrate for 30min, accurately weigh 745.5mg, dissolve it in pure water, transfer it to a 1000mL volumetric flask, and add water to the mark. 3.4.2.3 0.0025mol/L potassium nitride solution: Pipette 25mL of 0.01mol/L potassium chloride solution into a 100mL volumetric flask, add water to dilute to the mark. The conductivity of this solution at 20C is 328μS/cm. 3.4.3. Determination steps
Weigh 5.0g of raw sugar sample into a clean small beaker, After dissolving in pure water, transfer to a 100mL volumetric flask, rinse the beaker and glass rod with pure water several times, rinse and transfer to the volumetric flask, add pure water to the mark, and shake thoroughly. Rinse the dry clean small beaker used for conductivity measurement with the sample solution 2-3 times, then pour the sample solution, measure the conductivity of the sample solution with a conductivity meter, and immediately measure the temperature of the sample solution, and at the same time measure the conductivity of the pure water used for dissolving sugar.
The conductivity cell constant should be calibrated with 0.0025mol/L potassium chloride solution. 3.4.4 Calculation and nested expression
Conductivity ash X: Calculate according to formula (5), express as a percentage, and round the calculation result to two decimal places. X 18 × 10-4(C - 0.902)
Where: C,-—Conductivity of 5g/100mL sugar solution at 20℃, μS/cm; C, conductivity of pure water for dissolving sugar at 20℃, S/cm. 3.4.5 Temperature correction
The standard temperature for measuring conductivity is 20℃. If it is not at 20℃, it should be corrected according to formula (6), but the measuring temperature should not exceed the range of 15～25℃. As for the temperature correction of the conductivity of pure water for dissolving sugar, it can be ignored because of its small influence. C, Cu1 + 0. 023(20 - r)J
Where: C--conductivity of sugar solution at C, μS/cm+temperature of sugar solution when measuring conductivity, ℃. 3.5 Determination of color value
3.5.1 Instruments and equipment
3.5.1.1 Spectrophotometer: The wavelength error at 420nm is not more than ±1nm. 630
GB/T15108—94
3.5.1.2 Colorimetric III: The thickness of the colorimetric should be selected so that the instrument transmittance reading is between 20% and 80%. Generally, 1cm colorimetric III is used, and the difference in transmittance between the colorimetric room and the light path used in conjunction is not greater than 0.2%. 3.5.1.3 Abbe refractometer: The sugar concentration measurement range is 0~95%, and the minimum scale value of sugar concentration (%) on the scale plate is 0.5. 3.5.1.4 pH meter, the scale value or the minimum display value is 0.02pH. 3.5.1.5 Membrane filter, use a microporous membrane with a pore size of 0.45m. 3.5.2 Determination steps
According to the better filtration speed and colorimetric III thickness, select an appropriate concentration (generally 10Bx can be used) to weigh a certain amount of sugar sample and dissolve it with steamed stuffing water. Adjust the pH of the sugar solution to 7.0 ± 0.1 with about 0.01 mol/L sodium hydroxide or 0.01 mol/L hydrochloric acid solution. Pour into a filter pre-laid with a 0.45 m microporous membrane, filter under vacuum, discard the initial part of the slurry, and collect no less than 50 ml of the subsequent filtrate. Use an Abbe refractometer to measure the refractive hammer of the filtrate, then rinse the cuvette three times with the filtrate and fill it up again, measure its absorbance on a spectrophotometer at a wavelength of 420 nm, and adjust to zero with filtered distilled water. 3.5.3 Calculation and result expression
The color value X is calculated according to formula (7) in IU, and the calculation result is rounded to the nearest digit. X
Wherein: - absorbance of sample solution measured at 420nm wavelength; h
refractive index
colorimetric blood thickness, cm;
X 1000
sample solution concentration (obtained by looking up the refractive index corrected to 20°C in Table 2), g/mlTable 2 Comparison table of refractive index of sucrose solution and grams of sucrose per ml (in air)Concentration
0. 056 03
0. 059 16
0. 072 79
0. 077 01
0. 078 07
0. 081 25
refractive index
0. 084 44
0. 087 63
0. 088 69
0. 091 90
0. 094 04
0. 099 40
Refractive Rust
0,1442
Refractive Hammer
3.6 Determination of water-insoluble impurities
3.6.1 Apparatus and equipment
GB/T 15108--94
3.6.1.1 Glass filter: pore size 40~80μm. 3.6.1.2 Electric thermostatic box: 125~130℃. 3.6.1.3 Desiccator: equipped with color-changing silica gel. 3.6.1.4 Balance: accuracy reaches ±0.001g. 3.6.2 Reagents
3.6.2.11% α-naphthol ethanol solution.
3.6.2.2 Concentrated sulfuric acid.
3.6.3 Determination steps
Lay a layer of glass wool about 5mm thick washed with dilute hydrochloric acid solution and rinsed with distilled water on the filter plate of the glass filter. Then use a large amount of distilled water to filter and wash the glass filter under reduced pressure, and then dry and weigh it. Weigh 250.0g of the sample into a 1000mL beaker (if it is mixed with packaging fibers, fluff, etc., it should be removed before weighing), add about 700mL of distilled water, stir until completely dissolved, pour into the above-prepared glass filter, filter under reduced pressure, and wash the filter residue with distilled water until the washing liquid does not contain sugar. Dry the glass filter and the filter residue at 125-130℃, move it into a dryer, cool it to room temperature, and weigh it. Continue drying for about 30 minutes, cool and weigh once, until the difference between two consecutive weighings does not exceed 0.001g. 3.6.4 Calculation and result expression
The number of milligrams of water-insoluble impurities X contained in each dry gram of raw sugar sample is calculated according to formula (8), and the calculation result is rounded to the unit. X, = (W, - W.) X 4 000
W, —-the total weight of the glass filter and the filter medium after drying, gW, —-the total weight of the glass filter and the filter medium and the filter residue after drying, g. 4 Inspection rules
4.1 Each delivery of raw sugar is a delivery batch, and each batch of sugar must be accompanied by a quality certificate of the place of origin. The buyer receives the goods with the quality certificate and conducts sampling inspection at the delivery site.
4.2 Each delivery batch of raw sugar is an inspection batch. 4.3 Sampling method
4.3.1 Before sampling, the delivery batch, batch size and origin shall be verified, and the number of incremental samples of the delivery batch shall be determined. 4.3.2 The number of incremental samples is shown in Table 3.
Table 3 Number of incremental samples to be taken for each batch of raw sugar
Batch Q, t
Q≥20 000
15000≤Q<20000
10000≤Q<15000
5000≤Q<10 000
Q<5000
4.3.3 Quantity of incremental samples
The quantity of each incremental sample is generally 100-150g, and the amount of incremental samples taken shall be roughly equal. 4.3.4 Sampling
Number of incremental samples n, pieces
There are three sampling methods for raw sugar: systematic sampling, stratified sampling and two-level sampling. One method can be selected according to the actual situation. 4.3.4.1 Systematic sampling method
GB/T 15108-94
During the loading, unloading, processing or weighing of a batch of bulk raw sugar, incremental samples are taken at a certain mass or time interval. The interval between incremental samples can be calculated according to the number of incremental samples to be taken and the actual batch size specified in Table 3 according to formula (9). or t
Where: - sampling mass interval, t: or time interval, min; Q is the batch size of the inspection batch,;
n - number of incremental samples to be taken, pieces;
G - loading and unloading volume per hour, t.
* (9)
When taking the first incremental sample, it can be randomly determined within the first interval. However, it cannot start from the starting point of the first room. The subsequent sampling shall be taken at the calculated intervals, and the sampling intervals shall not be greater than the calculated intervals. If the number of samples to be taken in a fixed room has been completed, and the loading, unloading, processing or weighing of raw sugar is still in progress, the sampling shall continue to be taken at the original intervals until the entire batch of raw sugar has been moved. If sampling is taken at the conveyor belt or the end of the conveyor belt, the entire cross-section of the raw sugar flow shall be intercepted. If the grab, forklift or other tools are used for loading, unloading or stacking, sampling should be carried out during the loading, unloading or stacking process. The sampling tray should be loaded with a sampling shovel and the sampling points should be evenly distributed on the newly exposed sugar layer. The sampling points should be evenly distributed in all parts of the entire batch of raw sugar, not on its surface or local areas. 4.3.4.2 Stratified sampling method
During the loading, unloading, processing and stacking of a batch of raw sugar, for example, in a ship's hold, sampling can be carried out in several layers (not less than three layers). According to the mass of raw sugar in each layer, points are evenly distributed on the newly exposed surface in proportion, and the surface of the point is first scraped off about 3 cm thick to take the sample. The number of samples to be taken from each layer is calculated according to formula (10). n = nX Q/Q
In the formula: - the number of samples to be taken from each layer;
n the number of samples to be taken from the whole batch of raw sugar, pieces,
Q: the mass of each layer, t
Q is the batch size of the inspection batch,.
4.3.4.3 Secondary sampling method
*（10）
During the process of loading, unloading or processing and weighing, the number of samples to be taken shall be specified in Table 3. Sample bags shall be taken according to the mass (number of bags), and then the sample bags shall be laid flat, and part of the seams of the bag opening shall be opened. With the sampling fiber facing upward, the paired fiber lines shall be inserted obliquely to the bottom corner of the bag, and the bag shall be rotated 180°. The sample bag shall be stirred so that the sample fills the sampling slot, and then carefully drawn out and poured into a sample container with a lid as a sample. 4.3.4.4 In case of large batches, long loading time, high temperature, etc., samples shall be taken as soon as possible and kept properly to prevent water evaporation. If unloading is carried out on rainy days, rain and moisture absorption shall be prevented.
4.3.5 Sample preparation
4.3.5.1 During the sample preparation process, the composition of the sample shall be prevented from changing and contamination. 4.3.5.2 Place the sample on the mixing plate and mix it. Use a sample shovel to pile the sample into a cone shape. Each shovel should fall from the top of the round pile. Make sure that the sample is scattered evenly along the top of the pile. Be careful not to misalign the center of the round pile. Repeat this three times to mix it thoroughly. Then flatten the top of the cone and press it down from the top with a cross plate to divide it into four equal parts. Take any two diagonal equal parts. Repeat the operation and reduce it to the required sample volume. 4.3.6 Reduce the sample into 1000g each of analytical sample and retained sample and put them into sealed sample bottles, or seal them with three-ply thick food-grade plastic bags and attach labels respectively. Indicate the following items on the label. Precision.
Number and batch number:
Sample name and origin:
Batch,
Sampling location (ship name);
Sampling and sample preparation person;
Sampling and sample preparation date.
4.4 The analysis sample is divided into three parts and tested according to the test method specified in this standard. The average of the two closest measured values is used as the final test result of the inspection batch, or if the difference between the two measured values and the intermediate value is equal, the intermediate value is used as the final test result of the inspection batch. The inspection result is the average quality of the batch of raw sugar. 4.5 In the inspection result, if there are unqualified indicators, double the samples should be drawn and the unqualified indicators should be re-tested. The re-test results are the final results of the inspection batch. If the re-test results are unqualified, the inspection batch is judged to be unqualified. 4.6 The analysis samples should be properly kept for inspection. The storage period can be based on relevant regulations, but it shall not be less than 3 months. 5 Marking, packaging, transportation and storage
5.1 The certificate for each batch of raw sugar delivery should contain the following contents: a. Product name,
b. Net weight (t);
c. Country of production;
d. Production batch number.
5.2 Raw sugar can be packed in bulk or bags without pollution and in compliance with food hygiene standards. 5.3 The carriage, cabin or truck bed for transportation should be clean and without leaks. 5.4 It is not allowed to use vehicles that have been used to transport coal, ash, lime, salt, salted fish, oil and other smelly, toxic or easily contaminated goods and have not been cleaned.
5.5 During transportation, it is strictly forbidden to mix with toxic and harmful items. The sugar pile should be covered with rainproof cloth to prevent sun exposure, rain or dust. 5.6 Raw sugar should not be stored in the open air as much as possible. If it is necessary to store it in the open air, it should be covered with rainproof cloth to prevent sun exposure, rain or dust. 5.7 Bulk storage should be adopted as much as possible in warehouses. The sugar pile should be covered with clean canvas or plastic film. 5.8 The warehouse for storing sugar should be kept dry and clean, and the temperature should not exceed 40℃. 5.9 Avoid sudden cooling and heating when storing sugar. According to the principle of first in, first out, the sugar should be transported out in sequence. Additional remarks:
This standard is proposed by China Light Industry General Association.
This standard is under the jurisdiction of the National Sugarcane and Sugar Industry Standardization Center. This standard is drafted by the Sugarcane and Sugar Industry Scientific Research Institute of the Ministry of Light Industry. The main drafters of this standard are Zheng Changgeng, Chen Junjia and Zhang Lingling. 634
Tip: This standard content only shows part of the intercepted content of the complete standard. If you need the complete standard, please go to the top to download the complete standard document for free.