This standard explains and specifies the determination principle, reagents, instruments, samples, and determination steps of alcohol-insoluble solids in fresh corn and quick-frozen corn. This standard applies to the determination of alcohol-insoluble solids in fresh corn and quick-frozen corn. GB/T 15669-1995 Fruits, vegetables and their products Determination of alcohol-insoluble solids in fresh corn and quick-frozen corn GB/T15669-1995 Standard download decompression password: www.bzxz.net
This standard explains and specifies the determination principle, reagents, instruments, samples, and determination steps of alcohol-insoluble solids in fresh corn and quick-frozen corn. This standard applies to the determination of alcohol-insoluble solids in fresh corn and quick-frozen corn.

National Standard of the People's Republic of China
Fruits, vegetables and their products--Determination of alcohol-insoluble solids content in fresh or quick-frozen maizeGB/T15669--1995
This standard is equivalent to the international standard ISO8129-1:1984 "Determination of alcohol-insoluble solids content in fruits, vegetables and their products: Part 1 Determination method for fresh corn and quick-frozen corn". 1 Subject content and scope of application
This standard explains and specifies the determination principle, reagents, instruments and equipment, samples, and determination steps of alcohol-insoluble solids in fresh corn and quick-frozen corn.
This standard is applicable to the determination of alcohol-insoluble solids content in fresh corn and quick-frozen corn. 2 Principle of determination
The sample is extracted by boiling an ethanol solution modified with methanol, then filtered, and the insoluble solid matter is washed clean with a ternary solvent system consisting of ethanol, methanol and water, and then dried and weighed. 3 Reagents
All reagents used are analytical grade, and the water used to prepare the reagents is distilled water or deionized water. 3.1 95% (V/V) ethanol solution: Take 5 volumes of methanol and 95 volumes of anhydrous ethanol (GB678) and mix them evenly. 3.2 80% (V/V) ethanol solution: Take 3 volumes of water and 16 volumes of 95% ethanol solution (3.1) and mix them evenly. 4 Instruments
4.1 Analytical balance: sensitivity 0.001g.
4.2 Flat-bottom flask: 250mL, with a standard glass ground stopper and a reflux condenser. 4.3 Buchner funnel: diameter 9cm. bzxz.net
4.4 Pipette: 25mL, 50mL.
4.5 Porcelain plate: flat bottom, with lid.
4.6 Water bath: four holes in a single row.
4.7 Glass drying oven: use newly dried color-changing silica gel as desiccant. 4.8 Blast drying oven: can be controlled at a constant temperature of 100±2℃. 4.9 Filter paper: diameter 11cm, quantitative, medium speed. 4.10 Weighing box: aluminum, diameter × height = 9cm × 2cm. 4.11 Masher: with a 500mL volume mashing container. 4.12 Vacuum pump or water exhaust pipe.
Approved by the State Administration of Technical Supervision on August 18, 1995 210
Implemented on June 1, 1996
5 Samples
GB/T15669--1995
5.1 Place the covered container containing the quick-frozen corn products in a porcelain basin and slowly pour in tap water for running water thawing. Move the thawed corn products together with the liquid produced during the thawing process into a crushing container. Carefully remove all the kernels from the corn cob using appropriate equipment (such as a blade), taking care not to damage the kernels. Spread the corn kernels on a white porcelain plate and remove the corn silk, corn cob skin and other debris. Use the quartering method to reduce the sample, then weigh 100g of the sample (accurate to 0.05g) and place it in the crushing container.
For the whole corn kernel sample, also take a representative sample of 100g and place it in the crushing container. 5.2 Depending on the moisture content of corn kernels or products, add 25mL or 50mL to the crushing container with a pipette (4.4), and then crush the sample into a slurry without obvious particles. 6 Determination steps
6.1 Weighing: Weigh a slurry containing about 5g of the original sample (accurate to 0.005g) and place it in a flat-bottomed flask (4.2) by differential weight method. 6.2 Extraction: Add 100mL of 95% ethanol solution (3.1) to the flat-bottomed flask containing the sample, shake gently to disperse the sample, and then heat and reflux in a water bath (4.6) for 30min. 6.3 Weighing filter paper (4.9) and weighing box (4.10): Number the filter paper and weighing box, and place the weighing boxes with filter paper in order on the porcelain plate. Place the box cover next to the corresponding weighing box, and place the porcelain plate in a forced air drying oven (4.8) at 100 ± 2°C for 2 hours. Cover the box cover and take it out and place it in a glass desiccator (4.7) for 30 minutes, then weigh (accurate to 0.001g). 6.4 Filtration and washing: Use an appropriate ring to fold the filter paper around the inner diameter of the Büchner funnel (4.3) and place it on the bottom of the funnel. Make sure that the filter paper fits tightly to the bottom of the funnel to prevent air leakage. Then, under vacuum, carefully pour the upper clear liquid of the flat-bottomed flask into the funnel, and then use about 10mL of washing liquid to wash the remaining solids in the flask into the funnel. Repeat the washing and transfer of the flask three times, and then use the same amount of washing liquid to wash the solids on the filter paper three or four times to make the filtrate clear and colorless. Note that the solids should be drained before pouring or rinsing from the flask to the funnel each time, but the solids should not have cracks. The last wash should be drained as much as possible. 6.5 Drying and weighing: Move the washed and drained solids together with the filter paper into the corresponding weighing aluminum box, arrange the aluminum box on a white porcelain plate and place it in a cold blast drying oven (4.8) with the blast turned on in advance, heat it up, and when the temperature is constant at 100 ± 2℃, dry it for 2 hours, cover the box lid, take it out and put it in the original dryer to balance for 30 minutes before weighing (accurate to 0.001g). Continue drying for 30 minutes and repeat the above cooling, balancing and weighing operations until the difference between the two weighings does not exceed 0.002g. 7 Result Expression
7.1 Calculation method and formula:
Alcohol-insoluble solids (%)=\2=1 × 100 × mo
Where: mo—sample mass, g;
mi-—filter paper and weighing box mass, g;
m2—alcohol-insoluble solids, filter paper and weighing box mass, g; table—dilution multiple, the value without water is 1. The results are expressed as the arithmetic mean of parallel determinations, retaining one decimal place. 7.2 Repeatability: The relative difference between two parallel determinations is allowed to be no more than 5%. 211
Additional Notes:
GB/T15669-1995
This standard is proposed by the Ministry of Agriculture of the People's Republic of China. This standard is under the jurisdiction of the National Agricultural Analysis Standardization Committee. This standard was drafted by the Central Laboratory of Sichuan Academy of Agricultural Sciences. The main drafters of this standard are Hu Mobiao, Fu Shaoqing, Zheng Konglin and Luo Ling.
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