：Dry a sample of a certain mass at a certain temperature under normal pressure for a certain period of time. The solid content is expressed as the percentage of the mass of the sample after heating to the mass of the sample before heating.
1.2. Determine step aggregation
① Take three weighing bottles, dry them in an oven at (105±2) ℃ for 1.5 hours, cool them in a desiccator for 30 minutes, and then weigh them, record as m1.
② Weigh 1～2g (accurate to 0.0001g) of the sample into a dried weighing bottle, and record it as m.
③ Gently turn to the weighing bottle to make the sample evenly distributed on the bottom of the weighing bottle, slightly open the lid of the weighing bottle, place it in an oven at (105±2) ℃, turn on the blower, dry for 3 hours, and put the bottle Cover tightly, put it in a desiccator to cool for 30 minutes, weigh it, and record it as m2.
1.3. Calculation of results
The solid content of the sample is calculated by mass fraction X, and the value is expressed by (%), calculated according to formula (1):
m——The value of the mass of the sample. The unit is grams (g);
m1——The value of sample mass. The unit is grams (g);
m2——The value of the mass of the weighing bottle and the sample after drying. The unit is grams (g).
Take the arithmetic average of the two parallel determinations, and round to 0.1% according to GB/T8170-2008, which is the determination result. The difference between the two parallel determinations is not more than 0.3%.
2. Brix meter method
The sugar content of the solution measured by the principle of refraction is proportional to its solid content. By measuring the sugar content of the solution, the solid content of the sample can be converted according to a certain proportional coefficient.
2.2. Measurement steps:
The test should be carried out at room temperature, and the sample should be equilibrated to room temperature before measurement.
① Clean the surface of the prism of the brix meter, add about 0.3mL of water on the surface, and adjust the zero according to the operating instructions of the brix meter.
② Discard the water on the saccharimeter, dry the prism, add about 0.3mL of sample on the surface of the saccharimeter, and measure the saccharide of the sample according to the operation manual of the saccharimeter. The sugar content of the sample is stable and unchanged until the first and second readings, and it is recorded as the sample sugar content A.
③ Convert the solid content of the sample according to the proportional coefficient n between the solid content and the sugar content obtained by data accumulation.
Note: Because this method uses the principle of refraction for testing, do not use it for testing difficult-to-wash samples, otherwise it will contaminate the prism surface and the test will be inaccurate.
2.3. Calculation of results
The solid content of the sample is calculated by mass fraction X, and the value is expressed by (%), calculated according to formula (2):
X = n×A ---------- (2)
n——Conversion coefficient of solid content and sugar content
A——The sugar content of the sample,%
3. Fast solid content tester method
This method is faster than the oven method and more accurate than the sugar meter test. For the specific method, please refer to the manual of the fast solid content tester