The fruit acidity meter is mainly used to quickly measure the acidity (pH value or titratable acidity) of fruit juice. The steps for use can be simplified as "preparation calibration sampling measurement ending". The specific instructions are as follows:
1、 Preparation before use
Equipment inspection
Confirm that the acidity meter host has sufficient power (or connected to a power source), the display screen is not faulty, and the electrodes (probes) are not damaged or aged. If there is soaking solution inside the electrode protective cover, check whether the liquid is clear (if it is cloudy, it needs to be replaced).
Calibration preparation
Prepare 2-3 standard buffer solutions (commonly pH 4.00, pH 6.86, pH 9.18, depending on the acidity range of the fruit, such as selecting pH 4.00 and pH 6.86 for citrus fruits with strong acidity), as well as clean beakers, distilled water, and soft tissues.
2、 Instrument calibration (key steps to ensure accuracy)
Press the power button and wait for the instrument to complete self-test before entering "calibration mode".
Rinse the electrode with distilled water and gently absorb surface moisture with a soft tissue (to avoid wiping and damaging the electrode membrane).
Place the electrode in the first standard buffer solution, gently stir, and wait for the display screen value to stabilize. Press the "calibration button" to confirm, and the instrument will automatically record the calibration value for that point.
Repeat steps 2-3 and use the second standard buffer to complete two-point calibration. After successful calibration, the instrument will prompt "Calibration completed".
3、 Fruit acidity measurement
Sample processing
Take the fruits to be tested (such as apples and oranges), peel and remove the seeds, then take the flesh. Use a juicer to extract the juice, or use a grinder to grind the flesh into a homogenate. Filter out the residue with filter paper, and collect the clarified juice in a beaker.
Formal measurement
Rinse the electrode with distilled water and absorb the moisture. Slowly insert the electrode into the fruit juice (ensuring that the electrode head is completely submerged and does not touch the beaker wall).
Gently stir the juice for 10-20 seconds, wait for the display screen value to stabilize, and record the displayed pH value (some acidity meters can directly convert it to titratable acidity, such as% citric acid).
repeated measures
It is recommended to measure the same sample 2-3 times and take the average as the final result to avoid single measurement errors.
4、 Closing after use
Cleaning and maintenance
After the measurement is completed, immediately rinse the electrode with distilled water, absorb the moisture, and place the electrode back into the protective sleeve containing a special protective solution (3mol/L potassium chloride solution). Do not expose it to air for a long time.
Instrument storage
Turn off the power of the acidity meter, organize the host, electrodes, standard buffer solution, etc., and store them in a dry, dark, and non corrosive environment.