Peanut meal testing

The detection methods of peanut meal mainly include the following:

1. Sensory identification method
Preliminary judgment of peanut meal is made through sensory means such as vision, smell, and touch.

Color and shape: Normal peanut meal is light brown or dark brown, in the shape of small pieces or powder, and contains a small amount of peanut shells. Adulterated peanut meal is dull in color and may appear unnatural.
Smell: Normal peanut meal has a unique fragrance, while adulterated peanut meal may have a lighter smell or a strange smell.
Feel: Normal peanut meal feels loose when grasped by hand, while adulterated peanut meal may feel heavy or uneven in texture.
2. Conventional detection method
Laboratory testing of peanut meal moisture, crude protein, ash content, and other indicators to evaluate its quality.

Moisture content: Detect the moisture content in peanut meal to ensure that it is within the appropriate range.
Crude protein content: The crude protein content of a normal peanut meal is generally above 40%. By detecting the crude protein content, the nutritional value of peanut meal can be judged.
Ash content: The ash content of normal peanut meal should be below 7%. Too high ash content may indicate that impurities are mixed into the peanut meal.
3. Hydrochloric acid method
Use the characteristics of hydrochloric acid reacting with certain components in peanut meal to detect whether impurities such as sand and gravel are mixed into the peanut meal.

Sampling: Take an appropriate amount of peanut meal sample.
Add hydrochloric acid: Add an appropriate amount of 10% hydrochloric acid to the sample.
Observe the reaction: Normal peanut meal does not produce bubbles when an appropriate amount of 10% hydrochloric acid is added; peanut meal mixed with sand gravel and other substances adds 10% hydrochloric acid, and a large number of bubbles will be generated.
4. Identification method of mixed peanut shell powder
Through specific chemical treatment, a microscope is used to observe whether peanut meal contains peanut shell powder.

Sampling and treatment: Take 1 gram of peanut meal sample, place it in a 500 ml triangular flask, add 100 ml of 5% sodium hydroxide solution, boil for 30 minutes, add water to 500 ml, discard the supernatant after standing, add 200 ml of water, and boil for another 30 minutes.
Microscope observation: Take the residue and observe it under a microscope 50~100 times. If you see amorphous yellow-brown or even dark brown fragments, and fine fibers cross obliquely on the outer skin, it means that peanut shell powder is mixed in.
5. Other detection methods
Depending on the specific needs and detection conditions, other detection methods can also be selected, such as near-infrared spectroscopy analysis, gas chromatography-mass spectrometry, etc., to achieve accurate detection of specific components or impurities in peanut meal.

In summary, there are many detection methods for peanut meal, and the appropriate detection method should be selected according to specific needs and detection conditions. At the same time, the operating procedures should be strictly followed during the detection process to ensure the accuracy and reliability of the test results.