Fat identification refers to the use of chemical reagents to detect fat in biological tissues, and the chemicals commonly used to detect fat are Sudan 3 and Sudan 4 stains.
The principle of fat identification is that under the observation of microscope, fat can be stained orange by Sudan 3 dye and red by Sudan 4 dye, according to the color reaction caused by the use of chemical reagents, the presence of fat can be identified.
Identification of fat can be divided into taking, slicing, staining, washing away the floating color, and observation. Choose a soaked and peeled peanut as the experimental material, and use a razor blade to cut a number of thin slices in the cross-section of the peanut, and then placed in a petri dish of clean water for spare.
One of the slices was placed in the center of the slide and stained with 2~3 drops of Sudan 3 staining solution for three minutes. After three minutes, absorbent paper was used to remove the Sudan dye and 50% ethanol solution was added to wash away the floating color, then absorbent paper was used to remove the ethanol solution from the peanut sections, and a drop of distilled water was added to cover the coverslip to make a temporary specimen.
Afterwards, use a low-power microscope to find the thinnest part of the peanut, and then move to the center of the field of view. Adjust the object image to be clear for high magnification observation, the orange color is the fat particles.