Asparagus Tuber
Asparagi Tuber
Asparagus Tuber is the tuber of Asparagus cochinchinensis Merrill (Liliaceae), from which most of the cork layer is removed, usually, after being steamed.
Description:
Asparagus Tuber is a fusiform to cylindrical tuber, 5 - 15 cm in length, 5 - 20 mm in diameter; externally light yellow-brown to light brown, translucent and often with longitudinal wrinkles; flexible, or hard and easily broken in texture; fractured surface, grayish yellow, glossy and horny.
Odor, characteristic; taste, sweet at first, followed by a slightly bitter aftertaste.
Under a microscope, a transverse section of Asparagus Tuber reveals stone cells and bundles of them on outer layer of cortex; mucilaginous cells containing raphides of calcium oxalate in the parenchyma cells of cortex and stele; no starch grains.
Identification:
To 1 g of coarsely cut Asparagus Tuber add 5 mL of a mixture of 1-butanol and water (40:7), shake for 30 minutes, filter, and use the filtrate as the sample solution.
Perform the test with the sample solution as directed under
Thin-layer Chromatography. Spot 10 μL of the sample solution on a plate of silica gel for thin-layer chromatography, develop the plate with a mixture of 1-butanol, water and acetic acid (100) (10:6:3) to a distance of about 10 cm, and air-dry the plate. Spray evenly dilute sulfuric acid on the plate, and heat at 105oC for 2 minutes: the spot of a red-brown at first then changes to brown color appears at an Rfvalue of about 0.4.
Purity:
(1) Heavy metals. Proceed with 3.0 g of pulverized Asparagus Tuber according to Method 3, and perform the test. Prepare the control solution with 3.0 mL of
Standard Lead Solution (not more than 10 ppm).
(2) Arsenic. Prepare the test solution with 0.40 g of pulverized Asparagus Tuber according to Method 4, and perform the test (not more than 5 ppm).
Loss on drying:
Not more than 18.0z (6 hours).
Total ash:
Not more than 3.0z.
Containers and storage:
Containers.Well-closed containers.
