What is the origin of the latest yam?

The origin of Chinese yam was originally Jiaozuo in Henan Province, but now it is also produced in Hunan, Hubei, Shanxi, Yunnan, Hebei, Shaanxi, Jiangsu, Zhejiang, Jiangxi, Guizhou, Sichuan, Shandong and other places. On the banks of Sihe, Taiping Town, Shandong Province, the output of Chinese yam is small, but the quality is very high. It has a long history and was once a tribute of the Qing Dynasty.

Chen Da-Chao, a great poet of the Song Dynasty, in his "Yu Ting Zan", there is such a passage: "the mountain has an elixir, green as a fairy prescription, cut a few pieces of jade, pure flowers smell", referring to the winter good food-yam. 20 miles west of Ruichang City, Jiangxi Province, across the undulating mountain road, around the picturesque Longyuan Reservoir, along the newly built cement Township Road, is Luocheng Mountain, one of the yam bases in Nanyang Township. The parent soil formed by the weathering of limestone eroded by wind and rain for thousands of years provides a special living soil for the growth of Nanyang yam. Luocheng Mountain in Nanyang has a long history of planting yam. According to the Records of Ruichang County in Longqing of the Ming Dynasty, Ruichang yam has been cultivated for more than 500 years, and Luocheng Mountain in Nanyang was one of the important products and medicinal materials in Ruichang, Jiangxi Province at that time.

Authentic Chinese yam

The surface of ① authentic yam is yellowish white or light yellow, with longitudinal grooves, longitudinal wrinkles and whisker root marks, and occasionally light brown skin remains. Body weight, solid quality, not easy to break, cross-section white powder, with small punctate protuberances. The breath is slight, the taste is light, slightly sour, chewing sticky.

The starch granule of ② authentic yam is ovoid, oval-like, triangular-shaped or rectangular-shaped, 8 ~ 35 μ m in diameter, dotted, herringbone, cross-shaped or short suture-shaped, with lamellar lines, and the compound grain is rare, composed of 2-3 grains.

③ authentic yam calcium oxalate needle bundles exist in mucus cells, which are about 240 μ m in length and 2 ~ 5 μ m in diameter.

④ authentic Chinese yam has marginal holes, reticulation, thread and ring-shaped ducts with a diameter of 12 ~ 48 μ m.

Counterfeit Chinese yam

① cassava: often sliced, most of the skin has been removed, the residual skin is brown or brown, the section is white, powdery, obvious veins can be seen near the skin, there is a small wood heart in the center, some cracks, hands feel like talcum powder. The breath is weak and the taste is light.

② ginseng potato: irregular cylindrical or conical, the residual cork is thick, yellowish brown or reddish brown, woody patches fresh yellow (stone cells), easy to peel off. Solid, yellowish white in cross section, powdery, with a few light brown dots. Odorless, sweet, slightly sour, chewing sticky.

③ sweet potato: thick, round or irregularly shaped slice with a thick reddish or grayish brown remnant. The section is white or yellowish white, slightly elastic, yellowish brown "veins" spots or lines can be seen, and a yellowish brown ring can be seen near the skin. Crisp, powdery and sweet.