"How Much Do You Know About Food Nutrition" Series | One reason is enough to persuade you to eat more yam

Chinese yam is a treasure food in autumn, and it is also known as "food for gods". Recently, the Ministry of Agriculture and Rural Affairs released the list of 2023 agricultural brand boutique cultivation plan, and "Wenxian Iron Stick Yam" was on the list. "Iron Stick Yam" belongs to a variety in the yam family. What is so good about this "food for gods"? Today, let us unveil the mystery of Chinese yam.

1. Introduction to Chinese Yam

Chinese yam, a vine plant of the Dioscorea family, is also known as Chinese yam, white potato, sweet potato, and mountain potato. The name "Chinese yam" comes from the medical monograph "Shennong's Herbal Classic": "Chinese yam, also known as mountain yam, is called Yuyan in Qin and Chu, Tushu in Zheng and Yue, and Shanyang in Qi and Zhao." Chinese yam is native to Pingyao and Jiexiu in Shanxi Province, China, and is now distributed in various provinces and regions in North China, Northwest China, and the Yangtze River Basin, and is also distributed in Korea and Japan.

2. Edible value of yam

Yam can be used as both hot and cold dishes, both desserts and pastries, and can be mixed, fried, stewed, braised, and baked. For example, fried yam with black fungus, blueberry yam puree, yam stewed with pork ribs, yam steamed pumpkin, millet and yam porridge, etc.

Yam contains a variety of biologically active substances and various nutrients such as amino acids, starch, protein and vitamins, as well as a variety of inorganic elements.

Eating yam regularly can enhance immunity, help digest starchy foods, and is also beneficial for lowering blood sugar and anti-oxidation. In addition, the sticky juice of yam is mainly mannan polysaccharide and mucin, which can maintain blood vessel elasticity and moisturize the lungs and relieve cough.

3. Medicinal value of yam

Yam tubers are commonly used in traditional Chinese medicine "Huai yam". The "Shennong Bencao Jing" in the Qin and Han Dynasties recorded that the best yam is from Huaiqing, Henan. Jiaozuo was formerly known as Huaiqing Prefecture. It is backed by Taihang Mountain in the north and faces the Yellow River in the south. It has unique natural conditions. The "Four Huai medicines" of yam, rehmannia, chrysanthemum and Achyranthes bidentata are well-known both at home and abroad. Yam is warm and tonic, and is a model of "medicine and food have the same origin". It is a specialty of Jiaozuo City, Henan Province, and is also a national geographical indication product of China.

Yam contains amylase, polyphenol oxidase and other substances, which are beneficial to enhance the digestion and absorption function of the spleen and stomach, nourish the kidney and benefit the essence. Patients with spleen yang deficiency, stomach yin deficiency, kidney deficiency and spermatorrhea, excessive leucorrhea in women, frequent urination, etc. can eat yam.

The mannan polysaccharide in yam can effectively help repair pancreatic cells, improve the function of pancreatic cells, promote the secretion of insulin, and has a very good effect in assisting in lowering blood sugar.

4. Precautions when eating yam

Many people feel sticky when peeling yam, and even cannot escape the consequence of itchy hands. This is because the mucus secreted when the yam is peeled is mainly a complex polysaccharide composed of polysaccharides and proteins. These mucus contain substances that may cause people's hands to itch.

For most people, when washing yam, it is best to remember to wear gloves to avoid direct skin contact with yam mucus, or choose to steam it first and then peel it, because during the steaming process, the allergenic substances in the yam will be decomposed by heat, and it will not itch when handling.

Author: Zhou Zhihua and Lan Haobo from Luoyang Normal University

Review expert: He Jialiang, associate professor of the School of Food and Bioengineering, Henan University of Science and Technology