2, slightly flat, slightly curved head, brown color, or straight stem, solid texture; Or the shape of a small hand, are all good yam. If there are bumps, the taste may be slightly harder.
3. Then hold it in your hand. Hold the yam for a while, and after it is released, the skin of fresh yam will feel warm, and the stale yam will "sweat" and the skin will ooze tiny water drops. This is the frozen yam. Once yam is frozen, the content of polysaccharide and free amino acid in mucus will be destroyed, the nutritional value will be reduced and the taste will be poor.
4, you can open a little skin when buying, or look at the cut surface of yam, the meat is white, and the sticky juice is fresh yam; After the frozen yam is cut, the flesh is as red as rust and the heart is as hard as water.