Old-stored potatoes at room temperature for several weeks to reduce their levels of glucose and fructose, which otherwise cause the chips to brown too rapidly and develop a bitter taste. Internal black spots in potatoes are essentially bruises, formed when an impact during handling damages cells and causes the browning enzymes to create dark complexes of the amino acid tyrosine (alkaloid formation and therefore bitterness often rise also)
Nutritional Qualities Potatoes are a good source of energy and vitamin C. Yellow fleshed varieties owe their color to fat-soluble carotenoids (lutein, zeaxanthin), purple and blue ones to water-soluble and antioxidant anthocyanins. Potatoes are notable for containing significant levels of the toxic alkaloids solanine and chaconine, a hint of whose bitterness is part of their true flavor. Most commercial varieties contain 2 to 15 milligrams of solanine and chaconine per quarter pound (100 grams) of potato. Progressively higher levels result in a distinctly bitter taste, a burning sensation in the throat, digestive and neurological problems, and even death. Stressful growing conditions and exposure to light double or triple the normal levels Because light also induces chlorophyll for mation, a green cast to the surface is a sign of abnormally high alkaloid levels. Greened potatoes should either be peeled deeply or discarded, and strongly bitter potatoes should not be caren
Cooking Types and Behavior There are wo general cooking categories of potato, mealy" and the "waxy" for alled the their tex tures when cooked. Mealy types russets, blue and purple varieties, Russian and banana fingerlings) concentrate more dry starch in their cells, so they're denser than waxy types. When cooked, the cells tend to swell and separate from each other, producing a fine, dry, fluffy texture that works well in fried potatoes and in baked and mashed potatoes, which are moistened with butter or cream. In waxy