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 Yellowfleshed 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 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 can double or triple the normal levels Because light also induces chlorophyll formation, 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 eaten Cooking Types and Behavior There are two general cooking categories of potato, called the “mealy” and the “waxy” for their textures 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 ... Types and Behavior There are two general cooking categories of potato, called the “mealy” and the “waxy” for their textures when cooked Mealy types (russets, blue and purple varieties, Russian and. . .the throat, digestive and neurological problems, and even death Stressful growing conditions and exposure to light can double or triple the normal levels Because light... induces chlorophyll formation, 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 eaten