Question: Do you have a source of information about the amount of calcium in all types of food, including fast foods and convenience food items? I am particularly interested in food sources that are high in calcium but low in sodium.
Answer: "The Nutritive Value of American Foods in Common Units" (Agriculture Handbook No. 456) by Catherine F. Adams provides values for calories and nutrients (including calcium and sodium) by various household measures and market units of food. Available in government book stores, the handbook contains some of the most concise information available for nutrient values.
Another source is a book that is coming out this month called "The Calcium Bible" (Rawson: $13.95) by nutritionist Patricia Hausman. The book has a listing of high-calcium foods for special diets, including low-sodium, low-calorie, low-fat or high-potassium foods. Some high-calcium/low-sodium foods listed are: broccoli, instant cream of wheat, fresh-cooked collard and mustard greens and tofu. The appendix also has a listing of 300 foods that contain 100 milligrams or more of calcium, including natural foods, fast foods and convenience foods.
Q: While flipping through one of the cooking magazines one day in the doctor's office, I ran across a recipe substitute for sweetened condensed milk. The only thing I could remember was that it called for powdered milk, sugar and water. Have you ever heard of such a recipe? If so, please print it soon.
A: We found the recipe in a cookbook called "Out of the Nest, Into the Frying Pan" by Eileen Lafferty. (The cookbook is for kids who have left home and for "fledging gourmets," the author writes.) The recipe is equivalent to a 14-ounce can of regular sweetened condensed milk.
SUBSTITUTE SWEETENED CONDENSED MILK
1 cup instant powdered milk
1/3 cup boiling water
3 tablespoons butter, melted
2/3 cup sugar
1/2 teaspoon vanilla
Combine powdered milk, boiling water, melted butter, sugar, vanilla and salt in blender. Process until smooth, 3 to 4 minutes.
Q: I've discovered jicama and love it in salads or as is but I have to buy it in such big pieces. Is there any way it can be preserved?
A: Jicama is usually an excellent keeper in a cool, dry place. Keep it, whole, in the vegetable crisper up to one month. Extra peeled pieces may be stored covered with cold water in the refrigerator up to a week, if the water is changed every one to two days.
For longer storage, freeze the remaining peeled portions. Blanch in boiling water 1 to 2 minutes per pound, chill in ice water, then pack in freezer bags or containers.
Q: When I asked the produce man in our market why the White Rose potatoes (and the russets, from time to time) were green, he said that it was the effect of the fluorescent lighting in the store. Is there any truth to that? And if so, are the potatoes safe to eat? Or could the green color be the result of the use of pesticides or too early harvesting?
A: Your produce man was right in his theory, but he should have explained further that the greening on the skin surface was the result of the development of chlorophyll due to light, either artificial light or sunlight. The greening is also an indication of the possible presence of a bitter-tasting glycoalkaloid called solanine, which is poisonous. However, nearly 18 pounds of green potatoes would have to be consumed to make a person ill.
When preparing the potatoes for cooking, the green area should be completely peeled off. Always store raw potatoes in a cool, dark and dry area, away from onions. They can be stored in the refrigerator, but for best eating quality, the raw potatoes should not be chilled.
Address questions on food preparation to You Asked About, Food Section, The Times, Times Mirror Square, Los Angeles 90053. Personal replies cannot be given.