Buttermilk and Whey

The uses for buttermilk are similar to those for skim milk. It is a desirable component of bakery products and other foods, the condensed and dried forms being the most convenient ones. Fluid and condensed buttermilk are fed to animals and dried buttermilk is fed in mixed feeds. Casein made from buttermilk is different in many respects from skim-milk casein. For most purposes it is less desirable than casein from skim milk, but for casein paints it is especially suitable, provided it is used in paste form without being dried.

Despite the need in our diets for the calcium, phosphorus, and riboflavin readily available in whey, we drink no whey and consume as food practically none of it in its concentrated forms, except as a component of other foods. Feed uses account for the largest proportion of whey, increasing amounts being used in the dried condition, especially for feeding chickens. Dried whey, besides being of high general nutritional value, is Of specific use in the chicken industry, since the lactose acts as a preventive Of coccidiosis, and riboflavin is essential to hatchability of eggs and Optimal growth and aids in preventing curled toe paralysis. The most recent advance in manufacturing dried whey for feeding chickens is the use of bacteria to synthesize riboflavin in the whey before drying. This procedure was commercialized during the war when sufficient equipment was not available to dry enough whey to meet the needs for riboflavin in feed. It is possible to concentrate the riboflavin in whey, either normal or enriched, by absorbing it on lactose. By partly concentrating the whey, some of the lactose is caused to crystallize. On concentrating further, more lactose crystallizes, carrying with it most of the riboflavin of the whey. By careful regulation of the process, a bright yellow sugar can be obtained containing 0.3 milligram riboflavin per gram. Four grams of this lactose about one-seventh of an ounce can furnish a person's full daily requirement of riboflavin. This yellow lactose is also suitable for addition to bread and other foods to increase their riboflavin content.

Whey can be used as an ingredient in other foods either as fluid or concentrated whey. Fluid whey may be combined with vegetable juices, such as tomato juice, to produce beverages of improved food value, or with tomatoes, peas, or beans to produce soups. In acid soups, such as tomato, whey has the advantage over skim or whole milk that it does not form lumpy curds on heating, but, instead, gives a fine-textured, smooth body.

Sweetened condensed whey is a new product developed to provide a cheap nonperishable form of whey solids to be used wherever sugar is also needed. It is suitable for use in candies, especially those of the fudge type. It adds nutritive value, gives a smooth body, and aids in keeping the candy soft and fresh. Sweetened condensed whey has been used successfully also in canned puddings, and dried whey in canned brown bread. Formulas for all of these products have been developed in the Bureau of Dairy Industry.

Whey protein, isolated as a byproduct in the manufacture of lactose and lactic acid, finds use in feeds, and efforts have been made to isolate it in a condition suitable for use as food. One method that has been successful on a laboratory scale is to condense whey, remove the lactose that crystallizes, and dialyze it to remove the salts. Another method that shows promise is to stir spray-dried whey with 70 percent alcohol and tc filter out the whey protein promptly. Lactose crystallizes slowly from the filtrate and, after its removal, the alcohol may be recovered and the remaining liquid used as a source of riboflavin.