Fortification and Restoration in the Baking and Dairy Industries JAMES A. TOBEY AND WILLIAM H. CATHCART American Institute of Baking, New York, N. Y., and Chicago, Ill.
Since bread is a common staple food in this country, official and scientific bodies have urged that white and other breads be enriched in thiamin, nicotinic acid, and iron, with riboflavin, calcium, and vitamin D as optional added ingredients. The organized milling and baking industries have endorsed and accepted this program as a desirable contribution to national defense and as a permanent contribution to the public health. The ways in which bread can be nutritionally enriched, by the use of enriched flour, enriched yeast, etc., and the technical problems involved are discussed. The enrichment of milk with vitamin D and the possible addition of other nutrients are outlined, as is also the function of added vitamin A in margarine.
In its natural state milk is a relatively poor source of vitamin D, since it contains only 19 to 32 U. S. P. units to the quart. Milk is, however, a logical carrier for this vitamin because it is rich in calcium and phosphorus in the proper ratio, and because it is the principal food of the infants and growing children who require vitamin D in combination with these minerals for the proper development of the skeletal structure and the prevention of rickets. The requirements of adults for vitamin D are not definitely known, except possibly in the cases of pregnant and nursing women. The addition of vitamin A to margarine has also been in effect for approximately two years. Although this desirable practice has not had wide application to date, an increase in the production of margarine with added vitamin A may be expected. At present vitamin A is added in the form of fish liver oils; most fortified margarines contain a minimum of 7500 U. S. P. units of vitamin A per pound.
Enriched Bread The most recent and important addition t o the list of fortified foods is bread. Since early in 1939 scientists have been pointing out that certain important vitamins, particularly those of the B complex, and certain minerals that are natural to wheat are greatly reduced in the process of milling flour. In a symposium on the fortification of foods held by the American Institute of Nutrition in 1939, it was recommended that consideration be given to the restoration of these nutrients t o refined flour and white bread ( 3 ) . In accordance with these recommendations and similar action by the Council on Foods and Nutrition of the American Medical Association ( A $ ) , many bakers began in 1940 t o add thiamin, or vitamin B1, t o their white breads. This matter was further crystallized a t hearings before the Food and Drug Sdministration of the Federal Security Agency on proposed flour standards under the Federal Food, Drug, and Cosmetic Act. These hearings began in September, 1940, and were resumed in Kovember, a t which time many leading scientists advocated that milled flour should have restored t o it not only thiamin but other important members of the vitamin B complex, such as nicotinic acid (the pellagra-preventing vitamin), riboflavin (vitamin BJ,and such minerals as iron and calcium. The next development came when representatives of the milling and baking industries met in Chicago in October, 1940, with government officials and interested scientists t o consider practical ways to bring about fortification of flour and bread with vitamins and minerals. This historic occasion was followed by the appointment of a subcommittee on bread standards by the Committee on Foods and Nutrition of the Kational Research Council, which reported its recommendations t o the full committee on January 15, 1941.
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ECENT developments in the chemistry of nutrition have made possible some desirable improvements in the American dietary. As a result of the investigation, isolation, and synthesis of vitamins, many of these essential nutrients can now be added economically to our common foods. Minerals of recognized value in human nutrition can also be added in suitable forms to various foodstuffs. Dietary fortifications of this nature are not new, although the movement for the fortification and restoration of foods has received its greatest impetus within the past year. As early as 1923 there was devised and produced a white bread enriched with the vitamins and minerals which were then considered significant (7). Unfortunately this product had a rather brief career. A considerable portion of our market milk supply has been fortified with vitamin D for the past ten years. The first of the vitamin D milks, which appeared in 1931, was a certified milk in which the vitamin D content had been increased t o 430 U. S. P. units per quart by the method of feeding proper amounts of irradiated yeast to the producing cattle. I n the following year vitamin D fluid milks were produced by direct irradiation of the milk and by the addition of concentrates of vitamin D (1%’). Since 1934 the bulk of the canned evaporated milk produced for domestic use has been irradiated. It is estimated that in 1940 about 5,000,000 quarts were consumed in this country every day in the form of fluid and evaporated vitamin D milks. 714
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The result of these various deliberations and actions has been a new “enriched” flour and a new “enriched” bread, actual production of which began in March, 1941, and is now getting more fully under way. Legal standards for this enriched bread have not been promulgated by the Federal Government and are not likely to be issued until the end of 1941. Pending such standards, the recommendations of the Committee on Food and Nutrition of the National Research Council are being followed. Enriched bread may be defined as white bread, slightly darker bread made from special process flour, milk bread, or Taisin bread which contains in addition to the usual ingredients proper amounts of thiamin, nicotinic acid, and iron. It may also contain as optional added ingredients riboflavin, vitamin D, and calcium. In order properly t o be called “enriched”, a bread of the type enumerated must now have not less than 1 or more than 2 mg. of thiamin per pound of baked bread, not less than 4 or more than 8 mg. of nicotinic acid, and not less than 4 or more than 16 mg. of iron. If the optional ingredients are included, there must be in enriched bread not less than 0.8 or more than 1.6 mg. of riboflavin per pound of bread, not less than 150 or more than 600 U. S. P. units of vitamin D, and not less than 0.3 or more than 1.2 grams of calcium per pound.
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Comparison with Whole Wheat Bread
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The vitamin and mineral contents of whole wheat and of the breads made from it vary greatly; certain types of wheat, such as the hard northern varieties, are higher in these substances than others. There are also differences in single strains of wheat. From the data of many investigators, however, the thiamin content of 100 per cent whole wheat bread appears t o vary between 1.1 and 3.3 mg. per pound, with the average between 1.35 and 1.65 mg., or 450 to 550 International units (IS). The only published report on the nicotinic acid content of wheat gives a figure of 16 mg. per pound of whole wheat bread (1). Unpublished data also indicate that there is as much as 4.5 mg. of nicotinic acid in a pound of white flour. Studies on the iron content of wheat show variations from 4.4 to 22.1 mg. per pound for whole wheat bread (9). It is probable, however, that most whole wheat breads will contain from 9 to 15 mg. of iron per pound, with the majority reaching the higher figure. The investigations have also shown that the iron in wheat is a t least 81 per cent available to the organism. The minimum standards for the required ingredients in enriched bread do not, therefore, quite meet the amounts of thiamin, nicotinic acid, and iron which normally would be expected in the average 100 per cent whole wheat bread. Since regular white bread already contains from 0.15 to 0.45 mg. of thiamin per pound, 3.0 t o 3.5 mg. of nicotinic acid, and an average of 3.5 to 5.0 mg. of iron, enriched bread containing minimum amounts of the added required ingredients will approach whole wheat bread in these nutritional respects, and will equal or exceed it when higher amounts of thiamin, nicotinic acid, and iron are included. The minimum standards for riboflavin and calcium usually can be reached by the use of the proper amount of milk solids in white bread, since milk is an excellent source of these nutrients. If 6 per cent nonfat dry milk solids, on the basis of flour content, are included in the white bread formula, the resulting pound of bread will usually contain an average of 0.75 mg. of riboflavin. However, the riboflavin content of skim milk powder varies somewhat; analyses show a range from 19 to 25 micrograms per gram of milk powder (11). Thus, some skimmed milk powders may not produce the desired amount .of riboflavin in enriched bread.
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Investigations by Prouty and Cathcart (10)have shown that white bread made with the usual milk solids will average 0.08 per cent calcium on a 38 per cent moisture basis, or about 0.4 gram of calcium t o the pound. Calcium may also be added in small amounts to bread when dough conditioners containing calcium salts are employed.
Production of Enriched Bread Methods for the production of enriched bread include the use of enriched flour, the use of enriched yeast, the use of crystalline vitamins and suitable iron salts for direct addition to the dough, and combinations of these methods. Enriched flour is refined white flour to which crystalline thiamin and nicotinic acid, and iron phytate, sodium iron pyrophosphate, ferrum reductum, or some other suitable iron salt have been added in proper amounts. The addition of iron to flour is, in general, a much more difficult problem than the addition of the vitamins. If the iron salt is not entirely insoluble, it causes adverse reactions, such as rancidity in the flour. There is also the problem of the utilization of various forms of iron by the human body, especially since little, if any, information has been reported on the assimilability of the three iron salts now being employed for the enrichment of flour. According to standards of identity proposed for enriched flour by the Food and Drug Administration (6),such flour would contain in each pound not less than 1.66 or more than 2.50 mg. of vitamin B,, not less than 1.2 or more than 1.8 mg. of riboflavin, not less than 6 or more than 9 mg. of nicotinic acid, and not less than 6 or more than 24 mg. of iron. These standards differ from those recommended by the Committee on Food and Nutrition of the National Research Council in that riboflavin would be required instead of optional, and in suggesting slightly lower figures for nicotinic acid and iron. In the recommended standards for these added nutrients in enriched bread, allowance was made for the expected loss of thiamin due to baking. While this loss has been reported as 10 to 15 per cent and as occurring chiefly in the crust ( 8 ) , recent investigations would seem to indicate that this loss may be greater under certain conditions, especially when vitamin B1 is added in the form of crystalline thiamin hydrochloride. The loss of thiamin in baking apparently is less when enriched yeast is the source of the vitamin. Enriched yeast is bakers’ yeast which has been cultured to yield a product of high thiamin content, and to which nicotinic acid and iron have been added. It contains not less than 30,000 International units of thiamin to the pound, so that when the customary 2 per cent of this yeast is used in bread making, the resulting bread will have approximately 450 International units or 1.5 mg. of thiamin to the pound, and sufficient nicotinic acid and iron to meet the recommended minimum standards for enriched bread. An improved state of thiamin nutrition in human subjects due to the ingestion of white bread enriched in thiamin by the use of yeast containing this vitamin has been reported by Free (6),who states that this special bread contributed 34 per cent of the thiamin intake of seventeen young college women. Vitamin-iron tablets containing sufficient amounts of thiamin, nicotinic acid, and iron t o fortify 100 pounds of flour have been made available for use in the production of enriched bread. These preparations can be dissolved with the yeast and added with i t to the dough. Vitamin-iron mixtures are likewise available for direct addition to the flour in measured amounts that give the proper potencies. The vitamin and mineral contents of enriched bread must be checked occasionally by approved assay methods. Such procedures are available for the determination of iron, and
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methods for the assay of thiamin are being standardized. There is as yet no completely acceptable procedure for the determination of nicotinic acid by chemical means, and biological methods are not practical for routine use on bread samples. Bread and milk are among the most important foods in our national diet, both with respect to the quantities consumed and their qualities as economical sources of most of the nutrients necessary in a well-balanced daily diet. Together, bread, cereals, milk, and dairy products provide about half of the calories in the American diet. Of the 10.5 billion pounds of bakers’ bread consumed annually in this country, the greater part is in the form of the white yeast-raised product which is preferred by the majority of the people. The general fortification of this vast quantity of bread with vitamins and minerals that are natural t o whole wheat is a matter of significance to our national defense efforts, since enriched bread supplies substantial amounts of the vitamins that are conducive to physical fitness and morale. Even more significant, however, is the fact that the general production and consumption of enriched bread will be a permanent contribution to the public health ( 2 ) .
Vol. 33, No. 6
Literature Cited (1) Aokroyd, W. R., and Swaminathan, M.. I n d i a n J . Med. Research, 27, 667 (Jan., 1940). (2) Am. Inst. of Baking, “Putting Bakers’ Bread in the Preferred Class-Questions and Answers About Enriched Bread”, 1941. (3) Am. Inst. of Nutrition, Milbank Memorial Fund Quart., 3, 22162 (July, 1939). (4) Cowgill, G. R., J . Am. M e d . Assoc., 113, 2146-51 (1939). (5) Food and Drug Administration, Federal Register, April 1 , 1941, 1729-37. (6) Free, A. H., Cereal Chem., 17, 725-33 (1940). (7) Hoffman, C., IND. ENG.CHEM.,15, 1225-44 (1923). (8) Hoffman, C., Schweiteer, T. R., and Dalby, G., Cereal Chem., 17, 737-9 (1940). (9) Hoffman, C., Schweiteer, T. R., and Dalby, G., IND. EXQ. CHEM.,Anal. Ed., 12,454-5 (1940); Free, A. H., and Bing, F. C., J . Nutrition, 19, 449-59 (1940). (IO) Prouty, W. W., and Cathcart, W. H., J. Nutrition, 18, 217-26 (1939). (11) Supplee, G. C., personal communication. (12) Tobey, J. A,, Am. J . Nursing, June, 1936. (13) Williams, R. R.. and Spies, T. D., “Vitamin BI and Its Use in Medicine”, New York, Macmillan Co., 1938; Hoffman, C., Schweiteer, T. R., and Dalby, G., Cered Chem., 17, 733-6 (1940); Schultz, A. S., Atkin, L., and Frey, C. N., Ibid., 18, 106-13 (1941); Copping, A. M., Nutrition Abstracts & Revs., 8, 555-66 (1939).
What the Consumer Should Know about Fortified Foods HELEN S. MITCHELL Nutrition Divison, Health, Welfare, and Activities Affecting National Defense, Washington, D. C.
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HE consumer is fast becoming nutrition conscious, but in addition he is in danger of developing a complex on the subject of vitamins. He needs sane and conservative guidance through the maze of extravagant claims which he hears or reads. Popular education in nutrition is demanded. Recognition of the superior nutritive values of natural food as compared with the overrefined and processed foods has long prompted nutritionists to recommend natural foods where practicable. Some faddists have picked up the idea and carried it to silly extremes, recommending raw food exclusively as well as unrefined salt and sugar, and implying that certain refined foods such as sugar or white flour are positive poisons. Fortunately such extremists have relatively few converts, but they are apt to be quite audible. Nature has done a good job of providing necessary food constituents, and we should take advantage of this fact. However, tradition, taste, and digestibility have prompted us to refine, modify, or prepare foods in such fashion as to destroy or discard certain valuable ingredients. The food values remaining may be incomplete but in no sense negative or poison just because of refining. We cannot ignore tradition and taste but we may influence it for the better. The successful nutritionist must be a realist, aware of cultural patterns and food habits as well as the nutritive values of foods. He must realize that food habits are slow to change, particularly in low-income groups, and that to effect nutri-
tional improvement of the people on a large scale, devices other than education must be used. It must be made easy and convenient for people to get the kind of food they should have. Thus the attitude of the scientific nutritionist has changed from the idealistic-of educating everybody to choose foods for their nutritive value-to the realistic-of putting into certain foods nutritive factors which are essential and apt to be lacking in that food as commonly eaten. In many instances this may be a restoration of nutritive elements originally present in the natural food but lost in process of manufacture, as in the case of flour. I n other instances it may be fortification of a natural food with a nutritive factor originally present in too small amounts, as in the case of vitamin D milk.
Attitude of Federal Authorities The fortification of foods with minerals or vitamins should not be promiscuous or haphazard; it should be done through a planned program of making the average American diet more adequate in these factors, and it should be done without increasing the cost to the consumer. The problem of proper control of fortification is difficult and may not be solved immediately. Thus the consumer needs to be informed as to the significance of this popular movement. If not, there is the twofold danger: One may either be skeptical of all fortification claims and discount the whole movement, or one may rely upon fortification to ensure adequate nutrition with no effort t o select a balanced diet. Both of these reactions are unfortunate, but they are inevitable when the pendulum of popularity swings wide as it is doing a t the present time. There are potential dangers as well as benefits in the program.
