edited bv: MICHAEL R. SLAMUGH

HELEN J. JAMES Weber State College

Ogden. UT 84408

Butter and Margarine: Their William R. Oliver and Diana Combs McGill Northern Kentucky University, Highland Heights, KY 41076

The wide variety of margarine products on grocery shelves today would be surprising to a shopper of the 1920's. For many years, margarine was seen not only as a threat to the dairy industry, hut as a menace to natural food and health. Mark Twain denounced it as another sign of the artificiality of modern life and a Governor of Minnesota called "oleomar- garine and its kindred abominations", a "mechanical mix- ture" created by the "ingenuity of depraved human genius" ( 1 ) . ~-, .

As today's consumers decide whether to use margarine or hutter, it is likely that few are aware of either the difference in their chemistry or the intense passions that were engen- dered only a few years ago by the rising popularity of ma& rine. Economy-conscious buyers will note the lower price of margarine, and health-conscious buyers will note that mar- garine, in contrast to butter, contains little or no cholesterol. Some will prefer the "spreadahility" of margarine a t refrig- erator temperatures. Most consumers, however, probably prefer the taste of butter.

Stringent governmental controls over margarine manu- facture and marketing were only relaxed in 1950. Politically powerful dairy associations had pushed through state laws restricting margarine sales almost as soon as U.S. production began in 1875. By 1886, they were able to persuade Congress to pass the Oleomargarine Act. No detrimental effects had been established fo; margarine, but its use was severely taxed.

Nevertheless, by 1948, 67% of U.S. families were using margarine, and nutritionists and medical groups had begun speaking out on its advantages. Cottonseed and soybean growers, labor unions, and consumer groups focused public attention on the conflict, and by 1950 Congress had capitu- lated. All federal fees and taxes were removed by the Marga- rine Act (the misleading "Oleo" had been removed). An interesting social history of this problem has been provided bv Ball and Lillv (2).

-Even though~historically there have been conflicts he- tween the butter and margarine industries. the two products are remarkably similar in color, consistency, and'to some extent, taste. The difference most recognized by consumers is in the price, butter being considerably more expensive. The chemical differences begin with the starting ingredi- ents; hutter is produced from milk fat, and margarine is produced mostly from vegetable oils. I t is this difference in the starting fats that has led to much of the controversy and competition between the hutter and margarine industries.

History

The history of hutter is not one of great change; for centu- ries people have been churning milk fat to produce hutter. The major change in butter production has been the move- ment from farm to factory, and with this migration came an

Chemistry, Their Conflict

improvement in uniformitv of color. texture. and flavor (3). compared to butter, margarine has had a ielatively short historv. I t was developed hv a French chemist, Mege-Mour- ies, i n the late 1860'; in r&ponse to an award offered by Napoleon 111 for the person who could produce a butter substitute suitable for his troops. Mourie won the prize and later sold the rights of manufacture to E. Pellerin (2).

This first hutter substitute was known as oleomargarine (0.' Mouries digested beef fat with the enzyme pepsin a t 45 "C until the fat had separated from the other tissues. This fat was then mixed with salt and casein (milk protein), and cooled until it oossessed the consistencv of butter (5). . .

Since then, several important changes have occurred in the production of marearine. These changes include: the churning uf margarine "ils and milk: the u& of commercial culture.; of Iacti~ acid bacteria for controlled souring of the milk; the use of vegetable oils to replace animal fats;and the use of additives such as egg yolks and lecithin as emulsifiers, 0-carotene for coloring, and vitamins A and D (5). Although the "oleo" is misleading, the Oleomargarine Act forced its use until 1950.

Manufacture of Butter The manufacture of hutter begins with the separation of

whole milk into skim milk and cream. This senaration is accomplished by gravity or centrifugation because of the densitv differences between cream and serum. This isolated creamis usually 25-40% milk fat (6).

The next step in butter vroduction is the standardization of acidity of the cream. 1f sour, the cream is neutralized with a mixture of alkaline substances, such as lime or carbonates. The main reason for this neutralization step is to prevent rancidity and undesirable flavorine. I t also helps prevent fat losses that can occur when high-a&dcreams are churned (6). Most hutter is now made from sweet cream which does not require this treatment.

Pasteurization involves heating the cream sufficiently to destroy most of the organisms present and can he done in one of two ways. In flash pasteurization, the cream passes through the pasteurizer, is heated to 180 O F or higher, and then cooled immediately. In vat pasteurization, the cream is held at 145-165 O F for 30 minutes. and then cooled. This pasteurization also innctivafes any harmful en7ymes that ruuld impart undesirable flavors to the hutter (fij.

After pasteurization the cream may he ripened. Ripening can he defined as any change in flavor, aroma, or texture that occurs before churning. Today most ripening is controlled,

' Oleurn--Latin for oil; margariteGreek for pearl, the finished product having a granular structure (2'.

596 Journal of Chemical Education

using clearly specified hacterial cultures. Inoculation of the cream is not done directly, but rather is carried out through "starters", hacterial cultures used to inoculate a batch of pasteurized milk. The starter is allowed to grow and is then added to the cream for ripening (6).

The bacterial cultures used are various species of Strepto- coccus that are able to ferment lactose and citric acid. I t is the aerobic fermentation of citrates that gives butter most of its characteristic flavor and aroma. Diacetyl has been shown to be a major contributor to butter flavor and aroma (3,4). The fermentation pathway to produce diacetyl from citrate is a matter of some controversy. The pathway shown is that of Vedamuthu (4).

COOH

I acetyl CoA TWj HS-CoA

PO2 CH,--C---C-CH,

II II 0 0

TPP = thiamine pyrophosphate diacetyl

After t,he cream has been brought to a suitable condition ---..- ~ - ~ - ~ - ~ ~ ~ ~~~ "

by ripening, it is churned, a physical process that involves neitntion of the cream. The Duroose of this aaitation is to - -- . . - change the nature of the emulsion from the "fat-in-water" emulsion of cream to the "water-in-fat" emulsion that is characteristic of butter. When this change in emulsion char- acteristics occurs, the cream is said to "break" (6).

The natural yellow of hutter is due to any carotene that may be present in the butterfat that was used in the manu- facture. However, because the carotene content of hutter- milk can vary widely2, the coloring agent annatto, a yellow vegetable color, can he added to insure a uniform and stan- dardized color.

Ftnally, the huttw is slightly washed to remwe any excess buttermilk, salt is added for preservation and flavor en- hannment, and thr 1,utter ischillrd and cut into hlocks.

Manufacture of Margarine The manufacture of margarine begins with the prepara-

tion of the starting products. The oils used in margarine must be thoroughly mixed by melting any solid fats that are to he used, then stirring in the oils. The oils that are used are often partially hydrogenated by treatment with hydrogen gas in the presence of a suitable catalyst such as nickel. Many of these oils are also deodorized by a selective process

W nter butler, prodJced oy cows on dry feed, is subslantally lower n carotene than sdmmer ouner. produce0 on grass.

Rancidity in butler s caused from high bulyrlcacid content, hence the name "butyric" acid.

by which the more volatile compounds are driven off; steam distillation is the most common process used. The oils that are used in margarine include soybean, cottonseed, corn, peanut, and safflower seed, as well as some animal and milk fats.

The aqueous phase of margarine is most often skim milk, although dried milk and water can be used. The milk is prepared much as it is in hutter manufacture; it is first pasteurized, then ripened. A starter culture is used that has undergone bacterial souring. Bacteria that can produce lac- tic acid, such as Leuconostac cremorus or Streptococcus lactis diacetylactis, are used for this ripening. The extent to which the margarine has a buttery flavor depends almost entirely on this bacterial action, which produces diacetyl(4).

Salt and other preservatives, if used, are usually added to the milk after ripening (5). The milk is then added to the margarine oils, which are held in a liquid form and in an aeitated state. If emulsifiers. such as lecithin. are used. thev are added to the oils before the milk is added, as are vitamins A and D (3). The aeitation continues until the milk and oil . . "

emulsion has been churned to a suitable texture. The marga- rine is then chilled and packaged in a manner similar to hutter.

Composltlon and Nutritlve Content Under external inspection, butter and margarine appear

to he two very similar food products. However, the similarity ends when the fatty acid composition is investigated. Butter is produced from milk fat, which contains butyric acid, un- usual even for animal fats (71.3 I t contains almost 30% short- chain fatty acids and about 30% palmitic and stearic acids. This milkfat contains little or no polyunsaturated fats (PUFA) (8).

Margarine, on the other hand, is made mostly from vege- table oils and contains no hutyric acid or other short-chain fatty acids. I t contains mostly PUFA's, with only about 10% oalmitic and stearic acids.

The important nutritional difference between margarine and butter occurs in the fattv acid content. Maraarine con- tains approximately 25% linb~eic acid, whereas butter con- tains almost none. Linoleic acid has been shown to he an essential fatty acid, so in this respect, margarine is nutrition- ally superior (9). Hydrogenation of the vegetable oils causes some of the cis fatty acids to he converted to the trans isomer. I t is of some concern as to how the body uses these unnatural acids.

Another important difference between these two products is cholesterol content. Butter contains 35 mg cholesterol per tablespoon, while margarine contains no cholesterol when made exclusivelv from olant oils. This difference becomes significant when one considers the alleged correlation he- tween cholesterol intake and heart disease. Usina maraarine - - asa 1)utter sul~stitute is an important factor in trying to keep dailv intake ofcholesterol ar or below rhe W O ma day rerom- - . mended level (10).

The nutritional aspects of hutter and margarine are very similar in certain other areas. With respect to calories, both products contain 100 Cal per tablespoon, with the whipped variety of each containing fewer calories per tablespoon. In the vitamin category, they are nearly identical, both being fortified. on averaee. to the same extent with vitamins A and " . D. (10).

In considering whether hutter or margarine is best for any one particular diet, it is important to consider also the type of product in question. For example, regular butter and margarine are equal in calories, hut neither spreads very easily. (10). The whipped products, which have air or nitro- gen heaten into them, are usually lower in calories and spread much easier. Soft margarines are higher in PUFA, particularly in levels of the essential fatty acid, linoleic acid.

Volume 64 Number 7 July 1987 597

Palmitic acid Stearie acid

Linoleie aeid

&:: HO

Cholesterol

Liquid squeeze margarines are even higher in levels of PUFA's; however, they have not fared well on the American market. Diet margarine is made with skim milk and water as the aqueous phase and is whipped. Spreads are defined as any butter or margarine substitute that contains less than

80% fat. These products must be clearly labeled SPREAD, as the law prohibits the sale of any product labeled as butter or margarine that contains less than 80% fat (5).

Nutritionally, margarine is probably a wiser dietetic choice. However, other considerations such as personal taste and social reference nlav im~or tan t roles in the consumers' decisions. +he consumer"is now free to make these decisions without the influence of nolitics and nreiudice that nrevailed . "

only a few years ago.

Literature Cited 1. Christianson, Theodore. Minnssoro: the Land of Shy-Tinied Wnlars: American His-

torical society: N ~ W y a k . 1935. 2. Ball. R. A.;Lilly. J. R. SocinIProblrms 1382,29, 488. 3. Bailey, A . E . l n d u s f ~ 1 Oi londFai P~oducia:Intprscience: New York, 1946. 4. Vedamuthu, E. R. Dsuelopmrntr in Industrid Mirrobioio~s: Underklofer. L. A,. Ed.;

Society for Industrial Mierubiolopy: 1979: V o l 20, pp 187-202. 5 . Kirh-OfhmeiEncyclapPdio n/Chemical Terhnology, 2nd ed: Wilcy: New York, ,985:

Vol. 1% pp 5 6 4 6 . 6. Enryrlnpodia o/ Chemical Technology; Interscience: New York. 1949: Vol.4, pp 797-

806. 7. Hi1ditch.T. P.;Meara. M. L.Riochem J 1344.38.29. 8. Kirk-Olhmer Encyclopedia o/Chemicol Technology. 3rd ed.: Wiley: New York, 1978:

Ynl I S nn ho7-666 ~~ - . .-- . . .

9. Burr. G. 0.; Burr, M. 0. J.Aiol. Chrm. 1930.86.587. 10. Reed. P. B.Nuirition:AnAppliedScience: West: St. Paul. 1980.

598 Journal of Chemical Education