Stability of Cake Batters Effect of Variation
EMILY GREWE Washington, D. C.
in Hydrogen-Ion Concentration An emulsion foam is formed when the ingredients of cake are agitated together. The “curdling” or breaking down of the emulsion is one of the major problems in cake making. Sodium bicarbonate and acid potassium tartrate, the component parts of baking powder, were added t o fat, sugar, and egg mixtures. Changes in hydrogen-ion concentration were affected within a range of pH 8.3 and 4.5 by adding varying amounts of these two chemicals. The stability of the emulsion foam was tested by means of a settling test, viscosity, and specific gravity. The hydrogen-ion concentration of the emulsion without the addition of either chemical was pH 7.3. Hydrogenated fat, butter, and butter oil were used as the fats in the experiments. The emulsions containing hydrogenated fat tended t o decrease in stability with decrease in hydrogen-ion concentration expressed as pH. When butter and butter oil were used as the fats, the least stable emulsion was obtained a t a hydrogenion concentration of about 6.3 expressed as pH.
its component p q t s , sodium bicarbonate and acid potassium tartrate, and the effect on the stability of the emulsion foam was studied. The practical importance of this work is enhanced by the fact that it is possible for the baker to add baking powder in the form of its component parts.
Procedure Sodium bicarbonate was added in increasing amounts to mixtures of fat, sugar, and whole egg, and acid potassium tartrate was added to similar mixtures. The reactions of the emulsions ranged from alkaline to acid. Determinations were made of the hydrogen-ion concentrations of these mixtures and of the effects of variations in hydrogen-ion concentration upon the stability, viscosity, and specific gravity. I n making cake containing a fatty emulsion, the method generally used for mixing the emulsion is to agitate the fat and sugar, then gradually add the egg, and continue beating for some time after all the egg has been added until the foamy emulsion is formed. This was the basis of the method for making the emulsions in this study. I n cake making, the flour and milk are added to the emulsion, beginning and ending with flour. The salt, flavoring, and baking powder are added during the procedure. Although this study was limited to emulsions made with acid or sodium bicarbonate added directly to the emulsion, it is thought that the results are related to the stability of emulsions in batter; it is well known that the emulsion foam persists as such when agitated with the other ingredients of the batter. MATERIALS.The procedure used in preparing the emulsions was essentially the same as that followed in the earlier w0rk.l New samples of each ingredient were obtained, and they differed somewhat from those used in the previous experiment in length of time held in storage.
0
XE of the difficulties encountered in securing consistently uniform high quality in making cake, when the batter contains a large amount of butter or other fats, is the tendency for the emulsion of fat, sugar, and egg to break or “curdle” when it is being mixed or after it is incorporated in the batter. Curdling or separation of serum from the emulsion is regarded by the baking and related industries as a major problem. The stability of the emulsion is therefore a n important factor in cake making. I n previous work1 a method for determining the stability of fatty emulsions was developed, and the effect of the conditioning temperature of t h e fat on the stability of the emulsion was shown; a brief study was also made of the use of the stability test in creaming the egg. The present investigation was concerned principally with the effect of hydrogen-ion concentration. Varying amounts of the equivalent of baking powder were added in the form of 1
PH
FIGURE 1. EFFECTOF HYDROGEN-ION CONCENTRATION ON VISCOSITYAND STABILITY OF BUTTER-SUGAR-EGG EMULSIONS
Grewc, Emily, Cereal Chem., 14,802 (1937).
719
IhiDUSTRIAI, .4VD ENGINEERING CHEMISTRY
720
-Grams aodium biosrbonste added
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4
2
FIGURE
2.
EFFECT OB'
1
Annmo
BaKIXG
.----Grams
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POWDER ISGWEDIENTS
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For the urpose of this experiment it was considered desirable to cream t i e fat and the sugar together aa in cake manufacture.
These two ingredients were placed in the 3.5-quart bowl of s Hobart mixer and were blended by agitation with the flat paddle at the medium speed. The mixin%was done in a constmt-temperstme cabinet maintained at 22 to 23' C. The fat and the s u m were creamed toeether for 5 minutes. and the e m was added g&ually over a pe&d of 4 minutes. .The beathi was continued for 11 minutes after the egg had h e n added. TESTS. Viscositv was determined in the usual manner hv means of the MacMichael viscometer and is expressed in degrees MacMichrtel. The specific grsvity was determined by accurately weighing a known volume oi the emulsion. Bydrogen-ion concentration was determined oloctrometrically by means of a type K mtentiornoter and quinhvdrone elcotrodes. The determinacentimkors of seruin ¶ted ?ram 35 grams of the emulsified mixture is measured at a temperature slightly lower than the breaking temperature for diffcront periods of time.
made to ascertain wheGher the baking powder ingredient (sodium bicarbonate or acid potassium tartrate) should be added to the butter or the egg to produce the most stable emulsion. The results (Table I) indicate that E more stable emulsion was formed when the chemicals WRS
TABLEI. EFFECTOF ADDING SODIUM nICAnBonnTE OR ACID POTASSICM TARTRATE TO BUTTER OR TO Eoo
GTUM
+ 4 NaHCOi Egg + NsHCOa Butter + 7.5 KH(C.HaOs) Egg + 7.5 KH(C.H'Or) Butter
Concn. PH 8.2 8.2 4.8
4.9
BUTTER OIL,
MIXTURESCONTAININGBUTTER. Mixtures of butter, sugar, and egg were prepared and tested on nine different days; from four to six mixtures were prepared daily. The mixture of fat, sugar, and egg is very sensitive to slight variations in ingredients and to atmospheric conditions. Therefore, the results of the work done on different days showed slight variations. The data obtained from the tests of the mixtures prepared on one day are shown in Table 11.
TABLE11. EPFECTOF IfYDROGEN-ION CoNCENTXATIoN ON SPECIFIC GRAVITY, VISCOSITY,A N D STABILITY OF A MIXTUREOF B ~ E RSUQAR, , A N D EGG* KH(CtH
