Fig. 66 is a photomicrograph of cake batter that shows the butter dispersed as an oil-in-water emulsion. All the materials were incubated at

40°C. and mixed at this temperature. The butter was melted, and during mixing an emulsion was formed. This photomicrograph has a higher magnification than the other photomicrographs used in the illustrations, and shows how well the melted fat may be emulsified by mixing.

Myers studied the effect of two temperatures of ingredients at the time of combining on the fat distribution in the baked cake. The temperatures used were 25° and 30°C.; the methods of combining ingredients, the conventional-sponge and conventional; and the fats used, butter and both smooth and grainy lards. The two lards were from the same source. A sufficient amount of open-kettle rendered lard for the whole experiment was carefully melted and divided into two portions. One part was allowed to cool slowly in an incubator at 25 °C. with the result that it was granular or grainy with some separated oil. The other portion was cooled within a kettle set in a container into which tap water at 10°-15°C. was running constantly. More than an hour of constant stirring was required before the lard solidified. The product was then set in the constant temperature box at 25°C. for 12 hours, as suggested by a patent to Procter and Gamble Company. The resulting lard had a very desirable consistency, neither too soft nor too hard and waxy, and was very plastic.

The analysis of variance of total scores shows that the variation due to temperature, method of combining, and fat used were all highly significant. A total of 300 cakes was made and the average total scores are given in Table 57.

Average Total Cake Scores for Different Temperatures, Methods of Combining Ingredients, and the Different Fats Used (Myers)

Variation

Number of cakes

Total average score

Temperature of ingredients when combined,

°C

25..................................

150

76

30..................................

150

68

Method of combining the ingredients

Conventional-sponge..................

150

78

Conventional.........................

150

64

Fats used

Butter......................................................

100

76

Smooth lard..........................

100

73

Grainy lard..........................

100

64

The smooth-lard group of cakes scored highest at 25 °C. for both conventional-sponge and conventional methods, the butter second, and the

Cakes Part 7 128Cakes Part 7 129Cakes Part 7 130

Fig. 68. - Cake. Showing effect of extent of mixing on volume and texture when a tartrate baking powder is used. Experiment 84A. As shown in illustration the cakes are about seven-ninths actual size.

150 grams of the batter removed and baked after mixing, grainy lard third. But at 30°, butter scored first for both methods of combining, the smooth lard second, and grainy lard third. The distribution of the fat in the cake crumb, which was stained with osmic acid fumes, is shown for the two temperatures and methods of combining in the photomicrographs, Fig. 67.

At 25°, when the fats were firmer when combined, the fat in the cake

Cakes Part 7 131Cakes Part 7 132Cakes Part 7 133

Fig. 68.

1. 50 strokes.

2. 100 strokes.

3. 150 strokes.

4. 300 strokes.

5. 400 strokes.

6. 1000 strokes.

Crumb, depending somewhat on method and fat used, is more or less evenly distributed at the air/crumb interface. In general the more even this distribution the higher the scores received by the group of cakes. Of the 12 groups of cakes, those made with smooth lard, by the conventional-sponge

Cakes Part 7 134Cakes Part 7 135Cakes Part 7 136

Fig. 69. - Cake. Showing the effect of extent of mixing on volume and texture when a phosphate baking powder is used. Experiment 84B. Illustration is about seven-ninths actual size of cakes.

150 grams of batter removed and baked after mixing, method at 25°, scored highest and as a group had the most even distribution of fat at the air/crumb interface.

At 30°, when the fats were softer and more mobile, hence the squeezing effect exerted by the egg in forming oil-in-water emulsions encountered less resistance, the fat is distributed within the crumb, a fairly large portion as an oil-in-water emulsion. As a result the cakes were less palatable and received lower scores.

Cakes Part 7 137Cakes Part 7 138Cakes Part 7 139

Fig. 69.

1. 50 strokes.

2. 100 strokes.

3. 150 strokes.

4. 300 strokes.

5. 400 strokes.

6. 1000 strokes.

Extent of mixing and its effect on the baked cake. Several illustrations accompany this part of the discussion of cakes. For the illustrations 150 grams of batter were always used and the cakes were baked in pans of the same size. This small amount of batter was used so that the grain, holes, and imperfections of texture and the volume are shown nearly actual size. As reproduced the illustrations are seven-ninths of the actual size of the cakes. Incidentally, it is difficult to make cake without some irregular holes from enclosed air, and these imperfections show more in the picture than in the cake. The ingredients for the cakes were 23 °C. when mixed. The butter, sugar, and beaten egg were creamed only 75 turns with a rotary egg beater and 100 times with a wooden spoon, thus they were not thoroughly creamed, hence a coarser texture was produced. They were also baked at a lower temperature than now considered optimum. The very plain cake recipe, see Experiment 84, is used in the experimental outline because variations in extent of mixing and the proportion of ingredients show very distinctly. For a plain cake recipe for home use most people will prefer the sugar increased to 1 1/2 cups.