While the characteristics of various ingredients have been discussed in previous entries, this section serves as a reminder of their functions in cake making. It’s essential to note that each ingredient serves a specific function, and formulations are calculated for the inclusion of specific ingredients. Therefore, even a slight variation in ingredient quantities or types, such as replacing sucrose with glucose syrup, may necessitate reformulation by adjusting ingredient quantities.

Flour

The blog has already dedicated a specific entry to the necessary quality for wheat flours in the preparation of cakes. Here, we provide a brief reminder. First, it’s essential to consider that in the cake making, the gluten network does not develop due to a lack of mechanical work applied to the batters, given their more liquid nature and lack of resistance to the movement of the beaters. Therefore, gluten-related aspects, such as alveographic or farinographic analyses, are not important for the quality of cake flour. Instead, attention should be directed towards other factors.

On one hand, the starch content and related aspects are crucial. Starch is fundamental in the development of the final structure of the cake by gelatinizing during the baking process. A lack of starch can lead to the collapse of cakes, either during baking or cooling. However, as starch content is more challenging to analyse, emphasis is usually placed on protein content, which is simpler to measure. Thus, higher protein content corresponds to lower starch content, and vice versa. The content of damaged starch can also be important. This starch, generated in the milling process, has a higher water absorption capacity than undamaged starch and a greater thickening power. Therefore, changes in damaged starch content will result in changes in batter rheology. To avoid these issues, flours from soft wheat, with higher starch content and lower resistance to milling, and consequently lower damaged starch content, are often used.

It’s also important that the flour does not have a high enzymatic content, which can modify doughs in a short time. For this, it’s crucial that there is no infestation of “garrapatillo” (an insect injecting an enzymatic cocktail into the grain), or other insects like this, or germination problems.

A third crucial point is the particle size of the flours. For cake preparation, it’s essential that this is as fine as possible. This factor is particularly important in more aerated cakes, like foam-type cakes. The reason for the importance of this factor is that the starch released by these particles helps stabilize emulsions by surrounding the air bubbles. On the contrary, coarse particles may have the opposite effect, generating batters with larger and unstable bubbles. Fortunately, soft wheats produce finer flours, making them suitable for these types of preparations.

Certain measures, such as water absorption capacity, can also help decide on the suitability of a flour for sponge cake preparation, as it is related to dough rheology, starch content, damaged starch content, and particle size.

Although it’s possible to make cakes with gluten-free flours, the same parameters are essential. However, gluten-free grains tend to be harder than wheat, resulting in coarser flours (less suitable for these preparations) or with a higher content of damaged starch. It’s necessary to control these factors and obtain suitable, fine flours with consistent characteristics. Starches from different sources also have different gelatinization temperatures. This temperature is what determines the point at which the expansion of batters stops during baking, increasing dough consistency. For this reason, a change in starch type can affect the volume or shape of cakes. It’s important to note that wheat starch has one of the lowest gelatinization temperatures, although the presence of sugars increases this temperature, minimizing the differences.

In many treatises on sponge cakes, there is discussion of drying and humidifying ingredients. Flour is a dry product and falls under the category of drying ingredients.

Sugar

Sugar serves a clear flavouring function by adding sweetness to the final product. These sugars also influence the final aroma of the product through Maillard reactions that occur between sugars and amino acids at high temperatures. These reactions, along with sugar caramelization in the later stages of baking, contribute to the final colour of the cakes. Lastly, sugars also influence the final structure of the cakes, as evident when making a cake without sugar. The incorporation of sugars also dilutes the proteins in the flour, resulting in softer and more tender products.

In the case of wanting to make a sugar-free cake, simply substituting it with an intensive sweetener is not sufficient, as these do not have a structural function. It will be necessary to use a bulking agent such as polyols. Among polyols, maltitol and xylitol can replace sugar, yielding cakes with good volume and sensory characteristics, as they have a similar sweetening power. However, as they do not participate in Maillard reactions, these types of cakes tend to be lighter in colour. The most used polyols for making sugar-free cakes are maltitol and sorbitol, due to the high cost of xylitol.

It’s also important to note that crystalline sugar produces drier products, while the addition of liquid sugar or glucose syrup results in moister cakes. This is partly because glucose syrups contain some moisture, and therefore, have a lower sugar content than crystallized sugars. Substituting sucrose with other sugars often affects sweetening power and final colour. For example, glucose has lower sweetening power than sucrose, while fructose has higher sweetening power, as inverted sugar. All these sugars also have greater potential in Maillard reactions, producing somewhat darker colours. However, this difference is not always noticeable. The inclusion of high-sugar content products, such as honey or maple syrup, is more driven by marketing criteria or the pursuit of specific flavours. These sugars usually only partially replace sucrose.

A final important factor of sugars is that they raise the gelatinization temperature of starch, and not all sugars do this in the same way. Therefore, these changes can slightly affect the final characteristics of the cakes.

Fat

Fats play three main roles in the making of cakes. Firstly, they assist in retaining air during the creaming phase, thus influencing the volume of the final product. Secondly, they coat protein particles and starch, minimizing the formation of the gluten network, contributing to a softer texture. Finally, fats do not get lost during baking or storage, unlike some water content, and result in juicier crumbs and smoother textures.

During the creaming phase, where sugar and fat combine, air disperses in the solid phase. Specifically, plastic fats are responsible for retaining air bubbles in cakes that incorporate them. For this purpose, fats need to be solid and plastic to properly encase the bubbles. The addition of an emulsifier, such as monoglycerides, helps separate air bubbles and create a finer cell structure in the batter, producing products with a more uniform texture. The crystalline form of fat also has a significant influence. Fats can crystallize in α form, with a lower melting point, in β form, with an intermediate melting point, and in β’ form, with a higher melting point. Fats composed of a small number of triglycerides usually crystallize in the β form, while more heterogeneous fats, formed by a greater number of triglycerides, preferably crystallize in the β’ form. Crystals in β’ are finer and enhance air incorporation, while crystals in β form are larger and can give a granular texture, reducing air incorporation.

In the case of mixing in a single phase, incorporating all ingredients at the beginning, air becomes trapped in the aqueous phase rather than in the fat. Thus, a foam stabilized by egg and flour proteins will form. The addition of fats can destabilize this structure and reduce the trapped air volume. This is usually a problem with foam cakes, but not with fat-based cakes. In this case, the addition of certain emulsifiers, such as propylene glycol monoesters or polysorbates, helps minimize this effect. Emulsifiers create a film at the oil/water interface, separating the fat from the aqueous phase and preventing destabilization of the structure.

The inclusion of emulsifiers is often very useful in batters made with liquid oils. In these cases (use of oils instead of fats), a much softer cake texture is achieved at the expense of some volume loss, which can be minimized by incorporating the right emulsifiers. It also results in a more open cell structure, with larger cells, changes that can also minimise emulsifiers. While these changes may be viewed as negative in certain countries, it is not the case in Spain, where such preparations are common. Additionally, oils like olive or sunflower, commonly used in our country, have significant nutritional advantages over solid fats.

Dairy Products

The inclusion of dairy products in formulations is also common. If these are in a solid state, they will result in drier cakes, unlike when incorporated in a liquid state. Although this can be corrected by adding water. Milk will influence the taste and aroma of cakes, as well as the Maillard reactions due to its lactose and protein content. The influence of such products will depend greatly on their fat and sugar composition, and the same considerations for fats and sugars can be applied to them. In the case of incorporating yogurt, the pH of the batters will also be altered, impacting leavening, the final colour of the product, and its flavour. Despite their advantages in terms of colour and flavour, the presence of allergic reactions to dairy proteins and lactose intolerance leads to their omission in some preparations.

Egg Products

Eggs are one of the most important ingredients in cakes, especially foam-type cakes. Their influence on the final product depends on the type of egg product incorporated. Egg whites contribute to the formation of an airy structure due to their ability to trap air when beaten. Their water content is high, around 85%, and promotes the final moisture of the batter. Egg yolks are composed of 49% moisture, 32% lipids, and 16% protein. Due to their fat content, they contribute to the juiciness of the final product. It’s also important to note that egg yolks play a significant role as an emulsifier, thanks to their lecithin content, and contribute to flavour and colour. Whole eggs have a function more similar to the yolk than the white, as the ability to whip whites (trap air in a stable structure) is hindered by the presence of fat. In the industry, the use of pasteurized or powdered egg products is very common, either for hygiene or for the convenience of dosing or storage. In these cases, it’s essential to consider that egg products have undergone thermal treatment, more severe in the case of powdered products. This thermal treatment, besides causing losses of volatile components and hence their organoleptic properties, can affect egg proteins by partially denaturing them. Therefore, pasteurized egg products, and especially powdered egg products, lose some of their potential to retain air, affecting the quality and final volume of cakes, especially those that depend mainly on this ability, such as foam cakes.

Egg whites also serve an important structural function by coagulating during baking, helping to give cohesion and structure to the crumb, preventing collapse in the final stages. In gluten-free cakes, a less cohesive, more crumbly texture is often observed. This is because wheat proteins exhibit this functionality as they denature during baking. Therefore, in gluten-free cakes, the content of egg whites (or in some cases, whole eggs) is usually increased to compensate for this lack of cohesion.

Leavening Agents

It is common to include a leavening agent in cake formulations, although it is not necessary in all cases. These products generate CO₂ through the reaction of an acid and a base during baking, contributing to the expansion of the batter and the final volume of the cake. As explained in the corresponding entry, the choice of acid and base is crucial in their influence on the final characteristics of the cake. A balance must be found between when the leavening agent acts and when the starch gelatinizes. If the starch has not gelatinized, the batter’s viscosity is low, and the generated air usually escapes without affecting the cake’s volume. Therefore, leavening agents that act at low temperatures and rest times before baking should be avoided. On the contrary, if the leavening agent acts once the starch has gelatinized, the cake’s structure is very compact and unable to expand, leading to breakage. But if the leavening agent acts when the starch is gelatinizing (there is a certain window of temperatures or times), maximum expansion occurs. These parameters can also be manipulated to achieve cakes with a more defined crown or a flatter surface.

Salt

Finally, salt is usually included in the formulation as a flavour enhancer. It is also common to include some products with flavouring or aromatic effects, such as spices, flavours, cocoa, or nuts, even liquors.