Following the previous entry where we discussed general aspects of eggs and their functionality in baked product manufacturing, in this new entry, we will delve into the various egg products available in the market.

Fresh Eggs

Fresh eggs, or shell eggs, are commonly used in households. As previously explained, using this type of egg can pose significant bacteriological problems. For this reason, Spanish legislation prohibits its use unless the egg is subjected to temperatures exceeding 75ºC. In other countries, it is mandatory for eggs to be pasteurized before use in the industry and hospitality. This is why many companies have replaced fresh eggs in their formulations with alternative egg products.

It’s important to note that in the production of baked goods, the indicated temperatures are typically reached. Additionally, untreated eggs maintain all their functional properties intact. However, when treated, some of these properties may be modified. Therefore, some companies have been hesitant to change this ingredient in their formulations. However, at present, almost no major company continues to use this type of egg.

To use fresh eggs, a separation process of the shell is necessary, usually achieved through centrifugation. Extreme care must be taken with hygiene and storage conditions. Eggs can undergo a hydrothermal treatment for sanitization, where they are immersed in a bath at temperatures close to 60ºC for a specific duration. Temperatures higher than this risk coagulating the egg white. After treatment, a protective layer covers the egg, and it is refrigerated until use. Pasteurization does not eliminate all microorganisms but ensures the removal of pathogens. Irradiation of eggs has also been studied, although it is not a treatment commonly carried out in Spain, to my knowledge. Despite these treatments improving egg quality, the risk of recontamination in the workplace remains.

Pasteurized Liquid Egg

Pasteurized liquid egg is the most widely used egg product in the industry and hospitality sector. In the market, one can find whole eggs, as well as separated egg whites or yolks. However, liquid egg whites are more commonly found in stores. In bakery and pastry supply distributors, whole liquid eggs are also available, though liquid yolk may be less common.

In liquid egg factories, after reception and quality control, eggs are washed and go through cracking equipment, functioning similarly to home egg cracking. This allows effective separation of the shell. Subsequently, egg whites and yolks are separated as they fall through a channel due to their different density and consistency. Egg whites and yolks can be processed separately or combined in specific proportions to obtain whole liquid eggs, ensuring consistency in the ratio of egg whites to yolks in the final products.

The critical point in processing pasteurized liquid eggs is the pasteurization process. It requires achieving temperatures high enough to destroy pathogenic microorganisms but not so high as to coagulate the egg whites, preventing product flow inside heat exchangers. The whole egg is usually treated at temperatures around 60ºC for a minimum of 3.5 minutes. However, treating egg whites at these temperatures, given their pH (close to 9), results in denaturation of ovoproteins and undesired viscosity increase. To address this, temperatures for egg white treatment are reduced to 52-57ºC, and pH is lowered to around 7 to improve the stability of some ovoproteins. Additionally, salts are added for stabilization. The incorporation of the enzyme peroxidase, subsequently removed by catalase, is another method used. Regardless of the chosen method, manufacturers of egg products must ensure pasteurization while maintaining functionality. However, slight modifications in functionality are inevitable and depend on the treatment received. It is crucial to study how these variations affect the process and product, as not all functionalities of egg products are equally important for all products. In this way, the foaming properties are not as important in a foam cake as in the production of a cupcake, for example. It is also extremely important that our supplier guarantees consistency in the functional properties we are most interested in.

After pasteurization, egg products are prone to recontamination. Aseptic packaging is employed to prevent this. Plastic or brick containers, ranging from ½ to 5 kg for hospitality use, are commonly used. For industrial purposes, larger flexible multilayer containers, usually set in cardboard or other materials for structure during transport, can be obtained. The shelf life of these products is still limited, and refrigeration is preferable since they are not sterile but pasteurized, sufficient for distribution and use in the industry for several weeks.

Frozen Eggs

Although not commonly used in Spain, freezing eggs or their parts after pasteurization is frequent in other countries. This eliminates the need for aseptic packaging and ensures a longer shelf life. However, it involves higher costs for transportation and freezing storage, and careful attention is required during thawing to prevent changes in egg properties. It is recommended to thaw them at temperatures between 10-15ºC. Prolonged freezing storage can also result in some changes in the functional properties of eggs.

Dried or Powdered Eggs

To achieve a longer shelf life and reduce transportation and storage costs for egg products, drying can be employed. Atomization is commonly used for quick drying at low temperatures. Other drying methods, such as spreading thin layers of the egg product for extended dehydration, affect the functional properties differently.

When drying egg products, it may be essential to eliminate glucose present in them to prevent participation in Maillard reactions, generating darker colours and strange flavours. Fermentation with bacteria (for egg whites) or yeast (for yolks) or enzymatic treatments, such as involving glucose oxidase and catalase (for yolks and whole eggs), is used for glucose removal. It’s also crucial to note that desiccation treatments reduce the foaming capacity of eggs. To counter this effect, sugars (mainly sucrose or glucose syrup) are added, reaching up to 10% of the mixture. Additionally, when treating yolks or whole eggs, glucose syrup or salt incorporation is common to increase the coagulation temperature of egg white proteins and facilitate the dispersion of yolk components. While it may seem contradictory to eliminate glucose and then incorporate sugars, these are different approaches that allow for obtaining different products.

Thermal treatments also reduce the natural egg aromas or modify them, leading to the inclusion of external aromas in some dehydrated products.

For reconstituting original egg products, it’s important to note that, in the case of egg whites, they should be mixed with 7 parts of water, for yolks with 3 parts of water, and for whole eggs, with 4 parts. These calculations must be considered in formulations.

Selection

The choice of egg product depends on our needs. Generally, the less processed the egg or its parts are, the fewer losses in their functional properties. Liquid eggs are generally preferable, but dried products can be a good option, especially when large quantities are not used, and proper rotation is challenging.

The ability to obtain egg whites and yolks separately provides more flexibility than using whole eggs only. Therefore, it’s essential to study each case to determine whether to use them separately or use whole eggs and complement them with another egg product, depending on whether you want to enhance foaming or gelling capacity (egg whites) or colour and aroma (yolks).

The variations in the functional properties of egg products generated during processes, and their increased understanding, have led to the availability of products with specific properties that may be interesting. For example, in addition to normal egg whites, others with better foaming properties and those with improved gelling properties are offered. My advice is not to get carried away by the names and try them in your products. Sometimes these products are more expensive and can be avoided by increasing the amount of normal egg whites, sometimes they don’t work as well as they seem to, and sometimes they really make a difference. But their suitability will depend both on the product and its formulation, as well as on the production processes used.

Once we are clear about the product we are interested in and its properties, we must find a supplier that guarantees the regularity of these properties. As we have seen, this depends on many factors, and one of the most important criteria in the quality of eggs is their regularity. We can probably make a sponge cake with many different types of egg products, adapting formulations or processes, but we cannot be faced with unforeseen changes in each batch.