Dairy products have been a common ingredient in many bakery, pastry, and biscuit products. Recently, some of these products have come under scrutiny, and some companies prefer to eliminate them from their formulations. In this entry, we will explore their advantages and disadvantages.

Milk

In general, when we talk about milk, we refer to cow’s milk, although there are other types of milk that can be used in bakery and pastry. Milk is mainly composed of proteins, fat, and lactose, although it also contains minerals and vitamins in smaller proportions. Due to its protein quality, among other reasons, milk consumption has been emphasized as of great importance for infant nutrition, depending on countries and periods. This good reputation was due to its protein content and quality, as well as its calcium level. However, in many Western countries, milk consumption is currently being debated by different consumer groups.

On one hand, milk fat is not the best nutritionally, as it contains a higher percentage of saturated fats than most vegetable oils and certain amounts of cholesterol. Regarding proteins, despite their nutritional quality, some people are allergic to these proteins and must avoid their consumption. Concerning lactose, there is also a group of people intolerant to this sugar who must avoid or minimize its consumption. It’s essential to consider the growing number of vegans. This trend is increasing for various reasons, including nutritional and environmental factors, among others. Regardless of the reasons supporting this mindset, and whether it leads to an extreme or is combined with reduced consumption of certain animal products, depending on the market for which our products are intended, we must take it into account. Therefore, while milk and dairy products can fit perfectly into the diet of most people, there are certain groups that must or prefer to avoid the consumption of milk and dairy products.

Although a few decades ago, milk and dairy products were incorporated for the improved nutritional image they could provide, and it may still be the case in some countries, nowadays, at least in Spain, milk is usually incorporated for the organoleptic improvements it produces, primarily in flavour, aroma, and colour, and for tradition. Thus, there are different products in which certain dairy products, such as butter, give it its identifying character.

The milk consumed in households is cow’s milk that has undergone certain processes to eliminate impurities, normalize its fat content, and reduce microbial load, trying to minimize changes in its nutritional composition and organoleptic quality. If the thermal treatment is milder and only ensures the elimination of pathogenic microorganisms, it is called pasteurization. This type of milk must be stored in refrigeration, and its shelf life is limited. If the thermal treatment is more severe, it is called sterilization, and properly packaged, it has a long shelf life. This type of liquid milk can be used in small bakeries, but in the industry, it is very rare for them to be used. The main problem with these milks is that they contain a lot of water. Therefore, it forces us to transport and store water, a product that we can easily obtain in our industry. Nowadays, treatments for dehydrating milk have improved a lot and do not negatively affect the functionality of the milk, at least the functionality needed in baked products. Therefore, most industries use powdered milk, reducing transportation and storage costs.

In the market, there are also milk with reduced water content, such as evaporated or concentrated milk, but they are also not usually used in the baked goods industry for the same reason.

Whole milk powders have a high risk of becoming rancid, both due to their fat content and low humidity, so their shelf life is usually reduced compared to skimmed milk powders. For this reason, most milks used in the industry are skimmed milk powders. This way, we can also replace dairy fats with others of higher nutritional quality or eliminate them directly from the formulation. As a downside, it is essential to consider that by removing fat, we also eliminate fat-soluble vitamins present in milk, mainly vitamin A. To obtain them, impurities are removed, the fat is separated, and they undergo pasteurization before undergoing a drying process, either by heated drums or atomization. The final characteristics of the milk will largely depend on the drying treatment received. Milk obtained by atomization hydrates and reconstitutes more easily, but this is usually not the goal in the production of baked goods. On the other hand, roller drying usually modifies the taste and colour of the milk through Maillard reactions between proteins and lactose. The water absorption capacity of these powdered milks can also be affected by the treatments received, as well as the particle size of the obtained powder. It is essential to consider that thermal treatments denature proteins and can change their functionality. These modifications do not necessarily have to be negative; they can even be positive. The important thing is to take it into account when purchasing powdered milk and analyse the advantages or disadvantages in each product of such treatments. What we cannot do is change powdered milk suppliers without considering these characteristics.

If we want to reduce costs, whey powder can also be used. Whey powder is a by-product of the cheese industry, where, in addition to dairy fats, casein, proteins responsible for forming the structure of the cheese, have been removed. Some losses of lactose and minerals also occur, but these are minor. Therefore, whey is a product richer in lactose and serum proteins. As with powdered milk, the characteristics of whey will depend on its previous processing. Thus, whey from the production of different types of cheese will be different, as well as those that have received a different drying process. Another problem that whey powder usually presents is its excessively mineral taste, due to the presence of many mineral salts. To avoid it, whey usually undergoes a demineralization process. In general, whey powder is a product of lower nutritional and organoleptic quality than skimmed milk powder, but also of lower cost, so it can be an alternative in some products.

What milk contributes to baked products

One of the components of these products is lactose. It is essential to consider that lactose is a simple, non-fermentable sugar by baker’s yeast, although fermentable by other yeasts and bacteria, with very little sweetening power (less than 20% of sucrose). Therefore, this sugar will not help in the fermentative process and will remain in the dough at the time of baking. During baking, it aids in Maillard reactions and caramelizes (tends to caramelize at lower temperatures than sugars present in doughs, such as maltose, sucrose, or glucose). Thus, baked products with lactose or the incorporation of dairy products usually have a darker colour. The colour also has somewhat different shades, such as reddish, as the colours formed in Maillard reactions depend on the sugars present. For this reason, if the baker tends to stop baking just based on the colour of the pieces, it is possible that with the same colour, the dough may be slightly raw, as dark crust colours are achieved in less time. The aromas provided by Maillard reactions also change slightly. The final taste of the product will also be affected since, although lactose does not have great sweetening power, it remains in the final product, slightly modifying the taste of the product.

Lactose can also be acquired in pure form, as it can be obtained from whey. In these cases, it has a more defined functionality, without other modifications associated with other components, but the price is usually higher. It is essential to consider that there is a growing number of lactose intolerant individuals today, something that has also given a bad reputation to dairy products in certain population sectors. In any case, this must be taken into account when intending to incorporate a dairy product into a formulation.

Powdered milk also increases dough absorption, mainly due to its protein content, so it will be advisable to increase the amount of water in the formulation. This increased water absorption capacity also translates into a slightly longer shelf life for bread and bakery products.

Another effect to consider is the buffering power of milk. This means that doughs with milk tend to be more stable in terms of pH, and the logical acidification that occurs in the fermentation process is lower. This effect can delay fermentation, as it reduces the activity of amylases, and therefore the production of fermentable sugars. Therefore, in doughs with powdered milk, it may be advisable to increase fermentation times or try to force the pH drop with the incorporation of a product such as ascorbic acid. However, this will depend on the bread-making method used, the inclusion or not of sucrose or other fermentable sugars, etc.

Natural milk also has a high enzymatic level, which could affect bread-making processes. However, the thermal treatments that milk undergoes in its processing inactivate these enzymes, so they should not worry us when applied in bread-making.

Dairy protein also affects the products in which it is incorporated. On the one hand, due to its participation in Maillard reactions, and therefore in the colour of baked products. On the other hand, because it helps give structure to cakes, although this effect is usually not essential, unlike what happens with egg white protein. In the case of bakery products, they also interact with the gluten network, but the consequences of these interactions are not entirely clear. It seems that they will depend on the type of protein (with caseins being preferable to whey proteins), the previous treatments received (with a certain protein denaturation being preferable), and the type of bread-making process (with slower processes being preferable). As there are many factors, it is always preferable to check it based on the milk used and the product to be made. In general, the presence of these proteins increases kneading times and the tolerance of doughs in the final stages of fermentation.

In the market, we can find concentrates and isolates of dairy proteins. Isolates usually exceed 90% purity, while concentrates have variable concentrations, between 40% and 90% in most cases. These products can be based on casein, whey proteins, or both. We can also find them with different functionalities and, depending on the type of protein and the obtaining process, emulsifying, foaming, gelling, water absorption, solubility, etc., capacities can be enhanced. But as a general rule, dairy proteins are very soluble, with low thickening power, and do not increase their consistency with thermal treatments, as egg white proteins do. Therefore, they can be incorporated in high percentages without increasing the hardness of the products where they are incorporated, and without changing the rheological properties of the doughs much. However, their foaming properties are much lower than those of egg proteins (both air retention capacity and foam stability), and although they can be increased with some previous processing, they never reach the characteristics of these.

In a subsequent entry, we will talk about other dairy products such as butter, cheese, or acidified products, such as yoghurts.