Quality standards in bakery
Quality standards in bakery
How can we add more value to our products? This question is of paramount importance, but the answer cannot be provided directly. What I can do is provide some guidelines that may help you to add extra value. It is up to you to find the answer.
Netherlands is generally not known for high-quality bakery and confectionery products. Fortunately, there are exceptions, but overall, the quality of our products is mediocre and far from excellent. What I mean is that the Dutch often strive for an average quality instead of excellence, while we need to compete on the European market with suppliers of high-quality products. We seem to be content with an average level of quality and finishing.
Products with limited added value are increasingly being produced and delivered by countries with lower labor costs. For example, if you have visited the ISM fair in Cologne, you have seen examples of products at different levels. On one hand, there are companies offering genuinely innovative products, often using new technologies and specific knowledge for new users and applications. These companies have vision and continue to grow. On the other hand, many companies create variations on the same themes without real innovation. They change the size, thickness, chocolate coating, color, or try a 'new' flavor, but essentially, they offer more of the same. These are companies without vision that gradually lose margins and revenue. More and more cheaper providers are entering the market, offering familiar products at lower prices, whether it's biscuits, waffles, or candies; they are available at competitive prices.
In conclusion, despite our high labor costs, we should not compromise on the quality of raw materials, recipes, and production processes, nor on the costs of product development. Only through optimizing these factors can we gradually build a distinctive position. The sooner we start with this, the stronger our position will be in the future. Building this distinctive position, however, requires continuous knowledge development, both for yourself and your employees, as everyone plays a role in this process.
The Importance of Quality Raw Materials
In this section, we will frequently discuss raw materials, recipes, and processes, in varying order. This time, I'd like to focus on raw materials. When you review the list of raw materials in your company, you'll notice a strong dependency on suppliers, producers, importers, growers, harvests, and so forth. Various variations can have a significant impact on your process and your final product, sometimes without your knowledge or notice. There is only one way to reduce these variations, and that is by gaining knowledge about the raw material and its influence on the process and product. Without this knowledge, you are at the mercy of the supplier's expertise, which can make your position highly dependent. This dependence arises from both the unknown variations and your ability to differentiate yourself. The more complex the composition of the raw materials, the more dependent you become.
Your raw material suppliers make the raw materials more complex as they increasingly create mixtures of raw materials to provide you with convenience. These mixtures often serve to compensate for a lack of knowledge about the raw materials. However, relying solely on the supplier diminishes your ability to differentiate yourself from competitors who source from the same supplier, both nationally and internationally. If your company operates on a national and international scale, being distinctive is an absolute necessity.
In many companies, it is still common for the director to personally handle the procurement of raw materials such as flour, fats, fillings, coconut, and similar items. There is nothing inherently wrong with this, provided that purchases adhere to strict standards. It's understandable that you aim to pay the lowest possible purchase price, as you are often subjected to scrutiny by your customers' procurement teams. However, I frequently encounter situations where standards are not firmly established, leading to purchases based solely on price or flexible use of standards when prices are enticing. I want to emphasize once again that setting standards for raw materials is imperative. These standards should be comprehensive, especially in terms of legal and functional aspects.
By this, I mean the requirements set forth by the legislator concerning preparation aspects and food safety. You are undoubtedly aware that the government is increasingly vigilant about food and its preparation. Additionally, consumers are being better protected by the government, as exemplified by the Food Safety Act (HACCP). The Commodities Act specifically names a large number of raw materials, including the Flour Decree, Bread Decree, Cocoa and Chocolate Decree, and so on. These laws outline the minimum requirements that a product or raw material must meet. These requirements pertain to the origin of the raw material, storage, processing, the state in which it must be presented to processors, microbiological conditions, packaging, labeling, and more. Suppliers have long been obligated and accustomed to complying with these conditions, but some level of oversight remains necessary. Consider aspects such as salmonella levels in eggs, aflatoxin levels in peanuts, and peroxide levels in fats. Even if your supplier provides a certificate for every batch, it's still your responsibility to periodically verify the batches through random checks. Include this in your quality control program for your laboratory, whether it's internal or external.
The requirements imposed by HACCP compliance are much more recent. HACCP represents a significant upgrade of your products and processes in terms of food safety and contributes to clarity. In essence, the law states that you must purchase and produce in a way that ensures raw materials remain free from and uncontaminated by foreign substances. This is quite different from what was accepted in the past. When we talk about the food safety of raw materials, the presence of foreign substances was once tolerated to some extent. For instance, we used to say that a maximum of 5 pebbles per pallet of raisins was acceptable. Now, not a single pebble is allowed. The question then arises: how can this be achieved? You might say the law demands the impossible. However, that's not the case. Subjecting a batch of raisins to strict inspection won't make them entirely free of pebbles.
The only way to guarantee raisins free of pebbles is to source them from a supplier who has taken all necessary precautions to prevent pebbles from entering the product. The importer of Turkish raisins, for example, would need to go to Turkey and examine on-site how pebbles find their way into raisins and how this can be prevented. You and I both know that pebbles don't grow on grapevines; they end up in raisins during the drying process on the ground, and so on. Your supplier must import your raisins from a producer who cultivates, harvests, dries, and packages grapes according to HACCP standards. It's not impossible. The same principle applies to many other raw materials from abroad that have traditionally been prepared in a relatively straightforward manner.
Think of cocoa beans, coffee beans, coconut, hazelnuts, and so forth. The legislator requires you to address the issue, and the only effective way to do so is at the source. Prevention is better and ultimately more cost-effective.
The functional standards for raw materials are more intricate than the legal ones. Functional refers to the requirements imposed on a raw material to fulfill its role in the process and final product. These standards are essential for a smooth process and a high-quality product. Let's take, for example, the functional requirements of flour for baking a cake. I set the requirement for the flour to be capable of creating a good batter, producing a cake with desirable characteristics, and yielding a high-quality cake. But what do I mean by "good"? By good, I mean in line with the demands and preferences of both the preparer and the consumer. Therefore, it is necessary to determine the consumer's requirements for cake. This requires an understanding of consumer preferences and research. So, it's not the preparer, the cake producer, who determines how the cake should look, feel, be tender, or have shelf life, but rather the end user. You might think this goes without saying, but I believe it's worth emphasizing. Traditionally, bakers and producers have been accustomed to determining product quality because they are the experts, right? The consumer's role is merely to consume the product. However, that era has definitively passed. Determining quality has become a collaboration between the consumer and the expert. The expert asks the consumer how they like their cake, and the expert uses their craftsmanship to create such a cake. The expert doesn't ask the consumer how they think the cake should be made, but rather how the end result should be. So, as a cake producer, you conduct a survey with 50 consumers and ask the following questions:
- · How do you find the appearance?
- · How do you rate the color?
- · How does the cake feel?
- · How do you find the tenderness?
- · How is the cake to eat?
- · How does the cake taste?
- · What is your overall assessment?
- · What do you consider the most important aspects of cake?
You then assign values to the answers, for example, appearance, tenderness, and taste are the most important aspects according to consumers. You multiply those by three, the less important aspects by two, and the others by one. This provides you with a value-based assessment, and you set the standards for your end product. Your task is to derive the conditions for the process and raw materials based on those standards. To standardize the quality of cake flour based on functional requirements, you need to consider all factors that play a role.
There are two common methods for preparing cake: the cold method, where fat and sugar are creamed together and then eggs and flour are added, and the hot method or the "all-in" method, where eggs, sugar, and flour are beaten together with an emulsifier, and fat is added last. The cold method has largely replaced the hot method because it results in a more tender cake. Once you know the product and process requirements for your cake, you can begin to establish norms.
Example Cake Flour Standards
1. Protein Content: < 10%
2. Protein Quality: Zeleny Value 30 – 35 ml
3. Starch Gelatinization Characteristics: Amylogram 800 – 1000 BE
4. Ash Content: 0,40
5. Hagberg Falling Number: 300 sec.
6. Moisture Absorption: max. 55.0
What Do These Data Mean?
1. The protein content for this type of cake should not be too high, as excessive gluten influence on the batter can occur. This leads to excessive moisture binding by the flour proteins, causing the emulsion (fat + liquid) to break too much and reducing the workability of the batter. In practice, the protein content typically falls between 8 and 9%.
2. Protein quality is a complex concept in bakery circles. Let me try to explain what I mean. Flour proteins are mostly composed of gluten, as you know. These gluten can be further divided into glutenin and gliadin. According to the old theory, wheat varieties with more glutenin are suitable for bread, crusts, and the like, while those with more gliadin are best for cookies, biscuits, and cake, etc. Research has shown that the differences in glutenin and gliadin content are negligible, but the quality of glutenin determines the quality of the flour. I will delve further into these differences in one of the upcoming contributions. In any case, it has been established that the longer the chain length (molecular weight) of glutenin, the more stable the flour. Therefore, cake flour is preferably made from wheat varieties with a relatively high content of high-quality glutenin. Because the protein content should not be too high, cake flour is often milled in a special way, namely, using the air-sifting method, which removes some of the protein and leaves behind flour with a protein content between 8 and 9% and an increased starch content.
3. The flour I described above usually has a well-stabilized amylogram, around 1000 BU. The amylogram provides insight into the starch gelatinization when heated with water. The higher the number (Brabender Units), the more intensive the gelatinization. For cake, good gelatinization is crucial for proper heat setting.
4. The falling number provides an indication of the enzyme activity of the flour. The higher the number, the longer it took for the plunger to move from top to bottom, indicating less enzyme activity.
5. Moisture absorption is self-explanatory: the degree of moisture binding in the flour is mainly determined by the percentage of damaged starch in the flour. Therefore, cake flour is usually milled from soft wheat.
6. You should carefully document and discuss all standards with your supplier. These figures must be determined and provided for each batch of flour that is milled. The supplier must select their wheat varieties and process in a way that allows them to meet these standards. To achieve a good and stable final product, you can no longer simply purchase any flour from any supplier. You must know what you need and ensure that your supplier consistently provides it with each shipment. This is known as co-makership.
Flour: The Key Ingredient in Bakery
When we talk about flour in the bakery, we mainly refer to wheat flour, although rye flour is also well-known for specific products like gingerbread, but this article is not about that. Wheat flour is the primary ingredient in bakery production because it is a unique raw material. The unique characteristics of wheat are based on the specific action of wheat proteins, specifically gluten. In this article, I'd like to delve a bit more into these gluten proteins, as it's crucial to stay informed about the latest developments in this field. Much research is being conducted on the specific properties of wheat gluten because they play a crucial role in structuring bakery products. While most research is focused on bread-like products, we can also use this knowledge to gain insights into how wheat flour works in other bakery products. It's worth noting that despite significant advancements in grain chemistry and rheology, our understanding of gluten formation and structure remains somewhat limited, as noted by Amend et al. (1).
The Mechanism of Flour Protein
In 1936, Sullivan et al. (2) were among the first researchers to publish their findings on wheat protein in Cereal Chemistry. They had isolated a sulfur-containing compound in wheat gluten and showed that specific wheat proteins contained these sulfur groups. The presence of these sulfur groups imparts specific properties to the protein. Later, it was discovered that these sulfur groups can be categorized into two types: sulfhydryl and disulfide bonds. Sulfhydryl groups, also known as thiol groups, are represented in chemistry as SH. The amino acid cysteine, which contains an SH group, can be easily converted to cystine through oxidation. The same can happen with cysteine in a protein chain, creating a disulfide bond between two protein chains. Thus, theoretically, proteins in wheat flour containing SH groups can be oxidized into disulfide bonds, forming larger complexes. This oxidation can be accelerated, for instance, by adding oxidative flour improvers.
Pyler's book (3) provides an initial schematic representation of disulfide bond reduction and thiol group oxidation into new disulfide bonds (Figure 1). Graveland et al. (4) propose that gluten quality is inherently linked to gas-retaining capacity. Therefore, wheat flour is of fundamental importance to the bakery. However, the big question remains: why do gluten proteins have these unique characteristics, and how can we explain the differences between one wheat flour and another? Wheat gluten can be divided into two groups: glutenin and gliadin. Both are insoluble in water; gliadins are soluble in an alcohol-water mixture, while glutenins are not.
Graveland in a 1985 publication, introduced a model for glutenin polymers. They identified two key groups:
1. High molecular weight glutenin sub-units, which are highly hydrophobic and do not absorb water.
2. Low molecular weight sub-units that have water-binding capacity.
Glutenins are responsible for the elastic properties of gluten, while gliadins are responsible for its viscous properties. Graveland describes in a recent publication (5) a separation method to elucidate the elastic properties of different wheat varieties. In addition to separating gliadins and glutenins, he further divides glutenins into three fractions: I, II, and III. Fraction I, the largest of the three, mainly consists of high molecular weight glutenin with a small portion of low molecular weight. Fraction III consists exclusively of low molecular weight protein, and Fraction II contains both. Studies examining glutenin with Transmission Electron Microscopy (TEM) have shown that glutenin consists of aggregates of various sizes.
The main differences in the structure of glutenin among different flour types are:
1. The compactness of protein aggregates.
2. The size of protein aggregates.
3. Molecular structure.
Crucial for the viscoelastic properties of dough is the size of these protein aggregates. During dough kneading, glutenin chains will disaggregate (break apart), and during dough rest, they will reassociate (re-form). The speed of disaggregation and the extent of reassociation are essential quality characteristics of gluten. Weak flour, for example, experiences rapid glutenin breakdown with little or no reassociation, while strong flour has a slow breakdown. Each flour type has its own characteristic behavior. Graveland's schematic overview (4) of the mechanism of glutenin disaggregation and reassociation visualizes this process (Figure 1: different arrangements of glutenin aggregates). From a top view, you can observe how the clustered glutenin aggregates disintegrate into individual polymers (disaggregation), which have a highly compact structure. These polymers then unfold into extended chains during further processing, such as rolling and puffing. During dough rest, these unfolded protein polymers reassemble into a network. It is this network formation that is crucial for various factors like gas retention in bread dough and leavening in puff pastry. The speed and extent of these reactions depend on the quality of wheat flour.
What Do We Do with This Knowledge?
It is the responsibility of technology to ensure that the knowledge gained from chemical grain research is applied for everyday practical purposes. Therefore, it is of great importance to attempt to interpret research data. Because, in addition to various types of wheat varieties and flours, there are numerous application areas that require significantly different qualities and quantities of glutenin. Despite extensive research in this area, there are still many gaps in our understanding waiting to be filled.
It is helpful to categorize bakery products into several groups to gain a better understanding of the specific processes and the corresponding flour quality:
1. Doughs based on flour and water where gluten development through kneading is essential (yeast doughs, French crust doughs, etc.).
2. Doughs based on fat, sugar, and flour where no gluten development should occur during mixing (pastry dough, shortcrust dough, etc.).
3. Other doughs and batters where varying levels of gluten development are desired (sponge cakes, regular cakes, waffles, choux pastry, etc.).
Yeast and Crust Doughs
In all flour research, bread dough serves as a model for optimal flour. We refer to fully developed dough here, where gluten forms a network of large glutenin aggregates. Graveland (4) describes this model as follows: gliadins are either bound to the surface of glutenin aggregates or occupy the open spaces in between. Gliadins act as plasticizers through intermolecular interactions with glutenin aggregates. Adding extra gliadin to bread dough reduces the number of interactions and results in a more elastic or stiff dough.
Reconstructing dough experiments has revealed that the quality of gluten indicating the viscoelastic properties of bread dough is primarily determined by:
1. The ratio of gliadins to glutenins.
2. The size and structure of glutenin chains.
3. The conversion/alteration capacity of glutenin chains during the process (reducing power).
For yeast and crust doughs, one cannot simply choose any flour; a good understanding of the process is essential. It is possible to create a tailor-made flour for short, medium, and long processes, but it's essentially impossible to make a universal flour for all applications. For yeast and crust doughs, you need a flour that can provide well-developed dough, meaning it should contain a substantial amount of large glutenin I chains. Depending on the process and resting times, you should consider the rate of protein breakdown and development, which relates to its reducing and oxidizing capacity (redox reaction). If you use a retarded fermentation system for bread production, the redox reaction should be slower compared to continuous mixing, rising, and baking. The same principle applies to companies using the French method for crust dough.
If you have an automated production line, consider:
1. The duration and intensity of the processing line.
2. Whether the dough is immediately processed on the production line.
3. Whether the product is baked immediately or frozen as dough, and so on.
For compact crust dough lines with immediate baking, you'll need flour that contains the right glutenin but not in excessive quantities, with sufficient reducing power (glutathione) for a rapid conversion. On the other hand, for frozen crusts, you'll require flour with a higher protein content, abundant glutenin I, and relatively low reducing power.
Baking Molds and Extrusion/Cutting Dough
Traditionally, soft wheat has been used to make pastry flour. The traditional Zeeland flour was made from soft wheat that grew in a coastal climate. However, much has changed in recent decades. Firstly, the variety of wheat has completely changed, and the need for quality consistency in industrial bakeries has increased significantly. Additionally, our knowledge has expanded. Concerning the latter, we can broadly outline the requirements for modern pastry flour. Soft wheat remains a requirement for making good pastry flour because it results in low starch damage. Damaged starch is the primary cause of moisture binding in the dough, and moisture binding by flour in pastry dough should be limited. Since we now have a better understanding of the nature of gliadin during processing, specifically its rapid water absorption, the old theory that Zeeland flour should contain more gliadin is no longer valid. Because for these doughs, the less moisture binding, the better.
Regarding glutenin, as we mentioned earlier, longer chains, meaning more molecules bound together (referred to as molecular weight), result in slower moisture binding. Based on this theory, we conclude that good pastry flour should be made from soft wheat, contain not too much protein (approximately 10% of the flour), and not too many low-molecular-weight glutenin chains.
Other Doughs and Batters
Regarding biscuit flour, it's worth noting that there is, of course, a significant difference between biscuits. Pastry biscuit has a completely different dough composition and somewhat resembles a short and dry cookie dough. The biscuit that is cut out from a sheet requires an entirely different dough. Here, we can distinguish between the warm and cold dough methods. In any case, the choice of flour is crucial, and it should also be made from soft wheat with minimal starch damage, contain a limited amount of total protein (around 10-11% of the flour), have high-quality protein (a high content of glutenin I), and a fairly active reducing capacity.
In a good collaboration between flour producer and consumer, the above requirements should increasingly take the form of standards. Currently, millers strive to deliver as consistent flour as possible through the blending of related wheat varieties. As we become better at determining the desired gluten quality for each product, I believe the demand for more variety-specific flour types will grow. The interaction will then become increasingly tripartite, involving breeders, flour producers, and consumers. I see great potential in this development as it establishes an important link between flour quality and processing properties of bakery products.