Oats: A Unique and Interesting Cereal

Oats: A Unique and Interesting Cereal

Oats are a very curious and interesting cereal. Yet, at least in Spain, they are not experiencing the success they could. As we will see, this cereal shares similarities with others, but it also has significant differences, both in composition and morphology, that make it very special.

Let’s start by highlighting that oats are a husked cereal, like barley or rice (there are also husked wheats, but these are less common). This means that in companies that process oats, specific machinery is required to remove the outer hull. And this hull has no application in human nutrition, so it must be destined for other uses. In fact, a Finnish company has developed bags based on this material. It is true that there are varieties of naked oats (without hull), but these are, at least for now, in the minority.

If we remove the hull, oats have a morphology similar to that of other winter cereals (wheat, barley, and rye), with a central groove, although slightly longer than these. And like these, it is a soft cereal, as opposed to the greater hardness of others like rice or corn.

Oats and Celiac Disease

This similarity with winter cereals has greatly harmed oats since it has been identified as a toxic cereal for celiac patients, or one that contains gluten for them. In this sense, there has been much controversy, and there are still many consumers who are wary of the presence of oats in gluten-free or celiac-friendly products. Nowadays, we know that oats can be consumed by celiac patients, but this history deserves reflection.

The relationship between celiac disease and oats has never been entirely clear, but in general, the idea that celiac patients should avoid it has been conveyed to the celiac community, in many cases as a precaution (just in case). Although there have been studies claiming that certain oat varieties were toxic to celiacs, and others that were not, it seems that there were errors in these researches, and there are no toxic varieties. The historical problem with oats seems to have been cross-contamination with gluten products. There is talk of a high risk of oat contamination with barley since both are husked cereals with a similar morphology. But we must also consider that many facilities that process oats also process gluten-containing cereals, and it is practically impossible not to have contamination between them. Thus, for example, in Spain, the three oat milling companies I know also process other cereals such as wheat or rye. Therefore, even if they start with gluten-free oats in their processes, the final product is not gluten-free.

The history of how oats have become established as a gluten-free cereal is also interesting. Despite the doubts that arose, a country like Finland, with a long tradition of oat consumption, decided to approve the use of oats for the development of gluten-free products, provided that cross-contamination was ensured to be absent (obviously after seriously evaluating this issue). In this country, many companies adapted to this situation, taking extreme care to avoid cross-contamination, analysing the possible presence of gluten, and specializing in these types of products. The reality is that there have been no more hospital admissions for celiac patients in Finland, and the range of gluten-free products has increased. Furthermore, the organoleptic quality of some of them has improved, for reasons we will analyse later. As it is good to learn from the experience of others, some countries, seeing the Finnish success, began to approve oats in gluten-free products. This was the case in Canada and the United Kingdom. And, subsequently, the expansion to other countries has been inevitable. Spain was not among the countries that quickly joined this trend, but nowadays, the presence of oats in products for celiacs is accepted. In Spain, in general, there has been a tendency to be very cautious and restrictive in this regard, which is understandable.

Although it is now clear that oats are suitable for celiacs, in Spain, today, we have two important problems for their inclusion in these types of products. Firstly, the absence of national gluten-free oat flours and flakes, as the facilities that process these oats do not guarantee the absence of cross-contamination and do not certify them as gluten-free. Secondly, the poor image that oats gained among the celiac community at the time, which is difficult to eliminate. As has happened in other cases, such as wheat starch, it is logical that some companies will gradually take the risk, and the presence of oats in these products will gradually become normalized. And as has already happened, the company that leads this path can gain an interesting brand image for the future, although for now, it also faces a significant challenge.

Fat and Processing

The main difference between oats and other cereals is the presence of a high lipid content in its endosperm. There are many other cereals that have lipids in their composition. In fact, commercial oils are obtained from the lipids present in corn or rice. The difference is that in these cereals, lipids are more localized in certain parts, such as the germ or bran, which are relatively easy to separate. However, in oats, a significant portion of the lipids is in the endosperm, that is, in the part of the grain from which flour is obtained. Therefore, if we were to mill oats like any other cereal, we would obtain a flour that would quickly become rancid since, in the process, these lipids come into contact with oxidative enzymes, such as lipooxygenases. To solve this problem, it is necessary for oats to undergo a thermal treatment before milling, in order to eliminate the presence of lipooxygenases. This enzymatic inactivation practice is also known as stabilization.

There are many valid thermal treatments to stabilize oats, but there are two that are the most used, for their versatility and practicality. The first is extrusion. Through extrusion, we can provide a thermal treatment, choosing the temperature and treatment times, and even incorporate water to also regulate this factor. But the problem with extrusion is that it does not mill the grain. Therefore, oats must be milled beforehand and processed quickly to avoid the risk of rancidity. The truth is that this treatment is not usual for stabilizing flours, but it can be used for the production of expanded products. In general, oats are stabilized with a hydrothermal treatment on the whole grain. This treatment usually involves heating with steam. With this type of treatment, in addition to inactivating lipooxygenases, we facilitate de-hulling and soften the grain, so it can pass to the rolling lines to obtain oat flakes. In fact, these flakes are one of the most well-known products obtained from oats. Once the flakes are obtained, they are milled to obtain wholemeal flour. If most of the bran is separated using sieves, we obtain white flour.

The case of oats and the commercialization of the products obtained is again curious, and different from that of other cereals. Due to the high demand for oat bran and wholemeal flour, white flour may be somewhat more difficult to market (without it being a serious problem). That is, the opposite of what happens with other cereals.

Oat Composition

The composition of oats is once again distinct from that of other cereals. As mentioned, oats have a high level of lipids compared to other cereals. However, oats also have a high level of proteins, the highest among cereals on average. Considering that carbohydrates, lipids, and proteins make up almost 100% of the dry weight of cereals, if oats have more lipids and proteins, they will necessarily have fewer carbohydrates (assuming similar moisture content).

Regarding proteins, it seems that they are somewhat better balanced than those in other cereals. However, it must be clear that cereals are not the best source of proteins with a good balance of amino acids. Although the differences between oats and other cereals are significant, oat proteins are still of lower quality (or have a poorer balance of amino acids) than some animal proteins, such as those from eggs or milk. Additionally, consuming oat products occasionally will not have a noticeable effect on our bodies. However, both its protein content and amino acid balance make it particularly interesting for the development of gluten-free products, as these are usually deficient in protein (although the celiac diet usually is not). In fact, gluten-free products are usually made with starches or flours from rice and corn, primarily, and many of them incorporate external proteins to compensate for these deficiencies.

The carbohydrates present in oats are also unique. In addition to containing them in smaller proportion, oats are characterized by containing a higher percentage of fibre than other cereals. And if we combine a lower percentage of carbohydrates with the fact that there is a higher percentage of fibre among them, it is clear that the starch content will be considerably lower than in other cereals. This fibre is not only concentrated in the outer layers, as is the case with other cereals, but also in the endosperm. Therefore, while the fibre content of the bran is much higher, in the case of oats, white flour also contains a significant percentage of fibre, more than in other cereals.

Although there are other fibres in its composition, the fibre par excellence of oats is beta-glucans. This type of fibre, which is also found in barley, is a soluble fibre with a high water absorption capacity and therefore a high thickening power. For these reasons, among others, its effectiveness has been demonstrated in reducing the glycaemic index, lowering cholesterol levels, helping to reduce constipation problems, or showing some effectiveness against certain types of cancer. In fact, beta-glucans, more or less purified, are marketed for their nutritional advantages. However, by consuming oats, we can naturally incorporate these fibres into our diet. But, as I always say, occasional consumption of oat-based products will hardly affect anything in our bodies.

The starch in oats is nothing extraordinary, despite what you may see discussed in this regard. It is true that if we have less starch, and furthermore, this is mixed with beta-glucans, which help reduce the glycaemic index, the glycaemic load of oats will be lower than that of other cereals. The lower presence of starch should also be taken into account in some preparations where starch plays an important role, and where if we substitute another type of flour for oat flour, a certain reformulation may be necessary.

Finally, I would like to talk about the presence of minerals and vitamins. Despite seeing messages in favour of oats based on these components, the differences between oats and other grains are not very significant. Obviously, oats will have slightly more of some minerals and slightly less of others than other cereals, especially wheat. It is true that the consumption of whole oats is much more frequent, for example, in the form of flakes, than that of other cereals. And here it is true that the content of minerals and vitamins is much higher. But not because it is oats, but because it is whole. I think we should be very clear about this.

Just as in the case of minerals and vitamins, you will hear about oat polyphenols or their antioxidant substances. And although in a detailed study there will obviously be differences from those of other cereals, the truth is that the main difference lies in whether we take them in their whole or refined form.

That said, it is true that in the case of gluten-free products, the incorporation of wholemeal flours is much more complex, since in the case of rice and corn, they require specific processing, and their availability is limited. Some producers incorporate wholemeal flours of buckwheat or other grains, such as quinoa, amaranth, teff, or toasted millet, but you will see that in most cases, this incorporation is minimal (more marketing than anything else) and they usually mix them with significant amounts of starches or white flours. This is logical, both because of the higher cost of these flours and because of their influence, usually negative, on the organoleptic quality of these breads. In this sense, oats can help us achieve whole products with a much more interesting nutritional composition. In addition to better organoleptic characteristics, something we will talk about.

Oats and Health

Oat consumption has always been associated with better health. In fact, in its beginnings, it was sold in pharmacies. All studies that have been carried out on oats, and the actions to obtain nutritional claims in certain countries, have been favoured by the fact that there are some companies in the world that have made oats the focus of their operations, and they have a fairly prominent position in the market. That said, it is true that oats have some important advantages. The first, as we have said, if taken in whole form, since as we have mentioned in other entries, we should all consume more whole products, and these have shown their effectiveness for many things, but to summarize, to reduce the risk of mortality. We already talked about this topic. This is especially important in the case of gluten-free products, where it is very difficult to obtain quality whole products.

And although you may see studies on different components of oats associated with health, what truly sets oats apart from other cereals is its content of beta-glucans. Beta-glucans are well studied, and their efficacy has been proven, as we have already mentioned, against cholesterol, glycaemic index, cardiovascular diseases, constipation, or certain types of cancer. In Europe, a health claim associating the consumption of oat beta-glucans with the reduction of cholesterol and the risk of coronary heart disease is approved. But as I always point out, the effectiveness of this depends on the consumption of this product, and the EFSA, which usually does a pretty good job, clearly indicates that to achieve a beneficial effect, the consumption of oat beta-glucans should be 3 g/day. Therefore, the occasional consumption of these products will hardly have an effect on our health.

Another important point about beta-glucans is their size. To put it simply, the larger the molecular weight of beta-glucans, the greater their water absorption capacity and thickening power, and the greater their beneficial effect on health. Fortunately, those present in oats have a high molecular weight compared to those from other sources, such as barley. But in oats, there are also beta-glucanases that hydrolyze beta-glucans and can reduce their beneficial effects on health. In this sense, in products consumed with rapid processing, and where these enzymes have barely had time to act, such as flakes consumed with milk for breakfast, or cookies, where there is usually no resting time in their processing, they will have their maximum potential. In others like bread, where a fermentation occurs in which enzymes can act, we must try to minimize the hydrolysis of beta-glucans. For this, fortunately, in the previous processing of the flour, to inactivate the lipoxigenases, an inactivation, at least partial, of these enzymes also occurs. If we know that the inactivation is complete, we can be calm, but if this is not the case, we can also help by reducing fermentation times. In these cases, the use of oat flour with the presence of beta-glucanases in sourdough could have negative effects, at least on these properties. Another practice that is highly regarded for its nutritional advantages, and which in this case would be negative, is germination. The reason is that this enhances the creation of beta-glucanases, which partly already act in the grain, depending on the germination time, and partly are available for subsequent action.

Oat Products

Currently, there are many oat products on the global market, and some of them are closely associated with certain brands. Let’s talk about some of them because they can serve as an example. But in general, it must be said that the organoleptic quality of products with oat flour is usually very high. On the one hand, it does not impart strange flavours, provided it has been processed correctly, nor excessive bitterness, as some gluten-free flours do, especially in their whole form. And on the other hand, the lipids present in its composition provide a certain juiciness. This has made it one of the most valued cereals for making plant-based milk substitutes. And after the rise of soy-based products, oat-based products, both milk-like and yogurt-like, are currently experiencing a great boom. An example of a flagship company of this type of product is Oatly. This Swedish company is making a great effort in R&D to capitalize on some of the benefits obtained with its flagship product to continue obtaining derivatives of oats with high added value. Additionally, it has achieved a youthful image closely linked to sustainability issues. Although less known, there are also yogurt-like products or ice creams based on these types of beverages.

But perhaps the most iconic product worldwide from oats is flakes. In this sense, the world leader is Quaker, which belongs to the Pepsico group. Today, there are many companies that produce oat flakes, but this one has achieved a brand image linked to this product in almost all parts of the world.

As for flours, in Spain, there are two main producers, Emilio Esteban and Harivenasa, but as we have said, neither certifies their flours as gluten-free. Similarly, the less known Noalles and Balanzá. Here I also leave links to some Finnish companies, which have more tradition, that produce gluten-free oat flours, such as 65 Oats or Helsinki Mills. The Irish company Glanbia also offers this type of products. In Finland, there are also companies that produce cookies, cakes, and gluten-free bread based on these oat flours.

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