It is known that the Eatwell Plate is a visual guide to identifying the different food groups included in the diet of the average person. In Mexico, it is classified into three groups:

• Cereals
• Fruits and Vegetables
• Legumes and Animal Origin Foods

Out of these three, cereals tend to be associated with the intake of simple carbohydrates. Not-withstanding, complex carbohydrates are also considered–these are formed with sugar molecules which, together, form long chains. Whole grains are an example.

What Is the Difference Between Whole Grains and Refined Flours?

Each country has its own regulations and definitions on what whole grains are. The Whole Grain Council–institution dedicated to helping consumers find foods containing whole grains and understand their benefits–has agreed that “Whole grains or foods made from them contain all the essential parts and naturally-occurring nutrients of the entire grain seed in their original proportions. If the grain has been processed (e.g., cracked, crushed, rolled, extruded, and/or cooked), the food product should deliver the same rich balance of nutrients that are found in the original grain seed.”

In other words, a whole grain is one which keeps a natural relation between bran, germ, and endosperm in practically the same ratio after being processed. This includes baking and confectionery products, as well as ingredients used in other manufacturing processes. Regarding baking products, the most commonly used grains are wheat, rice, oats, and rye. The type of flour used has a direct impact on texture, flavor, and appearance of end products. Differences between products made with whole grains and refined flours is evident.

Most cereals grinded to get flour reduce in about forty-five per cent grain proteins since they get rid of the pericarp–the outer part of the seed–, also known as bran. This loss reduces in about eighty per cent the presence of fiber and other micronutrients like vitamins, minerals, and phytochemicals. This explains why products made with refined flours need to be fortified or enriched.

Consequently, the intake of whole grain cereals improves some metabolic functions of the body thanks to the contribution of their components. 

What Is Found in Whole Grains?

Fiber

Soluble and insoluble fibers slow digestion down and contribute–along with polyphenols–to a good health of the gut microbiota, positively stimulating the immune system. In the last decades, their effect on cellular protection has been proven as they reduce the damaged caused by free radicals.

The presence of fiber and its relationship with starch and proteins has been linked to differences in the speed with which products produced with whole grain cereals are digested, regulating insulin release and making glucose absorption more efficient.

Starch

The endosperm of a grain is mainly made up of starch and proteins. Starch, aside from being a source of energy, adds texture to baking products. In products manufactured with refined flours, the feeling of satiety can be regulated when combined with foods rich in proteins and lipids.

Proteins

Regarding protein content, those found in a greater proportion are prolamins. Prolamins found in rice are called oryzenin; in corn, zein; in oats, avenin; in the group of wheat grains, glutenin. A great part of the sensory properties of baking products are a direct result of the proteins contained in flour.

Wheat in Our Diet

From all the different cereals, wheat has historically been the basic ingredient for baking products given that wheat flour provides fermented products with unique characteristics–once hydrated with glutenin and gliadin, which make up gluten (wheat protein). Glutenin and gliadin are responsible for the volume, softness and texture of bread, as well as the flexibility of doughs. 

Since refined grain flours, also known as white flours, contain a higher percentage of endosperm, sensory qualities are accented in bread made with them compared to those produced with whole wheat or whole grain flours.

Starch present in wheat flour provides viscoelastic properties during the baking process, giving the product a fluffy texture with unique traits easily observed in the crumb. Germ has great nutritious importance due to the vitamins, minerals, proteins, phytochemicals, and antioxidants it provides.

The intake of whole grains helps regulate the antioxidant defense system, which protects against infections and improves anti-inflammatory functions. Phenolic compounds, mostly antioxidants, are present in whole grain cereals and bakery products. However, the presence of said compounds hinders or reduces mineral absorption.

White bread is part of the basic food basket in Mexico, and it is produced using wheat flour fortified with vitamins and minerals–it is a source of energy. White bread is also an important element in a healthy diet since it contains complex carbohydrates (71 kcal/slice). Eaten in proper portions, it contributes to meeting the energy needs in an intermediate glycemic load.

Consequently, refined wheat flours are an important source of energy from carbohydrates and proteins which, together with vitamins and minerals reintegrated in the process, are part of the essential nutrients for a proper physical, mental, and cognitive growth of those who eat them.  

Consumers are increasingly attracted to healthy products with better taste. In bread making, whole grains and seeds are ideal to meet both expectations. New technologies try to combine a wide array of grains and seeds which potentiate sensory and nutrition properties of products.

Food processing gives products a longer shelf life, which translates into more profitable processes as it happens with transformation in fermentation.

Processed foods are a good alternative to contribute to public health and compensate for vitamin and mineral deficiencies, such is the case of fortified flours byproducts or with added soluble or insoluble fiber that provide nutritional advantages to the consumer. In addition, prepackaged processed foods offer information that make possible for consumers to select the products that best adjust to their health conditions and preferences.

One of the main reasons why the baking industry uses refined flours in their recipes is to increase flour shelf life, since flours made with whole grains last less because they tend to stale more easily. 

In terms of energy contribution, simple carbohydrates have traditionally been the cheapest and most abundant source of energy. On the other hand, diets rich in fiber increase satiety sensation, which can lead to weight loss due to the fermentation process that takes place in the digestive system.

The United States Department of Agriculture (USDA) claims that–in order to reduce the chances of suffering non-communicable diseases such as cardiovascular diseases, obesity and diabetes–at least three food portions consumed should be cereal-based, what amounts to 48 g/day.

The challenges food processing faces to get sensory and nutritional benefits from flours have to do with using technology to develop products with a better nutritional balance. Still, the choice and control in the consumption of foods made with cereals (whether whole grain or refined flours) should take place under supervision of health experts to make sure these foods are correctly integrated to people’s diets.

Reference List

Arvola, A., Lähteenmäki, L., Dean, M., Vassallo, M., Winkelmann, M., Claupein, E., Saba, A., & Shepherd, R. (2007). Consumers’ beliefs about whole and refined grain products in the UK, Italy and Finland. Journal of Cereal Science, 46(3), 197–206. https://doi.org/10.1016/j.jcs.2007.06.001

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