Making bread from something other than wheat flour enjoys a long history of success. In the past, bakers commonly blended wheat with a mixture of nonwheat flours. The peasant breads of Medieval Europe often contained barley, rye, oats and even ground chestnuts, while the more refined wheat flours were the preserve of the rich or the miller.
With time and the plentiful supply of wheat, most consumers converted to eating breads made with white flours.
That is until the health benefits associated with whole-wheat and multigrain breads were realized, and so began the current trend to include grains and flours other than wheat.
So what are the benefits of using nonwheat cereals? What are the potential applications, and most importantly, what are the technical challenges that bakers face? Among the benefits of using nonwheat flours are:
•Nutritional improvements by complementing the proteins contributed by wheat.
•Inclusion of fiber in forms that may be more acceptable to consumers than the addition of wheat bran.
•Introduction of different flavors, textures and even color into baked products. •Technological benefits from “natural” sources of raw materials.
There are a number of traditional applications for nonwheat flours in baking such as the use of ground almonds in frangipane tarts, but today, we see most of their use in the manufacture of bread and fermented products.
There is a wide scope for innovation and new product development, but first, we must appreciate the full contribution of nonwheat flours, if products are to be successful in the market place.
A CHOICE OF SOURCES
Soya. Bakers are most familiar with the use of soya (soy) flour in breadmaking. The addition of soya flour brings benefits of increased dough water absorption, increased mixing tolerance, changes to dough rheology, increased product volume, improvements to crust appearance and crumb softness and extension of sensory shelf-life.
Perhaps the best known effect of adding soya flour is to improve crumb brightness. This occurs through the action of the lipoxygenase present in enzyme-active soya flour on the betacarotene flour pigments. There is also some oxidizing effect on the linoleic acid in the flour lipid. And in the presence of oxygen, this is responsible for the changes in dough rheology. The enzyme-inactive form of soya flour has been used as a moisture-retaining aid in cakemaking.
Soya flour has been commonly used as the main ingredient of bread improvers contributing levels of up to 2% of the flour weight in the recipe. Higher levels (up to 40%) may be used to create special bread and biscuit products where the combination of wheat and flour proteins provides a good nutritional balance.
Rye and triticale. There is a long tradition of manufacturing baked products, especially bread, using rye and more recently triticale (the wheat- rye cross). In Germany and the US, rye breads are common and long established. The lack of significant glutenforming properties and the predisposition to high levels of alpha-amylase and other enzymatic activity have resulted in the development of specialized preparation methods, one of which comprises scalding the rye flour as a pretreatment before use. Enzymatic activity may also be limited by using fermentation to lower pH and develop a rye sour.
Dried rye sours are becoming a more popular way of adding flavor to white and whole-wheat breads without the need for extended periods of fermentation before dough makeup. Rye has a high pentosan content and this increases dough viscosity in breadmaking.
Barley. The traditional role for barley flours in breadmaking has been to use a malted grain flour to provide diastatic enzyme activity. The suite of enzymes present helps improve dough rheology, but most importantly, the amylase enzymes present react with the damaged starch in wheat flour to yield maltose sugar that can be used by the yeast to generate carbon dioxide gas. The cereal amylase enzymes present in malted barley products also contribute to the gas retention properties of the dough that in turn increase bread volume and improve crumb softness.
Malted barley flours have largely been replaced with fungal and bacterial sources of amylase. Some specialty breads — malt loaves — contain sufficient malted barley flour to give them a rich, dark brown color, maltysweet flavor and sticky crumb.
Historically, un-malted barley flour was a common addition to wheat flour to make bread, and more recently, interest has again been generated in using such flours. This interest arises because of the presence of beta-glucan (a soluble fiber) in barley flour and its potential health benefits. One example of such barley-based products is Sustagrain Barley from ConAgra Mills, Omaha, NE, with “dietary fiber making up more than 50% of its carbohydrates and 40% of that in the form of cholesterol-lowering soluble fiber.” Sustagrain Barley can be used in products as diverse as breads, hot cereals, pasta and tortillas.
Oats. The cereal most often seen a key source of beta-glucan is oats. Like barley, until recently, oats were seen as an adulterant to flour, a source of specialist human food (for example, porridge) or feed for animals, but now oat flour is being added to bread to increase soluble fiber.
Oats have a distinctive taste that normally would have limited their use, but the addition of oat flour to bread for sandwiches has become very popular in the UK. Interestingly, sandwiches made with two slices of Pullman-style bread and cut diagonally to yield two triangular-shaped halves come under UK legislation covering products not made for immediate sale and requires them to be held at 5 to 8°C (41 to 46°F). At this temperature, bread staling proceeds at its fastest rate, but more importantly, if the sandwich is eaten cold, then white bread tends to lack flavor. The addition of oat flour improves the flavor profile of the product at these low temperatures. Malted barley flours have also become a flavor-enhancing addition to such sandwiches.
Maize (corn). Maize is not a grain that we would normally associate with mainstream breadmaking, but new uses are being found for this ancient cereal. It is readily recognized that increasing fiber consumption is good for all of us, and while whole-wheat and multigrain breads are readily available , market research shows that such products lack appeal for kids.
The latest innovations for fiberenriched breads are to use white or “invisible” fibers so that the bread still appears white and appeals to young- sters. One of the earliest attempts to deliver such “white” fiber-enriched product was based on the use of pea fiber flour. New products have been developed based on wheat fractions being added back to white flour, but more recently, the addition of maize starch has been finding success.
Hi-maize 260 from National Starch Food Innovation, Bridgewater, NJ, is an easy-to-use fiber suitable for adding to bread. It is also referred to as “resistant starch” because of its slower absorption in the digestive system. So its use offers opportunities for the development of low-GI (glycemic index) products and the delivery of prebiotic properties. Breads made with Hi-maize are now reaching grocery store shelves and consumers’ homes in many parts of the world.
Additions of maize flour are also useful in the manufacture of sweet pastes for fruit pies. In this product, the maize flour contributes to the textural characteristics of the finished product, giving a “golden” color to the paste and “shorter” eating qualities. The latter probably comes from the dilution of the wheat flour and disruption of its gluten-forming properties. This effect of maize flour is particularly useful in the manufacture of sweet pastes with lower fat levels and helps in the machinability of such pastes. While sweet pastes are not normally seen as a vehicle for delivering healthier baked products, there may be opportunities to make a small contribution to reducing the caloric value of fruit pies.
“Ancient” grains. A spin-off from the organic grains movement has been greater interest in the ancestors of modern wheats, in part because of their perceived health benefits as “natural” sources of vitamins and essential minerals. Grains such as spelt and Kamut are attracting increased interest. Spelt was popular in Roman times and Medieval Europe, and today , spelt bread has a growing following among consumers.
Another developing market is for products based on Kamut (pronounced ke-moot), which gets its name from an early Egyptian term for grain. Kamut is an ancient relative of modern durum wheat but with about twice the kernel size. The combination of ancient grains and organic products is set to become a powerful trend in the marketplace.
The manufacture of wheat- and gluten -free products is one area where nonwheat flours clearly come into their own. This is a specialty sector of bakery products, but one that continues to expand. The range of available products also is increasing as manufacturers learn more about the special properties of nonwheat flour.
Gluten-free breads have been known for many years and are based on wheat starch, but increasingly, other cereal flours are being used for such products. The successful manufacture of gluten-free breads relies on the manufacture of a “batter” rather than a dough, and in this context, the gelling properties of the starch become critical in forming the required product. Each of the nonwheat starches has unique gelling properties and gelatinization characteristics. So it has become common practice to make gluten-free breads and other products with a mixture of different flours and starches in the recipe. Examples of gluten-free products may include rice, maize, potato and even sorghum, millet and cassava flours.
The potential for exploiting nonwheat flours in baking has been known for some time, but marketed relatively little. Increasingly, as new products are sought, often based on the need for a “healthier” or “natural” image, the potential for nonwheat flours is being closely examined. A number of examples have been described above, but greater opportunities await a fuller understanding of nonwheat flour properties.
The main areas with potential for nonwheat flours may be as a source for “natural” enzymes such as lipase from oats and gelling agents because of the starch properties. In some cases, it may the soluble and insoluble fiber components that attract attention.
Along with the current focus on whole grains is an interest in adding many forms of seeds, sometimes whole and sometimes crushed or flaked. However, to exploit some of the potential for nonwheat grains, it may be necessary to consider using a fractionated material rather than the whole flour. Just as with wheat, some of the special components of nonwheat grains are concentrated in one or more parts of the material. Refinements in existing milling techniques or using alternative fractionation techniques will be required to aid the necessary extraction or concentration of some of the special components of nonwheat grains. This approach has been successful in the development of soya protein isolates and functional soya protein concentrates.
Our perception of nonwheat flours is about to undergo a transformation. For many years, they were viewed them as adulterants or poor substitutes for wheat flour. In many parts of the world, nonwheat flours were seen as a means for using indigenous grain to limit the importation of expensive wheat into poorer countries. However, the more we study these other grains, the more we begin to appreciate the special properties that they might bring to baked products.
Perhaps our ancestors appreciated more of those special properties, and it is only our modern view that sees nonwheat flours as the poor alternative to the “real thing” — wheat flour.
In 2004, Stanley P. Cauvain, Ph.D., and Linda S. Young, Ph.D., formed BakeTran, High Wycombe, UK, for which they are, respectively, vice-president of R&D activities and vice-president of systemization and training. Both have distinguished careers, most recently at the UK’s Campden & Chorleywood Food Research Association (CCFRA).
Drs. Cauvain and Young are frequent speakers at industry meetings and have between them 65 years of baking industry experience. Dr. Cauvain is the immediate past president of the International Association for Cereal Science and Technology (ICC). BakeTran is an independent, international consultancy providing support to milling and baking companies with new product development and innovation, quality optimization, training and knowledge systemization.