Often a challenge
to work with, bran
healthful source of
Although bran occupies a tiny corner of baking ingredient use — especially in proportion to the main byproduct of grain milling — flour — it serves an important dietary and nutritional function. Grain's outer layer is rich in dietary fiber, with varying levels of starch, protein and minerals depending on the bran's source. Bran is present in any type of cereal grain, including wheat, corn, oats and rice, and helps provide a whole grain identity to commercial baked products, as well as possible health claims.
Wheat bran contains 50 percent to 80 percent of the minerals in grain, including iron, copper, zinc and magnesium, as well as protein, fiber, B vitamins and phytochemicals. Mineral content varies significantly because of variety, crop year, fertilizer and soil type.
The importance of dietary fiber
As a result of refined flour and changes in dietary habits, consumption of dietary fiber has decreased by at least one-half during the past two centuries. Various studies link fiber ingestion with low incidence of cardiovascular disease. In addition, fiber can reduce blood sugar levels for people with type 2 (adult onset) diabetes, promote good gastrointestinal health and decrease blood pressure in hypertensive individuals.
In regards to oat bran, the FDA's Title 21 of the Code of Federal Regulations (21 CFR 101.81) allows a health claim linking the consumption of soluble fiber from certain foods to a reduced risk of coronary heart disease. Other studies show rice bran produces hypercholesterolemic effects as well.
Nutritionally, bran is a good bet for inclusion in baked product formulations, however, various factors determine bran-type selection and usage levels. Wheat, oat, corn and rice bran offer formulators a choice in terms of flavor, texture and functionality, such as water absorption.
SunOpta Ingredients Group, Chelmsford, Mass., a division of SunOpta Inc., concentrates on healthful ingredients for the food industry, such as fiber and bran, including stabilized red wheat, corn and oat bran, notes Rajen Mehta, Ph.D., director of fiber applications. Bran varies in fiber level from 16 percent to 80 percent and adds sensory characteristics, such as soft or crunchy texture or “toasted” to mild whole grain flavor notes, depending on application and type of bran.
The first step in creating any customized bran or fiber-based food product is to consult with the client to discover the product focus and marketing goals, Mehta notes. Then, product developers balance the use of bran along with other fiber sources, such as oat or soy “to give the desired textural characteristics. A client might like wheat, but want to add a bit of softness to the product or extend shelf life, so we recommend the best combination of fiber sources for optimum product characteristics,” Mehta adds.
These fiber combinations are key. By using this method, the product developer controls the texture and other properties, such as mouthfeel, while maximizing the desired fiber content, Mehta notes. As fiber specialists, SunOpta has assisted in creating bread with 19 g of fiber per 50-g serving and in the case of tortilla chips, managed to get to 9 g per 28-g (1-oz.) serving size.
The company also offers six “families” of oat fibers with different textures and properties in four grind sizes ranging from 33 microns to 150 microns. The minimally washed, largest size 150-micron fiber provides the crunchiest texture.
Mehta warns there is no single “magic bullet” for adding fiber or using bran in a product. While bran carries an attractive price tag, it has to be balanced with other fibers and ingredients, such as emulsifiers, for proper texture and extended shelf life. A heart-healthy claim on the label needs a minimum of 0.75 g of beta glucan per serving from oat bran.
While bakers can use different bran inclusions across the spectrum of baked products, adding health-claim levels of beta-glucan from oat bran is a challenge, Mehta says. “It is very hard to formulate because beta-glucan is a very gummy material, so you have to balance the formula by using other ingredients.”
Stabilized bran is another primary consideration, Mehta notes. Stabilization eliminates or minimizes microbial and enzymatic activity and helps extend product shelf life while decreasing the negative flavor notes enzymes induce in substrates. “You have to consider the lipase and protease activity and their impact on the substrates,” Mehta says. “But people don't usually worry about that; they just know they're getting a low loaf volume or bitter or rancid notes and wondering why. Stabilization is the key.”
A rice alternative
One company in agreement with the importance of stabilized bran ingredients is Phoenix-based NutraCea, which markets rice bran. Although rice bran is a relative newcomer, it has successfully been incorporated into multi-grain bread mixes and tortillas. In addition to a mild flavor and other functional differences, rice bran offers a gluten-free alternative to other brans and fibers, helping improve the nutritional profile in a food category often challenged to offer whole grain nutrition.
Bran stabilization is key to NutraCea. “When you mill the kernel and disturb the layers, the lipase enzyme attacks the oil in the bran,” says Bruce Sloan, vice president of the western region for NutraCea. “With up to 20 percent oil in the bran, this can then turn rancid in 24 hours to 36 hours. We deactivate the enzyme while retaining the nutritional value of the rice bran.” This stabilization process offered by NutraCea produces a rice bran ingredient with a one-year shelf life in dry storage. Wheat bran shelf life is much shorter and can turn rancid in as little as three months.
Compared to wheat, corn and oats, the company can grind rice bran in such a way that it will not decrease loaf volume. A typical usage level is 5 percent to 8 percent per hundredweight. Rice bran takes up three times its weight in water. Other grain-based fiber might take up to 10 times its weight in water during mixing but often releases it during baking, thus affecting mouthfeel, texture, shelf life and product consistency, Sloan notes.
Rice bran is extremely high in magnesium and potassium and, similar to oat bran, can help control blood sugar and reduce cholesterol when consumed in the right amount.
Whether choosing rice, wheat, corn, oats or ancient grains, bran is an economical addition to baked products that can reap impressive dividends in terms of potential health claims and nutritional profile.