Flavor in Processing

Northern countries like Finland, Canada, and Scotland have a long tradition of using oats in a variety of foods. Even in these countries, however, the consumption of oats is low in comparison with that of other cereals. Processing of oats is required to provide edible products that are stable in storage and have good sensory properties. Traditionally, oats are used as whole grains. The development of new ingredients, such as various milling fractions (i.e., bran, flour, and hulls) and enriched fractions (i.e., starch, protein, and b-glucan), started in the 1980s in response to accumulating evidence of the health benefits of oat dietary fiber. New functional oat foods conferring specific health benefits are needed to make the most of these nutritionally based assets of oats. Oats’ distinguishing features, in comparison with other cereal grains, are their high lipid and b-glucan concentrations and lower starch concentration. These features give rise to special challenges: lipid oxidation during storage and processing can cause rancid flavors, and the high viscosity of water-solubilized b-glucan—i.e., mixed-linkage (1→3)(1→4)-b-d-glucan—impacts texture and sensory characteristics. Oat starch is special in comparison with other cereal starches. It contains more lipids and has a lower gelatinization temperature and slower rate of retrogradation than cereal starches in general. Oat grain also contains dietary fibers other than bglucan, as well as vitamins, minerals, phenolic antioxidants, sterols, and proteins high in lysine (22,41). Appearance, odor, texture, and flavor are key attributes in determining the overall sensory characteristics of a food (Fig. 1). Since sensory quality is a crucial criterion in consumer food choice, control of sensory attributes is important to the attractiveness of new oat foods. Oats are considered by most people to make a tasty cereal, and they have a positive health image.