Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/25/1996
Publication Date: N/A
Interpretive Summary: The incorporation of products containing oats or oat bran into the diet can result in the lowering of serum cholesterol levels. A complex carbohydrate, called beta-glucan, appears to be responsible for this physiological, health-benefitting effect. Efforts to increase levels of beta-glucans in new cultivars of oats have been hampered by the complexity of the methods required to accurately measure this substance in experimental breeding lines of oat. We have found that the viscosity of oat flour and water slurries is related to the beta-glucan concentration of that flour. Because of this relationship, we have been able to estimate the beta-glucan concentration in different oat cultivars, simply by adding water to oat flour, and measuring the viscosity of the slurry with a rotational spindle-type viscometer, after a selected time period. We have also found that it is useful to steam-treat the grain before milling, because live grain contains enzymes that breakdown beta-glucans in water, and cause a degeneration of viscosity in slurries. This procedure may expedite the development of new oat cultivars with increased beta-glucan concentration and with enhanced health-benefitting properties.
Technical Abstract: The presence of beta-glucan from oat products in the human diet can lower serum cholesterol. The selection on new cultivars with higher beta-glucan concentration in the grain is usually limited by the efficiency of the analytical procedure required to measure this component. The relationship between beta-glucan concentration and flour slurry viscosity was investigated. Water was added to enzyme-inactivated oat flour to form a 23% dry matter mixture, and stirred to form a uniform slurry. Viscosity, as measured with a rotational spindle-type viscometer, increased hyperbolically with time. Viscosity measured three hours after water addition was exponentially dependent on flour content. Viscosity was linearly correlated with beta-glucan concentration in preliminary breeding lines of oat and barley. The procedure is effective with enzyme-inactivated (steam-treated) whole or dehulled grain, but the presence of endo-beta-glucanases in hulls of oats and barley prevent the application of this procedure with flours of raw whole oats and barleys.