Beta-Glucan Boosts Nutritional Value of Low-Fat Yogurt

PEORIA, Ill.Adding about one-quarter teaspoon of beta-glucan, a fiber-rich component of oats, boosts the nutritional value of low-fat yogurt without noticeably affecting the taste or texture, according to research conducted by researchers at USDAs Agricultural Research Service (ARS). Oat fiber is of interest to foodmakers and nutritionists because studies with volunteers have indicated that it can lower serum cholesterol, which may help improve heart health.

ARS food technologist Mukti Singh, research chemist Sanghoon Kim and their colleagues have experimented with adding oat beta-glucan to what's known in the dairy industry as low-fat yogurt mix. The mix is made up of low-fat milk and a selection of common, safe-to-eat bacteria, such as Lactobacillus acidophilus or various Bifidobacterium species, that ferment the milk.

Their intent was to see how much fiber they could add without altering the texture, viscosity or other aspects of the microscopic structure of the yogurt, its color, pH or fermentation time, for example. The idea of adding edible fiber to yogurt isn't new. But in studies such as this, the scientists are providing some missing details about how using oat beta-glucan as a source of fiber affects yogurt-mix qualities important to foodmakers and yogurt fans alike.

In their experiments at the ARS National Center for Agricultural Utilization Research in Peoria, Ill., the team added either zero, 0.1, 0.2, 0.3, 0.4 or 0.5% purified oat beta-glucan to low-fat yogurt mix. The team determined that up to 0.3% highly purified (95% pure) oat beta-glucan, which translates to 0.3 grams of beta-glucan per 100 grams of yogurt mix, could be added without significantly altering key yogurt qualities. But adding 0.4% or higher changed the yogurt's color, contributed to unwanted hardening and slowed fermentation.

The 0.3% level of fortification totals out at 0.75 grams of fiber, or about one-quarter teaspoon per 8-ounce serving of yogurt. Most Americans don't get enough fiber, so even this small addition to a familiar dairy product helps.