Enhancing Yogurt with Healthful Fiber From Oats

Small amounts of beta-glucan, a fiber-rich component of oats, can be added to low-fat yogurt without noticeably affecting the texture or other key characteristics of this increasingly popular dairy food, U.S. Department of Agriculture (USDA) researchers have shown.

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.

Agricultural Research Service (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.

The scientists' 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, or its color, pH, or fermentation time, for example.

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 percent purified oat beta-glucan to low-fat yogurt mix.

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.

The team determined that up to 0.3 percent highly purified (95 percent 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 percent or higher changed the yogurt's color, contributed to unwanted hardening, and slowed fermentation.

The 0.3 percent 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.

Researchers Singh, Kim, and Sean X. Liu, a research leader at the Peoria center, reported their findings in a peer-reviewed scientific article published in 2012 in the Journal of Food Science.

Read more about this research in the March 2013 issue of Agricultural Research magazine.

ARS is USDA's principal intramural scientific research agency.