Inulin and oligofructose (also known as fructooligosaccharide, or simply FOS) are soluble fiber ingredients that can be added to formulations often at very high levels, escaping detection by the consumer. Hence, they are known as invisible fibers.

Both are recognized prebiotic fibers, meaning they pass through the stomach and small intestine fully intact. Once they reach the colon, they are fermented by beneficial bacteria. This results in improved microflora, which enhances digestive health.

Found in numerous plants, including agave, beet, chicory root, garlic, Jerusalem artichoke and onion, these ingredients can vary in functionality based on origins and processing. They have become common additions to baked foods, often for reasons beyond fiber fortification.

For example, select inulin and FOS ingredients can improve bone health by increasing absorption of calcium and other minerals by humans, thus preventing chronic inflammatory intestinal disorders, according to Joseph O’Neill, president, BENEO, Inc., Morris Plains, NJ. “With a sweetness up to 65% that of sucrose, our oligofructose acts as a sugar replacer in some baked foods,” he said. “The gelling capacity of our inulin allows it to function as a fat replacer. Both contribute 1.5 Cal per g, which is much less than the ingredients they are replacing. Thus, a calorie reduction is possible, too.”

Sensus America, Inc., Lawrenceville, NJ, developed partially enzymatically hydrolyzed inulin syrup with 65% of the sweetness of sucrose. Functionally, it performs similar to high-fructose corn syrup and can replace the majority of sugars and some of the fats in many baked foods, according to Carl Volz, president. “This sweet liquid fiber ingredient is 75% fiber and 25% sugar and contains about 2 Cal per g,” he said. “It allows a reduction in calories, sugar and fat, and at the same time, it boosts fiber content.”

Mr. O’Neill noted prebiotic fibers such as inulin and oligofructose make it possible for bakers to take existing products and re-vitalize them, making the most of the opportunity to address the fiber gap.