Ideal ingredient calling card: Inulin

What it is

• A white, colorless polydisperse carbohydrate mainly, if not exclusively, made of fructosyl-fructose bonds
• Inulin from plants is linear with degree of polymerization (DP) ~10-12
• Inulin of bacterial origin is ~15 percent branched and has a high DP (106 to 107 Dalton)

Where it’s found

• Inulin was first isolated in 1804 from the herb Inula helenium by German scientist Rose
• Fructans are nature’s second-most abundant nonstructural polysaccharides, starch is the first
• In leek, onion, garlic, and asparagus (Liliaceae) & Dahlia, Jerusalem artichoke, chicory, and yacón (Compositae)
• Bacterial sources: Streptococcus mutans, the spores of Aspergillus sydowi  and Lactobacillus reuteri
• Leading producers:  Beneo GmbH (Belgium)—Orafti®, Cosucra (Belgium)—Fibruline®, Sensus (The Netherlands)—Frutafit®

Food or medicine?

• Legally classified as food or food ingredient; declared “Generally Recognized As Safe (GRAS)” in 1992 in the US
• Classified as “dietary fiber” in Europe and in most other countries
• Complies with the Codex Alimentarius definition of Dietary Fiber (Codex Guidelines on Nutrition Labelling CAC/GL 2-1985, Rev. 1, 1993).

Manufacturing pluses (+) and constraints (–)

  +  Can improve the organoleptic characteristics of food and drinks significantly

  +  Increases the stability of foams and emulsions

  +  Exhibits fatlike behavior when used as a gel in water

  +  Special “instant” qualities, which do not require shearing to form stable homogeneous gels

  –  Its subtle sweet taste may limit its application in savory food products

  –  At doses greater than 20g/day may cause gastrointestinal symptoms such as flatulence

  –  Properties may fluctuate with crop, weather and variety

Market drivers

• Growing consumer preference for “invisible” dietary fiber
• Consumers understand the value of prebiotics in their daily dose of probiotics
• Growing consumer preference for reduced fat, reduced calorie, and natural ingredients
• Advances in processing technologies to customize inulin fractions for specific functionality

Physiological effects

• Strong evidence: Nondigestibility and low caloric value (1–1.5kcal/g) soluble dietary fiber
• Suitable for people with diabetes
• Stool-bulking effect: increase in stool weight and stool frequency, relief of constipation
• Modulates gut flora composition; stimulates beneficial bacteria (Bifidobacteria); represses harmful microbes (Clostridia); prebiotic/bifidogenic effect
• Improves calcium and magnesium bioavailability

Surprising fact: The alcoholic drink tequila is produced by the digestion and fermentation of inulin from Agave Azul Tequila Weber (Liliaceae)

Resources

Glenn R. Gibson & Marcel B. Roberfroid, Handbook of Prebiotics, Taylor & Francis Group, CRC Press, 2008.

Susan Sungsoo Cho & E. Terry Finocchiaro, Handbook of Prebiotics and Probtiotics Ingredients | Health Benefits and Food Applications, Taylor & Francis Group, CRC Press, 2010.