What is Rhubarb Root?
Rhubarb root (rheum spp.) is a natural flavoring ingredient extracted from the rhizome and root portions of rhubarb plants, scientifically classified within the Rheum genus. The ingredient is identified by CAS Number 977039-94-3 and functions as a flavoring agent or adjuvant in food manufacturing. Rhubarb root contains naturally occurring organic acids, including oxalic acid, malic acid, and citric acid, along with aromatic compounds that contribute to its characteristic tart and slightly fruity taste profile. This ingredient represents a plant-derived alternative to synthetic flavoring compounds.
Common Uses
Rhubarb root flavoring is used across various food and beverage applications to enhance or create specific flavor profiles. Common applications include:
- Beverages: Juices, drinks, and cordials seeking tart, fruity notes
- Confectionery: Hard candies, gummies, and sour candies
- Dairy products: Yogurts and flavored milk products
- Baked goods: Breads, pastries, and cake fillings
- Dietary supplements: Herbal formulations and nutritional products
The ingredient's acidic profile makes it particularly useful in products where tartness is desired without the addition of synthetic acid regulators.
Safety Assessment
Rhubarb root as a flavoring agent has not reported any adverse events according to FDA records, and no product recalls involving this ingredient have been documented. The safety profile appears favorable based on available regulatory data.
It is important to distinguish between rhubarb root as a flavoring agent and rhubarb leaf, which contains higher concentrations of oxalic acid and anthraquinones and is not approved for food use due to potential toxicity concerns. Rhubarb root, by contrast, contains lower levels of these compounds and is generally recognized as having minimal safety concerns when used in typical flavoring applications.
Oxalic acid, naturally present in rhubarb root, is also found in many common foods including spinach, chard, and cocoa. When used in flavoring concentrations—typically trace to small amounts in final food products—exposure levels remain well below those associated with any documented adverse effects.
Regulatory Status
Rhubarb root is not designated as Generally Recognized as Safe (GRAS) by the FDA, meaning it has not undergone the formal GRAS notification process. However, the absence of GRAS designation does not indicate a safety concern; rather, it reflects whether manufacturers have submitted formal GRAS petitions or notifications.
The ingredient may be used in foods under FDA regulations as a natural flavoring when it complies with Part 182 natural flavoring guidelines. The European Food Safety Authority (EFSA) has also evaluated rhubarb-derived ingredients, with historical use supporting acceptance in food applications.
Manufacturers using rhubarb root must ensure it meets purity standards and is free from contaminants. The ingredient should be sourced from food-grade suppliers maintaining appropriate quality control measures.
Key Studies
Limited peer-reviewed literature specifically addresses rhubarb root as a food flavoring agent in isolation. However, extensive historical use data and traditional applications support its safety profile. Rhubarb has been used in food and traditional medicine for centuries, particularly in Asian cuisines and herbal preparations.
General research on rhubarb components indicates that oxalic acid levels in rhubarb root are substantially lower than in rhubarb leaves, supporting the safety distinction between these plant parts. The flavoring application uses minimal quantities, further reducing any theoretical exposure concerns.
Further research characterizing the exact composition and dose-response relationships of rhubarb root flavoring extracts would provide additional safety data, though current evidence does not indicate safety concerns at typical use levels.