Trans Configuration Properties & Quality Specifications of Food Grade Fumaric Acid E297 (CAS 110-17-8)

Technical Research Brief

Fumaric Acid (CAS 110-17-8), coded E297 in global food additive standards, is a unique unsaturated dicarboxylic acid distinguished by its trans molecular configuration. This article systematically interprets its molecular mechanism, dissolution characteristics, pH buffering principle and high-purity quality control standards.

Fumaric Acid (CAS 110-17-8), coded E297 in global food additive standards, is a unique unsaturated dicarboxylic acid distinguished by its trans molecular configuration. Unlike common food acids such as Citric Acid and malic acid, its trans double bond structure determines a series of exclusive physicochemical traits, including high thermal stability, ultra-low hygroscopicity, and temperature-dependent solubility. Many formulation engineers overlook its structural particularity, resulting in inaccurate material selection and system instability.

Disclaimer: This article focuses on physicochemical mechanism and technical analysis for industry reference only, without functional application commitment.

Ⅰ. Stereoisomeric Structure: Fundamental Difference Between Fumaric Acid and Maleic Acid

The fundamental difference between fumaric acid and maleic acid lies in stereoisomerism. Fumaric acid adopts a stable trans structure, while maleic acid exists in cis configuration. The trans spatial arrangement greatly reduces molecular polarity, endowing fumaric acid with stronger heat resistance and extremely low moisture absorption. Its critical relative humidity exceeds 75%, making it far less prone to deliquescence and caking than other organic acid powders. Meanwhile, the non-polar structural feature leads to poor solubility in cold water, while the solubility rises sharply with increasing temperature. This temperature-sensitive solubility is the core physical feature that separates Fumaric Acid from conventional acidity regulators.

Ⅱ. Dissociation Constant and pH Buffering & Auxiliary Antibacterial Mechanism

Fumaric acid owns dual dissociation constants of pKa₁=3.03 and pKa₂=4.44, forming a stable pH buffering range near pH 3.0. This specific interval effectively inhibits the growth of yeast and mold, providing auxiliary antibacterial effects for food systems. Different from the wide-range buffering of citric acid, E297 fumaric acid delivers more targeted pH stabilization in acidic food environments, helping formulas maintain stable taste and antibacterial performance during processing and long-term storage.

Ⅲ. 99.5% Min Food Grade Purity Control & Impurity Risk Analysis

High-standard food-grade E297 Fumaric Acid implements 99.5% minimum purity control. Strict restrictions are placed on cis-maleic acid isomer impurities, heavy metals, residue on ignition, solution color and moisture content. Trace cis-isomer impurities not only affect product purity but also cause potential compliance risks in food-grade applications. Reliable purification technology ensures stable batch consistency, eliminating abnormal taste, color deviation and system instability caused by unqualified raw materials.

Ⅳ. Physicochemical Basis for Raw Material Selection and Storage Requirements

Based on its comprehensive physicochemical properties, targeted selection and storage standards can be concluded. Benefiting from ultra-low hygroscopicity, fumaric acid powder maintains stable physical state in dry storage environments and is highly suitable for dry powder premix systems. Due to its poor cold-water solubility, it is not recommended for direct cold liquid formulation. Formulators should judge applicability according to production temperature, water activity and system form, so as to avoid crystallization precipitation and formula failure.

Disclaimer: Raw material crystal stability is subject to actual ambient temperature and relative humidity.