关键词: N-羟乙酰神经氨酸, 密度泛函理论, 解离能, 光谱

Abstract: N-Glycolylneuraminic acid, widely found in livestock products such as beef and pork, is considered one of the most important hazardous factors for the safety of livestock products due to its association with various intestinal inflammations. To understand its physical and chemical properties, the molecular structure of N-glycolylneuraminic acid was optimized at the M062X/6-31+G(d,p) level using density functional theory, and electronic structure parameters (molecular surface electrostatics, frontier molecular orbital, conceptual density functional activity index, natural population charge) were calculated as well as physicochemical constants (dissociation constants, octanol-water partition coefficients, bond dissociation energy). Furthermore, a theoretical simulation of infrared and ultraviolet (UV) spectra was conducted. Considering the food processing environment, seven solvents (benzene, carbon tetrachloride, ethanol, acetic acid, lactic acid, formic acid, and water) with different dielectric constants were selected for a comparison of activity parameters. The results showed that N-glycolylneuraminic acid exhibited higher electrophilic activity near the acetyl group and higher nucleophilic activity at the carboxyl group. The theoretical pKa value was 1.84, and the octanol-water partition coefficient was ?3.85. In the presence of lactic acid, the dehydrogenation dissociation energy of hydroxyl group at position O7 was the smallest, 433.413 0 kJ/mol, and the maximum UV absorption wavelength was 180.087 8 nm. The results of this study provide a theoretical basis for the dissociation or reduction of N-glycolylneuraminic acid in foods.

Key words: N-glycolylneuraminic acid, density functional theory, bond dissociation energy, spectroscopy