Morsali Mohammad Amin, Golmohammadi Behrang, Shekaari Hemayat
Department of Physical Chemistry, Faculty of Chemistry, University of Tabriz, 29 Bahman Boulevard, Tabriz, Iran.
Sci Rep. 2024 Sep 2;14(1):20372. doi: 10.1038/s41598-024-70275-z.
Aqueous amino acid solutions have been introduced as dietary supplements for both animals and humans. This study investigates the physicochemical properties of the solutions containing amino acids (L-glycine, D,L-alanine, L-proline), choline chloride, and water at temperature range of 288.15 to 318.15 K. The results show that increasing concentrations of amino acids and choline chloride lead to higher solution densities. Analysis of apparent molar volume (V) and apparent molar isentropic compressibility (κ) reveals that V values increase with choline chloride concentration and temperature, indicating enhanced solute-solvent interactions, while κ values decrease, suggesting increased solution compression. Thermodynamic analysis using the Redlich-Mayer model and COSMO-based modeling provides insights into molecular interactions. However, COSMO-based parameters show high average relative deviation percentage (ARD %) values, indicating poor predictive performance for the density of these systems. In contrast, the ePC-SAFT equation of state effectively predicts the densities, particularly for L-proline-based solutions, which show very low ARD % values, indicating high accuracy. The ePC-SAFT model also performs reasonably well for L-glycine solutions but shows poorer results for D,L-alanine-based solutions. The study also examines the sweetness and saltiness criteria (ASV and ASIC) of these solutions. The ASV values, which serve as a sweetness criterion, are higher than the ideal range of 0.5 < ASV < 0.7, suggesting an overly sweet taste. The ASIC values follow a similar trend, indicating increased saltiness. To achieve an appropriate grade of sweetness and saltiness, dilution to lower concentrations of the solution is recommended. Furthermore, the use of choline chloride is found to increase salt intake and enhance the taste of salt, which can be beneficial in amino acid supplements used in animal food.
氨基酸水溶液已被用作动物和人类的膳食补充剂。本研究考察了含有氨基酸（L-甘氨酸、D,L-丙氨酸、L-脯氨酸）、氯化胆碱和水的溶液在288.15至318.15 K温度范围内的物理化学性质。结果表明，氨基酸和氯化胆碱浓度的增加会导致溶液密度升高。对表观摩尔体积（V）和表观摩尔等熵压缩系数（κ）的分析表明，V值随氯化胆碱浓度和温度的升高而增加，表明溶质-溶剂相互作用增强，而κ值降低，表明溶液压缩性增加。使用Redlich-Mayer模型和基于COSMO的建模进行的热力学分析提供了分子相互作用的见解。然而，基于COSMO的参数显示出较高的平均相对偏差百分比（ARD%）值，表明对这些体系密度的预测性能较差。相比之下，ePC-SAFT状态方程有效地预测了密度，特别是对于基于L-脯氨酸的溶液，其ARD%值非常低，表明准确性高。ePC-SAFT模型对L-甘氨酸溶液的预测也相当不错，但对基于D,L-丙氨酸的溶液的预测结果较差。该研究还考察了这些溶液的甜度和咸度标准（ASV和ASIC）。作为甜度标准的ASV值高于理想范围0.5＜ASV＜0.7，表明味道过甜。ASIC值呈现类似趋势，表明咸度增加。为了达到合适的甜度和咸度等级，建议将溶液稀释至较低浓度。此外，发现使用氯化胆碱会增加盐的摄入量并增强盐的味道，这在动物食品中使用的氨基酸补充剂中可能是有益的。
