Mattar Ghadeer, Haddarah Amira, Haddad Joseph, Pujola Montserrat, Sepulcre Francesc
Departament d'Enginyeria Agroalimentària i Biotecnologia, Universitat Politècnica de Catalunya, Campus del Baix Llobregat, Carrer Esteve Terradas 8, Castelldefels, 08860 Barcelona, Spain.
Doctoral School of Sciences and Technology, Lebanese University, Rafic Hariri Campus, Hadath, Baabda 1533, Lebanon.
Foods. 2023 Jan 15;12(2):410. doi: 10.3390/foods12020410.
Although mineral chelates are widely produced to be used as food fortifiers, the proof that these complexes are chelates is still missing. In our present work, iron II complexes using citric acid in different ratios are produced, and the occurrence of chelation is investigated along with its behavior according to a molar ratio between the ligand and the mineral. High performance liquid chromatography (HPLC), flame atomic absorption spectroscopy (FAAS), ultraviolet-visible spectroscopy (UV-Vis), Fourier-transform infrared (FTIR), and near infrared spectroscopy (NIR) were used for a non-structural characterization of these complexes. In contrast to published work, our findings show that the chelation of citric acid is achieved in the liquid form and at a low pH and that the molar ratio is very important in setting the direction of the reaction, either toward chelation or dimer formation. The ratio citric acid:iron 1:4 seems to be the most convenient ratio in which no free citric acid remains in the solution, while the 1:3 ratio behaves differently, requiring further investigations by such techniques as extended X-ray absorption fine structure spectroscopy (EXAFS), among others, in order to deeply identify the structural organization occurring in this ratio. NIR, extensively used in industries, proved to be very useful in the demonstration and characterization of chelates. These findings are particularly advantageous for pharmaceutical and food industries in offering an innovative competent fortifying agent to be used in combatting iron deficiency.
尽管矿物螯合物作为食品强化剂被广泛生产，但这些络合物是螯合物的证据仍然缺失。在我们目前的工作中，制备了不同比例柠檬酸的亚铁络合物，并根据配体与矿物质的摩尔比研究了螯合的发生及其行为。高效液相色谱（HPLC）、火焰原子吸收光谱（FAAS）、紫外可见光谱（UV-Vis）、傅里叶变换红外光谱（FTIR）和近红外光谱（NIR）被用于这些络合物的非结构表征。与已发表的工作不同之处在于，我们的研究结果表明，柠檬酸的螯合在低pH值的液体形式下实现，并且摩尔比在设定反应方向（螯合或二聚体形成）方面非常重要。柠檬酸：铁1:4的比例似乎是最适宜的比例，此时溶液中没有游离柠檬酸残留，而1:3的比例表现不同，需要通过扩展X射线吸收精细结构光谱（EXAFS）等技术进一步研究，以便深入确定该比例下发生的结构组织。NIR在工业中广泛使用，事实证明对螯合物的论证和表征非常有用。这些发现对制药和食品行业特别有利，因为它们提供了一种创新的有效强化剂，可用于对抗缺铁。
