Speciation of essential nutrient trace elements in coconut water

Ghaya Alchoubassi (1) , Katarzyna Kińska (1) , Katarzyna Bierla (1) , Ryszard Lobinski (1) , Joanna Szpunar (1)

1 IPREM - Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux

Coconut water (Cocos Nucifera) is shown to be a source of essential elements present in the form of low-molecular weight stable complexes known for their bio-availability. The total element concentrations were in the range of 0.2-2.7, 0.3-1, 3-14 and 0.5-2 ppm for Fe, Cu, Mn, and Zn, respectively, and varied as a function of the origin of the nut and its maturity. Speciation was investigated by size-exclusion chromatography-inductively coupled plasma mass spectrometry (ICP MS), and hydrophilic interaction liquid chromatography (HILIC)electrospray-Orbitrap MS. The metal species identified included: iron complexes with citrate and malate: Fe III (Cit) 3 (Mal), Fe III (Cit) 2 (Mal) 2 , Fe III (Mal) 2 , glutamine: Fe III (Glu) 2 and nicotianamine: Fe II (NA); copper complexes with phenylanine: Cu II (Phe) 2 and Cu II (Phe) 3 and nicotianamine: Cu II (NA); zinc complexes with citrate: Zn II (Cit) 2 and nicotianamine Zn II (NA) and manganese complex with asparagine Mn II (Asp) 2. The contributions of the individual species to the total elements concentrations could be estimated by HILIC-ICP MS.

Mots clés: Coconut water; Trace elements; Speciation; SEC-ICP MS; ESI MS; HILIC; Low-molecular weight complexes

Domaines: Chimie analytique; Ingénierie des aliments

Ghaya Alchoubassi, Katarzyna Kińska, Katarzyna Bierla, Ryszard Lobinski, Joanna Szpunar. Speciation of essential nutrient trace elements in coconut water. Food Chemistry, 2021, 339, pp.127680. ⟨10.1016/j.foodchem.2020.127680⟩. ⟨hal-03133504⟩