Analytical Methods for Identification and Quantification of Quinoa Saponins: A Review

Quinoa saponins (SAPs) are key secondary metabolites occurring as complex mixtures mainly in the seed coat of <i>Chenopodium quinoa</i> Willd. Although traditionally removed due to their bitter taste and potential toxicity, quinoa SAPs display diverse biological activities, including anti-inflammatory, hypocholesterolemic, antifungal, molluscicidal, hemolytic, and cytotoxic effects, that support their potential applications in pharmaceuticals, functional foods, cosmetics, and biopesticides. Their amphiphilic nature also enables their use as natural emulsifiers. This review (1981-2024) summarizes advances in analytical methodologies for quinoa SAPs, emphasizing that while GC-MS and LC-MS/MS are widely applied for profiling, full structural elucidation still requires isolation and analysis by NMR and MS. We discuss key considerations for quinoa SAPs identification using GC-MS, LC-MS/MS, and NMR. Quantification remains challenging and is often based on relative estimations, with afrosymmetric, UV-vis, and GC-MS methods being the most frequently employed, while HPLC-DAD, LC-MS, and GC-MS/MS offer greater sensitivity. Ultimately, the selection of the analytical method and standard critically determines accuracy.