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 Chenopodium quinoa 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.