ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

A fast and selective method to determine phenolic compounds in quinoa (Chenopodium quinoa Will) seeds applying ultrasound-assisted extraction and high-performance liquid chromatography

Jonathan Carrasco-Sandoval, Paulina Rebolledo, Darlene Peterssen-Fonseca, Susana Fischer, Rosemarie Wilckens, Mario Aranda, and Karem Henríquez-Aedo

Laboratorio de Biotecnología Y Genética de Alimentos, Departamento de Ciencia Y Tecnología de Los Alimentos, Facultad de Farmacia, Universidad de Concepción, Concepción, Chile

E-mail: mario.aranda@uc.cl

Received: 16 April 2020  Accepted: 10 August 2020

Abstract:

A simple and fast ultrasound-assisted extraction (UAE) method was optimized employing a chemometric technique to determine caffeic acid, vanillic acid, quercetin 3-β-d-glucoside, p-coumaric acid, vanillin, trans-ferulic acid, benzoic acid, quercetin, kaempferol and myricetin in quinoa seeds. Applying a central composite design, UAE conditions were established at 39 °C for 10 min, which is up to 12-fold lower than reported extraction times. Chromatography was performed on Phenomenex Kinetex XB C₁₈ (150 mm × 4.6 mm, S-5 µm) column using a binary mobile phase composed of ammonium formate (0.01 mol L⁻¹, pH 3.0) and acetonitrile (0.1% formic acid) at a flow rate of 0.5 mL min⁻¹. Validation was performed following International Conference on Harmonization recommendations. Calibration data fitted a linear regression model with R² > 0.999. Repeatability (n = 6) and intermediate precision (n = 3) in matrix showed relative standard deviation (RSD) values lower than 2.89 and 3.61%, respectively. Selectivity was evaluated by mass spectrometry (MS), without observing interference compounds. The proposed method was applied to determine the phenolic compound content in ten quinoa seeds samples from different varieties, finding a concentration range from 1.1 to 2.0 mg kg⁻¹. The proposed method proved to be a fast and selective alternative to evaluate phenolic compounds in quinoa seeds.

Keywords: Ultrasound-assisted extraction; Quinoa; Polyphenols; Chromatography; Design of experiment

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-020-01313-z

Chemical Papers 75 (1) 431–438 (2021)