Analysis of anthocyanins in red onion using capillary electrophoresis‐time of flight‐mass spectrometry

Abstract

For the first time, a capillary electrophoresis-time of flight-mass spectrometry analysis method for detecting anthocyanins in red onion was developed. The analysis method included the use of silica capillaries coated with poly-LA 313 (polycationic amine-containing polymer) and an MS-compatible volatile background electrolyte (BGE). The method was environmentally friendly and sensitive; and its rapidness combined with an acidic BGE helped in preventing anthocyanin degradation. By using high-resolution TOF-MS with pre-run tuning of masses, low mass errors were achieved in the determination of conjugated anthocyanins in red onion, and a simultaneous up-front fragmentation provided confirmation of the aglycon backbone for their secure identification. Most anthocyanins (at least seven out of ten) known in red onion from the literature were found, as well as one new for this matrix.

Highly pigmented vegetables: Anthocyanin compositions and their role in antioxidant activities

“…pH and the glycosylation patterns can affect the color of the anthocyanins. Anthocyanins play important roles in plant-animal interactions and act as antioxidants, phytoalexins or plant's chemical defense mechanism infections (De Pascual-Teresa & Sanchez-Ballesta, 2008;Petersson, Puerta, Bergquist, & Turner, 2008). High intake of foods rich in anthocyanins has been shown to have potential health beneficial effects on various disorders like cancer, aging, neurological diseases, inflammation, diabetes as well as bacterial infections (De Pascual-Teresa & Sanchez-Ballesta, 2008;Hassan & Abdel-Aziz, 2010;Hudson, Dinh, Kokubun, Simmonds, & Gescher, 2000;Olsson et al, 2004;Yi et al, 2006).…”

CE‐TOF/MS: Fundamental concepts, instrumental considerations and applications

“…Each method allowed the determination of more than 45 analytes with acceptable repeatability. More recently, many groups have worked on the analysis of natural compounds by CE-ESI-TOF/MS [31,[104][105][106][107][108]]. An interesting study was performed by Simó et al [108], who compared IT and TOF, both hyphenated with CE-ESI for the analysis of biogenic amines in wine.…”

Recent food safety and food quality applications of CE‐MS

“…The method allowed the identification and quantification of the selected anthocyanins in red wine and must, which demonstrates its utility for monitoring wine-production technology. Other recent example of the application of CE-MS to the analysis of anthocyanins in foods is the work of Petersson et al [88], who developed a CZE-ESI-TOF-MS method for detecting pelargonidin, cyaniding, peonidin, delphinidin, petunidin, malvidin and their conjugated anthocyanins in red onion. The method used coated silica capillaries and a MScompatible volatile BGE (15.0 mM formic acid at pH 1.9).…”

“…Use of both acidic and basic electrolytes [80] Electrophoresis 2009, 30, 1624-1646 [88] Anthocyanins (cy-3-orutinoside, cy-3,5-diglucoside, cy-3-smbubioside, dp-3-sambubioside, dp-3-oglucoside, chlorogenic acid) flavor trends, etc. ), processing, adulteration, protein composition, etc.…”

“…They are therefore valuable for human health [110], for example by showing preventive action against cancer [111] and by improving visual functions [112]. In the last 5 years, only three works have been reported in the literature regarding the analysis of anthocyanins by CE-MS in foods [80,88,89], specifically in red wine and must [80], in red onion [88] and in nutritive supplements of karkade obtained from extracts of H. sabdariffa L. [89]. As an example, Bednar et al [80] investigated the detection of a group of anthocyanins (pelargonidin, cyanidin, delphinidin, malvidin, petunidin, peonidin, vitisin A and vitisin B) in red wine and must by CZE-ESI-TOF-MS n analysis using two electrolytes: an acidic one (200 mM ammonium chloroacetate at pH 2.0) and a basic one with selectivity toward derivatives containing vicinal hydroxyl groups (200 mM ammonium borate at pH 9.0).…”