Differentiation of Chia, Flax and Sesame: Polyphenol fingerprinting by HPLC-ESI-qTOF (MS)

BRIGANTE, F.; LUCINI, A.; PIGNI, N. B; BARONI, M. V.; WUNDERLIN, D. ; MARTINEZ, M.

Parma

Conferencia; FOODINTEGRITY 2017 CONFERENCE; 2017

Nowadays, there is a widespread preference for the consumption of foods that, in addition to its nutritional properties, provide components that could reduce the risk of certain diseases, leading to the concept of "functional food". Chia, flax and sesame seeds are a great source of polyphenols and have greatly increased their popularity among consumers due to their beneficial properties like reducing cancer risk, diabetes and heart disease, among others. The antioxidant activity shown by these compounds is responsible of the mentioned properties. Due to their great nutritional capacity, these seeds can be added to processed food to increase their nutritional value. Foodintegrity is the state of being whole, complete, undiminished or in perfect state in terms of quantity and quality, and this quality means to reach specific standards in sensory, microbiological and origin aspects of foodstuffs. There is a gap in the available scientific information to evaluate food attributes for complex foods. Many times it is difficult to assess the presence of a particular ingredient of nutritional importance within a complex food. So far, when a food product can be sold for a premium price because of its characteristics, it is of paramount importance that label claims and declarations on origin and identity can be certified.The aim of this work was to find polyphenols within each seed, which could be used as authenticity biomarkers in complex foods contaning these seeds. For this study we used defatted chia, flax and sesame flour obtained after oil extraction. Polyphenols were extracted by sonication of lyophilized defatted flour with ethanol 50% and identified and quantified by liquid chromatography coupled with time of flight mass spectrometry detection (HPLC-ESI-qTOF). The identification was done by MSn spectra, UV spectra and exact mass comparison and quantification was performed by external calibration curves using structurally related compounds. Nineteen polyphenols were found in the sesame flour, of which 11 were lignans (derivatives of enterolactone and enterodiol), 5 phenolic acids (being these the majority ones); and three flavonoids which were (-)-Epigallocatechin 3-O-gallate, Apigenin and Apigenin -6-glucoside.On the other hand, 13 compounds were found in chia flour and all of them were phenolic acids being the majority derived from caffeic acid (e.g. Salviaflaside and Rosmarinic Acid.)Finally 15 compounds were found in flax flour, 7 were phenolic acids (mainly Quinic acid and Caffeic acid derivatives such as O-caffeoyl-fructosyl-glucoside and Rosmarinic acid hexoside) and 8 were flavonoids derived from Quercetin mostly.There were ubiquitous compounds in the analyzed seeds such as Rosmarinic acid and Quinic acid. On the other hand, each seed showed distinctive compounds. In the case of sesame flour the lignans (e.g. Sesamolin, 7-Hydroxymatairesinol, Matairesinol-rhamnoside); in the case of the flax flour the flavonoids (Cyanidin-3-O-glucoside, Eriodictyol 7-O-glucoside, Gallocatechin, among others) and in the case of chia some phenolic acids like caftaric acid, fertaric acid, salvianolic acids, sagerinic acid and Danshensu.Therefore, these key polyphenols could be used to differentiate each seed and as well as markers of authenticity in bakery/complex products/foods. Further research is needed to evaluate the stability of these proposed markers after food processing.