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Natural food colorants derived from onion wastes: Application in a yoghurt product
Author(s) -
Mourtzinos Ioannis,
Prodromidis Prodromos,
Grigorakis Spyros,
Makris Dimitris P.,
Biliaderis Costas G.,
Moschakis Thomas
Publication year - 2018
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.201800073
Subject(s) - polyphenol , chemistry , ingredient , extraction (chemistry) , food science , quercetin , response surface methodology , glycerol , allium , yield (engineering) , central composite design , chromatography , botany , organic chemistry , antioxidant , materials science , biology , metallurgy
The valorization of onion ( Allium cepa ) solid wastes, a 450 000 tonnes/year waste in Europe, by a green extraction method is presented. Polyphenols of onion solid wastes were extracted using eco‐friendly solvents, such as water and glycerol. The 2‐hydroxypropyl‐β‐cyclodextrin was also used as a co‐solvent for the augmentation of the extraction yield. The process has been optimized by implementing a central composite face centered design of experiments, with two replicates in the central point, taking into consideration the following independent variables: glycerol concentration, cyclodextrin concentration and temperature. The assessment of the extraction model was based on two responses: the total pigment yield and the antiradical capacity. LC‐MS analysis was also employed in order to identify polyphenols and colorants of the obtained extracts. The main polyphenols found were quercetin and quercetin derivatives and the main colorant was cyanidin 3‐O‐glucoside. The extract was also tested as a food colorant in a yoghurt matrix. The onion leaf extract was found to be a stable natural colorant and could be utilized as an alternative ingredient to synthetic coloring agents.