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Production of an anthocyanin‐rich food colourant from Thymus moroderi and its application in foods
Author(s) -
DíazGarcía Miriam Cristina,
Castellar María Rosario,
Obón José María,
Obón Concepción,
Alcaraz Francisco,
Rivera Diego
Publication year - 2015
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.6821
Subject(s) - anthocyanin , polyphenol , chemistry , food science , bract , trolox , pomace , citric acid , botany , antioxidant , antioxidant capacity , biochemistry , biology , inflorescence
BACKGROUND Anthocyanins and other polyphenols from flowers and bracts of Thymus sp. are studied. An anthocyanin‐rich food colourant with interesting high antioxidant activity from Thymus moroderi has been obtained, and applied to colour foods. RESULTS Anthocyanins and other polyphenols from T. moroderi and another five Thymus sp. were extracted in methanol/hydrochloric acid 0.1 mol L −1 (50/50, v/v) 2 h stirring at 50 °C. They were identified and quantified by HPLC‐PDA‐MS and UHPLC‐PDA ‐fluorescence, as total individual polyphenols. Total polyphenols were also determined. Flowers had higher anthocyanins and other polyphenols concentrations than bracts; for example, total polyphenols content of T. moroderi were 131.58 and 61.98 g GAE kg −1 vegetal tissue, respectively. A liquid concentrated colourant was obtained from T. moroderi using water/citric acid as solvent. It was characterised and compared with other two commercial anthocyanin‐rich food colourants from red grape skin and red carrot (colour strength of 1.7 and 3.6 AU , respectively). T. moroderi colourant had 1.2 AU colour strength, and high storage stability (>97.1% remaining colour after 110 days at 4 °C). It showed a higher polyphenols content than commercial colourants. Its antioxidant activity was 0.707 mmol Trolox eq. g −1 plant dry weight, 69.5 times higher than red carrot. The three colourants were applied to colour yogurts, giving pinky tonalities. The colour did not change evidently (Δ E * ab < 3) when stored under refrigeration during 1 month. CONCLUSIONS T. moroderi can be a source of anthocyanin‐rich food colourant (E‐163) with both high polyphenols content and high antioxidant activity. This colourant gives a stable colour to a yogurt during 1 month. These results expand the use of natural colourants. © 2014 Society of Chemical Industry