Food & Nutrition

Arab Journal of Food & Nutrition
50. A Study of Some Chemical and Physical Properties of Anemone Anthocyanins
and Their Possible Use as Food Colorants (2001)
Enas K. Al - Tamimi\ University of Jordan
Supervisor: Dr. Ayed Amr
The objective of this study is to extract the anthocyanins from the petals of
Anemone, determine their chemical identity, study their stability under different
conditions, and to use them as food colorant.
The petals were extracted with several solvents, i.e. 1% HCl–MeOH, 0.1%
HCl–MeOH, 0.01% HCl–MeOH, 1% HCl–EtOH, 3% formic acid–water, 3% formic
acid–water, 3% citric acid–MeOH, and MAW (25:1:24). Total anthocyanins were
determined by pH differential method and/or single pH method.
The results showed that 1% HCl–MeOH was the most effective solvent for
extraction of the three flower pigments (1750, 487, and 987 mg/l for AE, RE, and PE
respectively), followed by 3% citric acid–MeOH (1200 and 474 mg/l for AE and RE
respectively).
Anemone pigments were purified using Amberlite XDA–7 column, separated
by Sephadex LH–20 and TLC (silica gel) plates. Then they were identified by
spectral and chemical analysis.
Anemone coronaria pigment was found to consist of three main anthocyanins,
and identified as pelargonidin and its derevatives, with glucose and arabinose as sugar
moieties, and coumaric acid as acyl group.
Stability of the three flower pigment extracts (AE, RE, and PE) to heat
treatment, pH, water activity, light, and storage (with/without antioxidant, sugar, and
in carbonated beverage at room and refrigeration temperatures) was evaluated. The
kinetic reactions, constant rates, and t1/2 describing thermal, pH, light, and storage
effects on anthocyanin degradation were calculated.
Stability studies showed that the heat treatment at 50C for seven hours gave
higher pigment retention (94 % for AE and RE, and 61 % for PE) than at 80C (62, 51,
38% for AE, RE, and PE respectively). The three pigments were better retained at
lower (2, 3, and 3.5) than higher pH values (4, 4.5, and 5) with higher degradation
rates under the combined treatments of pH and heating at 80C for 210 minutes. After
10 days exposure to direct light, the percentage of retained pigments were about 38,
41, and 42 % compared to their controls 93, 84, and 63% for AE, RE, and PE.
Addition of sugar tends to increase the degradation of the three pigments in both light
and dark stored samples. As water activity increased, the pigment retention decreased,
with higher stability of AE as compared to RE and PE. Long term storage of solutions
and carbonated beverages colored with theses pigments extracts at room and
refrigeration temperatures resulted in gradual decrease in pigment retention, with
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