Food & Nutrition

Arab Journal of Food & Nutrition
20. Extraction of Carotenoid Pigments from Tomato Pomance and its Use as A
Food Color (1996)
Dema Shaker Hussein\ University of Jordan
Supervisor: Dr. Ayed S. Amr
The objective of this study was to extract a pigment (carotenoid) from tomato
pomace, and to use it as a food colorant.
Tomato pomace was extracted with several organic solvents i.e., ethanol,
methanol, acetone, diethyl ether, butanol, hexane and petroleum ether at 40-60°C. In
addition the following solvent systems were used, carbon tetrachloride: ethanol (1:1)
trichloroethylene: ethanol (1:1), hexane: acetone (1:1) hexane:ethanol (1:1), hexane:
acetone: ethanol (2:1:1) and corn oil. Total carotenoids content was determined and
yields on dry matter basis were calculated.
Tomato pigment extract was purified and separated using MgO:Celite (1:1
wt/wt) column. Fractions were identified and their proportions were calculated.
Stability of the pigment extract to heat treatment, light, oxygen and pH was
evaluated and % concentration retentions of the pigment extract after each treatment
were calculated based on 100 concentration of a control sample. The kinetic order of
the thermal degradation and photodegradation reactions were determined and reaction
rate constants were calculated.
The pigment extract was applied to foods such as margarine, cream, cheese
spread, ice-cream, cake, kunafa, sausage, rice, popcorn, ready to fry extruded potato
chips, tomato ketchup, and juices.
The colored foods were evaluated by thirty taste panelists. Acceptance and
rejection of the colored foods were determined using the table for two tailed test.
Results showed that the solvent system hexane: acetone: ethanol (2:1:1) gave
high yields of pigments, and the safety of these solvents favor their use. Hexane:
acetone:ethanol extracted 149.06 mg pigment/kg wet tomato pomace.
Tomato pomace contained five carotenoids, phytoene and phytofluene (18.22 and
7.6 mg/kg respectively), β -carotene (6.1mg/kg), δ-carotene (3.24 mg/kg), γ-carotene
(4.03 mg/kg), and lycopene (97.58 mg/kg).
Stability studies showed that after heat treatment of the pigment extract at 35, 45,
55 and 65°C for 8 days, only 41, 37, 29, and 24% of the original pigment
concentrations were retained respectively. After 10 days of exposure of tomato
pigment to direct light, 41 % of the pigment was retained. Continuous oxygen flushing
for 96 hours caused 30% loss of the pigment. Acid and alkaline conditions did not
affect the pigment extract.
The pigment extract was applied as a food colorant to several foods. The sensory
evaluation results showed that only ice cream, margarine, ready to fry extruded potato
chips and rice were accepted.
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Volume 11, No. 25, 2011