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Abstract
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The purpose of this work was ultrasound-assisted
extraction of red quinoa carotenoid,
and antioxidant effect of the purified carotenoid on soybean oil stability was
compared with that of commercial carotenoid. Red quinoa carotenoid was extracted
using 50 ml ethanol as the solvent in an ultrasonic bath at 45 ± 1°C and 20 kHz for
3 min. After the carotenoid purification, its effect on the oxidative stability of soybean
oil was compared with that of commercial β-carotene
during 8 days of storage
at 60°C. Peroxide value (PV), conjugated diene value (CV), thiobarbituric acid (TBA)
value, and color parameters were measured. 100 mg/kg of the commercial and natural
carotenoids was the best concentration to decrease the TBA value during the
8 days of storage, compared with the other concentrations (200 and 300 mg/kg). On
the last day, the samples containing 100 mg/kg of the commercial and natural carotenoids
had the lowest CV, and TBA value, and lowest PV was in samples containing
200 mg/kg. In addition, the lowest PV (7.8 meq/kg) was obtained on the eighth day,
owing to the performance of β-carotene
at 200 mg/kg, while the samples free of
the carotenoids had the highest PV, CV, and TBA value. The samples containing the
commercial antioxidant had higher b* values than those with the natural antioxidant
because the commercial β-carotene
was yellower than the natural carotenoid. The
samples containing the commercial carotenoid had lower a* values than those containing
the natural one. Carotenoid extracted from red quinoa could influence the
oxidative stability of soybean oil.
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