Antioxidant activity of plant extracts on the inhibition of citral off-odor formation.
Grape seed, pomegranate seed, green tea, and black tea extracts were used to inhibit the off-odor from citral degradation. A 0.1 M citrate buffer (pH 3), containing 100 ppm citral and 200 ppm gallic acid equivalent plant extract, was incubated at 40 degrees C. The reaction mixtures were analyzed by high-performance liquid chromatography (HPLC) at days 0, 6, 10, 13, and 16 to monitor degradation of citral and formation of alpha, p-dimethylstyrene, p-cymene-8-ol, and p-methylacetophenone. The addition of plant phenolic extracts could not inhibit citral degradation, however, all four plant extracts significantly inhibited p-methylacetophenone formation. The samples, with the addition of plant extracts, exhibited higher concentrations of alpha, p-dimethylstyrene and p-cymene-8-ol than the control. This is presumed to be due to the oxygen-scavenging effect of plant extracts blocking the pathway from p-cymene-8-ol to p-methylacetophenone. Our results suggest that these plant extracts act as general antioxidants inhibiting the generation ofp-methylacetophenone regardless of the types of water-soluble phenolic compounds existing in the plant extracts.
Liang
Chia-Pei
CP
Department of Food Science, Rutgers University, New Brunswick, NJ 08901-8520, USA.
Wang
Mingfu
M
Simon
James E
JE
Ho
Chi-Tang
CT
D000080462:Acyclic Monoterpenes; D000975:Antioxidants / Q000494:pharmacology*; D028241:Camellia sinensis / Q000737:chemistry; D002849:Chromatography, Gas; D002851:Chromatography, High Pressure Liquid; D008401:Gas Chromatography-Mass Spectrometry; D029561:Lythraceae / Q000737:chemistry; D039821:Monoterpenes / Q000737:chemistry*; D009812:Odorants / Q000517:prevention & control*; D010636:Phenols / Q000494:pharmacology; D010936:Plant Extracts / Q000737:chemistry* / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry; D012639:Seeds / Q000737:chemistry; D027843:Vitis / Q000737:chemistry
D000080462:Acyclic Monoterpenes; D000975:Antioxidants; D039821:Monoterpenes; D010636:Phenols; D010936:Plant Extracts; C007076:citral