ANTIOXIDATIVE EFFECTIVENESS OF USED BLACK TEA ON SUNFLOWER OIL DURING HEATING | ||||
| Journal of Food and Dairy Sciences | ||||
| Article 2, Volume 25, Issue 1, January 2000, Page 297-304 PDF (624.27 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/jfds.2000.258309 | ||||
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| Author | ||||
| O. M. Barbary, | ||||
| Dept. of Food Sci. Fac. Of Agric. (Saba Basha) Univ. of Alexandria, Egypt. | ||||
| Abstract | ||||
| Antioxidative effectiveness (AE) % of used black tea and its extracts on sunflower oil (SO) during heating at 60°C for 20 days were investigated. Data revealed that addition of used tea powders at levels of 1,2,4,5, and 10 % to the SO showed only marginal AE % as compared to the synthetic antioxidant (BHT) used. The AE % increased as the level of tea powder increased. The used black tea was extracted with different solvents (ethanol, EE, methanol, ME, diethyl ether, DEE and methanol/diethyl ether, 2: 1, DEE). MDEE and DE gave the highest yields as compared to the other extracts. All extracts were added o SO at 200 ppm. Data revealed that the order of AE % for these extracts were ME (88.20)>M/DEE (87.06)>DEE (84.29)>BHT (79.50) and finally EE (40.24%) after heating at 60°C for 20 days. TBA values of SO increased progressively, with all extracts, with increasing the time of heating for 20 days. ME and M/DEE gave the lowest TBA values, respectively, as compared to the other extracts used. The control sample showed the highest TBA value. The antioxidant components in all extracts were tentatively identified using TLC to be phenolic compounds. The dominant compounds were identified in all extracts when reacted with ferric chloride to produce blue colour represents phrogallol, blue-black, represents trihydroxy phenolic compounds and green represents catechol. | ||||
| Keywords | ||||
| Used black tea; Antioxidative Effectiveness; Sunflower oil; Heating; and Phenolic compounds | ||||
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