Rathy Dewai Malayandy (2009) Antioxidant activity of Sabah tea leaves. Universiti Malaysia Sabah. (Unpublished)
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Abstract
In this study the antioxidant activity of methanol and hot water extracts of Sabah fresh tea leaves at different ages of shoot, young and old leaves were analyzed and their total phenolic and flavonoid contents were measured spectrophotometrically. The antioxidant activity of tea samples was determined by ferric reducing antioxidant power (FRAP)assay, DPPH (2, 2-diphenyl-l-picrylhydrazyl) radical scavenging assay and ABTS+ radical scavenging assay. The correlation that exists between total phenolic and antioxidant activity and also total flavonoid and antioxidant activity was determined by obtaining the correlation coefficient values. Outcomes of this study showed that methanol showed higher extraction efficiency than hot water. Methanol extract of tea leave samples at different ages contained relatively higher content of total phenolic and flavonoids than hot water extract. Total phenolic content in methanol extract of tea leaves of different ages ranged from 428.38 ± 17.93mg GAE/L to 231.95 ± 17.96mg GAE/L. Total flavonoid content of tea leaves of different ages in methanol extract ranged from 4.85 ± 0.04mg QEQ/ml to 2.07 ± 0.03mg QEQ/ml. A very strong antioxidant activity was also exhibited by methanol extract of tea leave samples. The highest total phenolic content, total flavonoid content and antioxidant activity were revealed by the methanol extract of shoot followed by young leaves and lastly old leaves. Methanol extract of shoot had FRAP value of 471.89 ± 35.33 uMol Fe2S04.7H20 /L, IC50 value of 0.73 ± O.61mg/ml, AEAC value of 9269.90 ± 11291.06mgAA/l00g and TEAC value of 1.29 ± 0.08 mgTROLOX Equivalent/ml. The correlation between total flavonoid content and antioxidant activity was found to be stronger in tea leave samples as compared to the correlation between total phenolic content and antioxidant activity.
| Item Type: | Academic Exercise |
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| Keyword: | Antioxidant activity, Extract methanol, Sabah tea, Tea leaves, Sabah |
| Subjects: | T Technology > TX Home economics > TX1-1110 Home economics > TX341-641 Nutrition. Foods and food supply |
| Department: | SCHOOL > School of Food Science and Nutrition |
| Depositing User: | ADMIN ADMIN |
| Date Deposited: | 17 Nov 2011 13:23 |
| Last Modified: | 12 Oct 2017 14:17 |
| URI: | https://eprints.ums.edu.my/id/eprint/675 |
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