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Application of Modern Chemical Methods for Detection of Deterioration and Pollution in Foods.
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Abstract: Tea is the most widely consumed beverage in the world. Green tea (Camellia sinensis) is a good source of bioactive compounds and it is gaining interest due to its health benefits. The present study was conducted to determine the quality of Egyptian tea samples which accessed by physichemical analysis (moisture, protein, , crude fiber, ether extracts and ash contents), mineral analysis, sensory evaluation, caffeine content, phytochemicals assays of riboflavin (vitamin B2), carotenoide, tannin, chlorophyll contents, the total polyphenols and total flavonoid content as well as the antioxidant activity of ethanolic extracts from different Egyptian tea samples. The determination process carried out using standard methods and quantified various phenolic and flavonoid compounds by using high performance liquid chromatography (HPLC) method. The comparison was also made between Egyptian tea samples and commonly tea samples in the markets. Results from this study showed that Egyptian green tea showed a significant higher values of total phenol and flavonoid, contents. The same trend was also observed in antioxidant activity as assessed using DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging assay. It revealed that the total antioxidant activity could be due to its total phenol content. The study concludes that ethanolic extracts of leaves of Egyptian green tea possessed (75.0 ± 1.41% inhibition of the DPPH radical), followed by Egyptian black tea and Egyptian fresh tea extracts (52.0 ± 1.13% and 49.0 ± 1.06%, respectively), compared to the commercial green label yellow tea and black label yellow tea antioxidant (54.0± 1.21% and 78.0± 1.60%).
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| Publication year |
2020
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| Publication Type |
PhD Thesis
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