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Challenges
Chemical differentiation of oolong tea and
black tea/orange pekoe tea
Variation of tea catechins content due to
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Different geographic locations
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Seasonal changes
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Different processing methods of tea products
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Different extraction methods
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Different solvents
Interference from other ingredients.
Existing Methods – General Literatures
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HPLC (UPLC) UV‐MS: Identification and quantitation
catechins, caffeine, flavonoids, phenolics, amino acids
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HPTLC: Identification
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NMR: Metabolic Profiling
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FTIR and NIR: Identification, Differentiation
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GC: Aroma and flavor
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UV: Total polyphenols