Determination of 21 free amino acids in 5 types of tea by ultra-high performance liquid chromatography coupled with tandem mass spectrometry (UHPLC–MS/MS) using a modified 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) method

Zhou, Peng; Zhao, Feng; Chen, Mingjie; Ye, Naixing; Qiu, Lin; Ouyang, Li-Qun; Cai, Xiaoming; Meng, Ping; Gong, Xuedong; Wang, Ying

doi:10.1016/j.jfca.2019.05.007

Cited by 36 publications

(27 citation statements)

References 30 publications

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“…Dark tea is a postfermented tea, with a long‐term microbial post fermentation process at higher temperatures and humidity (Zhu et al., 2016). The amino acid content of dark tea is significantly lower than that of other teas (average, 2.63 mg/g; Table 2), probably because of the effects of microbial extracellular enzymes and the Maillard reaction during the microbial postfermentation of dark tea (Zhou et al., 2019; Zhu et al., 2016).…”

Section: Resultsmentioning

confidence: 99%

Analytical strategy coupled to chemometrics to differentiate Camellia sinensis tea types based on phenolic composition, alkaloids, and amino acids

Jiang

Zhang

Wang

et al. 2020

Journal of Food Science

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Catechins, amino acids, and alkaloids are primary chemical components of tea and play a crucial role in determining tea quality. Their composition and content largely vary among different types of tea. In this study, a convenient chemical classification method was developed for six Camellia sinensis tea types (white, green, oolong, black, dark, and yellow) based on the quantification of their major components. Twenty-one free amino acids, 6 catechins, 2 alkaloids, and gallic acid in 24 teas were quantified using ultra-high-performance liquid chromatography (UHPLC). The total catechin contents in these tea samples ranged from 10.96 to 95.67 mg/g, while total free amino acid content ranged from 2.63 to 25.89 mg/g. Theanine (Thea) was the most abundant amino acid in all tea varieties. Catechin and amino acid levels in tea were markedly reduced upon fermentation of tea. Furthermore, high-temperature processing (roasting) during tea production induced degradation and epimerization of catechins, yielding epimerized catechins, simple catechins, and gallic acid. Principal component analysis revealed that major ester-catechins (EGCG and ECG), major amino acids (Thea), and major alkaloids (caffeine) are potential factors for distinguishing different types of tea. Linear discriminant analysis showed that 100% of teas were correctly classified in which (+)-catechin, ECG, EGC, gallic acid, GABA, cysteine, lysine, and threonine were the most discriminating compounds. This study shows that quantification of the major tea components combined with chemometric analysis, can serve as a simple, convenient, and reliable approach for classifying tea according to fermentation level.

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Section: Resultsmentioning

confidence: 99%

Analytical strategy coupled to chemometrics to differentiate Camellia sinensis tea types based on phenolic composition, alkaloids, and amino acids

Jiang

Zhang

Wang

et al. 2020

Journal of Food Science

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“…Indirect methods are more popular and widely used. They include pre-or post-column derivatization with various reagents, for instance ninhydrin, ortho-phthalaldehyd (OPA) [29,30], phenyl isothiocyanate (PITC) [31], 2,4-dinitrofluorobenzene (DNFB), dimethylaminoazobenzene sulfonyl chloride (Dabsyl-Cl), 9-fluorenylmethyloxycarbonyl chloride (FMOC-Cl) [32], 9-fluorenylmethoxycarbonyl glycine chloride, and 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate [33]. On other hand, direct methods are easier to apply and require no reagent.…”

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confidence: 99%

Comparative Investigation of Amino Acids Content in the Dry Extracts of Juno bucharica, Gladiolus Hybrid Zefir, Iris Hungarica, Iris Variegata and Crocus Sativus Raw Materials of Ukrainian Flora

et al. 2020

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The aim of this research was the comparative study of the amino acids content in the dry extracts of Iridaceae plants of Ukrainian flora: Juno bucharica leaves and corms, Gladiolus hybrid Zefir leaves, Iris hungarica and Iris variegata rhizomes, and Crocus sativus stigmas, flowers, leaves and corms. A gas chromatography–mass spectrometry (GC–MS) method has been used. Separation of amino acids in the samples was carried out using a Shimadzu GC-MS-QP2010 equipped with an Rxi-5ms (Restek Corporation capillary column (30 m long, 0.25 mm outer diameter and 0.25 µm) with a liquid stationary phase (5% diphenyl and 95% polysiloxane) after derivatization with N-(t-butyldimethylsilyl)-N109 methyltrifluoroacetamide (MTBSTFA) reagent. The results obtained have shown that extracts from the aerial parts of plants investigated have a higher amino acid content and more diverse composition than the underground organs. Experimental data showed that Crocus leaves and Juno leaves extracts contain the highest general content of amino acids—31.99 mg/g and 14.65 mg/g respectively. All samples showed a high content of L-pyroglutamic acid (0.33–12.35 mg/g). Moreover, Crocus leaves and Juno leaves extracts had the most suitable amino acids composition and are prospective for further pharmacological studies.

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“…However, there was a report of using OPA as pre-column derivatization to enhance sensitivity for fluorescent detection [ 137 ]. Derivatization process was made easier and simpler when using AQC as it is stable at room temperature for several days, has low toxicity, fewer side reactions and takes a shorter time to complete [ 143 ]. The use of other new derivatizing reagents are continually being reported and the main aim is to find a reagent that is fast reacted, highly sensitive and preferably stable at room temperature.…”

Section: Amino Acidsmentioning

confidence: 99%

“…A study using UHPLC-hydrophilic liquid chromatography (HILIC) in positive electrospray ionization (ESI) mode coupled with MS/MS (UHPLC-HILIC-ESI MS/MS) system to detect isobaric amino acids in cereal with a shorter run time was achieved using a tandem MS detection compared to using single MS detection [ 142 ]. A combined method of modified AQC and UHPLC-MS/MSto analyze amino acids in tea was developed with an improved detection sensitivity and resolution by increasing the separation of co-eluting compounds and shortening the chromatographic run time [ 143 ].…”

Section: Amino Acidsmentioning

confidence: 99%

Recent Techniques in Nutrient Analysis for Food Composition Database

et al. 2020

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Food composition database (FCD) provides the nutritional composition of foods. Reliable and up-to date FCD is important in many aspects of nutrition, dietetics, health, food science, biodiversity, plant breeding, food industry, trade and food regulation. FCD has been used extensively in nutrition labelling, nutritional analysis, research, regulation, national food and nutrition policy. The choice of method for the analysis of samples for FCD often depends on detection capability, along with ease of use, speed of analysis and low cost. Sample preparation is the most critical stage in analytical method development. Samples can be prepared using numerous techniques; however it should be applicable for a wide range of analytes and sample matrices. There are quite a number of significant improvements on sample preparation techniques in various food matrices for specific analytes highlighted in the literatures. Improvements on the technology used for the analysis of samples by specific instrumentation could provide an alternative to the analyst to choose for their laboratory requirement. This review provides the reader with an overview of recent techniques that can be used for sample preparation and instrumentation for food analysis which can provide wide options to the analysts in providing data to their FCD.

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Determination of 21 free amino acids in 5 types of tea by ultra-high performance liquid chromatography coupled with tandem mass spectrometry (UHPLC–MS/MS) using a modified 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) method

Cited by 36 publications

References 30 publications

Analytical strategy coupled to chemometrics to differentiate Camellia sinensis tea types based on phenolic composition, alkaloids, and amino acids

Analytical strategy coupled to chemometrics to differentiate Camellia sinensis tea types based on phenolic composition, alkaloids, and amino acids

Comparative Investigation of Amino Acids Content in the Dry Extracts of Juno bucharica, Gladiolus Hybrid Zefir, Iris Hungarica, Iris Variegata and Crocus Sativus Raw Materials of Ukrainian Flora

Recent Techniques in Nutrient Analysis for Food Composition Database

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