Authentication and discrimination of green tea samples using UV–vis, FTIR and HPLC techniques coupled with chemometrics analysis

Aboulwafa, Maram M.; Youssef, Fadia S.; Gad, Haidy A.; Sarker, Satyajit D.; Nahar, Lutfun; Al-Azizi, Mohamed M.; Ashour, Mohamed L.

doi:10.1016/j.jpba.2018.11.036

Cited by 65 publications

(61 citation statements)

References 15 publications

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“…These bands are characteristic of carbonyl groups derived from the conformational structures of MD and GA. Figure 2b shows all the treatments obtained, where it is possible to identify a third weak band at 327 nm. According to reports, this band is attributed to the presence of PC such as catechins, flavonoids and phenolic acids [43]; these phytoconstituents are characterized by the presence of various chromophores and conjugated systems that act as UV-absorbing systems. The presence of anthocyanins from Hibiscus was evidenced in the band at 532 nm [1].…”

Section: Scanning Electron Microscopy (Sem)mentioning

confidence: 99%

“…The activity for the DPPH radical, attributed to the solvent of extraction (water) and the extract: carrier ratio (1:1); when the encapsulate containing a smaller amount of carrier agents there are more hydroxyl groups available to react with the DPPH radical [43]. As well, this can be influenced by the condensed tannins derived from the heat treatment of calyces, since they exhibit a good (DPPH) AOX capacity mainly due to the tannins and flavonoids containing a variety of hydroxyl groups that show stronger AOX and elimination of free radicals of the PC present (see Supplementary Materials Table S2 and Figure S1) [48].…”

Section: Pc Content and Aox In Hibiscus Encapsulatesmentioning

confidence: 99%

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Use of a Taguchi Design in Hibiscus sabdariffa Extracts Encapsulated by Spray-Drying

Navidad-Murrieta

Pérez-Larios

Sánchez-Burgos

et al. 2020

Foods

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Aqueous and ethanolic extracts of Hibiscus sabdariffa were spray-dried using maltodextrin (MD) and gum arabic (GA) as carrier agents. A Taguchi L8 experimental design with seven variables was implemented. Physicochemical properties in the encapsulates were evaluated by Ultraviolet-Visible (UV-Vis,) X-ray Diffraction (XRD), spectroscopy and gravimetric techniques. Treatments with aqueous extracts showed the highest concentration of total soluble polyphenols (TSP) 32.12–21.23 mg equivalent gallic acid (EAG)/g dry weight (DW), and antioxidant capacity (AOX) in the 2,2-azinobis-3-ethylbenzotiazoline-6-sulfonic acid (ABTS) assay. The best treatment for TSP and AOX was T4: 2.5% Hibiscus w/w, aqueous extract, decoction, extract-to-carrier ratio 1:1 (w/w), proportion to carriers (MD:GA) 80:20 (w/w), 10,000 rpm, 150 °C. The Taguchi L8 design is a tool that allows the use of multiple variables with a low number of treatments that indicate the drying conditions that give the best parameters, focusing mainly on TSP and AOX, also, it is a good alternative for the preservation and stability of the phenolic compoudns in Hibiscus.

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Section: Scanning Electron Microscopy (Sem)mentioning

confidence: 99%

Section: Pc Content and Aox In Hibiscus Encapsulatesmentioning

confidence: 99%

Use of a Taguchi Design in Hibiscus sabdariffa Extracts Encapsulated by Spray-Drying

Navidad-Murrieta

Pérez-Larios

Sánchez-Burgos

et al. 2020

Foods

View full text Add to dashboard Cite

show abstract

“…For catechins monomers, the content of EGCG was the highest in all samples. EGCG, EGC, ECG, and EC represent the main catechins in green tea [ 19 , 20 ]. The lower the sample grade, the higher the contents of EGCG, EC, EGC, and GCG, which is consistent with the results reported by Pan [ 21 ].…”

Section: Discussionmentioning

confidence: 99%

“…Other researchers also used these digital instruments for tea classification. Aboulwafa et al found that the PCA plot of UV spectroscopic data can be used to separate two areas: low-quality Chinese tea, high-quality Chinese tea, and entire South Asian samples (from India and Sri Lanka) [ 20 ]. Dankowska and Kowalewski reported UV-Vis spectroscopy with PCA to identify six tea types; however, there were overlapping areas [ 22 ].…”

Section: Discussionmentioning

confidence: 99%

Rapid Identification of Different Grades of Huangshan Maofeng Tea Using Ultraviolet Spectrum and Color Difference

et al. 2020

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Tea is an important beverage in humans’ daily lives. For a long time, tea grade identification relied on sensory evaluation, which requires professional knowledge, so is difficult and troublesome for laypersons. Tea chemical component detection usually involves a series of procedures and multiple steps to obtain the final results. As such, a simple, rapid, and reliable method to judge the quality of tea is needed. Here, we propose a quick method that combines ultraviolet (UV) spectra and color difference to classify tea. The operations are simple and do not involve complex pretreatment. Each method requires only a few seconds for sample detection. In this study, famous Chinese green tea, Huangshan Maofeng, was selected. The traditional detection results of tea chemical components could not be used to directly determine tea grade. Then, digital instrument methods, UV spectrometry and colorimetry, were applied. The principal component analysis (PCA) plots of the single and combined signals of these two instruments showed that samples could be arranged according to grade. The combined signal PCA plot performed better with the sample grade descending in clockwise order. For grade prediction, the random forest (RF) model produced a better effect than the support vector machine (SVM) and the SVM + RF model. In the RF model, the training and testing accuracies of the combined signal were all 1. The grades of all samples were correctly predicted. From the above, the UV spectrum combined with color difference can be used to quickly and accurately classify the grade of Huangshan Maofeng tea. This method considerably increases the convenience of tea grade identification.

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“…The Figure 2b shows all the treatments obtained, it was possible to identify a third weak band at 327 nm. According to reports, this band is attributed to the presence of PC such as catechins, flavonoids and phenolic acids [30]; this phytoconstituents are characterized by the presence of various chromophores and conjugated systems that act as UV-absorbing systems. The presence of anthocyanins from Hibiscus was evidenced in the band at 532 nm [1].…”

Section: Scanning Electron Microscopy (Sem)mentioning

confidence: 99%

Use of a Taguchi Model in <em>Hibiscus sabdariffa</em> Extracts Encapsulated by Spray-Drying

Navidad-Murrieta¹,

Pérez-Larios²,

Sánchez-Burgos³

et al. 2019

Preprint

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Aqueous and ethanolic extracts of Hibiscus sabdariffa were spray-drying using maltodextrin (MD) and gum arabic (GA) as carriers agents. An experimental design Taguchi L8 with seven variables was implemented. Physicochemical properties in the encapsulates were evaluated by UV-Vis, XRD, spectroscopy and gravimetric techniques. Treatments with aqueous extracts showed the highest concentration of total soluble polyphenols (TSP) 32.12- 21.23 mg EAG/g DW, and antioxidant capacity (AOX) for ABTS assay. The best treatment for TSP and AOX was T4: 2.5% Hibiscus w/w, aqueous extracts, decoction, extract-to-carrier ratio 1:1 (w/w), proportion to carriers (MD:GA) 80:20 (w/w), 10000 rpm, 150°C. Taguchi L8 model is a tool that allows the use of multiple variables with a low number of treatments that indicate the drying conditions that give the best parameters, focusing mainly on TSP and AOX, in addition, is a good alternative for the preservation and stability of the PC in Hibiscus.

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Authentication and discrimination of green tea samples using UV–vis, FTIR and HPLC techniques coupled with chemometrics analysis

Abstract: The version presented here may differ from the published version or from the version of the record. Please see the repository URL above for details on accessing the published version and note that access may require a subscription.

Cited by 65 publications

References 15 publications

Use of a Taguchi Design in Hibiscus sabdariffa Extracts Encapsulated by Spray-Drying

Use of a Taguchi Design in Hibiscus sabdariffa Extracts Encapsulated by Spray-Drying

Rapid Identification of Different Grades of Huangshan Maofeng Tea Using Ultraviolet Spectrum and Color Difference

Use of a Taguchi Model in <em>Hibiscus sabdariffa</em> Extracts Encapsulated by Spray-Drying

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