The effect of pectin and other constituents on the antioxidant activity of tea

Soultani, Georgia; Evageliou, Vasiliki; Koutelidakis, Antonios E.; Kapsokefalou, Maria; Komaitis, Michael

doi:10.1016/j.foodhyd.2013.08.005

Cited by 25 publications

(11 citation statements)

References 35 publications

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“…Hot and cold water infusions had broadly similar antioxidant activity [50]. Soultani et al reported 2839 µmol FeEAC/g (green tea) and 1768 µmol FeEAC/g (black) for samples with total phenols content of 1111.0 µmol GAE/g and 723 µmol GAE/g(black tea) [33]. Other tea brands gave TptzFRAP(pH 3.6) results similar to values in this report ( Table 2).…”

Section: Tea Antioxidant Activity Total Phenols and Effect Of Phsupporting

confidence: 85%

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A FRAP Assay at pH 7 unveils Extra Antioxidant Activity from Green, Black, White and Rooibos Tea but not Apple Tea

Apenten¹

2015

F Nutr Reprt

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Aim: Realization of a ferric reducing antioxidant power (FRAP) assay at neutral pH and re-evaluation of tea antioxidant activity for comparisons with the standard FRAP assay. Method:A FRAP assay at neutral pH utilized ferrozine (7.3-(2-Pyridyl)-5, 6-diphenyl-1, 2, 4-triazine-4' , 4''-disulfonic acid; ferrozine) dye in conjunction with Tris-HCl buffer (0.1M. pH 7.0) with 280 µl of regent addition to 20 µl of tea infusions and absorbance measurements at 562 nm with a microplate reader. Results:The microplate ferrozine FRAP assay (mFzFRAP) gave linear calibrations for ascorbic acid, gallic acid, ammonium ferrous sulphate, (AFS), trolox, cysteine and glutathione (R 2 = 0.998 -1.000) with molar absorptivity (measures of sensitivity) similar to literature values. The analytical precision was 5-7% and the minimum detectable concentrations (MDC) were 1.4-2.8 µM (0.4-0.8 nanomoles).Discussion: Values for FRAP were higher at pH 7.0 compared to pH 4.0 for gallic acid, ascorbic acid, glutathione, and cysteine possibly due to their ionization at high pH. The assay sensitivity for AFS and trolox were unchanged at pH 4.0 and pH 7.0. When assayed at pH 7 the water infusions from green tea, black tea, white tea, and rooibos tea had 200-360% antioxidant activity normally observable at low pH. Conclusion:A FRAP assay at pH 7 unveils extra antioxidant activity for green, black, white and Rooibos teas compared to values from the standard TptzFRAP (pH 3.6) method. As a recommendation, the antioxidant activity of teas and other herbal preparations should be re-evaluated over a wide pH range.

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Section: Tea Antioxidant Activity Total Phenols and Effect Of Phsupporting

confidence: 85%

“…Tea antioxidant activity was evaluated using the standard TptzFRAP (pH 3.6) assay [30][31][32][33]. Consuming tea increased plasma antioxidant activity in healthy subjects as measured using the TptzFRAP (pH 3.6) assay [31,[34][35][36].…”

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confidence: 99%

A FRAP Assay at pH 7 unveils Extra Antioxidant Activity from Green, Black, White and Rooibos Tea but not Apple Tea

Apenten¹

2015

F Nutr Reprt

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“…Mangoes also have a strong flavor and substantial levels of pectin which can mask the astringency of the tamarind seed without affecting antioxidant activity (Laaksonen ; Soultani et al. ).…”

Section: Introductionmentioning

confidence: 99%

“…Thus, mango juice was selected because of the abundance, seasonal availability, popularity, and distinctive flavor and taste. Mangoes also have a strong flavor and substantial levels of pectin which can mask the astringency of the tamarind seed without affecting antioxidant activity (Laaksonen 2011;Soultani et al 2014).…”

Section: Introductionmentioning

confidence: 99%

Effect of tamarind (Tamarindus indica L.) seed on antioxidant activity, phytocompounds, physicochemical characteristics, and sensory acceptability of enriched cookies and mango juice

Natukunda

Muyonga

Mukisa

2015

Food Science & Nutrition

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Tamarind seeds are not consumed despite their high antioxidative activity. In this study, 0–10% tamarind seed powder (TSP) was incorporated into mango juice and cookies. Total phenolics (Folin–Ciocalteu assay), antioxidant activity (2,2‐diphenyl‐1 picrylhydrazyl (DPPH) radical scavenging assay), flavonoid (aluminum chloride assay), condensed tannins content (Vanillin‐HCl assay), and consumer acceptability (n = 50) of the products were determined. TSP increased the pH and viscosity and reduced titratable acidity of juice. Incorporation of TSP increased the: total phenolic content (6.84 ± 0.21 to 88.44 ± 0.8 mg GAE/100 mL); flavonoid (4.64 ± 0.03–21.7 ± 0.36 mg CE/100 mL); condensed tannins (0.24 ± 0.01–21.81 ± 0.08 mg CE/100 mL) and total antioxidant activity (4.65 ± 0.88–21.70 ± 0.03 mg VCE/100 mL) of juice. A similar trend was observed for cookies. Maximum sensorially acceptable TSP levels were 1.5% and 6%, respectively, for juice and cookies. TSP can thus be utilized as a source of natural antioxidants in food products.

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“…All leaf samples from the canopy were dried for 1 h at 80 °C and then ground into fine tea powder. The concentration of TP was measured by the Folin–Ciocalteu colorimetry method ( Singleton, Orthofer & Lamuela-Raventos, 1999 ; Li & Wang, 2009 ; Büyükbalci & El, 2008 ; Schulz et al, 1999 ; Soultani et al, 2014 ; Iwasa & Torii, 1962 ). The AA concentration was measured using the ninhydrin colorimetry method ( Lee & Takahashi, 1966 ; Rosen, 1957 ).…”

Section: Methodsmentioning

confidence: 99%

Tea cultivar classification and biochemical parameter estimation from hyperspectral imagery obtained by UAV

Bian

Wan

et al. 2018

PeerJ

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It is generally feasible to classify different species of vegetation based on remotely sensed images, but identification of different sub-species or even cultivars is uncommon. Tea trees (Camellia sinensis L.) have been proven to show great differences in taste and quality between cultivars. We hypothesize that hyperspectral remote sensing would make it possibly to classify cultivars of plants and even to estimate their taste-related biochemical components. In this study, hyperspectral data of the canopies of tea trees were collected by hyperspectral camera mounted on an unmanned aerial vehicle (UAV). Tea cultivars were classified according to the spectral characteristics of the tea canopies. Furthermore, two major components influencing the taste of tea, tea polyphenols (TP) and amino acids (AA), were predicted. The results showed that the overall accuracy of tea cultivar classification achieved by support vector machine is higher than 95% with proper spectral pre-processing method. The best results to predict the TP and AA were achieved by partial least squares regression with standard normal variant normalized spectra, and the ratio of TP to AA—which is one proven index for tea taste—achieved the highest accuracy (RCV = 0.66, RMSECV = 13.27) followed by AA (RCV = 0.62, RMSECV = 1.16) and TP (RCV = 0.58, RMSECV = 10.01). The results indicated that classification of tea cultivars using the hyperspectral remote sensing from UAV was successful, and there is a potential to map the taste-related chemical components in tea plantations from UAV platform; however, further exploration is needed to increase the accuracy.

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The effect of pectin and other constituents on the antioxidant activity of tea

Cited by 25 publications

References 35 publications

A FRAP Assay at pH 7 unveils Extra Antioxidant Activity from Green, Black, White and Rooibos Tea but not Apple Tea

A FRAP Assay at pH 7 unveils Extra Antioxidant Activity from Green, Black, White and Rooibos Tea but not Apple Tea

Effect of tamarind (Tamarindus indica L.) seed on antioxidant activity, phytocompounds, physicochemical characteristics, and sensory acceptability of enriched cookies and mango juice

Tea cultivar classification and biochemical parameter estimation from hyperspectral imagery obtained by UAV

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