Analysis of catechins from milk–tea beverages by enzyme assisted extraction followed by high performance liquid chromatography

Ferruzzi, Mario G.; Green, Rodney J.

doi:10.1016/j.foodchem.2005.08.010

Cited by 76 publications

(51 citation statements)

References 33 publications

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“…Under these operating conditions, the retention times in minutes for the studied compounds were as follows: EGC (8.1), +C (10.2), caffeine (13.5), EC (14.8), EGCG (16.4), ECG (21.7), GC (6.1) and GA (4.3) (Figure 2). Previously, results for green tea (Ferruzzi and Green, 2005) and for clonal fresh leaves (Ender et al, 2004) were comparable to the observed results.…”

Section: Resultssupporting

confidence: 87%

Antioxidant capacity of different types of tea products

Karori¹,

Wachira²,

Wanyoko³

et al. 2007

Afr. J. Biotechnol.

173

133

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In the present study, twelve different types of commercial tea samples were assayed to determine their phenolic composition and antioxidant activity. Reverse phase high performance liquid chromatography using a binary gradient system was used for the identification and quantification of individual catechins. Subsequently, total phenolic content was determined spectrophotometrically according to the Folin-ciocalteus method. Total theaflavins and thearubigins were also determined. The radical scavenging behavior of the polyphenols on 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) was also studied spectrophotometrically. The results showed that total polyphenols, total catechins and antioxidant activity were significantly (P<0.05) different in the commercial tea samples. Green tea had the highest levels of catechins, total polyphenols and total antioxidant activity. White tea (silvery tip) a rare specialty type of tea was not significantly different from green tea. Statistical analysis showed an essential catechin content influence of the tea extracts on antioxidant activity. Epigallocatechin gallate (EGCG) was the most potent catechin and the most potent in antioxidant activity (r = 0.989***). Epigallocatechin (EGC) (r = 0.787, P<0.001), epicatechin (EC) + catechin (+C) and epicatechigallate (ECG) also showed significant (P<0.05) antioxidant activity. Black tea contained high levels of theaflavins and thearubigins, which accounted for most of the antioxidant potential in this type of tea product (r = 0.930*** and r = 0.930*** respectively). These results suggest that conversion of catechins during black tea processing did not affect the free-radical potency of black tea. Gallic acid (GA) also showed significant(r = 0.530*) contribution to the antioxidant activity in black tea. Green, black and white tea products processed from Kenyan tea cultivars originally selected for black tea had significantly (P<0.05) higher antioxidant activity than green tea processed from tea cultivars from Japan and China. These results seem to suggest that the cultivar type is critical in determining the antioxidant potency of tea product and that black teas processed from suitable cultivars could be potent in antioxidant activity when compared to green teas.

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Section: Resultssupporting

confidence: 87%

Antioxidant capacity of different types of tea products

Karori¹,

Wachira²,

Wanyoko³

et al. 2007

Afr. J. Biotechnol.

173

133

View full text Add to dashboard Cite

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“…NIR spectroscopy has been used to measure gallic acid in alcoholic beverage (Dmitrienko et al 2002), citric and tartaric acids in orange juice (Cen et al 2007), anthocyanins in red wine (Soriano et al 2007), the quality parameters (including pH) of spirit beverages (Lachenmeier 2007), the energetic value of fruitand milk-based beverages (Moros et al 2005), soluble solids and pH of bayberry juice (Shao and He 2007), alcoholic strength of white and red wines (Rocchia et al 2007), SSC and pH of rice vinegar (Liu et al 2008), SSC and pH of rice wine (Liu et al 2007), catechins in tea beverage (Ferruzzi and Green 2006), metal content of tea beverages (Fernández et al 2002), and SSC in tea soft drink (Li et al 2007a).…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Least Squares Support Vector Machine Regression and other Multivariate Calibrations in Determination of Internal Attributes of Tea Beverages

Liu

2008

Food Bioprocess Technol

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This research aimed to explore the relationship between internal attributes (pH and soluble solids content) of tea beverages and diffuse reflectance spectra. Three multivariate calibrations including least squares support vector machine regression (LSSVR), partial least squares (PLS), and radial basis function (RBF) neural network were adopted for development of internal attributes determination models. Ten kinds of tea beverages including green tea and black tea were selected for visible and near infrared reflectance (Vis/NIR) spectroscopy measurement from 325 to 1,075 nm. As regard the kernel function, least squaressupport vector machine regression models were built with both linear and RBF kernel functions. Grid research and tenfold cross-validation procedures were adopted for optimization of LSSVR parameters. The generalization ability of LSSVR models were evaluated by adjusting the number of samples in the training set and testing set, and sensitive wavelengths that were closely correlated with the internal attributes were explored by analyzing the regression coefficients from linear LSSVR model. Excellent LSSVR models were built with r=0.998, standard error of prediction (SEP)=0.111, for pH and r=0.997, SEP=0.256, for soluble solids content, and it can be found that the LSSVR models outperformed the PLS and RBF neural network models with higher accuracy and lower error. Six individual sensitive wavelengths for pH were obtained, and the corresponding pH determination model was developed with r=0.994, SEP=0.173, based on these six wavelengths. The soluble solids content determination model was also developed with r=0.977, SEP=0.173, based on seven individual sensitive wavelengths. The above results proved that Vis/NIR spectroscopy could be used to measure the pH and soluble solids content in tea beverages nondestructively, and LSSVR was an effective arithmetic for multivariate calibration regression and sensitive wavelengths selection.

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“…In responded to document health benefits of tea catchenis, new products have been developed with tea as an energetic ingredient such as tea beverages, ice creams, cereal and elziney@yahoo.com pet foods. It is reported that tea is produced with milk in different concentrations to order to enhance sensory characteristics however; tea herb is not regularly consumed with milk hence though new formula of green tea with soy and other milk products are increasing [10]. Implementation of green tea infusion during yoghurt production led to enhance the antioxidant capacity in final product and promote the growth of Lactobacillus spp.…”

Section: Introductionmentioning

confidence: 99%

Protective Effects of Green Tea and Moringa Leave Extracts and Their Bio-Yoghurts against Oxidative Effects of Lead Acetate in Albino Rats

El-Ziney¹

2017

JNHFS

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Background: Health benefits of designed functional foods using dairy fermented products in co-production with medicinal herbs are under comprehensive investigations. Yoghurt has triggered a functional food revolution while green tea and Moringa oleifera represent precious source of high content of various types of antioxidants and micronutrients. Oxidative stress and lipid peroxidation are suggested mechanisms involved in lead toxicity. The aim of present study was to assess protective effects of green tea and moringa leave extracts and their bio-yoghurts against lead acetate-induced oxidative stress in male rats by following liver weight and enzymes and lipids profile.

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Analysis of catechins from milk–tea beverages by enzyme assisted extraction followed by high performance liquid chromatography

Cited by 76 publications

References 33 publications

Antioxidant capacity of different types of tea products

Antioxidant capacity of different types of tea products

Evaluation of Least Squares Support Vector Machine Regression and other Multivariate Calibrations in Determination of Internal Attributes of Tea Beverages

Protective Effects of Green Tea and Moringa Leave Extracts and Their Bio-Yoghurts against Oxidative Effects of Lead Acetate in Albino Rats

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