Different Withering Times Affect Sensory Qualities, Chemical Components, and Nutritional Characteristics of Black Tea

The present study emphasizes the effect of withering time set at 4 ± 0.5 h (WT4), 6 ± 0.5 h (WT6), 8 ± 0.5 h (WT8), 10 ± 0.5 h (WT10), and 12 ± 0.5 h (WT12) on the sensory qualities, chemical components, and nutritional characteristics of black tea. The sensory evaluation revealed high total quality scores at WT8 and WT10. Polysaccharides, amino acids, and soluble sugars significantly increased with an increase in withering time, and an apparent peak value was obtained at WT10. However, polyphenols, flavonoids, glycosides, organic acids, catechins, alkanoids, and theaflavins decreased with an increase in withering time. With an increase in withering time, the content of aromatic substances showed a trend of increasing first and then decreasing. The peaks of alcohols, aldehydes, and acids appeared at 10 ± 0.5 h, 10 ± 0.5 h, and 8 ± 0.5 h, respectively. The content of esters, ketones, and hydrocarbons showed a downward trend with an increase in withering time. Aroma analysis revealed that withering time could not exceed 10 ± 0.5 h. Black tea withered up to WT10 showed enhanced inhibition of α-glucosidase and α-amylase activity with good sensorial attributes. Glucose uptake inhibition capacity increased up 6 ± 0.5 h and then decreased, while antioxidant capacity decreased with an increase in withering time. The overall results show that the 8 ± 0.5 h to 10 ± 0.5 h withering time could improve black tea quality and nutritional characteristics.

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Assessing black tea quality based on visible–near infrared spectra and kernel-based methods

Journal of Food Composition and Analysis ◽

10.1016/j.jfca.2021.103810 ◽

2021 ◽

Vol 98 ◽

pp. 103810

Author(s):

Guangxin Ren ◽

Ying Liu ◽

Jingming Ning ◽

Zhengzhu Zhang

Keyword(s):

Infrared Spectra ◽

Near Infrared ◽

Black Tea ◽

Near Infrared Spectra ◽

Tea Quality

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Determination of the Chemical Composition of Tea by Chromatographic Methods: A Review

Journal of Food Research ◽

10.5539/jfr.v4n3p56 ◽

2015 ◽

Vol 4 (3) ◽

pp. 56 ◽

Cited By ~ 34

Author(s):

Alexandr Ya Yashin ◽

Boris V. Nemzer ◽

Emilie Combet ◽

Yakov I. Yashin

Keyword(s):

Chemical Composition ◽

Volatile Compounds ◽

Black Tea ◽

Storage Conditions ◽

Organoleptic Evaluation ◽

Chromatographic Methods ◽

Tea Quality ◽

Processing And Storage ◽

And Storage

<p>Despite the fact that mankind has been drinking tea for more than 5000 years, its chemical composition has been studied only in recent decades. These studies are primarily carried out using chromatographic methods. This review summarizes the latest information regarding the chemical composition of different tea grades by different chromatographic methods, which has not previously been reviewed in the same scope. Over the last 40 years, the qualitative and quantitative analyses of high volatile compounds were determined by GC and GC/MS. The main components responsible for aroma of green and black tea were revealed, and the low volatile compounds basically were determined by HPLC and LC/MS methods. Most studies focusing on the determination of catechins and caffeine in various teas (green, oolong, black and pu-erh) involved HPLC analysis.</p> <p>Knowledge of tea chemical composition helps in assessing its quality on the one hand, and helps to monitor and manage its growing, processing, and storage conditions on the other. In particular, this knowledge has enabled to establish the relationships between the chemical composition of tea and its properties by identifying the tea constituents which determine its aroma and taste. Therefore, assessment of tea quality does not only rely on subjective organoleptic evaluation, but also on objective physical and chemical methods, with extra determination of tea components most beneficial to human health. With this knowledge, the nutritional value of tea may be increased, and tea quality improved by providing via optimization of the growing, processing, and storage conditions.</p>

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A Novel Technique of Black Tea Quality Prediction Using Electronic Tongue Signals

IEEE Transactions on Instrumentation and Measurement ◽

10.1109/tim.2014.2310615 ◽

2014 ◽

Vol 63 (10) ◽

pp. 2472-2479 ◽

Cited By ~ 18

Author(s):

Pradip Saha ◽

Santanu Ghorai ◽

Bipan Tudu ◽

Rajib Bandyopadhyay ◽

Nabarun Bhattacharyya

Keyword(s):

Electronic Tongue ◽

Black Tea ◽

Quality Prediction ◽

Novel Technique ◽

Tea Quality

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Differential Responses of Two Broccoli (Brassica oleraceaL. var Italica) Cultivars to Salinity and Nutritional Quality Improvement

The Scientific World JOURNAL ◽

10.1100/2012/291435 ◽

2012 ◽

Vol 2012 ◽

pp. 1-12 ◽

Cited By ~ 18

Author(s):

Chokri Zaghdoud ◽

Carlos Alcaraz-López ◽

César Mota-Cadenas ◽

María del Carmen Martínez-Ballesta ◽

Diego A. Moreno ◽

...

Keyword(s):

Nutritional Quality ◽

Genetic Background ◽

Nutritional Value ◽

Soluble Sugars ◽

Root Hydraulic Conductance ◽

Nutritional Properties ◽

Specific Strategy ◽

Nutritional Characteristics ◽

Salinity Levels

The comparative responses of two broccoli cultivars (Brassica oleraceavar. Italica, cv. Parthenon and cv. Naxos) to a 15 d exposure to different NaCl levels were investigated. Salinity led to increased concentrations of Na+and Cl−ions in both cultivars, a disruption of the endogenous minerals levels in the shoots and roots—that varied with the cultivar and salt concentration—and decreases in the osmotic potential (Ψπ), root hydraulic conductance (L0), and stomatal conductance (Gs). The reduced biomass of Naxos at moderate NaCl indicates greater sensitivity to salinity, compared with Parthenon. Parthenon accumulated more soluble sugars, for osmotic adjustment, whereas Naxos accumulated proline, which gave the two cultivars differing nutritional characteristics. The total glucosinolates (GSLs) content was not affected by salinity in Parthenon while it decreased significantly in Naxos as a consequence of the decrease in the indole GSL. However, Naxos accumulated more aliphatic GSLs under salt stress than Parthenon, which confers on this cultivar a greater nutritional value when cultivated under salinity.These results suggest that, at distinct salinity levels, each broccoli cultivar adopts a specific strategy, indicating the crucial role of the genetic background on the organoleptic and nutritional properties that each cultivar acquires.

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How does the nature of forages and pasture diversity influence the sensory quality of dairy livestock products?

Proceedings of the British Society of Animal Science ◽

10.1017/s175275620001156x ◽

2005 ◽

Vol 2005 ◽

pp. 245-245

Author(s):

B. Martin ◽

I. Verdier-Metz ◽

S. Buchin ◽

C. Hurtaud ◽

J. B. Coulon

Keyword(s):

Dairy Products ◽

Sensory Quality ◽

Health And Nutrition ◽

Production Factors ◽

Microbiological Characteristics ◽

Nutritional Characteristics ◽

Sensory Qualities ◽

Livestock Products ◽

Basic Link

The characteristics of dairy products depend on both the processing technology and the chemical and microbiological characteristics of milk. The milk properties depend themselves on a number of production factors linked to animals (genetic and physiology) or feeding. Some of these factors, the way animal are fed in particular, are increasingly becoming the focus of consumers’ concern. In particular, grass-based diets are sensitive because grass carries a positive image that can be attractive to some, because it may confer special nutritional characteristics to the products and also because grass feeding is part of the basic link between products and their original land which is important in the case of labelled products (Protected Denomination of Origin [PDO]). The aim of this text is to take stock of the recent studies (Coulon et al., 2004), which have studied the effect of grass on the sensory qualities of cheeses and butter. Other dimensions of quality. i.e., health and nutrition, are not investigated.

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Impact germination in the content of the chemical components of Homs and sensory qualities of Biskt plant it,

Baghdad Science Journal ◽

10.21123/bsj.2.1.47-52 ◽

2005 ◽

Vol 2 (1) ◽

pp. 47-52

Author(s):

Baghdad Science Journal

Keyword(s):

Crude Protein ◽

Chemical Constituents ◽

Chemical Components ◽

Treatment Control ◽

Organoleptic Properties ◽

Germination Period ◽

Germination Process ◽

Sensory Qualities ◽

The Impact

This study was conducted to identify the impact of germination in the ratio Almaah of Chemical Constituents of Homs and in the organoleptic properties of the Biskt plant it and compare the results with the treatment control (seeds Almnepth) Adhrt results for a significant increase in the percentage of crude protein with the progress of the process of germination, reaching 24.5% in percentage of crude protein with the progress of the germination process Krbu hydrate college during the germination period, reaching 59.2% in the fourth day

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Antioxidant Activity and Main Chemical Components of a Novel Fermented Tea

Molecules ◽

10.3390/molecules24162917 ◽

2019 ◽

Vol 24 (16) ◽

pp. 2917 ◽

Cited By ~ 7

Author(s):

Tao Tong ◽

Ya-Juan Liu ◽

Jinhong Kang ◽

Cheng-Mei Zhang ◽

Seong-Gook Kang

Keyword(s):

Antioxidant Activities ◽

Reducing Power ◽

Black Tea ◽

Chemical Components ◽

Total Phenolic ◽

Food Ingredient ◽

Functional Activities ◽

Overall Acceptability ◽

High Level

In the present study, we aimed to develop a novel fermented tea (NFT) product and to evaluate their in vitro antioxidant potential and chemical composition. We found that NFT contained a high level of total phenolic compounds (102.98 mg gallic acid equivalents/g extract) and exhibited diverse antioxidant activities, such as scavenging of 1,1-diphenyl-2-picryl-hydrazyl (DPPH) and hydroxyl radicals, as well as reducing power. The total catechins in NFT were comparable to those of Lipton black tea (LBT), but lower than those of Boseong green tea (BGT) or Tieguanyin oolong tea (TOT). Among all catechins tested, epigallocatechin (EGC) and epigallocatechin-3-O-gallate (EGCG) were the predominant compounds in NFT. In particular, the contents of total theaflavins (TFs), theaflavin (TF), theaflavin-3-gallate (TF3G), and theaflavin-3’-gallate (TF3’G) in NFT were significantly higher than that of BGT, TOT, or LBT. NFT had the highest level of total essential amino acid and γ-aminobutyric acid (GABA) compared with BGT, TOT and LBT. Furthermore, the sensory evaluation results showed that NFT had satisfactory color, aroma, taste, and overall acceptability scores. Our results highlight the potential usefulness of this novel fermented tea as a nutraceutical food/ingredient with special functional activities.

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A predictive approach to the antioxidant capacity assessment of green and black tea infusions

Journal of Food Measurement & Characterization ◽

10.1007/s11694-020-00727-3 ◽

2020 ◽

Author(s):

Małgorzata Muzolf-Panek ◽

Anna Kaczmarek ◽

Anna Gliszczyńska-Świgło

Keyword(s):

Data Mining ◽

Antioxidant Activity ◽

Antioxidant Capacity ◽

Black Tea ◽

Multivariate Adaptive Regression Splines ◽

Total Phenolic ◽

Data Mining Techniques ◽

Tea Quality ◽

Tea Infusions ◽

Green And Black Tea

AbstractContemporary consumers drink significant amounts of tea because of its health–benefits mainly associated to the presence of polyphenols with high antioxidant activity. Therefore, the information how to obtain tea infusion of the highest quality, i.e. with high antioxidant capacity is needed. In this study, the various models for the prediction of total polyphenols and antioxidant activity of green and black tea infusions were developed and compared. Three mathematical equations: Spiro’s, Peleg’s and logarithmic, and two data mining techniques: multivariate adaptive regression splines (MARS) and artificial neural networks (ANNs) were used to build the predictive models. The results obtained show that Spiro’s model could be used for the prediction of green tea quality expressed as total phenolic content or the antioxidant activity (determination coefficients above 0.99), whereas Peleg’s model is more suitable for black tea quality prediction (determination coefficients above 0.99). Data mining techniques (MARS and ANNs) enable to create models fast and of simple application with very good acceptability (determination coefficients above 0.99).

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