Black Tea Research Articles

Effect of green tea or black tea extract on lipid and protein oxidation in Cantonese sausage.

Natural polyphenols offer a safer alternative to synthetic antioxidants in meat products. This study investigated the efficacy of green tea and black tea extracts as natural antioxidants in Cantonese sausages to inhibit lipid and protein oxidation. Sausages were prepared with the addition of different concentrations - 100, 300, and 600 mg kg-1 total polyphenols (TP) - of green tea or black tea extract. Oxidation of the sausages was assessed through thiobarbituric acid reactants, carbonyl content, and thiol content, whereas consumer acceptability was evaluated based on texture, color, and sensory analysis. The tea extracts inhibited malondialdehyde production and reduced the thiobarbituric acid reactive substance value from 23.72 mmol MDA g-1 to less than 1.94 mmol MDA g-1. However, the addition of tea extracts decreased the thiol content and caused the loss of myosin heavy chain and actin bonds in sodium dodecyl sulfate polyacrylamide gel electrophoresis. Although the addition of tea extracts increased the redness and hardness of the sausage, no significant difference in consumer acceptance between the control and treatment groups was observed in the sensory analysis. The tea extract inhibited the oxidation of lipids in Cantonese sausage. There was no negative effect on the sensory characteristics of sausages. The use of tea extracts as natural antioxidants in Cantonese sausage is therefore feasible. © 2024 Society of Chemical Industry.

Black tea caffeine in the radiochemical separation of 89Zr produced from alpha particle irradiation on natY

Black tea caffeine in the radiochemical separation of 89Zr produced from alpha particle irradiation on natY

Optimization of ultrasonication-assisted enzymatic extraction of Kangra orthodox black tea for the development of low-calorie ready-to-drink tea

Optimization of ultrasonication-assisted enzymatic extraction of Kangra orthodox black tea for the development of low-calorie ready-to-drink tea

A novel Co/Zn-ferrite molecularly imprinted polymer-based electrochemical assay for sensing of gallic acid in plant extracts, wine, and herbal supplement.

In this study, a new molecularly imprinted polymer (MIP)-based sensor platform was developed for the electrochemical determination of gallic acid (GAL) in plant extracts, wine, and herbal supplements. Gallic acid is known for its natural antioxidant properties, which play an important role in preventing cell deterioration that can lead to various diseases. In addition, gallic acid has therapeutic potential due to its anticancer, antiinflammatory, antimicrobial, and neuroprotective properties. Accurate analysis of gallic acid in complex matrices, in mixed samples where different components coexist, is necessary to evaluate the efficacy and safety of this compound. Cobalt ferrite-zinc-dihydro caffeic acid (CFO_Zn_DHCA) nanoparticles, sphere-like in shape and 5 ± 1nm in size, were incorporated into the MIP-based electrochemical sensor design to enhance the active surface area and porosity of the glassy carbon electrode (GCE) surface. The functional monomer chosen for this study was aminophenyl boronic acid (3-APBA). In the GAL/CFO_Zn_DHCA/3-APBA@MIP-GCE sensor, which was developed using photopolymerization (PP), 3-APBA as a functional monomer was designed, and obtained in the presence of basic monomer (HEMA), cross-linker (EGDMA), and initiator (2-hydroxy-2-methyl propiophenone) by keeping it under a UV lamp at 365nm. It aims to detect GAL in real samples such as Punica granatum (pomegranate) peel, Camellia sinensis (green and black tea leaves), wine, and herbal supplements. Morphological and electrochemical characterizations of the designed GAL/CFO_Zn_DHCA/3-APBA@MIP-GCE sensor were carried out using scanning electron microscopy (SEM), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The linear range for the determination of GAL using the indirect method (5.0mM [Fe(CN)6]-3/-4) was found to be 1.0 × 10-13M-1.0 × 10-12M, and the limit of detection (LOD) and limit of quantification (LOQ) for standard solutions werecalculated as 1.29 × 10-14 and 4.29 × 10-14M, respectively. As a result of the study, the developed MIP-based electrochemical sensor was suitable for detecting GAL with high specificity, selectivity, and sensitivity. Recovery studies were performed to determine the practical applicability of the sensor, and the results were satisfactory. This innovative sensor platform stands out as a reliable and sensitive analytical tool for determining GAL.

ECONOMIC FEASIBILITY STUDY FOR THE IMPLEMENTATION OF A MICRO-INDUSTRY PRODUCING KOMBUCHA FLAVORED WITH PASSION FRUIT FROM THE CAATINGA.

Kombucha is a fermented beverage of Chinese origin produced from the infusion of black or green tea from the Camelia sinensis plant, sugar and a symbiotic culture known as SCOBY. After fermentation, the drink becomes rich in natural nutrients with functions that are beneficial to health such as organic acids, amino acids, vitamin C, polyphenols and antibiotic substances. The present work aims at carrying out a study of the economic feasibility of opening a micro-industry for the production of a black tea kombucha flavored with passion fruit from the caatinga. The caatinga passion fruit is a species native to the dry areas of northeastern Brazil. This fruit is rich in flavonoids, vitamin C and carotenoids, which have antimicrobial and antioxidant properties. For the development of the study, specifications of processes, equipment and analysis of financial and economic indicators were carried out. The evaluation of the investments was carried out using the internal rate of return (IRR), minimum attractiveness rate (TAM), net present value (NPV), simple payback and discounted payback methods. The initial investment for the production of 2,000 L of kombucha flavored with passion fruit from the caatinga was R$ 187,199.78. The economic indicators obtained resulted in NPV of R$ 253,154.68, IRR of 22%, TAM of 13.34% p.a. and simple payback of 3.9 years considering a useful life of 10 years. The positive IRR reflects that the enterprise is economically viable and profitable, making it possible to invest and generate income for cooperatives and family farmers.

Abderrahmane Sissako, dir. Black Tea. 2024. 110 minutes. Mandarin Chinese and French, with French subtitles. France, Mauritania, Luxembourg, Taiwan, and Ivory Coast. Gaumont. €19.99.

Abderrahmane Sissako, dir. Black Tea. 2024. 110 minutes. Mandarin Chinese and French, with French subtitles. France, Mauritania, Luxembourg, Taiwan, and Ivory Coast. Gaumont. €19.99.

Metabolomics reveals a differential attitude in phytochemical profile of black tea (Camellia Sinensis Var. assamica) during processing

Black tea's quality and flavor are largely influenced by its processing stages, which affect its volatile and non-volatile phytochemicals. This study aimed to optimized black tea manufacturing by investigating withering time, fermentation time, and temperature's impact on sensory quality. Using a U*15 (157) uniform design, optimal conditions were determined: 14 h of withering, 5.6 h of fermentation, and a 34 °C temperature. A verification experiment analyzed the volatile and non-volatile profiles. HPLC, GC–MS, and LC-MS revealed dynamic changes in phytochemicals. Among 157 VOCs and 2642 metabolites, 19 VOCs (VIP > 1.5) were crucial for aroma, while 50 (VIP > 1.5, p < 0.01) characteristic metabolites were identified. During processing, fragrant volatile compounds like linalool oxides, geraniol, benzeneacetaldehyde, benzaldehyde, methyl salicylate, and linalyl acetate increased, contributing to rose and honey like aromas. These changes were crucial in developing the characteristic flavor and color of black tea. Twenty-four new compounds formed, while 80 grassy odor volatiles decreased. Non-volatile metabolites changed notably, with decreased catechins and increased gallic acid. Theaflavin compounds rose initially but declined later. This study outlines metabolite changes in Yunkang 10 black tea, crucial for flavor enhancement and quality control.

An improved deep convolutional generative adversarial network for quantification of catechins in fermented black tea

The rapid and non-destructive quantification of catechins in fermented black tea is crucial for evaluating the quality of black tea. The combination of hyperspectral imaging and chemometrics has been applied for quantitative detection, but its performance is usually constrained by the limited dataset size. Targeted at the challenge of insufficient samples in regression analysis of catechins, this study proposes an improved deep convolutional generative adversarial network with labeling module, named as DCGAN-L for hyperspectral data augmentation. The DCGAN-L consists of the spectral and label generating modules. First the synthetic spectra were generated, and an indicator was proposed to evaluate their quality. Then, the corresponding label values were generated, including epicatechin gallate (ECG), epicatechin (EGC), catechin (C), and total catechin (CC). For label generating, the Euclidean distances between the synthetic spectrum and all true spectra were measured, followed by allocating weights for calculating the label values based on these distances. Subsequently, the training dataset was augmented with the generated synthetic data. The effect of data augmentation was finally evaluated based on two regression models of random forest (RF) and broad learning system (BLS) for the quantification of catechins. Compared with the results before data augmentation, the average R2 of RF and BLS models increased by 0.044 and 0.164, respectively. The proposed DCGAN-L model allows for the rapid, non-destructive quantification of catechins in black tea in the case of limited sample size.

Design of a Portable Spectrophotometer Based on Raspberry Pi for Tea Type Classification Using Machine Learning

Abstract The use of spectrophotometers in food and beverage quality analysis has become common. However, portability and high cost have long been a problem for food industry players and small-scale laboratories. In this study, a more compact and low-cost spectrophotometer has been developed using raspberry pi. To validate its performance, the prototype was used to classify green tea, black tea, and oolong tea types. The research started with designing and assembling the hardware using a raspberry pi camera with Complementary Metal Oxide Semiconductor (CMOS) sensor, Digital Versatile Disk (DVD) as diffraction grating, white LED as light source and 3D printer as casing. The prototype was then used to acquire data from green tea, black tea and oolong tea solutions. In the tea type identification process, Principal Component Analysis (PCA) was applied to the data obtained. The experiment involved 30 solution samples of each of the three types of tea. The light source was directed past the sample towards the slit and DVD, then the spectrum image of the light source was displayed through a user interface built using python programming. This research resulted in a spectrophotometer with dimensions of 260 mm x 120 mm x 63 mm that is capable of capturing light spectra in the range of 400 - 700 nm. Based on the experimental results, the classification accuracy of the three types of tea using CNN and Decision Tree reached 100%.

Dynamic changes in microbial communities and volatile compounds in kombucha fermentation using Flos sophorae and Elm fruits, compared to black and green tea

The dynamic changes in physicochemical properties, microbial communities, and volatile compounds in kombucha made from Flos sophorae (FLSK) and Elm fruit (EFK) were compared to those of black tea (BTK) and green tea (GTK) over a 12-day fermentation period. The results revealed that overall flavonoid and polyphenol content, as well as antioxidant activity, increased initially and then decreased, accompanied by a steady reduction in pH within the fermentation broths investigated. Notably, the GTK exhibited stronger antioxidant activity than the other fermentation broths. Furthermore, 16S rRNA gene sequencing revealed that Komagataeibacter rhaeticus, Komagataeibacter saccharivorans, and Acidovorax wautersii were the dominating microbial species in the fermentation broths under this study. Komagataeibacter rhaeticus initially reduced and then increased throughout the FLSK fermentation, whereas Komagataeibacter saccharivorans increased from day 0 to day 6, and remain stable by day 12 during the EFK fermentation. Comparative analysis revealed that Komagataeibacter rhaeticus was more abundant in the FLSK and GTK than in the EFK and BTK, whereas Komagataeibacter saccharivorans showed a higher abundance in the EFK relative to the other fermentation broths. Gas chromatography-mass spectrometry identified acetic acid, linalool, ethanol, and ethyl acetate as the major volatile chemicals that rose significantly in fermentation mixtures of the examined substrates. The FLSK had a much higher linalool concentration than the other fermentation broths, although the EFK and GTK had higher ethanol content. Correlation study found that Komagataeibacter rhaeticus was negatively related with alcohol compounds, but Komagataeibacter saccharivorans was positively associated with a diverse spectrum of acids, alcohols, and esters. The study found changes in bioactive chemicals as well as interactions between bacterial populations and volatile compounds throughout fermentation in the substrates investigated.

Utilizing nontargeted metabolomics integrated with quality component quantitation via differential analysis to reveal the taste differences between and metabolite characteristics of hawk black tea and hawk white tea

This study conducted a comprehensive analysis of the differences in the taste characteristics of hawk black tea and hawk white tea, exploring the intrinsic relationship between nonvolatile metabolites and these taste characteristics. The results revealed significant differences in taste properties of the two types of hawk tea. Hawk black tea mainly exhibits a fresh, sweet, and sweet aftertaste quality, whereas hawk white tea offers a mellow and pure taste. Comparative analysis revealed that the content of amino acids and carbohydrates in hawk black tea was significantly higher than that in hawk white tea, while the content of flavonoids and organic acids was relatively lower. Quality composition results indicated significant differences in the 13 major quality components and water extracts between the two hawk teas, aligning with the quantitative descriptive analysis results. Additionally, through weighted gene coexpression network analysis, significant associations were found between 671 metabolites across 155 metabolic pathways and 9 taste characteristics. Among them, flavonoid biosynthesis and degradation are the main metabolic pathways of the two types of hawk tea. And it was found that butin, phlorizin, naringin, dihydrokaempferol, sakuranetin, apigenin, (−)-epicatechin, (+)-gallocatechin, caffeoyl shikimic acid, homoeriodictyol, which are 10 flavonoids, are the key metabolites affecting the taste difference of hawk black and white tea. Additionally, this study found that hawk tea does not contain caffeine, which is of great significance for the development of caffeine-free beverages in the future.

A black tea quality testing method for scale production using CV and NIRS with TCN for spectral feature extraction

To rigorously assess black tea quality in large-scale production, this study introduces a multi-modal fusion approach integrating computer vision (CV) with Near-Infrared Spectroscopy (NIRS). CV technology is first applied to evaluate the tea's appearance quality, while NIRS quantifies key chemical components, including tea polyphenols (TP), free amino acids (FAA), and caffeine (CAF). Additionally, different methods are employed to extract potential quality features from NIR spectra. The information are then fused, and a classifier is utilized to accurately identify tea quality. Results show that the Temporal Convolutional Network (TCN) fused model achieves a 98.2 % accuracy rate, surpassing both the Convolutional Neural Network (CNN) fused model and traditional methods. This study demonstrates that TCNs effectively extract spectral features and that data fusion significantly enhances tea quality testing, offering valuable insights for production optimization.

New insights into the role of lipids in aroma formation during black tea processing revealed by integrated lipidomics and volatolomics

New insights into the role of lipids in aroma formation during black tea processing revealed by integrated lipidomics and volatolomics

Information fusion of hyperspectral imaging and self-developed electronic nose for evaluating the degree of black tea fermentation

Fermentation is a crucial step in the processing of black tea. Currently, the evaluation of the fermentation degree of black tea relies mainly on manual experience, which suffers from subjectivity and lacks quantifiability. This study proposed the fusion of hyperspectral imaging and electronic nose to evaluate the degree of black tea fermentation. The self-developed electronic nose was used to acquire aroma information, while hyperspectral imaging was used to obtain color and spectral information during the fermentation process. The samples were collected at different fermentation time including insufficient, moderate, and excessive fermentation. Then, the classification models were constructed based on individual types of information. Subsequently, the electronic nose data were fused with the hyperspectral data using different information fusion strategies (low-level, middle-level, high-level) and the classification models were built accordingly. Six types of classifiers were established. Results showed that with deeper levels of fusion, the accuracy of the model on the test set gradually improved. In the high-level fusion, the accuracy of the test set reached 100 %, with improvements of 10.34 % and 8.62 % compared with that solely based on electronic nose and hyperspectral imaging, respectively. This indicates that the proposed information fusion method is highly effective, providing state-of-the-art insights into and technologies for the evaluation of black tea fermentation degree.

Teh Hitam Cammelia Sinensis Dan Manfaatnya Untuk Kesehatan Pendekatan Berbasis Sains Dan Nilai Islam

Black tea from Camellia sinensis has been a highly popular beverage in Indonesia since the 17th century. Various types of Camellia sinensis tea include white tea, green tea, oolong tea, and black tea. Each type of tea has a distinct antioxidant profile, with black tea containing the highest caffeine content. All types of tea are rich in antioxidants like polyphenols, which play a crucial role in protecting the body from free radicals and reducing the risk of various diseases such as Alzheimer's, diabetes, stroke, hypertension, obesity, cancer, and have antibacterial properties while also serving as an anti-aging treatment for the skin.From an Islamic perspective, the Quran contains numerous verses that command humans to observe and study Allah's creations. This underscores the belief that nothing Allah has created is without purpose, implying that every creation has significant benefits. The consumption of black tea aligns with the principle of maintaining physical health as a form of spiritual responsibility, as also instructed in the Quran. The integration of scientific approaches with religious values elevates black tea beyond merely a beverage enjoyed for its taste, tradition, and health benefits, making it a part of a holistic healthy lifestyle. Utilizing tea production technology and advancing research to uncover the benefits of black tea is a way of expressing gratitude and is considered an act of worship, as its development adheres to the principle of benefiting others.

How the Dimensions of Plant Filler Particles Affect the Oxidation-Resistant Characteristics of Polyethylene-Based Composite Materials

This study analyzed the possibility of using plant-originated waste materials (black and green tea dust) as functional polyethylene fillers. The dependence between the size of the filler particles and their antioxidant potential is discussed. Six fractions were selected: below 50 µm, 50–100 µm, 100–200 µm, 200–400 µm, 400–630 µm and 630–800 µm. Significant differences between the effect of particle size and the antioxidant properties of black and green tea were found using the extraction method to analyze antioxidant activity (DPPH method) and total phenolic content (Folin-Ciocalteu method), suggesting a higher potential for using green tea as a filler with antioxidant properties, as well as the benefits of finer active filler distribution. Biomass waste fillers were mixed with low-density polyethylene LDPE SEB 853 I’m Green®, Braskem. Those samples were oxidized at 100 °C for 5 and 15 days to investigate the radical scavenging properties of fillers in composites. Fourier transform infrared spectroscopic studies show that the addition of both types of filler prevents the thermo-oxidation of polyethylene for 5 days. After 15 days, all samples except the BTW 400–630 and 630–800 µm exhibited oxidation. The mechanical properties of the LDPE and its’ composites were tested, and we noted an increased brittleness of neat LDPE after thermal oxidation. The addition of black tea particles above 100 µm in size prevents this behavior.

Utilization of azamacrocyclic ionophores as recognition elements for the potentiometric determination of gallic acid in various matrices

Gallic acid is a naturally occurring low molecular weight triphenolic molecule identified as a potent antioxidant, protecting against various types of reactive species and non-radicals. Three novel carbon paste electrodes were developed for the potentiometric determination of gallic acid. Azamacrocyclic ionophors; cyclen, hexacyclen, and kryptofix-22 were utilized as recognition ionophores separately. A multi-walled carbon nanotubes/titanium oxide nanocomposite was employed as the ion-to-electron transducer in the designed sensors. The prepared transducer was characterized by FT-IR and TEM. Molecular docking was implemented to study the recognition mechanism between these ionophores and the gallic acid molecule. It revealed promising binding interactions between gallic acid and the three recognition ionophores, especially hexacyclen and Kryptofix-22. In studying the potentiometric response of the proposed sensors, they exhibited high stability, sensitivity, accuracy, and precision in the quantitation of gallic acid. Gallic acid can be accurately quantified over the linearity range of 1 × 10−1–1 × 10−3 M, 1 × 10−2–1 × 10−6 M, and 1 × 10−2–1 × 10−6 M with a Limit of detection (LOD) 4 × 10−4 M, 3 × 10−7 M, and 7 × 10−7 M, for CPE1, CPE 2 and CPE 3, respectively. The electrodes showed high efficiency in determining gallic acid in Krameria lappacea root alcoholic extract, black tea, green tea, and human plasma without sophisticated pretreatment steps.

THE EFFECT OF DIFFERENT STAINING SOLUTIONS ON THE COLOR STABILITY OF PERMANENT INDIRECT COMPOSITE RESINS PRODUCED BY ADDITIVE AND SUBTRACTIVE TECHNIQUES

Objective: To investigate the effects of various beverages on the color stability of permanent composite resins produced by additive (AM) or subtractive manufacturing (SM) techniques comparatively. Materials and Methods: Six composite resin materials produced by SM (Vita Enamic-VE, Cerasmart-CE, Lava Ultimate-LU) and AM (Varseo Smile Crown plus-VSC, Saremco print Crowntech-SPC, Formlabs 3B Permanent Crown-FPC) techniques were selected and soaked in different solutions (artificial saliva, black tea, coffee) for different times (0, 1 and 7 days). L*, a*, b* values of the samples were recorded using a spectrophotometer. The color changes of the samples were determined using the CIELAB formula. In determining the color differences between the test materials, Kruskal-Wallis analysis was used when one-way analysis of variance wasn’t available. Results: Group VE was the least stained group on the 1st and 7th day of artificial saliva solution and the 7th day of coffee solution, while Group CE was the least stained group on the 1st day of coffee solution. In the tea solution, on the 1st and 7th days, there wasn’t difference in the materials' color change (p&amp;gt;0.05). Tea and coffee solutions caused statistically significantly more color change in all test materials than artificial saliva (except Group CE on the 7th day, Group VSC and FPC on the 1st day) (p&amp;lt;0.05). Conclusion: 3D permanent composite resins generally showed more staining than CAD/CAM milled composite resins. Tea and coffee staining solutions changed the color of the materials compared to artificial saliva. As the storage time increased, more color changes were observed.

Comprehensive Isolation and Characterization of Theaflavins, Thearubigins and Caffeine as Bioactive Compounds from Darjeeling Black Tea

The present study aimed to isolate and characterize three major bioactive components viz. theaflavins, thearubigins and caffeine from Darjeeling black tea, which contribute significantly to the cup characteristics and health benefits of black tea. Theaflavins were isolated using Soxhlet extraction followed by column chromatography, HPLC and UV spectroscopy. HPLC showed effective separation of four major theaflavins. Thearubigins were isolated using liquid-liquid extraction and characterized through NMR, FTIR-ATR and UV spectroscopic techniques. The NMR spectral studies suggested thearubigins to be polymeric oxidation products of catechin groups, while FTIR spectral studies indicated similarity with proanthocyanidin-like polymers. Caffeine was isolated via a solid-liquid extraction followed by liquid-liquid extraction and identified using TLC, NMR, UV and SEM techniques. TLC showed an Rf value of 0.65, which is consistent with standard caffeine. The NMR confirmed the purity of isolated caffeine and SEM revealed its needle-shaped crystal morphology. The results show that these bioactive compounds may be efficiently isolated and characterized using chromatographic and spectroscopic methods.

Functional Properties and Sensory Quality of Kombucha Analogs Based on Herbal Infusions.

Traditionally, kombucha is produced by the fermentation of black or green tea infusions with the use of SCOBY (Symbiotic Culture of Bacteria and Yeasts). However, SCOBY exhibits the ability to ferment other substrates as well, which can be used to create novel products with new sensory and health-promoting properties. This paper investigates the antioxidant activity, chemical composition, and sensory properties of mint, nettle, and blackcurrant leaf-based kombucha analogs. It has been demonstrated that the fermentation process with SCOBY significantly influenced (p ≤ 0.05) sugar, organic acids, and mineral contents, with the increase in iron, magnesium, and calcium amounts in all tested herbal kombucha. The study shows that the type of herb infusion has a significant influence on the parameters associated with antioxidant potential. The fermentation with SCOBY resulted in an increase in antioxidant activity as measured by the superoxide anion radical (O2•-) inhibition of all three tested herbal infusions, with the greatest changes observed in nettle kombucha. Herbal kombucha was characterized by significantly increased total phenolic content as determined by Folin's reagent and a changed phenolic compound profile by LC-MS/MS (liquid chromatography with tandem mass spectrometry) in comparison to nonfermented infusions. Very high sensory scores were achieved for fermented mint and blackcurrant-based kombucha.