Crush, Tear, Curl Research Articles

Zooming into CTC black-tea wine metabolites: A GC-MS-based study

This research was designed to propose a report on fermentation metabolomics of CTC (crush-tear-curl) tea wine (TW), a yeast-fermented broth of sugared CTC black tea infusion. The gas chromatography-mass spectrometry analysis of the tea wine revealed the presence of thirty-five metabolites, including the major compound glycerine with some potential antioxidant molecules and other bioactive agents (4H-pyran-4-one, 2,3-dihydro-3,5-dihydroxy-6-methyl-; furfural; furfuryl alcohol; succinic acid; levulinic acid; palmitic acid; tyrosol, pyruvaldehyde; and 1-hexadecanol). The role of metabolites in the physicochemical, biochemical, and medicinal properties of TW has been discussed. Biomolecules responsible for the flavour of TW were as follows: glycerine derivatives; pyruvaldehyde; furfural; furfuryl alcohol; acetic, levulinic, succinic, and palmitic acids, etc. – which might develop a sweet, caramel-like, astringent, slightly sour and wine-like flavour and taste. Furthermore, on the basis of yeast metabolism, possible biosynthesis pathways of metabolites were designed aiming for fermentation metabolomics. The outcome of this study cross-verified physicochemical, biochemical, and medicinal properties of TW suggesting its acceptability. As the fields of both wine research and tea science continue to evolve, the findings of this study may encourage fermentation technology for product development from tea that may also boost the growth of the tea industry.

Crush Tear Curl (CTC) Green Tea Processing: A Modified form of Green Tea for the Tea Lovers

An experiment was conducted following three factor factorial CRD to compare CTC green tea with conventional green tea on the basis of processing dynamics and biochemical characters of processed green tea as per the leaf standard of one leaf and a bud, two leaf and a bud and three leaf and a bud obtained from two tea clones namely TV1 and S3A3. Highest amount of polyphenol (245.65 mg g-1) was recorded in case of steaming done for 4 minutes and processed by CTC method using one leaf and a bud of TV1. Lowest antioxidant activity, in terms of DPPH scavenging (%) was recorded (74.02%) in case of CTC green tea processed by steaming done for 6 minutes using three leaves and a bud of TV1. Highest amount of total flavonoid content (22.92 mg g-1 of QE) was found in case of Orthodox green tea using one leaf and a bud of S3A3 where roasting done for 4 minutes.

Tracing the geographic origin of CTC black tea based on colorimetric sensor array response to taste substances combined with chemometrics

The quality of crush–tear–curl black tea (CTC-BT) varies greatly by geographic origin. Origin traceability is crucial for consumer interest protection, market order regulation, and food safety monitoring. This paper proposes a fast and accurate method for qualitative discrimination of CTC-BT origins and quantitative detection of its key taste-presenting substances. The method involves a simple colorimetric sensor array and ultraviolet–visible spectroscopy. The effects of various variable screening methods on modeling results were compared. A particle swarm optimization–based support vector machine achieved the highest performance in qualitative discrimination, with a correct classification rate of 99.48%. Based on their origin-distinguishing contributions and dose-over-thresholds, seven key taste-presenting substances were screened, namely, theaflavin, caffine, vitexin-2-O-rhamnoside, rutin, epigallocatechin gallate, epicatechin gallate, gallic acid. A least squares-support vector regression model achieved accurate quantification of the seven aforementioned compounds (square root of determination coefficient of prediction >0.9698, residual prediction deviation >2).

Green tea processing by pan-firing from region-specific tea (Camellia sinensis L.) cultivars - a novel approach to sustainable tea production in Dooars region of North Bengal

The black crush-tear-curl (CTC) tea constitutes the bulk tea production in Dooars region of North Bengal while green tea processing is confined to fewer tea estates, however, recent trends of the tea industry indicate gradual inclination towards green tea production. Our novel research findings on pan-fired green teas from twelve cultivated region-specific tea varieties at three flushes and data analysis of chemical and sensory quality attributes showed diversity in the leaf chlorophyll and carotenoid contents, as well as wide ranges of variation in green tea quality constituents including Polyphenols, Total Catechins, Catechin fractions, caffeine, free amino acids, Polyphenol to Amino acids ratio, Soluble Solid content and tasters’ quality scores. Most parameters differed significantly among the tea cultivars and between the three flushes within a certain cultivar. This study has highlighted the role of genetic variability of tea cultivars, processing conditions, and seasonal influence in determining green tea quality.

Metabolomic exploration of CTC tea manufacturing waste validates its potentiality as organic fertilizer

Valorization of agro-industrial waste resources is today’s main focus for agribiotechnologists. This research work was designed to valorise tea industrial waste, i.e., manufactured by-products from crush-tear-curl (CTC) tea factory. Physicochemical analysis has been carried out to characterize tea waste treated soil. Pot experiment with cowpea [Vigna unguiculata (L.) Walp.] was considered to study the impact of tea waste on plant growth. Morphological parameters such as length of plants and pods, and girth diameter were considered for growth study. Effect of tea factory waste on soil nutrition was found remarkable with increased organic carbon, organic matter, nitrogen, phosphorus, potassium and sulphur content. Pot culture revealed impact of tea waste composted soil on boosted plant growth. GC-MS based metabolite profiling revealed xanthosine and caffeine as major compounds in tea waste extract. A possible pathway has been proposed to explain the role of xanthosine and caffeine breakdown in fertilization of soil and plant growth. Disposal of tea wastes produced during tea manufacturing can be managed in a sustainable manner if this research is implemented industrially. This research portrays a notable nutrient richness in tea waste treated soil. Detection of purine metabolites revealed remarkable fertilizing and plant growth promoting properties of CTC tea waste.

Chemical Profiling of Crush, Tear, Curl (CTC) Tea Waste of Eastern Sub-Himalayan Regions: An Elemental and Spectroscopic Analysis

Tea is not only the most popular beverage in the world but also producing a large quantity untreated wastes product every year. In particular, the tea gardens of eastern Sub-Himalayan region cumulatively produce 15 million kg of crush, tear, curl (CTC)-factory tea waste (FTW) every year, which primarily includes discarded tea leaves, leaf fibers, buds and tender stems of tea plants. Beside that ~ 80% population of Indian subcontinent consume CTC tea regularly at their homes, tea stalls, market, cafe etc. and the waste produced from it, is called CTC domestic tea waste (DTW). Thus, not only factory tea waste but also a large quantity of domestic CTC tea waste (DTW) is exposed into the environment regularly. In present study, an attempt has been made for primary screening of the compounds in both the CTC-tea wastes. It has been shown that FTW sample contains greater amount of non-metal elements such as sulfur, calcium, phosphorus and metal elements like potassium and iron compared to DTW sample. Abundance of aromatic compounds has been seen to be higher in FTWs whereas, DTW primarily contains aliphatic compounds. Using Orbitrap-HRLCMS analysis allowed to make accurate predictions about the molecular structures of the likely organic chemicals found in tea trash. Thus, various bioactive organic compounds, micronutrients and trace elements from tea waste were found.

Quality chemical analysis of crush-tear-curl (CTC) black tea from different geographical regions based on UHPLC-Orbitrap-MS.

Crush-tear-curl (CTC) black tea is a popular beverage, owing to its unique taste characteristics and health benefits. However, differences in the taste quality and chemical profiles of CTC black tea from different geographical regions remain unclear. In this study, 28 CTC black tea samples were collected from six geographical regions and analyzed using electronic tongue and ultrahigh performance liquid chromatography-Orbitrap-mass spectroscopy. The e-tongue analysis indicated that each region's CTC black tea has its own relatively prominent taste characteristics: Sri Lanka (more umami and astringent), North India (more umami), China (more sweetness and astringent), South India (moderate umami and sweetness), and Kenya (moderate umami and astringent). Based on multivariate statistical analysis, 78 metabolites were tentatively identified and used as potential markers for CTC black tea of different origins, mainly including amino acids, flavone/flavonol glycosides, and pigments. Different metabolites, which contributed to the taste characteristics of CTC black tea, were clarified by partial least squares regression correlation analysis. Our findings may serve as useful references for future studies on origin traceability and quality characteristic determination of CTC black teas. PRACTICAL APPLICATION: This study provides useful references for future studies on the origin traceability and taste characteristic determination of CTC black teas from different geographical regions.

Improving black tea quality through optimization of withering conditions using artificial neural network and genetic algorithm

Polyphenol oxidase and peroxidase activity and moisture loss have been used for optimization of withering parameters in black tea production. Leaves of TV25 clone were withered at different air temperature (25, 30, 35°C) and relative humidity (RH) (60, 75, 85%), with constant air flow rate. With higher air temperature, Polyphenol oxidase specific activity decreased, whereas peroxidase specific activity was enhanced. A multilayered feed forward artificial neural network, with single hidden layer, was trained and validated using experimental data based on mean square error and coefficient of determination (R2). Optimized withering parameters for both crush-tear-curl (CTC) and orthodox tea production were obtained using Genetic Algorithms to maximize enzyme activity and bring down moisture content within desired range. A penalty function based on distance from feasible region was incorporated in Genetic Algorithm. Optimized parameters are: CTC – temperature: 29.13°C, RH: 79.58%, duration: 11.41 hr; Orthodox – temperature: 33.04°C, RH: 77.27%, duration: 10.60 hr. Novelty impact statement Polyphenol oxidase and peroxidase enzyme activity has been used as optimization criteria, along with moisture loss, for selection of withering parameters. Soft computing methods like Artificial Neural Network and Genetic Algorithms have been employed for modeling and optimization of the nonlinear relation between withering parameters and enzyme activity and moisture content with penalty function for constrained optimization of moisture content in leaves. In this study, optimum withering conditions in terms of air temperature, relative humidity, and duration were found out to obtain maximum enzyme activity and desired moisture content in leaf for producing better quality tea.

Determination of Green Tea Recovery Percentage and Its Relation to Different Weather Parameters

Aims: Green tea is one of the most popular drinks and millions of cups are consumed every day in entire world. In Bangladesh, people mainly prefer CTC (Crush-Tear-Curl) black tea but now-a-days health conscious people are being habituated to green tea due to its beneficial effect to health. Since our green tea production is very little compared to black tea production, our concept and knowledge about green tea is also very low. This experiment was conducted with two main objectives: to determine the green tea recovery percentage and to find its relation to different weather parameters.
 Study Design: This experiment was conducted by following Factorial Completely Randomized Design (CRD) with four replications.
 Place and Duration of Study: This experiment was conducted at Miniature Factory of Bangladesh Tea Research Institute (BTRI) Sreemangal, Moulvibazar-3210 from March 2017 to November 2017.
 Methodology: BTRI recommended green tea manufacturing process (Green Leaves→ Steaming→ Cooling→ Rolling→ Drying) was followed in this experiment to calculate the recovery percentage. Weight of green leaves after each stage and recovery percentage were calculated. Monthly weather data of four parameters: temperature (°C), rainfall (mm), relative humidity (%) and sunshine hour were also collected. Correlation Coefficient (r) was calculated by Pearson’s mathematical formulation to quantify the degree of relationship. Linear regression equation was also generated to predict recovery percentages against different weather parameters only when the relationship was significant.
 Results: In case of BTRI recommended green tea manufacturing process the average recovery percentage was 19.19% with an average moisture content of 3.72%. Among four weather parameters, temperature (°C) has negative insignificant (correlation coefficient, r=-0.43 and P=0.2523) relation on recovery percentage. But there was a strong significant (P=0.000146) negative effect (r=-0.942) of rainfall on recovery percentage. While a moderate non-significant (P=0.322807) negative relation (r=-0.37) of relative humidity and a considerable high positive non-significant (P=0.073687) relation (r=0.62) of sunshine hour on recovery percentage was found in this study.
 Conclusion: Green tea recovery percentage was 19.19% with an average moisture content of 3.72% which can be different with different weather conditions in every month. Among four weather parameters, mainly rainfall was responsible for the variation of recovery percentages in different months.

Analysis and modeling of major polyphenols during oxidation in production of black tea

Analysis of four different catechins, four theaflavins (TF), and thearubigin (TR) in oxidizing macerated CTC (crush–tear–curl) and rolled orthodox leaves of TV25 clone was done. Tea leaves were oxidized at different air temperatures (20, 25, 30, and 35°C) and thickness of oxidizing leaf bed (2 and 5 cm). Rate of depletion of catechins was modeled using Michaelis–Menten equation. Depletion of dihydroxylated catechins (EC, ECG) was found to be more affected by change in air temperature than trihydroxylated catechins (EGC, EGCG). Amount of maximum total TF at different temperatures was in the range of 1.19%–1.3% for CTC-macerated leaves and 0.33%–0.43% for rolled orthodox leaves. Quadratic and linear regression equations, developed to model the change in TF and TR contents, respectively, were good fit. Bed thickness does not have any significant effect on TF content in both CTC and orthodox leaves as revealed from ANOVA. Practical applications Oxidation or fermentation of macerated leaves is a crucial step in black tea processing that needs to be carefully monitored. Tea processing facilities maintain only air humidity level during fermentation. Air temperature is also an important factor affecting the degradation of catechins and formation of different pigment compounds. Optimum amount of unoxidized catechins and oxidized compounds TF and TR affects the quality of final product. Modeling of catechin, TF, and TR contents in oxidizing leaves will help to manipulate processing conditions such as air temperature, duration, and bed thickness to produce good quality black tea.

Automation Strategy for Black Tea Production Line

Tea is one of the primary beverages consumed with its added health benefits. India enjoyed supremacy in its production till a significant period. But, recently it is lagging behind in the race being surpassed by some neighbouring countries. The aforesaid issue is a matter of serious concern as it has a major share to contribute in the Gross Domestic Product (GDP) of the country and hence is a sizeable foreign exchange earner. The effect has arisen due to lack of varieties and cumbersome approach to the production of tea. Hence, this paper focuses on Computer Integrated Manufacturing (CIM) of tea industry which leads to automated production and scope of implementation of mixed assembly lines, thereby increasing the scope of the global market capture of sales. The automation is designed on Programmable Logic Controller (PLC) based control of the CTC (Crush, Tear & Curl) tea manufacturing processes. The user interface has been proposed to be developed with the help of a SCADA software. The interfacing of PLC and SCADA can be achieved by OPC communication. Virtual commissioning of the entire production line can be achieved by plant simulation.

Mass transfer coefficient and mass diffusivity of O2 and CO2 during oxidation of macerated CTC and rolled orthodox leaves in black tea manufacturing

AbstractOxidation of withered and macerated crush‐tear‐curl (CTC) and rolled orthodox tea leaves of TV25 clone was carried out in a closed chamber and oxygen and carbon dioxide concentration inside the chamber was measured at small time intervals. From the O2 consumption and CO2 production pattern during oxidation, mass transfer coefficient (ky′) and mass diffusivity (DAB) of O2 and CO2 was calculated considering equimolar counterdiffusion of the gases. Change in mass transfer coefficient and mass diffusivity of O2 and CO2 with duration of oxidation was fitted into exponential equation. Value of R2 for all the relationships were greater than .80 and reduced chi‐square values was less than 1. Values of ky′ and DAB at the initial stage of oxidation are higher for macerated CTC leaves and they reduce at a faster rate for oxidation of CTC tea than orthodox leaves.Practical applicationFermentation (oxidation) in black tea processing is the most important processing step responsible for characteristics tea quality in terms of color, flavor, and aroma. This step consists of several biochemical reactions which are associated with consumption of O2 and production of CO2 gas. Mass transfer coefficient and mass diffusivity of O2 and CO2 gas during oxidation in CTC granules and rolled orthodox leaves were estimated in this study. This would help with the control of air flow rate in designing continuous fermentation machines and also the number of changes in room air required for floor/gumlah/trough fermentation and thereby improved tea quality.

Determination of total quality of black tea fanning grade using near-infrared spectroscopy

Generally, the quality assessment of black tea from Camellia sinensis is determined by three important aspects including appearance, liquor, and infusion. Traditionally, the assessment is carried out by highly trained people using an organoleptic method. However, this method requires good physical and psychological health conditions as it relies on the sensitivity of their taste and flavor sensory. The method requires three to five people to avoid unfairness and to guarantee the level of consistency. In this paper, a new technique is reported for tea quality determinations using near-infrared spectroscopy followed by partial least squares (PLS) regression. The technique was developed by collecting 69 grade fanning (FANN) black tea samples of crush-tear-curl (CTC) type from 10 estates in Java and Sumatera. The samples were randomly divided into two groups consisting of 50 and 19 samples. The first group was used for developing a training set while the latter was applied for a validation set. Near-infrared spectra in the range of 4000-7500 cm−1 (interval 4 cm−1) were collected from the 69 samples without sample modifications or pretreatments. Then, the second derivative spectra of the training set were used to build a PLS model and validation procedures. The training set utilized results obtained from an organoleptic assessment of the same sample to calculate the predictor’s coefficient along the energy axis. The validation set then examined the prediction accuracy of the near-infrared and PLS model. The results show that the near-infrared and PLS technique successfully built a regression model based on the training set samples and properly predicted the scores obtained by the organoleptic determinations of the three quality parameters including appearance, liquor, and infusion using samples from the validation set. It can be concluded that the nondestructive measurement by near-infrared spectroscopy followed by PLS regression calculations successfully determined the black tea quality of FANN. Also, it provides an opportunity for the rapid determination of tea quality from a large number of tea samples at the market site.

Tea-Carbon Dots-Reduced Graphene Oxide: An Efficient Conducting Coating Material for Fabrication of an E-Textile

The present study reports a facile and green method for reduction of graphene oxide using carbon dots (CDs) derived from “Assam CTC (crush tear curl) Tea”. The efficient reduction of graphene oxide by tea-CDs was monitored using UV–visible spectroscopy. The reduced graphene oxide (rGO) prepared by this method adsorbs some amount of tea-CDs on its surface and forms a very good dispersion in aqueous medium without the use of any other capping or stabilizing agents. Subsequently, the tea-CDs reduced graphene oxide (TCD-rGO) was used for fabrication of a cotton-based conducting fabric with anticipated applicability in different electronic gadgets where high flexibility of the conducting material is required. Coating of cotton with TCD-rGO improved the thermostability of the fabric. The initial degradation temperature for the TCD-rGO coated fabric was found to increase by 30 °C compared to that of the bare cotton fabric. The electrical property of the coated fabric was evaluated. TCD-rGO coated fabric possessed a sheet resistance of 229 ± 20 Ω/sq and electrical conductivity 623 ± 54 S/m, which was comparable to that of the other graphitic conducting textile materials reported so far. The ohmic behavior and the electrical stability of the material was also studied. This particular approach eliminates the use of any toxic chemicals and other high cost synthetic products for fabrication of conducting textiles. Finally, to test the practical viability of the material developed, a stripe from the fabricated conducting fabric was used in a circuit to light up a series of light-emitting diode bulbs.

Economic, social and environmental impacts and overall sustainability of the tea sector in Sri Lanka

This evidence based study uses combined lifecycle and value/supply chain analysis to examine the sustainability (environmental, social and economic impacts) of tea manufacturing in Sri Lanka, a major export earner and employment creating product. Environmental indicators assessed include carbon emissions and energy use, social indicators include labour use and gender, and the economic indicator is cost. These indicators are assessed at all stages of production, processing, export, use and disposal. A cross-section of Low, Medium and High grown tea factories producing Crush, Tear, Curl (CTC) and Orthodox and Green tea (where available) were investigated. The study uncovered many issues including energy efficiency of the industry, Green House Gas (GHG) emissions, and occupational health hazards. One key result is that at the cultivation and processing stage, low grown orthodox tea is the most efficient in terms of labour use, energy use and carbon emissions. Energy use is highest in the use phase due to the high amounts of energy needed to heat water for a 2.5g tea bag. CO2 emissions are highest in the packaging stage due to the large amount of materials such as cardboard needed to package tea bags. Labour use is highest in the labour intensive cultivation stage. Costs are also highest in the cultivation stage/purchase of tea leaves, due to the high labour use.

COMPOSITION ANALYSIS OF OTD AND CTC BLACK TEAS (Camellia sinensis) FOR THE VOLATILE PROFILE DIFFERENTIATION BY HS-SPME/GC-MS

A total of fourteen different commercial brands of black teas including Orthodox (OTD) teas and Crush Tear Curl (CTC) teas were collected at different markets with origin from 07 countries, and their volatile flavour compounds (VFC) were compared by analyses, using headspace solid-phase micro-extraction coupled with gas chromatograph mass spectrometry (HS-SPME/GC-MS). Among the 60 volatiles identified, terpenes (10.28%-59.88% PAR), ketones (1.85%-22.02% PAR) and esters (3.13%-418% PAR) represented the most abundant compounds. The result showed that the number of volatile compounds detected in the aromas of CTC teas were lower than in orthodox tea. Furthermore, the low contents of aldehydes and alcohols in the volatile profile of CTC tea in comparison with OTD tea, while the content of esters in the CTC teas is higher than those of OTD teas were found. Both teas, Orthodox tea and CTC tea, could be classified base on volatile profiles analysis by carrying out principal component analysis (PCA) and cluster analysis. The data presented in this studied also suggest that, for geographical origin of teas, Terpene Index can be used as a means of discrimination.

Monitoring the Fermentation Process and Detection of Optimum Fermentation Time of Black Tea Using an Electronic Tongue

This paper presents a new methodology to monitor the fermentation process and detect the optimum fermentation time of crush tear curl black tea with a voltammetric electronic tongue. An electronic tongue with an array of five noble metal working electrodes has been developed for this purpose. A suitable large amplitude pulse voltammetric waveform has been employed for probing the chemical changes in tea samples under fermentation. Good correlation between the electronic tongue responses and the biochemical changes has been obtained by principal component analysis (PCA) during various stages of fermentation. The electronic tongue fermentation profile has been derived from PCA analysis and it is observed that such a profile enables detection of optimum fermentation times. Finally, a model based on partial least squares regression technique has been developed for real-time indication of fermentation level. The optimum fermentation times observed from the electronic tongue fermentation profiles derived from PCA and partial least squares regression correlate by a factor of 0.97 and 0.96, respectively, with the reference values obtained from an ultraviolet-visible spectrophotometer-based instrumental analysis.

Detection of Optimum Fermentation Time of Black CTC Tea Using a Voltammetric Electronic Tongue

A voltammetric electronic tongue (E-tongue) has been used to detect the optimum fermentation time (OFT) of crush tear curl black tea. An E-tongue with an array of five noble metal working electrodes has been developed for this purpose. A suitable large amplitude pulse voltammetric waveform is used and a simple feature extraction technique based on the charge activity of working electrodes is proposed. The principal component analysis reveals a significant correlation between the E-tongue responses and the biochemical changes during various stages of fermentation. Principal component regression models are developed to assess the effectiveness of the features derived from E-tongue response to model the temporal variations of theaflavins, a key quality compound of tea, produced during the fermentation process. The OFTs detected by the E-tongue correlate by a factor of 0.97 with the estimates obtained from an ultraviolet-visible spectrophotometer-based reference method.

Variation in major phenolic compounds and quality potential of CTC black tea elicited by Saccharomyces cercevisiae and its correlation with antioxidant potential

Changes in phenolic compounds along with quality parameters of CTC (Crush, Tear, Curl) black tea (BT) during yeast fermentation was revealed. The level of epigallocatechin-3-gallate (EGCG) and caffeine content increased at 12h but prolonged period of treatment decreased their levels. Due to the changes in (+)-catechin, epicatechin (EC) and gallic acid content the level of total phenolic contents increased at 24h. These changes reflected in quality constituents such as theaflavin (TF) and thearubigin (TR) contents of BT increased with 24h of yeast interaction. Prolonged incubation time reduced the liquor brightness (LB) but increased the level of total liquor colour (TLC). The improvement in phenolic content resulted in high antioxidant activity in samples treated with yeast for a period of 24h. Applying this method can bring forth improvement in product quality and antioxidant potentiality of CTC black tea.

Significant physical attributes affecting quality of Indian black (CTC) tea

In this research work, an attempt was made to discriminate different grades of black crush-tear-curl (CTC) tea based upon their physical attributes such as color of brewed liquor, texture, size and shape of the tea granules obtained by machine vision technique. The principal component analysis (PCA) was applied over two types of data. First, tea samples with seven different quality grades but same mechanical grading and second, samples with same quality grade but nine different mechanical grades (Brokens, Fannings and Dust) were considered for analysis, respectively. The results of PCA showed that best discrimination (100%) in both types of data was given by color attributes only. Correlations among tea samples and physical attributes were determined. Based upon these results it may be concluded that color only attributes are the most significant and sufficient for quantification of tea quality whereas other physical attributes contribute so little to quality estimation that they may be ignored.