Preparation of partially decaffeinated instant green tea

Variation of Major Chemical Composition in Seed-Propagated Population of Wild Cocoa Tea Plant Camellia ptilophylla Chang

Excessive intake of high-caffeine tea will induce health-related risk. Therefore, breeding and cultivating tea cultivars with less caffeine is a feasible way to control daily caffeine intake. Cocoa tea (Camellia ptilophylla Chang) is a wild tea plant which grows leaves with little or no caffeine. However, the vegetative propagation of cocoa tea plants is difficult due to challenges with rooting. Whether natural seeds collected from wild cocoa tea plants can be used to produce less-caffeinated tea remains unknown, because research on the separation of traits among the seed progeny population is lacking. The present study was set to investigate the variation of caffeine and other chemical compositions in seed-propagated plant individuals using colorimetric and HPLC methods. It shows that there were great differences in chemical composition among the seed-propagated population of wild cocoa tea plants, among which some individuals possessed caffeine contents as high as those of normal cultivated tea cultivars (C. sinensis), suggesting that the naturally seed-propagated cocoa tea seedlings are not suitable for directly cultivating leaf materials to produce low-caffeine tea. Therefore, the cocoa tea plants used for harvesting seeds for growing low-caffeine tea plants should be isolated in order to prevent their hybridization with normal cultivated C. sinensis plants. Interestingly, the leaves of cocoa tea seedlings contained high levels of gallocatechin gallate (GCG) and would be a good source of leaf materials for extracting more stable antioxidant, because GCG is a more stable antioxidant than epigallocatechin gallate (EGCG), the dominant component of catechins in normal cultivated tea cultivars. Some plant individuals which contained low levels of caffeine along with high levels of amino acids and medium levels of catechins, are considered to be promising for further screening of less-caffeinated green tea cultivars.

Caffeine-free hawk tea lowers cholesterol by reducing free cholesterol uptake and the production of very-low-density lipoprotein

Medicinal plants show important therapeutic value in chronic disease treatment. However, due to their diverse ingredients and complex biological effects, the molecular mechanisms of medicinal plants are yet to be explored. By means of several high-throughput platforms, here we show hawk tea extract (HTE) inhibits Niemann-Pick C1-like 1 (NPC1L1)-mediated free cholesterol uptake, thereby inducing the transcription of low-density lipoprotein receptor (LDLR) downstream of the sterol response element binding protein 2 (SREBP2) pathway. Meanwhile, HTE suppresses hepatocyte nuclear factor 4α (HNF4α)-mediated transcription of microsomal triglyceride transfer protein (MTP) and apolipoprotein B (APOB), thereby decreasing the production of very-low-density lipoprotein. The catechin EGCG ((-)-epigallocatechin gallate) and the flavonoids kaempferol and quercetin are identified as the bioactive components responsible for the effects on the NPC1L1-SREBP2-LDLR axis and HNF4α-MTP/APOB axis, respectively. Overall, hawk tea works as a previously unrecognized cholesterol-lowering agent in a multi-target and multi-component manner.

Extraction and preparation of high-aroma and low-caffeine instant green teas by the novel column chromatographic extraction method with gradient elution

The lack of aroma and natural taste is a critical problem in production and consumption of instant green teas. A method to prepare instant green teas high in-natural-aroma and low-caffeine by the novel column chromatographic extraction with gradient elution is reported. This method simultaneously extracted aroma (or volatile) and non-aroma compounds from green tea. Green tea was loaded into columns with 2.0-fold of petroleum ether (PE): ethanol (8:2). After standing for 3 h until the aroma compounds dissolved, the column was sequentially eluted with 3.0-fold 40% ethanol and 3.5-fold water. The eluant was collected together and automatically separated into PE and ethanol aqueous phases. The aroma extracts was obtained by vacuum-evaporation of PE phase at 45 °C. The ethanol aqueous phase was vacuum-concentrated to aqueous and partially or fully decaffeinated with 4% or 9% charcoal at 70 °C. A regular instant green tea with epigallocatechin-3-gallate: caffeine of 3.5:1 and a low-caffeine instant green tea (less than 1% caffeine) with excellent aroma and taste were prepared, by combining the aroma and non-aroma extracts at a 1:10 ratio. This work provides a practical approach to solve the low-aroma and low-taste problems in the production of high quality instant green teas.

Cellular antioxidant, methylglyoxal trapping, and anti-inflammatory activities of cocoa tea (Camellia ptilophylla Chang)

Cocoa tea, a naturally low caffeine-containing but GCG-rich tea cultivar, exhibited strong cellular antioxidant, methylglyoxal trapping, and anti-inflammatory activities.

Cocoa tea (Camellia ptilophylla) water extract inhibits adipocyte differentiation in mouse 3T3-L1 preadipocytes

Cocoa tea (Camellia ptilophylla) is a naturally decaffeinated tea plant. Previously we found that cocoa tea demonstrated a beneficial effect against high-fat diet induced obesity, hepatic steatosis, and hyperlipidemia in mice. The present study aimed to investigate the anti-adipogenic effect of cocoa tea in vitro using preadipocytes 3T3-L1. Adipogenic differentiation was confirmed by Oil Red O stain, qPCR and Western blot. Our results demonstrated that cocoa tea significantly inhibited triglyceride accumulation in mature adipocytes in a dose-dependent manner. Cocoa tea was shown to suppress the expressions of key adipogenic transcription factors, including peroxisome proliferator-activated receptor gamma (PPAR γ) and CCAAT/enhancer binding protein (C/EBP α). The tea extract was subsequently found to reduce the expressions of adipocyte-specific genes such as sterol regulatory element binding transcription factor 1c (SREBP-1c), fatty acid synthase (FAS), Acetyl-CoA carboxylase (ACC), fatty acid translocase (FAT) and stearoylcoenzyme A desaturase-1 (SCD-1). In addition, JNK, ERK and p38 phosphorylation were inhibited during cocoa tea inhibition of 3T3-L1 adipogenic differentiation. Taken together, this is the first study that demonstrates cocoa tea has the capacity to suppress adipogenesis in pre-adipocyte 3T3-L1 similar to traditional green tea.

Efficient extraction strategies of tea (Camellia sinensis) biomolecules

Tea is a popular daily beverage worldwide. Modulation and modifications of its basic components like catechins, alkaloids, proteins and carbohydrate during fermentation or extraction process changes organoleptic, gustatory and medicinal properties of tea. Through these processes increase or decrease in yield of desired components are evident. Considering the varied impacts of parameters in tea production, storage and processes that affect the yield, extraction of tea biomolecules at optimized condition is thought to be challenging. Implementation of technological advancements in green chemistry approaches can minimize the deviation retaining maximum qualitative properties in environment friendly way. Existed extraction processes with optimization parameters of tea have been discussed in this paper including its prospects and limitations. This exhaustive review of various extraction parameters, decaffeination process of tea and large scale cost effective isolation of tea components with aid of modern technology can assist people to choose extraction condition of tea according to necessity.

Catechin concentrates of garden tea leaves (Camellia sinensis L.): extraction/isolation and evaluation of chemical composition

BACKGROUND

Solid-liquid (SLE) and liquid-liquid (LLE) extraction techniques were applied to extract catechins and caffeine from quick mechanically expelled tea leaf juice (QMETLJ) and freeze-dried (FD)-QMETLJ of Camellia sinensis L. The concentrates obtained were analyzed for total polyphenol content and antioxidant activity (DPPH(•) inhibition, FRAP and phosphomolybdenum assay). Catechins were identified and quantified using HPLC.

RESULTS

Overall, 95% (v/v) ethanol was the best solvent system for extracting total polyphenols (355.26 ± 23.68 to 457.89 ± 28.94 g GAE kg(-1) extractable solid yield (ESY)) and antioxidants (DPPH(•) inhibition, 16.97 ± 0.52 to 20.83 ± 3.11%; FRAP, 4.15 ± 0.32 to 6.38 ± 0.57 mmol TE g(-1) ESY; Mo(V) reduction, 2.47 ± 0.19 to 3.84 ± 0.39 mmol AAE g(-1) ESY) from FD-QMETLJ. Similarly, in LLE, ethyl acetate showed the best results for recovering polyphenols (960.52 ± 7.89 g GAE kg(-1) ESY) and antioxidants (DPPH(•) inhibition, 42.39 ± 0.91%; FRAP, 11.39 ± 0.83 mmol TE g(-1) ESY; Mo(V) reduction, 6.71 ± 1.14 mmol AAE g(-1) ESY) from QMETLJ.

CONCLUSION

It was found that 95% ethanol can be used to increase the total polyphenols and antioxidants in extracts from FD-QMETLJ, while ethyl acetate can be effectively employed for concentrating catechins from QMETLJ.

Design, formulation and evaluation of green tea chewing gum

Background:

The main purpose of this study is to design, formulate and evaluate the green tea gums with a suitable taste and quality in order to produce an anti-oxidant chewing gum.

Materials and Methods:

Fresh green tea leaves obtained from Northern Iran for extraction. Maceration is the extraction method that is used in this study. The contents of caffeine, catechin and flavonoids of the hydro alcoholic extract were measured. Various formulations of the 120 mg green tea extract chewing gums with different sweeteners, flavoring agents and various gum bases were prepared afterward release pattern, content uniformity, organoleptic results and other properties were characterized.

Results:

The contents of caffeine, catechin and flavonoid of the hydro alcoholic extraction were 207.32 mg/g, 130.00 mg/g and 200.82 mg/g, respectively. Release pattern of green tea chewing gum with different gum base ratios and various sweeteners in phosphate buffer were prepared. A total of 60 persons who were 20-30 years of age, participated in our panel test for organoleptic properties such as taste, stiffness, stickiness, etc., Acceptable gum was the one with the same ratio of the used rubber bases. Cinnamon selected as the preferred taste by volunteers. Combination of aspartame, sugar and maltitol has appropriate taste. The effect of various sweetener on release pattern was negligible, on the other hand rubber bases ratio variation, changed the release pattern obviously.

Conclusion:

The green tea chewing gum with sugar, maltitol and aspartame sweeteners and cinnamon flavor, using the same rubber bases ratio may be a desirable antioxidant product.

Adsorption characteristics of (-)-epigallocatechin gallate and caffeine in the extract of waste tea on macroporous adsorption resins functionalized with chloromethyl, amino, and phenylamino groups

According to the Friedel-Crafts and amination reaction, a series of macroporous adsorption resins (MARs) with novel structures were synthesized and identified by the Brunauer-Emmett-Teller (BET) method and Fourier transform infrared (FTIR) spectra, and corresponding adsorption behaviors for (-)-epigallocatechin gallate (EGCG) and caffeine (CAF) extracted from waste tea were systemically investigated. Based on evaluation of adsorption kinetics, the kinetic data were well fitted by pseudo-second-order kinetics. Langmuir, Freundlich, Temkin-Pyzhev, and Dubinin-Radushkevich isotherms were selected to illustrate the adsorption process of EGCG and CAF on the MARs. Thermodynamic parameters were adopted to explain in-depth information of inherent energetic changes associated with the adsorption process. The effect of temperature on EGCG and CAF adsorption by D101-3 was further expounded. Van der Waals force, hydrogen bonding, and electrostatic interaction were the main driving forces for the adsorption of EGCG and CAF on the MARs. This study might provide a scientific reference point to aid the industrial large-scale separation and enrichment of EGCG from the extracts of waste tea using modified MARs.

Producing low-caffeine tea through post-transcriptional silencing of caffeine synthase mRNA

In this study, attempt has been made to produce a selected cultivar of tea with low-caffeine content using RNAi technology. The caffeine biosynthetic pathway in tea has been proposed to involve three N-methyltransferases such as xanthosine methyltransferase, 7-N-methylxanthine methyltransferase and 3, 7-dimethylxanthine methyltransferase. Last two steps of caffeine biosynthesis in tea have been known to be catalyzed by a bifunctional enzyme known as caffeine synthase. To suppress the caffeine synthesis in the selected tea [Camellia sinensis (L.) O. Kuntze] cv. Kangra jat, we isolated a partial fragment of caffeine synthase (CS) from the same cultivar and used to design RNAi construct (pFGC1008-CS). Somatic embryos were transformed with the developed construct using biolistic method. Transformed somatic embryos showed reduction in the levels of CS transcript expression as well as in caffeine content. Plants were regenerated from the transformed somatic embryos. Transgenic plants showed a significant suppression of CS transcript expression and also showed a reduction of 44-61% in caffeine and 46-67% in theobromine contents as compared to the controls. These results suggest that the RNAi construct developed here using a single partial fragment of CS gene reduced the expression of the targeted endogenous gene significantly. However, the reduction in theobromine content in addition to caffeine documented the involvement of this single CS in the catalysis of last two methyl transfer steps in caffeine biosynthesis of tea.

Adsorption behavior of the catechins and caffeine onto polyvinylpolypyrrolidone

Adsorbent is one of the most important factors for separation efficiency in fixed-bed purification techniques. The adsorption behavior of catechins and caffeine onto polyvinylpolypyrrolidone (PVPP) was investigated by static adsorption tests. The results showed that catechins rather than caffeine were preferred to adsorb onto PVPP since the adsorption selectivity coefficient of total catechins vs caffeine was around 22.5, and that adsorption of catechins could be described by the pseudo-second-order model. Adsorption amount of caffeine onto PVPP in green tea extracts solution was much higher than that in purified caffeine solution although the initial concentration of caffeine was similar in the two solutions, indicating the caffeine might be attached with catechins which were adsorbed by PVPP instead of being adsorbed by PVPP directly. The results also showed that the adsorption capacity of catechins and caffeine decreased with an increase in temperature, and that Freundlich and Langmuir models were both suitable for describing the isothermal adsorption of catechins, but not suitable for caffeine. The predicted maximum monolayer adsorption capacity of total catechins by PVPP was 671.77 mg g(-1) at 20 °C, which was significantly higher than that by other reported adsorbents. The thermodynamics analyses indicated that the adsorption of catechins onto PVPP was a spontaneous and exothermic physisorption process, revealing lower temperature was favorable for the adsorption of catechins. Elution tests showed that the desorption rates of catechins and caffeine were higher than 91% and 99% after two elution stages; in detail, almost all of the caffeine could be washed down at the water eluting stage, while catechins could be recovered at the dimethyl sulfoxide/ethanol solution eluting stage. Thus, the PVPP could be used as an excellent alternative adsorbent candidate for separating catechins from crude tea extracts, although some investigations, such as exploring the new eluants with low boiling point and high desorption efficiency, should be conducted furthermore.

Using tea stalk lignocellulose as an adsorbent for separating decaffeinated tea catechins

Lignocelluloses prepared from woody tea stalk, pine sawdust and sugarcane bagasse were used as adsorbents to isolate decaffeinated catechins from tea extracts and compared with synthetic macroporous resin HPD 600. HPD 600 had the highest adsorption capacity to catechins, followed by tea stalk lignocellulose while lignocelluloses of pine sawdust and bagasse the least. Tea stalk lignocellulose absorbed preferentially tea catechins and showed a good selectivity. HPD 600 absorbed caffeine and tea catechins simultaneously. The kinetics data of tea stalk lignocellulose showed a good fit with the Langmuir isotherm model. It is considered that tea stalk lignocellulose is an alternative low-cost adsorbent for preparing decaffeinated tea catechins.

Characterization of the constituents and antioxidant activity of Brazilian green tea (Camellia sinensis var. assamica IAC-259 cultivar) extracts

Freeze-dried extracts from Camellia sinensis var. assamica IAC-259 cultivar named Brazilian green tea were prepared by hot water and ultrasound-assisted extractions using leaves harvested in spring and summer. Their caffeine and catechin contents were measured by high performance liquid chromatography-diode array detector. The antioxidant activity of the major green tea compounds and Brazilian green tea extracts was evaluated using a 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The levels of caffeine were higher in the summer samples (p < 0.05); otherwise, there were no significant variations related to the catechin contents between spring and summer samples. The sonication method using water/acetone as solvent had a high efficiency to extract not only epigallocatechin gallate but also epicatechin gallate (p < 0.05). Antioxidant activities of the Brazilian green tea extracts were not significantly different among seasons and extraction systems. The antioxidant data (IC50) of the Brazilian green tea extracts showed a significant correlation with their epigallocatechin gallate and epicatechin gallate contents (p < 0.05).

Designed polar cosolvent-modified supercritical CO2 removing caffeine from and retaining catechins in green tea powder using response surface methodology

This study examines cosolvent-modified supercritical carbon dioxide (SC-CO2) to remove caffeine from and to retain catechins in green tea powder. The response surface method was adopted to determine the optimal operation conditions in terms of the extraction efficiencies and concentration factors of caffeine and catechins during the extractions. When SC-CO2 was used at 333 K and 300 bar, 91.5% of the caffeine was removed and 80.8% of catechins were retained in the tea: 3600 g of carbon dioxide was used in the extraction of 4 g of tea soaked with 1 g of water. Under the same extraction conditions, 10 g of water was added to <800 g of carbon dioxide in an extraction that completely removed caffeine (that is, the caffeine extraction efficiency was 100%). The optimal result as predicted by three-factor response surface methodology and supported by experimental data was that in 1.5 h of extraction, 640 g of carbon dioxide at 323 K and 275 bar with the addition of 6 g of water extracted 71.9% of the caffeine while leaving 67.8% of the catechins in 8 g of tea. Experimental data indicated that supercritical carbon dioxide decaffeination increased the concentrations of caffeine in the SC-CO2 extracts at 353 K.