Assam Tea Research Articles

Changes in Bioactive Compounds, Antioxidant Activities and Chemical Properties of Pickled Tea By-Product Fermentation: Promising Waste Management and Value-Added Product

Pickled tea is an ethnic fermented product produced using Assam tea (Camellia sinensis var. assamica) leaves. It is produced in large quantities every year and the liquid waste from its production is estimated to be up to 2500 mL per every kilogram of pickled tea production. To reduce the waste, pickled tea juice remaining from the process was developed into (1) pineapple kombucha and (2) formulated functional drinks as “value added” products. The juice used for making kombucha was collected at 15 days of pickled tea fermentation due to its high value in antioxidant activity (previous study, 2250 µmol TE per g DW). After fermenting the juice with starter culture, the properties of pineapple kombucha were assessed at 0, 1, 3, 5, 7, 9, 11 days. Results showed that the total phenolic of pineapple kombucha was reduced, while antioxidant assay (FRAP and ORAC) slightly increased. The most suitable fermentation period of pineapple kombucha was at day 3. The formulated drink was made from mixing pineapple kombucha with ginger and lemon juice at various ratios including 100:0:0, 80:10:10 and 80:15:5. The ratio 80:10:10 gave the highest TP and antioxidant activity for the functional drink. In addition, for sensory analysis, liking attribute of 80:15:5 fermented juice kombucha pineapple favor was significantly higher compared to other formulations. The study demonstrates the promising second fermentation process of by-product juice from pickled tea production for the conversion to value-added functional drink with reasonable antioxidant properties.

Physical and antioxidant properties of selected tea varieties

Tea (Camellia sinensis L.) is amongst the most popular beverages around the globe. Tea contains polyphenols and flavonoids, which have huge health significance. Hence, polyphenols and flavonoids can be considered as good indicator for tea quality. In the present investigation four different tea varieties i.e., Nilgiri, Darjeeling, Assam and Munnar were analyzed for their moisture content, water activity, total phenol content and total flavonoid content using UV-visible spectrophotometer. The total amounts of phenol content and total flavonoids were determined by Folin-Ciocalteu and Aluminium chloride method respectively. The total phenol was obtained as in the range of 20.76 ± 0.010 to 25.97 ± 0.027 mg gallic acid equivalent (GAE)/g of dry weight and flavonoids were expressed between 45±0.012 to 53.84±0.017 mg/g of catechin equivalents (mg/g of Catechin of extracted compound) for the sample taken. Nilgiri and Assam tea infusion were determined to have the highest phenol and total flavonoid contents i.e., 25.97 ppm and 53.84 ppm respectively.

Improvement of Sourdough and Bread Qualities by Fermented Water of Asian Pears and Assam Tea Leaves with Co-Cultures of Lactiplantibacillus plantarum and Saccharomyces cerevisiae.

Qualities of sourdough and sourdough bread using fermented water from Asian pears and Assam tea leaves with Lactiplantibacillus plantarum 299v and Saccharomyces cerevisiae TISTR 5059 as starter cultures were evaluated. Changes in the growth of lactic acid bacteria and yeast, pH, sourdough height, total phenolic contents (TPCs) and antioxidant activities detected by ORAC, FRAP and DPPH radical scavenging assays were monitored during sourdough production. Mature sourdough was achieved within 4 h after 18 h retard fermentation and used for bread production. The bread was then analyzed to determine chemical and physical properties, nutritional compositions, TPCs, antioxidant activities and sensory properties as well as shelf-life stability. Results showed that fermented water significantly promoted the growth of yeast and increased TPCs and antioxidant activities of sourdough. Compared to common sourdough bread, fermented water sourdough bread resulted in 10% lower sugar and 12% higher dietary fiber with improved consumer acceptability; TPCs and antioxidant activities also increased by 2–3 times. The fermented water sourdough bread maintained microbial quality within the standard range, with adequate TPCs after storage at room temperature for 7 days. Fermented water from Asian pears and Assam tea leaves with L. plantarum 299v and S. cerevisiae TISTR 5059 as starter cultures improved dough fermentation and bread quality.

Comparison of supercritical CO2 and screw press extraction methods for producing oil from Camellia sinensis var. assamica seeds: Physicochemical properties and antioxidant activity

The quality of Assam tea seed oil obtained by supercritical CO2 extraction was evaluated and compared to that of tea obtained using a screw press. Supercritical CO2 extraction produced a higher oil yield (12.94–16.53 % w/w) compared to the screw press method (9.96–12.18 % w/w). Using a higher temperature for supercritical CO2 and screw press extraction caused a decrease in the saponin content from 32.12 to 25.07 mg saponin equivalents/g oil and from 39.28 to 35.60 mg saponin equivalents/g oil, respectively, and for supercritical CO2 extraction also increased the flavonoid content from 0.84 to 1.75 mg/mL quercetin equivalents but did not affect the flavonoid yield for screw press extraction (1.02–1.07 mg/mL quercetin equivalents). The tannin content obtained from supercritical CO2 and screw press extraction was not significantly different (31.67–36.30 and 29.49–32.12 mg/mL tannin equivalents, respectively). Increasing the temperature of supercritical CO2 extraction resulted in a decrease in acid value and free fatty acids. No significant differences in acid value or free fatty acids were observed for oil extracted using the screw press method. Iodine and saponification values of oil obtained by supercritical CO2 extraction decreased when the extraction temperature increased, and screw press oil had higher iodine and saponification values when the temperature was increased. All of the extracted Assam tea seed oils, obtained by both methods, overwhelmingly contained oleic acid (48.55–50.14 %), linoleic acid (24.14–25.52 %), and palmitic acid (18.74–19.95 %). In addition, an increase in temperature promoted the extraction of phenolic compounds for both extraction methods (9.21–22.01 mg GAE/100 g oil), resulting in an increase in the antioxidant capacity of the extracted oil. These results indicate that supercritical CO2 extraction could be competitive with the screw press method, providing an environmental approach and enhancing the quality of the oil obtained.

Beyond “Enclaves”: Postcolonial Labor Mobility to and from Assam Tea Plantations

AbstractLabor mobility to and from tea plantations in India has been treated as an exception. Plantations continue to be imagined as unaltered enclaves with an immobile, bonded, or fixed labor force as their key feature. Based on ethnographic fieldwork in India, this article investigates forms of labor mobility to and from Assam tea plantations. While tea labor is not spatially immobile, I argue that spatial mobility does not necessarily lead to upward social mobility. Based on this observation, I reconsider the plantation in the twenty‐first century in two ways: first, plantations are permeable and transforming spaces, due to ongoing labor mobility and evolving changes in the political economy of Assam tea production; second, certain forms of inequality and injustice attributed to plantation economies need to be located beyond the Plantationocene.

Impact of work-life balance on the wellbeing of employees in the tea gardens of Bodoland territorial region

Work-Life Balance as a major problem for employees in the tea garden workers community, whether in public or private life. Men and women both aspire for a balanced personal life and professional life. Assam's tea plantation sector encompasses many places and ranks first in the Indian economy. The study's goal is to look into the influence of work-life balance on employee happiness in the tea gardens of the Bodoland territorial region. The tea workers' quality of life has a considerable influence on the tea industry's smooth operations. Wage labor is the primary occupation of Tea Garden workers. The Tea Garden community's financial situation is not particularly good. The researcher defines the notion of work-life balance and discusses the tea garden workers' society's socio-cultural, vocational, and religious lives. The community of tea garden workers has formed a new socio-cultural identity & contributed to developing a new composite society. These cultural characteristics establish them as a separate community in new surroundings. The study looks at the lives of women who work in tea gardens in Assam & their social standing, and the key issues they face. In Assam's tea gardens, women workers make up most of the workforce.

Studying the effect of different drying methods on phenolic content, antioxidant activity, color and antimicrobial activity in Assam tea (Camellia assamica)

Studying the effect of different drying methods on phenolic content, antioxidant activity, color and antimicrobial activity in Assam tea (Camellia assamica)

Tea for Minds and Hearts: A Scoping Review

Tea is a ubiquitous and staple beverage for many people globally. It is well documented that mental well being and cardiovascular health are both recognized as being important in determining general health. The two are intricately linked as people with mental health issues are more likely to have heart disease. We systematically searched the PubMed database and selected studies by predefined eligibility criteria. The reviewed studies presented a large body of evidence indicating that black tea drinking could benefit markers of heart health, including vascular and endothelial function. There is emerging evidence that tea drinking (black and green) and aromatic inhalation of certain teas (e.g., Darjeeling and Assam teas) could aid relaxation, lower stress, dementia risk and cognitive decline and potentially improve attention and psychomotor speed in advanced age. Further human trials are warranted.

Simultaneous Production of Multiple Antimicrobial Compounds by Bacillus velezensis ML122-2 Isolated From Assam Tea Leaf [Camellia sinensis var. assamica (J.W.Mast.) Kitam.

Bacillus velezensis ML122-2 is an antimicrobial-producing strain isolated from the leaf of Assam tea or Miang [Camellia sinensis var. assamica (J.W.Mast.) Kitam.]. The cell-free supernatant (CFS) of strain ML122-2 exhibits a broad-spectrum antimicrobial activity against various Gram-positive and Gram-negative bacteria as well as the mold Penicillium expansum. The genome of B. velezensis ML122-2 was sequenced and in silico analysis identified three potential bacteriocin-associated gene clusters, that is, those involved in the production of mersacidin, amylocyclicin, and LCI. Furthermore, six gene clusters exhibiting homology (75–100% DNA sequence identity) to those associated with the secondary metabolites bacilysin, bacillibactin, surfactin, macrolactin H, bacillaene, and plipastatin were identified. Individual antimicrobial activities produced by B. velezensis ML122-2 were purified and characterized by Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry analysis, revealing three antimicrobial peptides with molecular masses corresponding to surfactin, plipastatin, and amylocyclicin. Transcriptional analysis of specific genes associated with mersacidin (mrsA), amylocyclicin (acnA), plipastatin (ppsA), and surfactin (srfAA) production by B. velezensis ML122-2 showed that the first was not transcribed under the conditions tested, while the latter three were consistent with the presence of the associated peptides as determined by mass spectrometry analysis. These findings demonstrate that B. velezensis ML122-2 has the genetic capacity to produce a wide range of antimicrobial activities that may support a specific community structure and highlight the biotechnological properties of Assam tea.

An Updated Global Species Diversity and Phylogeny in the Genus Wickerhamomyces with Addition of Two New Species from Thailand.

Ascomycetous yeast species in the genus Wickerhamomyces (Saccharomycetales, Wickerhamomycetaceae) are isolated from various habitats and distributed throughout the world. Prior to this study, 35 species had been validly published and accepted into this genus. Beneficially, Wickerhamomyces species have been used in a number of biotechnologically applications of environment, food, beverage industries, biofuel, medicine and agriculture. However, in some studies, Wickerhamomyces species have been identified as an opportunistic human pathogen. Through an overview of diversity, taxonomy and recently published literature, we have updated a brief review of Wickerhamomyces. Moreover, two new Wickerhamomyces species were isolated from the soil samples of Assam tea (Camellia sinensis var. assamica) that were collected from plantations in northern Thailand. Herein, we have identified these species as W. lannaensis and W. nanensis. The identification of these species was based on phenotypic (morphological, biochemical and physiological characteristics) and molecular analyses. Phylogenetic analyses of a combination of the internal transcribed spacer (ITS) region and the D1/D2 domains of the large subunit (LSU) of ribosomal DNA genes support that W. lannaensis and W. nanensis are distinct from other species within the genus Wickerhamomyces. A full description, illustrations and a phylogenetic tree showing the position of both new species have been provided. Accordingly, a new combination species, W. myanmarensis has been proposed based on the phylogenetic results. A new key for species identification is provided.

Empire remembered: the intimate economy of tea in Assam and the making of ‘Chameli Memsaab’

ABSTRACT This essay examines the complex intertwining of colonial and postcolonial subjectivities in the making of memories about the colonial past. The essay uses literature and cinema as archive and intersubjectivity as the lens to argue that memories of the Empire are culled in the complex intersection of the subjective experiences of the individual and a community's collective perceptions of the past and the present. Accordingly, the essay calls for due diligence to the immediate postcolonial context in which the colonial memory project is ordained. At a more elementary level, the essay argues that the reduction of colonial experiences to a conflictual negation of the imperialist project impairs our understanding of the myriad factors mediating the colonial encounter. The polysemy of colonial memories reflects the multiplicity of intersubjective exchanges within a community. In this case, the Assamese short story, ‘Chameli Memsaab', written by Nirode Choudhury, and describing the affection of a benign planter sahib for Chameli, a coolie woman, becomes our focal point for entry into the neglected domain of Assamese literary representations of the European planter, that put a gloss on the dark side of Plantation abuses in Assam, to project the plantation economy as a desirable addendum to the Raj. Our survey of short stories written in Assamese, in the nineteenth and the twentieth centuries, reveal a profoundly ambivalent attitude towards the unequal sexual exchange between the European sahib and the coolie woman, which we call ‘the intimate economy of tea’ in Assam, and which, as the coercive underside of the economy, denuded the production relations on the plantations of their putatively capitalist character.

The Latin name for Assam tea revisited and the further nomenclatural significance of the three editions of Julius Bosse's Vollständiges Handbuch der Blumengärtnerei – and contemporary compendia

AbstractTwo early validly published names for Assam tea (Camellia sinensis var. assamica “(Choisy) Kitam.)”) are identified: Thea assamica Royle ex Hook. 1847 and T. assamica Hort. Belg. ex Bosse 1854; an amended synonymy and a neotypification (with D.‐W. Zhao) for the name of Assam tea, C. sinensis var. assamica (Hook.) Steenis, are provided. The three editions (1829–1861) of Bosse's Vollständiges Handbuch der Blumengärtnerei are also the neglected places of publication of some plant‐names (or their basionyms) in current use; Grevillea lawrenceana Bosse (neotype designated here by P.M. Olde) is an earlier name for G. curviloba McGill. (Proteaceae); Hedera algeriensis (Araliaceae), the name used by Bosse for a now much‐cultivated ivy, was first published by Morren in 1853; an early valid, available name for the florist's cineraria (Senecio hybridus Bosse) is Cineraria ×kewensis Rob. (Compositae), here neotypified (with D.J.N. Hind); the basionym for the well‐known garden plant‐name, “Erysimum ×kewense” (Cruciferae) is identified and neotypified (with D.J.N. Hind), the accepted binomial validated. The currently accepted name for commercial fustic, Maclura tinctoria (Moraceae), was first validly published in Loudon's Hortus Britannicus (1830).

Locating 'Coolie' Women's Health in Tea Plantation Environments in Colonial Assam

Abstract The history of Assam tea plantations in India is well-documented, yet a gender sensitive environmental history of these colonially-introduced plantation landscapes is absent. The colonial tea planters saw advantages in a growing female presence in their plantations, in terms of increased male ties to the plantation, lower wages for female workers and the added benefit of biological reproduction that would fulfil the need for manual labour in these plantations for generations. This paper attempts to understand how this plantation structure in general and the work regime in particular relied on a particular type of gender identity, which in turn had a detrimental effect on the health of the women labourers in this new landscape.

PROTEIN PRECIPITATION BY TEA POLYPHENOLS, IN-SILICO ANALYSIS OF ITS BIOAVAILABILITY, AND BINDING TO SARS-COV-2

This study is undertaken to see precipitation of protein non-specifically by tannin in tea, a plant secondary metabolite. Tannins that are present as a part of the defense system of the plant get oxidized to its quinone/semiquinone state and readily react with protein to form a precipitate. In this study, we have estimated the polyphenol content of Assam tea which was decreased by 9.33% due to the precipitation reaction with BSA. We have visualized the precipitation of protein by tannin/polyphenol. In our studies, we have tried to remove highly reactive or protein precipitating polyphenols from ready-to-drink black tea with the help of charcoal beads. Bioavailability, including absorption, metabolism, distribution, and excretion of different types of tea polyphenols in the human body have been assessed using bioinformatics methods. Polyphenols are high molecular weight compounds and are less absorbable through the GI tract. We have also analyzed the binding affinity of 24 tea molecules to spike glycoprotein of SARS -CoV-2.

Volatile profiles and antioxidant activity of different cultivars of Camellia sinensis var. assamica grown in Thailand

Tea is considered as the most consumed drink in the world containing high antioxidant capacity. In this study, the volatile compounds, the phenolic content, catechins and caffeine including antioxidant activities of 22 Camellia sinensis var. assamica (Assam tea) cultivars were investigated. The volatile compounds were investigated by GC-MS. At least forty-five volatile compounds representing 94.99-99.65% of all cultivars were identified. Limonene, trans-linalool oxide, cis-linalool oxide, linalool, and furfural were detected as the major components among these cultivars. Varied ranges were found in all Assam tea cultivars for the contents of phenolics (113.45-245.55 mg gallic acid/g dry weight), total catechins (170.03-355.59 mg/g dry weight), caffeine (0.92-3.40 mg/g dry weight), and antioxidant activities (1418.68-2728.46 µmol Trolox/g dry weight and 1448.98-2864.17 µmol Trolox/g dry weight for DPPH and ABTS assay, respectively). The antioxidant activity was correlated with phenolic compounds such as epigallocatechin gallate, epicatechin gallate, and catechin gallate. The specific differences among Assam tea cultivars are dependent on the tea cultivar and altitude which may play a significant role in breeding Assam tea cultivars in Thailand for providing its potential health benefits.

Culturable Bacterial Community on Leaves of Assam Tea (Camellia sinensis var. assamica) in Thailand and Human Probiotic Potential of Isolated Bacillus spp.

Assam tea plants (Camellia sinensis var. assamica) or Miang are found in plantations and forests of Northern Thailand. Leaf fermentation has been performed for centuries, but little information is available about their associated microbial community. One hundred and fifty-seven bacterial isolates were isolated from 62 Assam tea leaf samples collected from 6 provinces of Northern Thailand and classified within the phyla of Firmicutes, Actinobacteria, and Proteobacteria. Phayao and Phrae provinces exhibited the highest and the lowest bacterial diversities, respectively. The bacterial community structural pattern demonstrated significant differences between the west and the east sides. Since some Bacillus spp. have been reported to be involved in fermented Miang, Bacillus spp. isolated in this study were chosen for further elucidation. Bacillus siamensis ML122-2 exhibited a growth inhibitory effect against Staphylococcus aureus ATCC 25923 and MRSA DMST 20625, and the highest survival ability in simulated gastric and intestinal fluids (32.3 and 99.7%, respectively), autoaggregation (93.2%), cell surface hydrophobicity (50.0%), and bacterial adherence with Vero cells (75.8% of the control Lactiplantibacillus plantarum FM03-1). This B. siamensis ML122-2 is a promising probiotic to be used in the food industry and seems to have potential antibacterial properties relevant for the treatment of antibiotic-resistant infections.

Economic sustainability of organic cultivation of Assam tea produced by small-scale growers

The last few decades have seen a significant increase in the land under tea cultivation in the major tea growing regions of the world, mostly owing to the increase in the number of small-scale tea growers. These small-scale tea growers often resort to unsustainable agricultural practices. However, some of the growers in a few tea growing regions are converting to sustainable production systems like organic cultivation. The present study uses a collective case study approach and mixed methods to understand the economic sustainability of organic tea cultivation for the small-scale tea growers. It uses primary data of the small-scale tea growers in the largest contiguous tea producing region of the world, Assam in India. The findings reveal that the yearly income from a hectare of tea cultivation for small-scale organic growers, which is found to be INR 85,000 (USD 1,156.83), is better than the income for the conventional growers, which is INR 77,000 (USD 1,047.95) if the organic growers could attain the average yield of 15,000 kg as usually achieved in a conventional system. However, the income for the organic growers reduced to INR 71,500 (USD 973.10) for a 10% decrease from the above-mentioned yield. In a long-term perspective, organic cultivation is found to be an economically viable option for small-scale tea growers over a period of 10 years provided the growers achieve good and stable yield after organic conversion. Income from organic tea may increase further if the growers resort to optimal utilization of resources, best farm management practices, and an organic premium on green leaves is introduced. Further, there is a need to understand organic cultivation in a broader socioeconomic context to push a larger section of the small-scale tea growers towards environmentally sustainable cultivation.

Corporate Responsibility for Human Rights in Assam Tea Plantations - A Business and Human Rights Approach

This paper explores how UK-based companies deal with their responsibility to respect the human rights of Assam (India) tea plantations workers. Using publicly available corporate reports and other documents, it investigates how companies approach, and communicate on, their potential human rights impacts. It highlights the gap between well-documented human rights issues on the ground and corporate reports on these issues. It aims to answer the following research question: in a context where the existence of human rights violations at the end of the supply chain is well-documented, how do companies reconcile their possible connection with those violations and the corporate responsibility to respect human rights under the United Nations Guiding Principles on Business and Human Rights? The paper reveals the weakness of the current CSR approach from the perspective of rights-holders. It supports a business and human rights approach, one that places the protection of human rights at its core.

Corporate Responsibility for Human Rights in Assam Tea Plantations: A Business and Human Rights Approach

This paper explores how UK-based companies deal with their responsibility to respect the human rights of Assam (India) tea plantation workers. Through qualitative content analysis of publicly available corporate reports and other documents, it investigates how companies approach and communicate their potential human rights impacts. It highlights the gap between well-documented human rights issues on the ground and corporate reports on these issues. It aims to answer the following research question: in a context where the existence of human rights violations at the end of the supply chain is well-documented, how do companies reconcile their possible connection with those violations and the corporate responsibility to respect human rights under the United Nations Guiding Principles on Business and Human Rights? This paper reveals the weakness of the current corporate social responsibility (CSR) approach from the perspective of rights-holders. It supports a business and human rights approach, one that places the protection of human rights at its core.

Evaluation of Multifarious Plant Growth Promoting Trials of Yeast Isolated from the Soil of Assam Tea (Camellia sinensis var. assamica) Plantations in Northern Thailand.

Some soil microorganisms, especially bacteria and mycorrhizal fungi, play a role in the promotion of plant growth. However, plant growth promotion involving yeasts in soil has not yet been extensively investigated. This study aimed to isolate and identify yeast strains obtained from soils of the Assam tea plant (Camellia sinensis var. assamica) in northern Thailand and to investigate their plant growth promoting capabilities. A total of 42 yeast strains were obtained and identified by analysis of the D1/D2 domain of the large subunit ribosomal RNA gene. We identified 35 strains of six species belonging to the phylum Ascomycota, namely Aureobasidium melanogenum, Kazachstania aquatica, Saturnispora diversa, Saturnispora sekii, Schwanniomyces pseudopolymorphus and Wickerhamomyces anomalus, and six species were determined to belong to the phylum Basidiomycota, namely Apiotrichum scarabaeorum, Curvibasidium pallidicorallinum, Papiliotrema laurentii, Rhodosporidiobolus ruineniae, Trichosporon asahii and Trichosporon coremiiforme. Seven strains were representative of potential new species and belonged to the genera Galactomyces and Wickerhamomyces. A total of 28 strains were found to produce indole-3-acetic acid (IAA) in a range of 2.12 to 37.32 mg/L, with the highest amount of IAA produced by R. ruineniae SDBR-CMU-S1-03. All yeast strains were positive in terms of ammonia production, and only eight strains were positive for siderophore production. Two yeast species, P. laurentii and W. anomalus, were able to solubilize the insoluble form of calcium and zinc. The ability to produce amylase, endogulcanase, lipase, pectinase, protease and xylanase was dependent upon the yeast species and strain involved.