Tea Production Research Articles

Nationwide Investigation on Organophosphate Flame Retardants in Tea from China: Migration from Packaging Materials and Implications for Global Risk Assessment.

In this study, we measured 15 common organophosphate flame retardants (OPFRs) in six categories of tea samples across China. OPFRs were found in all the tea samples, with the total concentrations of OPFRs (∑OPFRs) at 3.44-432 ng/g [geometric mean (GM): 17.6 ng/g]. Triphenyl phosphate (TPhP) was the dominant OPFR, accounting for 39.0-76.2% of ∑OPFRs across all tea categories. The potential factors influencing the residual OPFRs in tea were thoroughly examined, including the agricultural environment, fermentation, and packaging of teas. Tea packaging materials (TPMs) were then identified as the primary sources of OPFRs in teas. The migration test revealed that OPFRs with lower molecular weights and log Kow values exhibited a higher propensity for facilitating the migration of OPFRs from TPMs to teas. The estimated daily intakes of OPFRs from teas were relatively higher for the general populations in Mauritania, Gambia, Togo, Morocco, and Senegal (3.18-9.79 ng/kg bw/day) than China (3.12 ng/kg bw/day). The health risks arising from OPFRs in Chinese teas were minor. This study established a baseline concentration and demonstrated the contamination sources of OPFRs in Chinese tea for the first time, with an emphasis on enhancing the hygiene standards for TPMs.

Past shadows and gender roles: Human elephant relations and conservation in Southern India

Some conceptual thinking about human-wildlife relations has lacked translations into empirical studies with an in-depth enquiry into social, cultural, economic and ecological aspects. This study explores human-elephant relations in a cohabited landscape in the Western Ghats of India, with a focus on 'more than conflict' relations. The Valparai plateau, in the Indian Western Ghats, is a landscape dominated by tea estates and remnants of rainforest fragments where human communities cohabit and closely interact with wildlife. We offer an empirical contribution on the variegated and paradoxical relation between care and fear, between empathy and hate and between the residents and elephants of Valparai. Where conflicts occur between elephants and humans, they have multiple meanings. Gender and unpleasant memories serve as drivers of negative attitudes towards wildlife. A conservation intervention based on engagement and collaboration with local people was perceived as highly effective. Preventive and mitigative, rather than reactive conflict mitigation strategies may have a significant role to play in maintaining the social carrying capacity of local communities towards elephants. We explore the many facets of human-elephant relations, and the numerous entanglements between them, thereby adding multiple layers to the extant knowledge of human-animal relations in the Western Ghats.

Competitiveness Analysis of Exported Indonesian Black Tea in International Market

Black tea is processed from tea plant and generated from fermented tea leaves. Black tea has become one of the favourite commodities from Indonesia sub-sector plantation. Research aimed to analyze the structure of world black-tea market, comparative advantage and competitive advantage of Indonesian black tea in world market, and Indonesia’s trading position of black tea commodity from 2010 to 2019. Herfindahl Hirschman Index (HHI), Concentration Ratio (CR), Revealed Comparative Advantadge (RCA), Export Dynamic Product (EPD) dan Trading Specialization Index (TSI) were the analytical instruments used in this research. Benchmarking countries were Kenya, Sri Lanka, India, and China. Meanwhile, the countries of destination of exported black tea were Malaysia, Russia, Pakistan, Germany, and the USA. Research results are the structure of world market of black tea is moderate oligopoly. Indonesia shows comparative advantage for its black tea in the countries of exporting destination. Indonesian black tea does not show competitive advantage in the countries of exporting destination. Indonesia’s trading position of black tea commodity is as an exporting country.

Multidisciplinary advances in kombucha fermentation, health efficacy, and market evolution.

Kombucha, a fermented tea beverage, has seen a significant rise in global popularity. This increase is attributed to its reported health benefits and extensive cultural heritage. The comprehensive review examines kombucha through microbiology, biochemistry, and health sciences, highlighting its therapeutic potential and commercial viability. Central to kombucha production is the symbiotic culture of bacteria and yeasts (SCOBY), which regulates a complex fermentation process, resulting in a bioactive-rich elixir. The study examines the microbial dynamics of SCOBY, emphasizing the roles of various microorganisms. It focuses the contributions of acetic acid bacteria, lactic acid bacteria, and osmophilic yeasts, including genera such as Saccharomyces, Schizosaccharomyces, Zygosaccharomyces, Brettanomyces/Dekkera, and Pichia. These microorganisms play crucial roles in producing bioactive compounds, including organic acids, polyphenols, and vitamins. These bioactive compounds confer therapeutic properties to kombucha. These properties include antioxidant, antimicrobial, anti-inflammatory, antidiabetic, antihypertensive, cancer prevention, hepatoprotective, and detoxifying effects. The review also explores the growing market for kombucha, driven by consumer demand for functional beverages and opportunities for innovative product development. It emphasizes the necessity of standardized production to ensure safety and validate health claims. Identifying research gaps, the review highlights the importance of clinical trials to verify therapeutic benefits. Ultimately, this study integrates traditional knowledge with scientific research, providing directions for future studies and commercial expansion, emphasizing the role of kombucha in health and wellness.

Influence of steaming duration, chlorophyll-a and -b content and ratio, and pH on the color of green tea processed from multiple tea (Camellia sinensis L.) cultivars.

The color of green tea is an important quality indicator. In recent years, shading of tea (Camellia sinensis L.) plants has been widely adopted for green tea production to enhance its green color and umami taste. In this study, we identified factors that influence green tea color by (i) examining variation in the chlorophyll content of fresh new tea shoots among cultivars, cropping seasons, and the degree of shading, (ii) investigating the rate of conversion of chlorophyll to pheophytin during the tea manufacturing process, specifically with steaming duration, and (iii) analyzing the effects of the new tea shoot properties and the steaming process on colorimetric values of the steamed new tea shoots. Multiple regression analysis revealed that three factors contributed to the rate of conversion of each chlorophyll type to pheophytin in steamed new tea shoots (ranked by importance): steaming duration > each chlorophyll type (chlorophyll-a and chlorophyll-b) content of fresh new tea shoots > pH. The colorimetric hue angle (h) value of steamed new tea shoots was influenced by four factors (ranked by importance): steaming duration > total chlorophyll (chlorophyll-a + chlorophyll-b) content in fresh new tea shoots > pH > chlorophyll-a/chlorophyll-b ratio in fresh new tea shoots. Differences in the color of new tea shoots can be explained by the aforementioned four factors. The findings will be useful for cultivar selection, and determining the appropriate degree of shading and steaming duration, to produce high-quality green teas with a good appearance. © 2024 Society of Chemical Industry.

Clustering Consumer Adoption Behavior with Respect to Innovative Tea Products in the Chinese Market

Clustering Consumer Adoption Behavior with Respect to Innovative Tea Products in the Chinese Market

The trade-offs effect of ecosystem health and socio-economic development on tea production

Ecosystem health (EH) maintenance and improvement are important goals in environmental and ecological management, and help realize regional sustainable development goals. EH assessment and the regulatory mechanism have remained popular research fields in landscape ecology science. However, the improvement in EH assessment methods is ongoing, the influences of EH and socioeconomic development on agricultural production remain unclear. In this study, we chose Fujian Province in China as the study area, first quantitatively assess EH based on the Vigor–Organization–Resilience–Services (VORS) model, and thereafter explore the response of tea production to EH and socioeconomic development using the structural equation model (SEM). We found that the mean EH value in Fujian Province was 0.52 in 2010, which was 6.12% and 10.64% higher than that in 2000 and 2020, respectively. The high-EH-value regions were distributed in the northwest, while the southeastern regions exhibited low-EH-value agglomerations. According to the temporal evolution characteristics of EH, the kernel density curve patterns exhibited single peaks, and the curves shifted from a broad to a narrow peak from 2000 to 2020, indicating a trend toward a more balanced distribution of EH spatially. SEM results showed a significant positive effect of EH on tea production with a coefficient of 0.86. However, there is a significant trade-off between EH and economic development, as indicated by a coefficient of −0.6. There are also negative indirect effects on tea development when mediated by economic development. However, the overall effect of EH on tea production is 0.8, indicating that EH is still effective in promoting tea production. The results of this study have implications for the integration of ecosystem management and agricultural production management in the region.

The Effect of Fermentation Time Variation on Antioxidant Activity of Fermented Robusta Coffee Leaves (Coffea canephora Pierre ex A.Froehner) Brew

Antioxidants are electron-donor compounds that can delay, slow down and prevent free radical reactions. Fermentation is a chemical change that occurs due to the activity of microorganisms which can increase the amount of phenols in tea thereby increasing its antioxidant activity. Fermentation is carried out with the help of a Symbiotic Culture of Bacteria and Yeast (SCOBY) culture, which is commonly used in the production of kombucha. Kombucha is a fermented tea drink produced from leaves that contain high phenols such as robusta coffee leaves (Coffea canephora Pierre ex A.Froehner). Factors that affect the fermentation process are pH and fermentation time. This study aimed to explain the effect of fermentation time on the antioxidant activity of fermented robusta coffee leaves brew. Brewed robusta coffee leaves were made by brewing robusta coffee leaves simplicia powder, adding kombucha liquid starter, then fermented for 0; 3; 7; 14; and 21 days, then pH and antioxidant activity was measured using UV-Visible spectrophotometer using the 2,2-dipheny-1,1-picrylhydrazyl (DPPH) at a wavelength of 516 nm. This study showed that 0; 3; 7; 14; and 21 days fermented robusta coffee leaves brew have pH of 6,07; 4,62; 4,07; 3,21; and 2,74, and IC50 values is 285,1645 μg/ml; 219,7012 μg/ml; 192,2325 μg/ml; 187,0434 μg/ml; and 173,9249 µg/ml. There is an effect of fermentation time variation on the antioxidant activity of fermented robusta coffee leaves brew. Keyword: Antioxidant, Fermentation, pH, Robusta coffee leaves, Time variation

Kinerja Ekspor Produk Teh Indonesia di Pasar Internasional: Asesmen Perjanjian Perdagangan Indonesia

The decline in Indonesian tea products export performance does not correspond to the Government initiatives to reduce barriers through trade agreements. This research aims to analyse the export performance and the role of trade agreements towards Indonesian tea products export. This study employs panel data regression with a 15-year time series (2007-2021) and a cross-section of 40 destination countries. The data are analysed using a modified export approach gravity model with Poisson Pseudo-Maximum Likelihood (PPML) estimation. The research results show that the Indonesian tea products export destinations are dominated by Asia (19 countries) and Europe (12 countries). The regression results suggest that the implementation of trade agreements with Asian and European region countries has not effectively increased Indonesian tea products export. On the other hand, the implementation of trade agreements with other region countries, i.e., Australia and New Zealand, has successfully promoted export towards Indonesian tea products. Those can be attributed to trade agreements underutilization and trade barriers imposed by the trade agreement members. Hence, inward and outward-looking strategies are necessary to promote the export creation effect of implemented trade agreements towards Indonesian tea product exports.

Characteristic of phenotype, amino acids and volatile compounds for fresh tea leaves of Korean tea cultivars (Camellia sinensis (L.) O. Kuntze)

Tea (Camellia sinensis (L.) O. Kuntze) is a popular beverage consumed worldwide. To establish fundamental scientific data, we analyzed the amino acids and volatile compounds in seven tea cultivars grown in Korea investigated phenotype also. Phenotypically, the leaf area and greenness index of young shoots and leaf blades were particularly different among the four Korean cultivars. Nine amino acids were detected from each cultivar, with the total amino acid and theanine contents being 9.08–41.42 and 2.81–24.60 mg/g, respectively. Moreover, 107 volatile compounds were identified as common components among tea cultivars using headspace solid-phase microextraction / gas chromatography–mass spectrometry (HS-SPME/GC-MS), and 38 key compounds were identified using partial least squares-discriminant analysis (PLS-DA) and hierarchical cluster analysis (HCA). The (Z)-linalool oxide (furanoid) concentrations were significantly high in Korean tea plant cultivars, and linalool concentrations were also high or low, but had high relative contents. Linalool and its various oxides are the major compounds responsible for the tea aroma. In conclusion, Korean tea cultivars have distinct characteristics, and the results of this study will form the basis for identifying Korean tea plant cultivars that can produce high-value tea products.

Research on the Development and Operation Model of Yunnan De'ang Sour Tea Featured E-commerce Information Platform

This study aims to provide empirical research on the application of rural e-commerce in rural revitalization through in-depth analysis of the De'ang sour tea industry, and explore how to effectively protect and inherit intangible cultural heritage through e-commerce platforms and digital technology, while promoting the comprehensive development of rural economy and society. Through this study, we aim to provide strategic recommendations for the protection, inheritance, and market development of De'ang sour tea production techniques, and contribute wisdom and strength to the implementation of rural revitalization strategies.

Assessing the antioxidant capacity of Ganoderma-infused white tea via electrochemical sensing techniques

This study presents a novel electrochemical method for assessing the antioxidant capacity of Ganoderma-infused white tea using carbon black-gold nanoparticle (CB-AuNP) modified glassy carbon electrodes and in situ generated superoxide radicals. The CB-AuNP nanocomposite was characterized using scanning electron microscopy and cyclic voltammetry, revealing an increased electrochemical active surface area of 0.158 cm2, which is 2.2 times larger than that of the bare glassy carbon electrode. Optimal conditions for superoxide radical generation were established using the xanthine oxidase-hypoxanthine system (0.10 U/mL XOD, 0.5 mM HX, 10 minutes incubation). The antioxidant capacity of Ganoderma-infused white tea was evaluated using cyclic voltammetry and chronoamperometry, and expressed as Trolox equivalent antioxidant capacity (TEAC). The proposed method demonstrated a strong linear relationship between TEAC values and Ganoderma extract concentration (R2 = 0.9995), with TEAC values ranging from 0.54 ± 0.03–2.85 ± 0.12 mM Trolox/g tea for 0.1–1.0 % w/v Ganoderma-infused white tea. The method exhibited good agreement with conventional spectrophotometric assays (DPPH, ABTS, and FRAP), showing strong correlations (R > 0.997) for all three assays. The practical applicability of the method was validated using commercial tea products, revealing a positive correlation between antioxidant capacity and Ganoderma polysaccharide content (R = 0.9958). The proposed electrochemical method offers a rapid, sensitive, and reliable approach for assessing the antioxidant capacity of functional tea products, with potential applications in quality control and product development.

The mining of thermostable β-glucosidase for tea aroma enhancement under brewing conditions

The β-glucosidases known to improve tea aroma are all mesothermal enzymes, limiting their use under brewing conditions. Based on the properties analysis and molecular docking, the thermostable β-glucosidase (TPG) from Thermotoga petrophlia showed potential to enhance tea aroma. Treatment by recombinant TPG at 90 °C, the floral, sweet and grassy notes of instant Oolong tea were increased, while the roasted, caramel and woody notes were decreased. The improved floral, sweet and grassy notes were related to increase releasing of benzyl alcohol (floral), geraniol (floral), (Z)-3-hexen-1-ol (grassy), benzaldehyde (sweet) and 1-hexanol (grassy) by TPG hydrolyzing of (Z)-3-hexenyl-β-D-glucopyranoside, hexanyl-β-D-glucopyranoside (HGP), benzyl-β-D-glucopyranoside, prunasin and geranyl-β-D-glucopyranoside (GGP), respectively. Although the catalytic efficiency of TGP to GGP was about twice that to HGP, HPG was more competitive than GGP when they mixed. Combined with microstructure analysis, the structure-function relationship of TPG-influencing tea aroma were understood. This study provided the method of how to mining new function of characterized β-glucosidases, as well as a theoretical basis for the development of new tea products.

Fluorine accumulation characteristics of 85 tea tree (Camellia sinensis) varieties and its potential risk assessment

Tea tree is a fluorine (F)-enriched plant, leading to much concern about the safety of drinking tea from tea tree (Camellia sinensis (L.) Kuntze). Tea tree is a perennial leaf-harvested crop, and tea production in China is generally categorized as spring tea, summer tea and autumn tea in its annual growth rounds. However, the seasonally dynamic changes of F content and accumulation in the leaves and its drinking safety are poorly understood. In this study, 85 tea varieties cultivated under the same conditions were investigated to analyze the seasonal variation of F content and it’s relationships with F accumulation, aluminum (Al), calcium (Ca) and manganese (Mn) and hazard quotient (HQ) in young leaves (one bud and two leaves, YL) and mature leaves (canopy leaves, ML). The average F contents and accumulations were 350 mg kg−1 and 203 g ha−1 in YL, and they were 2451 mg kg−1 and 2578 g ha−1 in ML, respectively, with F mainly accumulated in ML. As the growing season progresses, the F content showed a gradual increase in YL, while a decrease in ML, inferring that F may be redistributed from mature leaves to young leaves. Additionally, the F content was quite different among tea varieties which are suitable for processing oolong tea, green tea, and black tea, with higher F accumulation in oolong tea varieties than in green and black tea varieties. Moreover, F content and accumulation could be obviously affected by the geographical origin of the tea tree varieties, with significantly higher F content in the varieties from F rich fluorite belts than other regions. Furthermore, F content and accumulation showed a significant positive correlation with the content of Al and Mn (p < 0.05). Based on a daily tea consumption of 8.7 g, the HQ was investigated to show that the proportion of tea leaves with HQ<1 made from spring, summer and autumn tender leaves of 85 varieties was 100 %, 90.6 % and 50.6 %, respectively, indicating that the tea with the best drinking safety comes from spring, followed by summer, and then autumn. This result suggests that it could be necessary to avoid planting tea trees in fluorite mining areas, choose low F tea tree varieties, and control the tenderness of fresh leaves in order to ensure the safety of tea drinking.

Sensory evaluation and chemical composition of Solanum nigrum and Solanum torvum herbal tea and spice.

Herbal teas are ingested for various purposes and by diverse populations across the globe. There is a growing recognition among individuals of the advantages associated with the use of this beverage, leading to a heightened demand for the manufacture of herbal tea derived from therapeutic plants. Spices on the other hand add flavour to food but could pose harm if it is high in phytates and oxalates. The objective of this study was to develop natural spices and herbal tea with health beneficial properties using Solanum nigrum and Solanum torvum berries. Herbal tea samples from S. nigrum were prepared by sorting berries, maceration, divided into two (fermenting at 18 °C and non-fermenting) and dried at 60 °C for 12 h in a hot oven. Spices from S. torvum and S. nigrum were prepared by removing the berries from the stalk, freeze-drying and smooth milling into fine powder. In addition, antinutrient, phytochemical and sensory evaluation studies were conducted on these spices and herbal teas. A nine-point hedonic scale was utilized for the purpose of conducting a consumer acceptability sensory evaluation test using 101 untrained panelists. Data was then analyzed by t-test, one-way analysis of variance (ANOVA) and the level of significance (p < 0.05) was assessed using Tukey's and Dunnett's multiple comparison tests. The panellists expressed a favourable perception towards Solanum nigrum unripe unfermented green herbal tea (6.65 ± 2.08) as compared to the other formulated teas due to the components working together in a way that produces a nice tea sample. Both Solanum nigrum and Solanum torvum spices contained various levels of catechins, saponins, flavonoids, oxalates, phytates and tannins comparable to literature. The herbal tea samples exhibited a range of catechin content, varying from 0.255 to 0.756 mg/g. The antioxidant activity of the various herbal tea samples ranged from 66.37 ± 0.24 to 78.53 ± 0.18 µg/mL GAE as determined by the DPPH free radical assay Fermented black herbal teas recorded higher total phenols (2.80 ± 0.09d), total flavonoids (21.84 ± 1.84c) and showed greater antioxidant activity (78.53 ± 0.18a) as compared to the unfermented green herbal teas. The process of fermentation resulted in a decrease in pH from 7.22 to 6.53 within a period of 12 h. The Total Titratable Acidity (TTA) grew as the fermentation period progressed, whereas the Total Soluble Solids (TSS) decreased. Phytates were the least antinutrients among the two Solanum species accounting for 0.02 mg/100 g and 0.03 mg/100 g in S. torvum berries (STBs) and (S. nigrum berries) SNBs respectively.

The Effect of Drying Temperature and Time on The Chemical Characteristic, Total Phenolic Content, and Organoleptic Properties of Black Garlic Herbal Tea

Black garlic is a functional food known to be beneficial for health. Most people favor the organoleptic properties produced, so it needs handling to improve, namely by drying, which produces black garlic herbal tea products. This study aims to determine the effect of drying temperature and time on chemical characteristics, total phenolic content, and the organoleptic properties of black garlic herbal tea. The experiment was conducted with a two-factor, completely randomized design. The first factor is drying temperature, which consists of two levels (50 and 60⁰C). The second factor is drying time, which consists of two levels (5 and 6 hours). The observation results were analyzed using analysis of variance (ANOVA) and continued with DMRT further test at a 5 % confidence level. The results showed that black garlic herbal tea's temperature and drying time significantly affected chemical characteristics, total phenolic content, and color but had no significant effect on aroma, taste, and overall. The chemical characteristic results in the 60 ⁰C drying temperature for 6 hours contained 7.65 % moisture content, 2.98 % ash, and 4.06 mgGAE/g total phenolic content.

Potential probiotic and functional properties of Brettanomyces strains isolated from kombucha tea.

Kombucha, a beverage traditionally obtained through the fermentation of tea, is believed to have beneficial health properties. Therefore, characterizing the microorganisms responsible for this fermentation is essential to demonstrate its potential health benefits and to identify candidates for new probiotics. In this study, four probiotic yeast strains isolated from kombucha tea were identified, by the PCR-RFLP analysis of the ribosomal ITS region and the sequence of the D1/D2 domain of the 26S rDNA, as Brettanomyces bruxellensis (UVI55 and UVI56) and B. anomalus (UVI57 and UVI58). Properties relevant to probiotics were also studied in these strains. All of them showed excellent survival in simulated gastric (99%-100%) and duodenal (95%-100%) juices. The ability to self-aggregate (38%-100%), adhesion to xylene (15%-50%) and, above all, adhesion to Caco-2 cells (4%-21%), revealed its potential capacity to adhere to the intestinal epithelium. In addition, the tested strains showed excellent antioxidant capacity (82%-94%), antimicrobial activity against different pathogens (Escherichia coli, Staphylococcus aureus, Salmonella enterica, Listeria monocytogenes, and Bacillus cereus), as well as remarkable cytotoxic activity against colon, melanoma and ovarian tumor cell lines. Finally, using Caenorhabditis elegans as a model, strain UVI56 exhibited ability to both extend the lifespan of the nematode and protect it against infection by S. enterica. These results support the probiotic and functional properties of the analyzed strains. In conclusion, the study revealed that kombucha tea could be a source of potential probiotics that contribute to its health-promoting properties and that the characterized Brettanomyces strains could be exploited directly as probiotics or for the development of new functional foods.

An improved 3D-SwinT-CNN network to evaluate the fermentation degree of black tea

Fermentation is a key process in forming the flavor quality of black tea. Evaluating the degree of fermentation during black tea processing is difficult. This paper proposes an improved 3D-SwinT-CNN network for the end-to-end processing of black tea's hyperspectral images to evaluate the degree of fermentation. The model incorporates dilated convolution and a shifted window self-attention mechanism, expanding the network's receptive field and capturing both local spatial-spectral and global features of black tea hyperspectral images. The accuracy is 98.13% on the test set. Compared to manual feature extraction methods, the accuracy improved by 3.45%. Compared to baseline 3D-CNNs, 3D-SwinT-CNN demonstrates superior spatial-spectral feature extraction, achieving an average accuracy improvement of 10.17%. Ablation experiments were conducted to further verify the effectiveness of the introduced modules. The proposed 3D-SwinT-CNN aims to establish a research foundation for online evaluation of black tea's fermentation degree.

Process Optimization and Quality Components Analysis of γ-Aminobutyric Acid Pickled Tea.

Pickled tea is an anaerobically fermented tea common in Thailand, Myanmar and Yunnan minority areas. γ-aminobutyric acid (GABA) is non-protein amino acid with multiple bioactives, which can be easily produced under anaerobic conditions. During the processing of pickled tea, controlling the process parameters is effective for the production of GABA-rich products; however, the precise parameters remain to be clarified. In the present study, the fresh leaves of Camellia sinensis (L.) Kuntze (C. sinensis) 'FudingDabai', C. sinensis 'MabianLv No. 1', C. sinensis 'Wuniuzao' and C. sinensis 'Fuxuan No. 9' were used as raw materials to process GABA-rich pickled tea. Single-factor and orthogonal experiments were conducted to determine the best tea cultivars and optimize the best processing parameters via comparing the content of GABA, tea polyphenols (TPs) and other biochemical components of GABA-rich pickled tea. The results of the signal-factor experiment showed that the fresh leaves of C. sinensis 'MabianLv No. 1' had the highest GABA content of 2.61 mg·g-1 after treatment with vacuum for 6 h; therefore, C. sinensis 'MabianLv No. 1' was selected as the raw material for the subsequent experiments. Orthogonal experiments showed that the highest GABA content of 2.53 mg·g-1 was found in the pickled tea with 8 h of vacuum treatment, 20 min of rolling after microwave fixing, 20 min of spreading and 20 d of anaerobic fermentation at room temperature. Further, the sensory evaluation showed that it possesses a strong sour taste with a slight sweetness and a light yellow color and better comprehensive quality. This indicates that these parameters are optimal for the processing of GABA-rich pickled tea. This study will provide scientific basis for the subsequent production of high GABA tea.

Advancing jasmine tea production: YOLOv7-based real-time jasmine flower detection.

To produce jasmine tea of excellent quality, it is crucial to select jasmine flowers at their optimal growth stage during harvesting. However, achieving this goal remains a challenge due to environmental and manual factors. This study addresses this issue by classifying different jasmine flowers based on visual attributes using the YOLOv7 algorithm, one of the most advanced algorithms in convolutional neural networks. The mean average precision (mAP value) for detecting jasmine flowers using this model is 0.948, and the accuracy for five different degrees of openness of jasmine flowers, namely small buds, buds, half-open, full-open and wiltered, is 87.7%, 90.3%, 89%, 93.9% and 86.4%, respectively. Meanwhile, other ways of processing the images in the dataset, such as blurring and changing the brightness, also increased the credibility of the algorithm. This study shows that it is feasible to use deep learning algorithms for distinguishing jasmine flowers at different growth stages. This study can provide a reference for jasmine production estimation and for the development of intelligent and precise flower-picking applications to reduce flower waste and production costs. © 2024 Society of Chemical Industry.