Brewed Tea Research Articles

Determination of four aflatoxins on dark tea infusions and aflatoxin transfers evaluation during tea brewing

In daily tea drinking, little is known on aflatoxin transfers from tea-leaf to infusion during brewing and the actual intake. A verified aflatoxins analytical method on tea infusion is significant to the exposure assessment. Here, an optimal method 3 (M3) was screened and validated on four aflatoxins (B1, B2, G1 and G2) simultaneous determination. Recoveries of AFG1 and AFB1 were 87.37 %±1.99 %-102.03 %±8.62 %, and AFG2 and AFB2 were 83.99 %±8.65 %-100.14 %±1.69 %. The correlation coefficient on the fortified samples determination was > 0.99 for each aflatoxin. In accuracy and precision validation, aflatoxins recoveries in high and low fortified samples were 85.94 %-103.83 %, and RSDs were 2.20 %-9.15 %. Method applicability test showed that the M3 was qualified for six different dark tea types. Extraction rate of 30-days stored AFB1 fortified tea-leaf by acetonitrile–water (84:16, v/v) was < 50 %; meanwhile, only 2.94 % spiked AFB1 was released by ten times tea brewing which indicated that Puerh tea have strong adsorbability to aflatoxin.

Effect of brewing condition on the quality of Apocynum venetum tea

Apocynum venetum tea is increasingly being recognized for its health benefits. Given that brewing conditions affect the flavor and quality of the final brew, optimal brewing conditions need to be determined to produce high-quality A. venetum tea. In this study, different brewing strategies (hot brewing, room temperature brewing, and cold brewing) were used to prepare A. venetum tea. Subsequently, the physicochemical indexes, functional components, antioxidant activity, and aroma compounds of the brews were compared. The brewing conditions affected the soluble solid content of the brews, as well as their pH, color, polyphenol content, flavonoid content, and aroma compounds. Ketones and aldehydes were the most abundant aroma compounds in the teas prepared using the three brewing conditions. Hot brewing tea had the highest content of functional components and antioxidant activity with aromas of grassy alcohols and caramel, sweet, nutty furans and ethers. Room temperature brewing tea was rich in esters with floral and fruity aromas. In contrast, cold brewing tea had a blue-green color; the most abundant compound in this tea was 2,5-dimethylbenzaldehyde, and it had a grassy and floral aroma. These results showed that hot brewing is the most suitable method for Apocynum preparation of A. venetum tea. Practical applications Apocynum venetum tea has become an ingredient in natural health teas in recent years. The brewing conditions will affect the flavor and quality of the final brewing. Therefore, it is necessary to determine the best brewing conditions to produce high-quality A. venetum tea, so as to provide theoretical support for the determination of brewing conditions for A. venetum tea.

Colour Change of Hot Immersed Polymerized Acrylic Resin Steeped into Roselle Tea (Hibiscus sabdariffa) and Black Tea (Camellia sinensis)

Steeping rosella tea and black tea are effective as denture cleaning agents as they contain flavonoids that can inhibit the growth of C. Albicans. Flavonoids in the brewing of rosella tea and black tea are found in pigment compounds, so when the acrylic resin is soaked in the steeping of roselle tea and black tea, it can cause discoloration.This study aims to compare the color changes of acrylic resin soaked in roselle tea and black tea with the same treatment. A total of 18 samples of acrylic resin were divided into three groups; six samples immersed in 20% concentrated roselle tea, six samples immersed in 20% concentration of black tea, and six samples immersed in steeping mineral water for 22 hours 30 minutes at room temperature. The research results' data were analyzed using the one-way Anova test. Acrylic resin soaked in steeping roselle and black tea experienced a color change, and the largest color change occurred in acrylic resin soaked in black tea. The results showed that hot polymerized acrylic resin soaked in black tea had a greater color change than that of acrylic resin soaked in roselle tea.

Influence of different processing method on lignan content of selected Malaysian plant-based foods

This research assessed the influence of pickling, fermentation, germination, and tea brewing on lignan content of a variety of food highly consumed in Malaysia. Lignans have been measured by a validated LC-MS/MS method. Secoisolariciresinol (SECO) was the most abundant compound in fermented and germinated samples. Pickling significantly decreased larisiresinol content by approximately 86 %. Fermentation increased lignan content in a mixture of flaxseed and mung beans (799.9 ± 67.4 mg/100 g DW) compared to the unfermented counterpart (501.4 ± 134.6 mg/100 g DW), whereas the fermentation of soybeans and mung beans did not significantly affect the SECO content. Germination increased lignan content, which reached its peak on day 6 of germination for all the tested matrixes. In tea brew, lignans concentration increased with brewing time reaching its highest concentration at 10 min of brewing. The results of this study expand the knowledge on the effect of processing on lignan content in food.

Analysis of the microscopic interactions between processed Polygonatum cyrtonema polysaccharides and water

The dissolution and microscopic interactions of processed Polygonatum cyrtonema polysaccharides in water are extremely important because they strongly influence the process to extract these polysaccharides from water. In this paper, molecular dynamics simulation methods were used to analyse the influence of extraction temperature, concentration and molecular weight on the radial distribution function (RDF), mean square displacement (MSD), diffusion coefficient (D), radius of gyration (Rg), and microstructure of processed Polygonatum cyrtonema polysaccharides in water as well as the intrinsic viscosity (η), hydrogen bond characteristics and microscopic interactions in the solutions. The research results showed that the extraction temperature, concentration and molecular weight of the polysaccharides had important effects on the RDF, MSD, D, Rg, η, hydrogen bond characteristics and the microstructure of the polysaccharide molecules, but there were some major differences. The order of the influence of the factors affecting the dissolution of polysaccharides in water was temperature > concentration > molecular weight. Extraction temperature, material fluid ratio and molecular weight had greater influence on the fluidity and dissolution state of the polysaccharides in water. As the solute concentration and molecular weight increased, hydrogen bonds between polysaccharides and water inhibited their dissolution and diffusion. Properly increasing the temperature, reducing the concentration and selecting low molecular weight polysaccharides enhanced the dissolution and diffusion of the polysaccharides in the solution system. Molecular weight was the main factor affecting the η of the polysaccharide solutions. These results can provide theoretical guidance for the extraction or tea brewing process of Polygonatum cyrtonema polysaccharides in future work.

The Effect of Variations of Red Bricks, Sand, Sawdust, and Green Tea (Camellia sinensis) Media on the Fat Content of Salted Egg Yolks

Salting is done to extend the shelf life of duck eggs. A variety of media can be used for salting eggs, including a mixture of salt, sand, red brick, sawdust, and brewed tea. Salted eggs are popular among the general public, but they contain a lot of fat, which, if consumed in excess, can cause blood vessel blockage (atherosclerosis). Green tea is a plant that has many benefits, one of which is that it can help people lose weight. Duck eggs were ripened for 12 days in a variety of salting media with different ingredients for this study. Red bricks, sand, sawdust, salt, and brewed green tea are among the materials used. This study aimed to determine the fat content of salted egg yolks using the Soxhlet extraction method, as well as the color, aroma (smell), and taste of salted eggs. The data in this study were analyzed using One-Way ANOVA and the results revealed that variations in salting media had a significant effect on fat content in salted egg yolks. The results showed the changes in fat content in salted egg yolks without treatment with a fat content of 36.28 percent, and with treatment with media A (sand, red bricks, and sawdust); media B (sand, red bricks, and sawdust); media 1 (media A added with green tea); and media 2 (media B added with green tea), with the fat contents of 35.22%; 32.86%, and 30.49%. Mixed media of green tea affects the fat content of salted egg yolks, from 36.50% to 32.86% and 30.49%.

Improvement of Antioxidant Activity and Sensory Quality of Pagilaran’s Tea Clones Treated by Tannase

PT. Pagilaran developed five new clones named PGL 9, PGL 10, PGL 11, PGL 12, and PGL 15 for black tea. These clones can be potentially made into ready-to-drink (RTD) instant tea beverages with low antioxidant activity. Tannase is an industrial enzyme with great potential for application in the food industry used to hydrolyze gallated ester catechin in green tea. There were no findings on the effects of this enzyme treatment on the chemical composition of PT Pagilaran’s tea clones. Therefore, this study is aimed to observe the effects of tannase treatment on five clones of black tea extracts to the antioxidant activity, profile of phenolic compounds, the tea brew color, consumer acceptance, and volatile compounds. The leaves of the plucking medium were traditionally processed into black tea. Furthermore, the tea brew was added at a 100 mg/100 mL concentration and then incubated for 1 hour at 37 °C. Additional tannase increased their antioxidant activities, the gallic acid, EC, and EGC concentrations due to hydrolysis of ECG, EGCG, or their derivatives. The color of the tea brew was brighter and yellower than the untreated, but the level of consumer acceptance was still good. The profile aroma and volatile compounds showed no significant changes after enzymatic treatment.

Antioxidant and Anti-Inflammatory Properties of Prunella Vulgaris Tea

Prunella vulgaris is a traditional herb commonly consumed as brewed tea in Asian and European countries. The therapeutic antioxidant and anti-inflammatory activity of this traditional herbal tea are relatively unknown. The study examined, using established in vivo markers of oxidative stress and inflammation, the antioxidant and anti-inflammatory actions of Prunella vulgaris tea in-vitro, which were compared with those measured from green and black tea. Prunella vulgaris tea significantly decreased the human neutrophilic formations of F2-isoprostanes, lipid hydroperoxides, and leukotriene B4, while increasing those of nitrite and nitrate. The measured antioxidant and anti-inflammatory effects were greater than those from green and black tea. Prunella vulgaris tea exerted antioxidant effects via electron-transfer radical scavenging and up-regulated antioxidant enzyme activities, and anti-inflammatory effects by modulating 5-lipoxygenase, myeloperoxidase, and inducible nitric oxide pathways. The study results provide evidence supporting further investigations in the in vivo conditions.

Sense‐making in Taiwan's tea art ritual

This paper analyzes Taiwan's contemporary public tea gatherings from the perspective of “sense-scape,” the cultural world of sensory experiences. Performing elegance by way of tea brewing, bodily gestures and movements, costumes, utensil arrangements, and spatial design represents what is innovative about Taiwan's tea art culture, often referred to as “literati tea.” As the fragrance and flavors of tea, light and shadows, sounds and music, visual presentations of utensils, and space, as well as the general atmosphere of these events are captured by the senses and organized by the emotions, they inform us about who we are and who the other is. Despite its Japanese cultural infusion and Chinese cultural legacy, which have always complicated claims of a truly Taiwanese origin, Taiwan's tea art has been eagerly adopted by mainland Chinese tea communities since the late 2000s. That a local practice and invented tradition strongly identified with Taiwan has been embraced as “traditional” cultural practice in contemporary China presents a paradox that deserves our attention.

Evaluation of stability and quality characteristics of moringa (Moringa oleifera) herbal tea during storage

Determining the product’s shelf life was necessary to ensure its quality, effectiveness, and safety. This study aimed to determine the stability of moringa tea products. The real-time stability test was carried out at room temperature (28.5‒33.5°C) with 50‒75% relative humidity, and the sampling interval was once every third month (Month-0, Month-3 and Month-6). Physical parameters (organoleptic properties and moisture content), chemical parameters (total phenolic content and total flavonoid content), and microbial parameters (total plate count and total yeast and mould count) were measured using the standard procedures. The organoleptic test showed no changes in colour, taste, smell, and shape of the teabag and brewed tea products up to the sixth month of evaluation. However, there were significant changes in the moisture content (MC), total phenolic content (TPhC), and total plate count (TPC) of the teabag and only in the TPhC of the brewed tea product throughout the quality control. Physical, chemical, and microbial parameters still met the quality requirements set by the Pharmacopoeia Herbal Indonesia and the Indonesian Food and Drug Authority. The qualities of moringa tea bags and brewed moringa teas stored at room temperature (28.5‒33.5°C) and 50‒75% relative humidity showed good physicochemical properties and stability in the test during six months of observation.

Optimizing NPK fertilizer requirements for Jatropha zeyheri tea under greenhouse conditions

Jatropha zeyheri is an indigenous crop to South Africa, which contains tea brewing and medicinal properties commonly utilized by local communities in rural areas of South Africa. Domestication and commercialization of indigenous herbal teas have gained popularity in recent years however, domestication of J. zeyheri will require optimum NPK fertilizer mixture to improve the yield and quality. Therefore, the study was intended to determine whether different fertilizer application rates will optimize yield parameters of J. zeyheri tea under greenhouse conditions. At two-leaf stage, J. zeyheri seedlings were transplanted into 25 cm diameter plastic pots. Each pot was filled with heated-pasteurised sandy soil and Hygromix at 3:1 (v/v) ratio and placed in a spacing of 0.30 m × 0.30 m inter-and intra-row spacing. Six treatments constituting NPK fertilizer rates (0, 2, 4, 8, 16 and 32 g) were arranged in a randomized complete block design, with five replications. Treatments were initiated a week after transplanting, and 130 days after that, treatments had highly significant effects on chlorophyll content, leaf width and dry root mass, contributing 70, 78 and 62% in total treatment variation (TTV), respectively. In contrast, vine length, stem diameter and leaf length were significant, contributing 47, 60 and 49% in TTV, respectively. However, treatments had no significant effects on normalized difference vegetation index, number of leaves and dry shoot mass. Jatropha zeyheri plant variables exhibited positive quadratic relations with increasing fertilizer levels. Fertilizer requirements for J. zeyheri were optimized at 3.34 g fertilizer/plant, which translates to 33 kg NPK fertilizer/ha for 10 000 plants of J. zeyheri. In conclusion, J. zeyheri appears to qualify as a low-input tea crop.

Optimizing NPK fertilizer requirements for Jatropha zeyheri tea under greenhouse conditions

Jatropha zeyheri is an indigenous crop to South Africa, which contains tea brewing and medicinal properties commonly utilized by local communities in rural areas of South Africa. Domestication and commercialization of indigenous herbal teas have gained popularity in recent years however, domestication of J. zeyheri will require optimum NPK fertilizer mixture to improve the yield and quality. Therefore, the study was intended to determine whether different fertilizer application rates will optimize yield parameters of J. zeyheri tea under greenhouse conditions. At two-leaf stage, J. zeyheri seedlings were transplanted into 25 cm diameter plastic pots. Each pot was filled with heated-pasteurised sandy soil and Hygromix at 3:1 (v/v) ratio and placed in a spacing of 0.30 m × 0.30 m inter-and intra-row spacing. Six treatments constituting NPK fertilizer rates (0, 2, 4, 8, 16 and 32 g) were arranged in a randomized complete block design, with five replications. Treatments were initiated a week after transplanting, and 130 days after that, treatments had highly significant effects on chlorophyll content, leaf width and dry root mass, contributing 70, 78 and 62% in total treatment variation (TTV), respectively. In contrast, vine length, stem diameter and leaf length were significant, contributing 47, 60 and 49% in TTV, respectively. However, treatments had no significant effects on normalized difference vegetation index, number of leaves and dry shoot mass. Jatropha zeyheri plant variables exhibited positive quadratic relations with increasing fertilizer levels. Fertilizer requirements for J. zeyheri were optimized at 3.34 g fertilizer/plant, which translates to 33 kg NPK fertilizer/ha for 10 000 plants of J. zeyheri. In conclusion, J. zeyheri appears to qualify as a low-input tea crop.

Concentrations, generation and risk characterization of phthalimide in tea-derived from folpet or not?

The fungicide folpet is rapidly degraded into phthalimide (PI) during both thermal processing and analytical procedures in sample preparation; thus, its residue definition has been modified into the sum of itself and PI. Tea is one of the world's most popular nonalcoholic beverages, where folpet is not listed as an applicable pesticide. To demonstrate how serious false-positives and overestimation in dietary risk are caused by the application of a new residue definition, the residue pattern of PI in made tea and processed tea leaves, along with its transfer rate during tea brewing and corresponding dietary risk, were investigated in the present study. The results revealed that PI residue in tea ranged from <10 μg/kg to 180 μg/kg with a median value of 10 μg/kg, 7.3 % of which was over the maximum residue limit established by EU (100 μg/kg, expressed as folpet). The PI residue in green tea was obviously higher than that in black, dark and oolong tea. Simulated heating experiments revealed that PI can arise from improper heating of folpet-free fresh tea leaves, and thus green tea bears a higher risk for its manufacturing employing a comparatively higher temperature. The transfer rate of PI during tea brewing was 104 ± 14 %. Nevertheless, the risk of PI through drinking tea was negligible to humans depending on the risk quotient (RQ) value, which was significantly lower than 1.

Glycyrrhizinic acid in licorice products on the Danish market

Glycyrrhizinic acid (GA) is a natural compound found in licorice root and its extract, and is used in a large number of food products. It has been documented that excess consumption of licorice can cause adverse health effects, due to their content of GA. Mandatory labelling rules are therefore in place in the EU to inform consumers of the possible adverse health effects. In this study, 219 samples of confectionery, ice cream, and tea with licorice were sampled in Denmark and analyzed for their GA content. The content of GA was measured with an UPLC-UV method. The results showed that 10% of the samples were inadequately labelled. The samples in each category reaching the highest GA content were confectionery made of pure licorice extract at 23,154 mg/kg, ice cream at 1690 mg/kg, and brewed tea at 1203 mg/L. An intake of 4.3 g of confectionery, 59 g of ice cream, or 83 ml of tea, would surpass the provisionary limit of 100 mg GA/day for regular ingestion. In addition to this health risk scenario from high content products, a larger consumption of licorice products with a lower GA content could also pose a health risk. We suggest campaigns to increase public awareness of the potential adverse health effects of excessive licorice consumption. In addition, it was investigated if 18β-glycyrrhetinic acid (GE) was liberated during the processing steps of licorice production. GE is the pharmacologically active aglucone of GA. 18β-Glycyrrhetinic acid was not identified in any product.

On the relative extraction rates of colour compounds and caffeine during brewing, an investigation of tea over time and temperature

Abstract Various beliefs are common about the extraction of soluble compounds from leaf tea, suggesting that cold brewed tea or tea brewed for a shorter time than usual may contain a higher polyphenol-to-caffeine ratio, a selling point due to the potential health benefits of polyphenolic compounds. To test these beliefs, we investigated the effect of brewing time and temperature on the colour intensity and caffeine content of the extract of one type of black tea. Results showed that the extraction of the two components of interest had different half-lives, with an initial large variation of the ratio between them rapidly reaching a quite constant value. At different temperatures, a significantly different ratio between caffeine and colour compounds was observed. Although the difference in relative concentration was small, the range of brewing temperatures tested was only 20 Kelvin, so it seems possible to increase this difference. A difference in total extraction efficiency of both components together was noted too. To effectively change the ratio of the components using the extraction time would require using accurate times of less than 3 minutes and accurate temperatures unusual in a home environment.

Characterization of Roasting Time on Sensory Quality, Color, Taste, and Nonvolatile Compounds of Yuan An Yellow Tea.

Roasting is crucial for producing Yuan An yellow tea (YAYT) as it substantially affects sensory quality. However, the effect of roasting time on YAYT flavor quality is not clear. To investigate the effect of roasting time on the sensory qualities, chemical components, odor profiles, and metabolic profile of YAYTs produced with 13 min roasting, 16 min roasting, 19 min roasting, 22 min roasting, and 25 min roasting were determined. The YAYTs roasted for 22 min got higher sensory scores and better chemical qualities, such as the content of gallocatechin (GC), gallocatechin gallate (GCG), free amino acids, solutable sugar, meanwhile the lightness decreased, the hue of tea brew color (b) increased, which meant the tea brew got darker and yellower. YAYTs roasted for 22 min also increased the contents of key odorants, such as benzaldehyde, nonanal, β-cyclocitral, linalool, nerol, α-cedrol, β-ionone, limonene, 2-methylfuran, indole, and longiborneol. Moreover, non-targeted metabolomics identified up to 14 differentially expressed metabolites through pair-wise comparisons, such as flavonoids, phenolic acids, sucrose, and critical metabolites, which were the main components corresponding to YAYT roasted for 22 min. In summary, the current results provide scientific guidance for the production of high quality YAYT.

Synthesis of polydopamine coated magnetic halloysite nanotubes for fast enrichment and extraction of anthraquinones in brewed slimming tea

In this work, a magnetic halloysite nanotubes composite material modified with polydopamine (MHNTs@PDA) was synthesized through a facile and green synthesis strategy, and employed as an efficient adsorbent for magnetic solid-phase extraction (MSPE) of three anthraquinones. The material showed very fast adsorption ability (adsorption time of 3 min), good reusability and strong magnetic response. The main parameters affecting the extraction efficiency of MSPE, including adsorption time, amounts of adsorbent, sample pH, salt concentration and desorption conditions, were investigated and optimized. By coupling MHNTs@PDA-based MSPE with HPLC-UV, the method exhibited good linearity (R2 ≥ 0.9944) in the concentration range of 5–1000 μg L-1 and low limits of detection (1.0–1.5 μg L-1) for anthraquinones. Finally, the developed method was successfully applied to determine anthraquinones in brewed slimming tea, and the obtained recoveries were in the range of 73.5–119.1%, with RSD less than 9.7%.

Prediction and Health Risk Assessment of Copper, Lead, Cadmium, Chromium, and Nickel in Tieguanyin Tea: A Case Study from Fujian, China.

Heavy metal is widespread in food and the environment due to multiple origins, raising concerns over their persistent potential health risks. Contamination of multiple heavy metals in tea leaves is frequently reported. However, the dietary exposure risk that heavy metals in Tieguanyin tea (a famous type of oolong tea,) pose to different subpopulations has not been explored. In this study, contaminations of five heavy metals (Cu, Pb, Cr, Cd, and Ni) of concern in Tieguanyin tea were monitored, then the related health risk was assessed for six different subpopulations based on tea brewing experiments and a previous consumption survey. Results show that the mean levels found were as follows: 8.18 mg/kg (Cu), 0.84 mg/kg (Pb), 0.51 mg/kg (Cr), 0.04 mg/kg (Cd), and 1.90 mg/kg (Ni), respectively, and their transfer rates during tea brewing varied within 10.2–70.4%. All estimated daily intakes of individual targeted elements via Tieguanying tea consumption were far below their corresponding tolerable limits. The adjusted hazard index value ranged from 1.1 × 10−2 to 1.7 × 10−2, indicating that exposure to these five elements via drinking Tieguanyin tea would not pose significant non-cancer risks for six subpopulations under the current consumption habit. In addition, the carcinogenic risks associated with heavy metals (Pb, Cd, and Cr) were acceptable because no total cancer risk values exceeded the 10−4 threshold. However, in order to improve consumer protection, we still suggest that considerable attention should be paid to Pb, Ni, and Cd because of their high concentration in infusion, high extraction rate, and major carcinogenic risk contribution, respectively.

Unravelling the comparative metabolite fingerprints and therapeutic effects of diverse teas

The comparative metabolite fingerprinting and bioactivity of different teas viz. green tea, oolong tea, white tea, orthodox black tea, and Cut/crush, Tear and Curl (CTC) black tea as compared to unprocessed tea leaves (GTL) were elucidated. The fresh tender tea shoots collected from single location were processed into different tea forms and brewed homogenously. The mass fingerprinting analysis using ultra high performance liquid chromatography ion mobility quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-IMS) revealed substantial variability of key metabolites among different tea brews. Statistical analysis (Venn-diagram, Heatmap and PCA) has revealed significant variation in metabolites content among different teas. Catechins and caffeine were identified and quantified in all infusions using high-pressure liquid chromatography analysis. 2,2-diphenyl-1- picrylhydrazyl (DPPH) free radical scavenging assay, 2,2′-azino-bis (3 ethylbenzothiazoline-6-sulphonic acid (ABTS) radical cation decolourisation assay and ferric-reducing antioxidant power (FRAP) assay unveiled significant antioxidant potential by all the infusions. The results of α-glucosidase inhibition by different teas showed positive effects in management of postprandial hyperglycemia. The tea samples also unveiled significant results for nitric oxide inhibition in lipopolysaccharide-stimulated RAW 264.7 macrophages and cytotoxicity against A-549 and CT26.CL25 cancer cells. Hence, it has established that tea processing has substantial role on key metabolite composition and therapeutic potential of different tea infusions.

Dissipation pattern and conversion of pyrrolizidine alkaloids (PAs) and pyrrolizidine alkaloid N-oxides (PANOs) during tea manufacturing and brewing

Pyrrolizidine alkaloids (PAs) and pyrrolizidine alkaloid N-oxides (PANOs) are toxic secondary metabolites in plants, and one kind of main exogenous pollutants of tea. Herein, the dissipation pattern and conversion behavior of PAs/PANOs were investigated during tea manufacturing and brewing using ultra high-performance liquid chromatography tandem mass spectrometry. Compared with PAs (processing factor (PF) = 0.73–1.15), PANOs had higher degradation rates (PF = 0.21–0.56) during tea manufacturing, and drying played the most important role in PANOs degradation. Moreover, PANOs were firstly discovered to be converted to corresponding PAs especially in the time-consuming (spreading of green tea manufacturing and withering of black tea manufacturing) and high-temperature tea processing (drying). Moreover, higher transfer rates of PANOs (≥75.84%) than that of PAs (≤56.53%) were observed during tea brewing. Due to higher toxicity of PAs than PANOs, these results are conducive to risk assessment and pollution control of PAs/PANOs in tea.