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16 pages, 5527 KB

Open AccessArticle

Revealing the Differences in Taste/Mouthfeel Quality of Raw Pu-erh Tea Under Different Drying Methods Based on Nontargeted and Targeted Metabolomics

by Zhengfei Luo, Linlong Ma, Faxing Wan, Xueyan Liu, Yangtao Zhang, Ting Xu, Qiqian Su, Dan Cao, Yanli Liu, Xiaomei Yan, Yanhong Liu and Xiaofang Jin

Foods 2026, 15(11), 1918; https://doi.org/10.3390/foods15111918 - 28 May 2026

Abstract

Drying plays a critical role in shaping tea quality. This study systematically investigated the differences in the taste/mouthfeel quality of hot-air drying raw Pu-erh tea (HDRPT), pan-fired drying raw Pu-erh tea (PDRPT), and sun drying raw Pu-erh tea (SDRPT). The results showed that [...] Read more.

Drying plays a critical role in shaping tea quality. This study systematically investigated the differences in the taste/mouthfeel quality of hot-air drying raw Pu-erh tea (HDRPT), pan-fired drying raw Pu-erh tea (PDRPT), and sun drying raw Pu-erh tea (SDRPT). The results showed that SDRPT exhibited a mellow and thick mouthfeel with a sweet aftertaste, and significantly higher intensities of umami and sweetness compared to PDRPT and HDRPT. The relatively higher contents of amino acids such as theanine, glutamic acid, aspartic acid, and glutamine, along with water-soluble sugars, and relatively lower contents of catechins, including ECG and EGCG, were identified as key material bases contributing to the unique taste/mouthfeel quality of SDRPT. A total of 1987 non-volatile components were detected, from which 137 differential non-volatile components were screened. Among these, 75 components in SDRPT showed significant differences from both PDRPT and HDRPT, with the majority exhibiting higher relative contents in SDRRT, particularly notable among lipids, phenolic acids, and terpenoids. Furthermore, all 75 differential components were significantly correlated with at least one taste/mouthfeel attribute, with most showing significant positive correlations with umami, sweetness, and sourness, and significant negative correlations with bitterness and astringency. These findings provide a theoretical foundation for understanding the mechanism by which drying techniques influence the taste/mouthfeel quality formation of raw Pu-erh tea, and offer a scientific basis for improving its quality. Full article

(This article belongs to the Special Issue Production, Quality, Flavor Characteristics and Health Benefits of Tea: 2nd Edition)

13 pages, 1242 KB

Open AccessArticle

Antagonistic Polyphenol Interactions Underlie the α-Glucosidase Inhibitory Activity of Keemun Black Tea

by Xiao-Lan Yu, Xizhe Zhu, Xinxin Lv, Jingming Ning and Haibo Yuan

Foods 2026, 15(6), 1061; https://doi.org/10.3390/foods15061061 - 18 Mar 2026

Cited by 1 | Viewed by 467

Abstract

The α-glucosidase inhibitory activity of Keemun black tea arises from complex interactions among its major polyphenols, which cannot be reliably predicted from the activities of isolated compounds. In this study, eight dominant polyphenols were investigated using a quantitative reconstruction–omission framework designed to reflect [...] Read more.

The α-glucosidase inhibitory activity of Keemun black tea arises from complex interactions among its major polyphenols, which cannot be reliably predicted from the activities of isolated compounds. In this study, eight dominant polyphenols were investigated using a quantitative reconstruction–omission framework designed to reflect typical household tea brewing. The fully reconstructed system recovered approximately 72% of the inhibitory activity of the diluted native infusion, supporting the functional representativeness of the selected compounds. Systematic omission experiments revealed that antagonistic interactions, particularly among theaflavins, dominated the net inhibitory outcome, with removal of the most potent inhibitor, theaflavin-3,3′-digallate (TFDG), paradoxically increasing overall activity. Pairwise Combination Index analysis further demonstrated concentration-dependent biphasic interactions, exemplified by the epigallocatechin-3-gallate (EGCG)–TFDG pair, while molecular docking suggested overlapping binding sites as a potential structural basis for competitive inhibition. Collectively, this work provides a system-level dissection of α-glucosidase inhibition in black tea. Although the reconstructed system does not fully capture all contributions, the proposed framework offers a generalizable strategy for investigating interaction-driven bioactivity in complex dietary matrices and for further mechanistic studies. Full article

(This article belongs to the Special Issue Production, Quality, Flavor Characteristics and Health Benefits of Tea: 2nd Edition)

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15 pages, 4278 KB

Open AccessArticle

Unraveling Variations in Primary Metabolites of Longjing Green Tea During Processing and from Different Geographical Origins

by Zhiyuan Lin, Mei Chen, Bo Zhou, Junfeng Tan, Liang Zeng, Zhi Lin, Jinchi Tang and Weidong Dai

Foods 2026, 15(5), 865; https://doi.org/10.3390/foods15050865 - 4 Mar 2026

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Abstract

(1) Background: Primary metabolism is essential for tea quality formation, however systematic analysis of tea primary metabolites remains limited; (2) Methods: An orthogonal design was used to optimize the pre-column derivatization reaction conditions for the tea matrix. Using the optimized method, gas chromatography–mass [...] Read more.

(1) Background: Primary metabolism is essential for tea quality formation, however systematic analysis of tea primary metabolites remains limited; (2) Methods: An orthogonal design was used to optimize the pre-column derivatization reaction conditions for the tea matrix. Using the optimized method, gas chromatography–mass spectrometry (GC–MS) was employed to analyze Longjing green tea (LJGT) samples from different processing stages and regions; (3) Results: Optimal derivatization was achieved with 75 μL of methoxamine hydrochloride pyridine solution at 30 °C for 1.5 h. A total of 52 primary metabolites were identified in LJGT. Processing analysis showed that 8 metabolites associated with carbohydrate metabolism significantly decreased during spreading. Five reducing sugars significantly decreased, while sucrose, turanose, and quinic acid significantly increased due to the thermal action during pan-fixation. Additionally, 15 key differential compounds were identified among three regions (Xihu, Qiantang, and Yuezhou) of LJGT. Quantitative analysis revealed that shikimic and quinic acid contents were significantly higher in the Xihu region compared to other regions; (4) Conclusions: This study established a pre-column derivatization GC-MS method for primary metabolite profiling, elucidated metabolic regulation during LJGT processing, and identified differences in primary metabolite content among LJGT from different geographical origins. Full article

(This article belongs to the Special Issue Production, Quality, Flavor Characteristics and Health Benefits of Tea: 2nd Edition)

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17 pages, 3182 KB

Open AccessArticle

Spreading Degree Modulates Floral Aroma Development in Green Tea: Integrated GC-E-Nose, Metabolomics, and Molecular Docking Reveals Key Odorants and Olfactory Receptor Interactions

by Jiajing Hu, Xianxiu Zhou, Guangyue Hou, Jiahao Tang, Yongwen Jiang, Haibo Yuan, Daliang Shi and Yanqin Yang

Foods 2026, 15(4), 735; https://doi.org/10.3390/foods15040735 - 16 Feb 2026

Cited by 1 | Viewed by 542

Abstract

The spreading process constitutes a pivotal stage in green tea manufacturing. This study integrated GC-E-Nose with targeted metabolomics to comprehensively elucidate the dynamic changes in sensory characteristics and aroma substances of green tea across varying spreading degrees. Our findings demonstrated that spreading degree [...] Read more.

The spreading process constitutes a pivotal stage in green tea manufacturing. This study integrated GC-E-Nose with targeted metabolomics to comprehensively elucidate the dynamic changes in sensory characteristics and aroma substances of green tea across varying spreading degrees. Our findings demonstrated that spreading degree significantly modulated green tea’s aroma profile, with lighter degree particularly promoting the development of desirable floral aroma. GC-MS/MS quantification identified 70 volatile compounds, among which 38 exhibited spreading-dependent differential accumulation (VIP > 1.0, p < 0.05). Five key odorants, including indole, β-ionone, nerolidol, cis-jasmone, and β-damascenone, were highlighted as essential contributors to the floral aroma. Molecular docking simulations indicated stronger binding affinities between these five odorants and the olfactory receptor OR1D2 (<−6 kcal/mol), primarily via hydrogen bonding and hydrophobic interactions. These findings indicate that modulating the spreading degree is an effective processing strategy to enhance the development of floral aroma in green tea, offering valuable insights for precision-driven optimization of tea processing protocols. Full article

(This article belongs to the Special Issue Production, Quality, Flavor Characteristics and Health Benefits of Tea: 2nd Edition)

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18 pages, 2729 KB

Open AccessArticle

Enhancement Effect of Lemon Flower on the Flavor Quality of White Tea and Its Formation Mechanism

by Jun Wang, Yiwen Hu, Deyu Hu, Zhihong Lu, Li Xiang, Jinsong Xiang, Min Hong, Lili Ling and Yanyan Ma

Foods 2026, 15(3), 596; https://doi.org/10.3390/foods15030596 - 6 Feb 2026

Cited by 1 | Viewed by 580

Abstract

This study involved developing a novel lemon flower-scented white tea (LT) through multiple aroma-imparting cycles, and taking an integrated approach to investigating its flavour formation mechanism. Sensory evaluation and electronic tongue analysis revealed that the LT exhibited more balanced taste characteristics, with significantly [...] Read more.

This study involved developing a novel lemon flower-scented white tea (LT) through multiple aroma-imparting cycles, and taking an integrated approach to investigating its flavour formation mechanism. Sensory evaluation and electronic tongue analysis revealed that the LT exhibited more balanced taste characteristics, with significantly reduced bitterness and astringency, attributed to the decreased caffeine content and conversion of esterified catechins. Electronic nose and HS-SPME/GC-MS results confirmed that the LT had acquired a distinctive aroma characterised by floral and citrus notes, primarily originating from lemon flower volatiles such as methyl anthranilate and limonene. Multivariate statistical analysis identified 32 key differential compounds (variable importance in projection value > 1), with methyl anthranilate, β-ionone, and geraniol (relative odour activity value > 80) jointly forming the shared flavour base among teas. These findings demonstrate that lemon flower infusion can effectively enhance the sensory quality of white tea and provide theoretical support for the development of diverse floral teas. Full article

(This article belongs to the Special Issue Production, Quality, Flavor Characteristics and Health Benefits of Tea: 2nd Edition)

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22 pages, 10561 KB

Open AccessArticle

FSCA-EUNet: Lightweight Classification of Stacked Jasmine Bloom-Stages via Frequency–Spatial Cross-Attention for Industrial Scenting Automation

by Zhiwei Chen, Zhengrui Tian, Haowen Zhang, Xingmin Zhang, Xuesong Zhu and Chunwang Dong

Foods 2025, 14(21), 3780; https://doi.org/10.3390/foods14213780 - 4 Nov 2025

Viewed by 992

Abstract

To address the challenge of monitoring the postharvest jasmine bloom stages during industrial tea scenting processes, this study proposes an efficient U-shaped Network (U-Net) model with frequency–spatial cross-attention (FSCA-EUNet) to resolve critical bottlenecks, including repetitive backgrounds and small interclass differences, caused by stacked [...] Read more.

To address the challenge of monitoring the postharvest jasmine bloom stages during industrial tea scenting processes, this study proposes an efficient U-shaped Network (U-Net) model with frequency–spatial cross-attention (FSCA-EUNet) to resolve critical bottlenecks, including repetitive backgrounds and small interclass differences, caused by stacked jasmine flowers during factory production. High-resolution images of stacked jasmine flowers were first preprocessed and input into FSCA-EUNet, where the encoder extracted multi-scale spatial features and the FSCA module incorporated frequency-domain textures. The decoder then fused and refined these features, and the final classification layer output the predicted bloom stage for each image. The proposed model was designed as a “U-Net”-like structure to preserve multiscale details and employed a frequency–spatial cross-attention module to extract high-frequency texture features via a discrete cosine transform. Long-range dependencies were established by NonLocalBlook, located after the encoders in the model. Finally, a momentum-updated center loss function was introduced to constrain the feature space distribution and enhance intraclass compactness. According to the experimental results, the proposed model achieved the best metrics, including 95.52% precision, 95.42% recall, 95.40% F1-score, and 97.24% mean average precision, on our constructed dataset with only 878.851 K parameters and 15.445 G Floating Point Operations (FLOPs), and enabled real-time deployment at 22.33 FPS on Jetson Orin NX edge devices. The ablation experiments validated the improvements contributed by each module, which significantly improved the fine-grained classification capability of the proposed network. In conclusion, FSCA-EUNet effectively addresses the challenges of stacked flower backgrounds and subtle interclass differences, offering a lightweight yet accurate framework that enables real-time deployment for industrial jasmine tea scenting automation. Full article

(This article belongs to the Special Issue Production, Quality, Flavor Characteristics and Health Benefits of Tea: 2nd Edition)

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19 pages, 5328 KB

Open AccessArticle

Effects of Solid-State Fermentation with Eurotium cristatum on the Physicochemical, Sensory, and Volatile Profiles of Summer–Autumn Green Tea

by Su Xu, Linyao Song, Yichen Zhao and Degang Zhao

Foods 2025, 14(21), 3681; https://doi.org/10.3390/foods14213681 - 28 Oct 2025

Cited by 6 | Viewed by 1413

Abstract

Summer–autumn green tea (SAGT) is a high-yield green tea often compromised by pronounced bitterness, astringency and a weak aroma, which severely limit its consumer acceptability and economic value. To enhance its quality, this study employed solid-state fermentation with Eurotium cristatum, the core [...] Read more.

Summer–autumn green tea (SAGT) is a high-yield green tea often compromised by pronounced bitterness, astringency and a weak aroma, which severely limit its consumer acceptability and economic value. To enhance its quality, this study employed solid-state fermentation with Eurotium cristatum, the core probiotic fungus in Fu brick tea (FBT), to investigate its effects on the physicochemical, sensory, and volatile profiles of SAGT. The findings showed that after fermentation, the tea leaves developed a golden-yellow color, and the tea infusion turned brown. Moreover, the contents of flavonoids, tea polyphenols, soluble sugars, catechins, and free amino acids showed decreases of 3%, 33%, 38%, 41%, and 48%, respectively, when compared to SAGT. At the same time, the astringency and bitterness levels of the infusions significantly diminished (p < 0.05) post-fermentation, and the 8-day fermented tea sample was the most preferred by the sensory panel. During fermentation, E-nose, GC-MS, and GC-IMS analyses revealed a substantial transformation of the volatile profile, with a total of 104 and 129 volatile organic compounds (VOCs) were identified using GC-MS and GC-IMS techniques, respectively. The ROAV analysis highlighted 22 aroma-active compounds, particularly linalool and methyl salicylate, whose values increased significantly (p < 0.05), reaching values of 19,561.95 and 109.56, respectively, making them key contributors to the prominent floral and minty fragrance in the fermented tea. Additionally, PLS-DA analysis revealed 22 and 33 differential VOCs in the GC-MS and GC-IMS methods, respectively, with the majority stemming from the PAL and MEP metabolic pathways. This study provides theoretical insights aimed at enhancing the flavor quality of SAGT. Full article

(This article belongs to the Special Issue Production, Quality, Flavor Characteristics and Health Benefits of Tea: 2nd Edition)

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15 pages, 2715 KB

Open AccessArticle

Unraveling the Key Odorants in Floral-Fruity Aroma Pu-Erh Tea via GC-O-MS, GC-MS/MS, Aroma Recombination, and Omission Tests

by Xianxiu Zhou, Jiajing Hu, Hongchun Cui, Jiahao Tang, Yongwen Jiang, Haibo Yuan, Jiahua Li and Yanqin Yang

Foods 2025, 14(18), 3223; https://doi.org/10.3390/foods14183223 - 17 Sep 2025

Cited by 5 | Viewed by 1557

Abstract

Floral–fruity aroma Pu-erh tea (FFAPET) is highly valued by consumers for its distinctive and appealing fragrance. This study conducted a comprehensive investigation into the volatile components of FFAPET using advanced analytical techniques, including GC-O-MS, GC-MS/MS, aroma recombination, and omission tests. Compared with traditional [...] Read more.

Floral–fruity aroma Pu-erh tea (FFAPET) is highly valued by consumers for its distinctive and appealing fragrance. This study conducted a comprehensive investigation into the volatile components of FFAPET using advanced analytical techniques, including GC-O-MS, GC-MS/MS, aroma recombination, and omission tests. Compared with traditional stale aroma Pu-erh tea, FFAPET exhibited higher levels of alcohols and alkenes. Through GC-O-MS combined with OAV analysis, 10 key active-aroma compounds were identified in representative FFAPET samples. These compounds included (E, E)-2,4-heptadienal, phenylethyl alcohol, geraniol, (E, Z)-2,6-nonadienal, (Z)-4-heptenal, 2-phenethyl acetate, 2,2,6-trimethylcyclohexanone, D-limonene, β-ionone, and linalool, all of which made significant contributions to the development of the characteristic floral–fruity aroma profile. Tests involving aroma recombination and omission further confirmed that seven of these odorants played essential roles in defining the overall aroma of FFAPET. These findings offer valuable theoretical insights for the enhancement and regulation of Pu-erh tea flavor, particularly for the optimization of the floral–fruity aroma characteristics. Full article

(This article belongs to the Special Issue Production, Quality, Flavor Characteristics and Health Benefits of Tea: 2nd Edition)

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15 pages, 3395 KB

Open AccessArticle

Effects of Different Fertilization Patterns on the Content of Quality Indices and the Formation of Aroma Characteristics of Tea Leaves

by Qi Zhang, Songhan Guo, Yulin Wang, Yangxin Luo, Yankun Liao, Xiaoli Jia, Bitong Zhu, Jianghua Ye and Haibin Wang

Foods 2025, 14(18), 3194; https://doi.org/10.3390/foods14183194 - 13 Sep 2025

Cited by 1 | Viewed by 1346

Abstract

Fertilization is a necessary measure in the cultivation and management of the tea bush, and the use of different fertilizers significantly affects the quality of tea leaves. In this study, 100% chemical fertilizer (CF), 100% organic fertilizer (OF), and 50% chemical fertilizer + [...] Read more.

Fertilization is a necessary measure in the cultivation and management of the tea bush, and the use of different fertilizers significantly affects the quality of tea leaves. In this study, 100% chemical fertilizer (CF), 100% organic fertilizer (OF), and 50% chemical fertilizer + 50% organic fertilizer (COF) were used to analyze the effects of different fertilizer treatments on the quality indices and volatile component compositions of tea leaves. The results showed that COF treatment significantly increased the content of water extract, tea polyphenols, theanine, free amino acids, and soluble sugar, but decreased the content of total flavonoids and caffeine, indicating that COF treatment has an advantage in improving the overall quality of tea leaves. Analysis of volatile components showed that different fertilizer treatments significantly affected the content of eleven characteristic metabolites in tea bush leaves, of which four characteristic metabolites were most abundant under CF treatment, eight under OF treatment, and only one under COF treatment. The odor characteristics and their intensity analyses showed that the 11 characteristic volatile components mainly exhibited three types of odor characteristics, such as woody, green, and floral, of which OF treatment enhanced woody and green intensities, while CF treatment enhanced floral intensity. Taken together, different fertilizer treatments could regulate the quality indices and volatile components of tea leaves, while the use of chemical fertilizers or organic fertilizers alone was conducive to enhancing the intensity of individual special odor characteristics in tea leaves. Overall, the combination of chemical fertilizers and organic fertilizers was more conducive to the improvement of tea quality. This study provides a theoretical basis for optimizing the fertilization strategy of tea bushes to improve tea quality. Full article

(This article belongs to the Special Issue Production, Quality, Flavor Characteristics and Health Benefits of Tea: 2nd Edition)

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15 pages, 1355 KB

Open AccessArticle

Effect of Pressing Process on Metabolomics Profiling and Sensory Properties: A Comparative Study of Fu Brick Tea Versus Fu Loose Tea from Identical Raw Dark Tea

by Yan Liang, Jialin Zou, Fanhua Wu, Xiaofang Zhu, Xin Hu, Haoan Zhao and Wei Cao

Foods 2025, 14(17), 3053; https://doi.org/10.3390/foods14173053 - 29 Aug 2025

Viewed by 1572

Abstract

Fu tea is a unique microbially fermented tea from China, and has two types. The primary distinction between these two types—Fu brick tea (FBT) and Fu loose tea (FLT)—is that FBT is compressed into bricks, whereas FLT is maintained as loose leaves. To [...] Read more.

Fu tea is a unique microbially fermented tea from China, and has two types. The primary distinction between these two types—Fu brick tea (FBT) and Fu loose tea (FLT)—is that FBT is compressed into bricks, whereas FLT is maintained as loose leaves. To investigate the differences in the chemical composition and sensory characteristics between the two types of Fu tea, this study utilized samples produced from the same batch of raw dark tea material to ensure comparability. Multiple analytical approaches were applied, including main active component analysis, sensory flavor evaluation, metabolomics, and differential characteristic component analysis. These methods were employed to comprehensively compare and characterize the two tea types. The results showed that compared to FBT, FLT exhibited a longer-lasting fungal flower aroma and a mellower taste. Furthermore, the quantity of Eurotium cristatum in FLT was 56.7% higher than that in FBT, indicating a significant difference. Untargeted ultrahigh-performance liquid chromatography–mass spectrometry was used to screen metabolites in Fu tea samples, and after multivariate statistical analysis, 12 differential metabolites were finally identified, including phenolic acids and their derivatives, coumarins and their derivatives, phenylpropanoids, and flavonoids and their glycosides. Subsequently, a targeted UHPLC-QQQ-MS/MS-based method was established and validated for the main differential metabolites, phenolic acids and catechins. The results indicated that gallic acid, catechin, and epicatechin can serve as characteristic markers for distinguishing between FBT and FLT. Notably, the content of gallic acid in FLT was 168.6% higher than that in FBT. These findings elucidate the impact of the pressing process on Fu tea, provide guidance for discriminating between FBT and FLT, and are significant for quality control in the industrial production of Fu tea. Full article

(This article belongs to the Special Issue Production, Quality, Flavor Characteristics and Health Benefits of Tea: 2nd Edition)

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17 pages, 3328 KB

Open AccessArticle

Widely Targeted Metabolomics Decodes Metabolic Remodeling and Functional Shifts in Ganoderma lucidum-Fermented Green Tea Infusion

by Xuzhou Liu, Ying Ju, Shuai Wen, Hongzhe Zeng, Chao Wang, Mingguo Jiang, Bingchuan Tian, Jianan Huang and Zhonghua Liu

Foods 2025, 14(16), 2855; https://doi.org/10.3390/foods14162855 - 18 Aug 2025

Cited by 2 | Viewed by 1876

Abstract

This study used a targeted metabolomics approach to examine changes in metabolites within green tea infusions fermented by G. lucidum (TFG) and evaluate the in vitro antioxidant and lipid-lowering properties of TFG. Fermentation decreased tea polyphenols, flavonoids, caffeine, soluble sugars, theaflavins, and catechins, [...] Read more.

This study used a targeted metabolomics approach to examine changes in metabolites within green tea infusions fermented by G. lucidum (TFG) and evaluate the in vitro antioxidant and lipid-lowering properties of TFG. Fermentation decreased tea polyphenols, flavonoids, caffeine, soluble sugars, theaflavins, and catechins, while increasing free amino acids and theabrownins. The microbial bioconversion process led to the generation of decorated flavonoids, phenolic acids, terpenoids, alkaloids, nucleotides, and amino acids. This process shifted the tea’s taste from bitter and astringent to mellow, primarily due to the transformation of flavonoid glycosides, caffeine, catechins, 5′-guanosine monophosphate, 5′-uridine monophosphate, and theabrownins. Volatile metabolites added woody, floral, sweet, and fruity aromas. Reduced gallic acid and catechins lowered antioxidant activity, whereas increased theabrownins enhanced lipid-lowering activity and imparted a reddish-brown color. These findings indicate that fermentation significantly affects the flavor, aroma, and lipid-lowering ability of green tea infusion. Full article

(This article belongs to the Special Issue Production, Quality, Flavor Characteristics and Health Benefits of Tea: 2nd Edition)

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18 pages, 5623 KB

Open AccessArticle

Rapid and Quantitative Prediction of Tea Pigments Content During the Rolling of Black Tea by Multi-Source Information Fusion and System Analysis Methods

by Hanting Zou, Ranyang Li, Xuan Xuan, Yongwen Jiang, Haibo Yuan and Ting An

Foods 2025, 14(16), 2829; https://doi.org/10.3390/foods14162829 - 15 Aug 2025

Cited by 1 | Viewed by 1281

Abstract

Efficient and convenient intelligent online detection methods can provide important technical support for the standardization of processing flow in the tea industry. Hence, this study focuses on the key chemical indicators—tea pigments in the rolling process of black tea as the research object, [...] Read more.

Efficient and convenient intelligent online detection methods can provide important technical support for the standardization of processing flow in the tea industry. Hence, this study focuses on the key chemical indicators—tea pigments in the rolling process of black tea as the research object, and uses multi-source information fusion methods to predict the changes of tea pigments content. Firstly, the tea pigments content of the samples under different rolling time series of black tea is determined by system analysis methods. Secondly, the spectra and images of the corresponding samples under different rolling time series are simultaneously obtained through the portable near-infrared spectrometer and the machine vision system. Then, by extracting the principal components of the image feature information and screening characteristic wavelengths from the spectral information, low-level and middle-level data fusion strategies are chosen to effectively integrate sensor data from different sources. At last, the linear (PLSR) and nonlinear (SVR and LSSVR) models are established respectively based on the different characteristic data information. The research results show that the LSSVR based on middle-level data fusion strategy have the best effect. In the prediction results of theaflavins, thearubigins, and theabrownins, the correlation coefficients of the testing sets are all greater than 0.98, and the relative percentage deviations are all greater than 5. The complementary fusion of the spectrum and image information effectively compensates for the problems of information redundancy and feature missing in the quantitative analysis of tea pigments content using the single-modal data information. Full article

(This article belongs to the Special Issue Production, Quality, Flavor Characteristics and Health Benefits of Tea: 2nd Edition)

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16 pages, 1817 KB

Open AccessArticle

Development of Pretreatment Approaches for Authentic Representation of Tea Infusion Aroma

by Mingming Zhang, Zhihui Feng, Fang Wang, Jianxin Chen, Yifan Li, Yuqiong Chen and Junfeng Yin

Foods 2025, 14(16), 2759; https://doi.org/10.3390/foods14162759 - 8 Aug 2025

Cited by 1 | Viewed by 1230

Abstract

Appropriate aroma extraction methods are crucial prerequisites for accurately and objectively characterizing the authentic aroma profile of samples. Purified water and ionized water were used as brewing water, and the effects of different tea-to-water ratios, extraction temperatures, and extraction times on the aroma [...] Read more.

Appropriate aroma extraction methods are crucial prerequisites for accurately and objectively characterizing the authentic aroma profile of samples. Purified water and ionized water were used as brewing water, and the effects of different tea-to-water ratios, extraction temperatures, and extraction times on the aroma authenticity and component enrichment of tea infusions were compared. The conditions of a tea-to-water ratio of 1 g:10 mL, extraction at 30 °C for 30 or 45 min were identified as the optimal parameter range, which could maximize the enrichment of aroma while maintaining fidelity. The cosine value of the aroma attribute scores between the optimal parameter set and the control group (tea brewed at 1 g:10 mL ratio for 4 min) exceeded 0.979, and the correlation coefficient surpassed 0.828. Test evaluation results indicate the method had good reproducibility and effectively highlighted the differential impacts of ionic content in brewing water on tea aroma constituents. This approach effectively solved the problem of sensory distortion caused by conventional high-temperature and long-duration extraction, enabling precise analysis of how water quality authentically influences tea infusion aroma characteristics. Full article

(This article belongs to the Special Issue Production, Quality, Flavor Characteristics and Health Benefits of Tea: 2nd Edition)

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22 pages, 1886 KB

Open AccessReview

Deciphering the Flavor Chemistry, Processing and Quality Evaluation Methods of Milk Tea: A Comprehensive Review

by Jiayin Geng, Hongchun Cui, Yuwan Wang, Haowei Sun, Jiaqi Xu, Weiwei Wang, Feng Chen, Yun Zhao, Junfeng Yin and Jianyong Zhang

Foods 2026, 15(4), 681; https://doi.org/10.3390/foods15040681 - 12 Feb 2026

Cited by 1 | Viewed by 1205

Abstract

Milk tea is a globally popular new-style tea beverage product. In recent years, the industry has achieved rapid development in terms of scale expansion and quality iteration and upgrading. The flavor quality and product stability have become the focus of attention and research [...] Read more.

Milk tea is a globally popular new-style tea beverage product. In recent years, the industry has achieved rapid development in terms of scale expansion and quality iteration and upgrading. The flavor quality and product stability have become the focus of attention and research hotspots in this field. The chemical foundation of milk tea flavor, processing methods, and flavor quality evaluation approaches are thoroughly elaborated. The chemical basis of tea-based, milk-based, and milk tea flavors is systematically summarized, primarily including the analysis of key flavor compounds and the interactions between tea-based and milk-based substances. Subsequently, the tea-based production methods, mixed processing techniques, and factors influencing storage and preservation of milk tea are discussed. Furthermore, evaluation methods for milk tea flavor quality, including traditional sensory evaluation and intelligent assessment techniques are systematically outlined. This review not only summarizes the recent research progress but also looks forward to the interdisciplinary work that needs to be carried out in the future. These efforts aim to provide information on the transformation from the research stage of tea milk product formulas to the development of solutions with controllable quality. Thus, they offer valuable theoretical guidance for the formation and regulation of tea milk flavor and quality as well as the development of new products. This work aims to provide theoretical insights and technical support for the translation from laboratory formulations to quality-controlled industrial solutions. Full article

(This article belongs to the Special Issue Production, Quality, Flavor Characteristics and Health Benefits of Tea: 2nd Edition)

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