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Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Food & Fermentation Industries is the property of Food & Fermentation Industries and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To reveal the chemical composition profile of Camellia ptilophylla, a rare natural low-caffeine tea variety, non-targeted metabolomics based on high-resolution mass spectrometry (HR-MS) was employed to identify the metabolite composition of green tea and black tea from C. ptilophylla and C. sinensis var. assamica. Additionally, the metabolomic differences between the two types of tea and between the two tea varieties were analyzed using principal component analysis (PCA), cluster analysis (CA), and orthogonal partial least squares-discriminant analysis (OPLS-DA). Differential metabolites were identified using standards and database. A total of 152 metabolites were identified in the four tea samples, the major ones being flavonoids (42%). These metabolites were categorized into four clusters. The metabolomic difference between C. ptilophylla and C. sinensis var. assamica was more pronounced than that between green and black teas. Notably, 24 metabolites including theasinensin B isomers, theobromine and 14 flavonoids such as tetrahydroxyxanthone and epitheaflagallin 3-O-gallate, which were more abundant in C. ptilophylla green tea than in C. sinensis green tea, were considered as the characteristic metabolites of C. ptilophylla green tea. In black tea from C. ptilophylla, 40 characteristic metabolites were identified including 25 flavonoids such as gallocatechin-3,5-digallate, tetrahydroxyxanthone and dihydromyricetin; 4 tannins such as theaflavin 3-gallate, theasinensin A isomers and theaflavin 3,3’-digallate; and theobromine. This study provides a reference for further exploration of bioactive compounds in C. ptilophylla.

This study used widely targeted and targeted metabolomics based on headspace solid-phase microextraction combined with gas chromatography-mass spectrometry (HS-SPME-GC-MS) to analyze the non-volatile metabolites, volatile metabolites, and major quality components in congou black teas produced from the high-aroma black tea cultivars ‘Jinmudan’ and ‘Jinguanyin’, and it explored the differences in chemical characteristics between the two teas. The results showed that a total of 1 318 non-volatile metabolites were identified in the two teas, and the differential metabolites between them were most enriched in flavonoid-related synthesis pathways. Among them, catechins and quercetin-3-O-glucoside were significantly upregulated in ‘Jinmudan’ black tea, while chrysin and apigenin-7-O-neohesperidoside were significantly upregulated in ‘Jinguanyin’ black tea. A total of 759 volatile compounds were identified, among which 12 compounds, including β-ionone, geraniol, decanal and methyl benzoate, were the key aroma components of both teas. The results of relative odor activity value (ROAV) analysis indicated that aroma components such as indole, δ-decanolactone, trans-nerolidol, phenylacetaldehyde and jasmonone responsible for floral, fruity and milky aroma characteristics were more abundant in ‘Jinmudan’ black tea, which may be the key compounds contributing to the floral, fruity and peach-like aromas of ‘Jinmudan’ black tea. Aroma components such as methyl salicylate, (Z)-3-hexenol, and hexanol responsible for fresh and floral aromas were more abundant in ‘Jinguanyin’ black tea, which may be the key compounds contributing to its long-lasting aroma. The results of this study are helpful to elucidate the flavor and quality characteristics of ‘Jinmudan’ and ‘Jinguanyin’ black tea, providing a scientific basis for the development of black tea products from the excellent high-aroma tea cultivars ‘Jinmudan’ and ‘Jinguanyin’.

Using black tea and peanut as the primary raw materials, fat-free milk powder and white granulated sugar as auxiliary materials, a black tea-peanut protein compound beverage with rich nutrition and good taste was prepared. The study aimed to analyze the sensory score, protein content, fat content and osmotic pressure of the black tea-peanut protein compound beverage to study the best technological conditions and nutritional characteristics. The results showed that the optimal process conditions of the black tea-peanut protein compound beverage were as follows: the volume ratio between peanut protein pulp to black tea juice was 1:2, the addition of fat-free milk powder was 10%, and the addition of white granulated sugar was 2%. Under these conditions, the prepared compound beverage had the highest sensory score (86 points). The protein content was 5.51 g/100 g, fat content was 5.90 g/100 g, total phenolic content was 139.04 µg/mL, total flavonoid content was 258.98 µg/mL, the fat droplets were evenly distributed and had a smaller mean particle size (7.54 µm), the osmotic pressure (336.00 mmol/kg) was close to the human blood osmotic pressure, which could meet consumers' pursuit of sensory quality and health diet. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Black tea is the most important in the world tea production, and is very popular in the world tea market. China has abundant tea resources, especially unused tea leaves in summer and autumn, and there are a few new ways to develop them, such as processing black tea or deep processed products. Application of exogenous enzymes with good functional characteristics, can improve the quality of summer and autumn black teas, and their deep processed products. This article reviews that, the current status and existing problems of exogenous enzymes application in black tea processing in recent years, as well as the types and acting mechanisms of frequently-used exogenous enzymes, transformation of tea components catalyzed by exogenous enzymes during withering, rolling, and fermentation in black tea processing. Utilizing exogenous enzymes to promote the synthesis of theaflavins, a unique component of black tea, and the quality changes in deep-processing of black tea, are also summarized. Exploring the enzymatic processing methods, could promote the efficient utilization of tea resources, and regulate quality of summer and autumn black tea, as well as their deep-processed products, in the future.

Copyright of Science & Technology of Food Industry is the property of Science & Technology of Food Industry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Food Safety & Quality is the property of Journal of Food Safety & Quality Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

According to the results of sensory evaluation performed by experts, 14 black tea samples were divided into two groups based on their aroma quality: high-quality and quality-deficient black tea. Using fast gas chromatography-electronic-nose (GC-E-Nose) and gas chromatography-mass spectrometry (GC-MS) combined with multivariate statistical analysis, discriminant analysis of the two groups were carried out, and the key differential components between these groups were selected. The results showed that 117-dimensional dataset was obtained by the fusion of the GC-E-Nose (44-dimensional) and GC-MS (73-dimensional) data and used to establish a model for accurate classification of the two types of black tea employing orthogonal partial least squares-discriminant analysis (OPLS-DA). The model’s explanatory and predictive capacity (R2Y = 0.976, Q2 = 0.959) were better than those of the model established based on the GC-E-Nose or GC-MS data. Based on variable important in projection (VIP) scores > 1.6 and P < 0.05, eight key aroma components including dimethyl sulfide (B3 and B25), β-ionone (A59), (3E)-4,8-dimethylnon-1,3,7-triene (A20), dihydroactinidiolide (A64), linalool (A17), phenylethyl alcohol (A19), δ-octyl lactone (A41) and γ-nonalatone (A45) were selected, which played an important role in the classification. These results showed that GC-E-Nose combined with GC-MS allows rapid and accurate discrimination between quality-deficient and high-quality black tea, which can be used as a supplement to traditional sensory evaluation, providing technical support for quality control and improvement of black tea.

‘Ming guan’ is a new excellent albino tea variety bred from the descendants of Bai jiguan. In order to explore the quality difference of Ming guan multi tea processing, the fresh leaves of Ming guan were used as raw materials to make the corresponding tea types according to the processing methods of green tea, black tea and white tea, and sensory quality evaluation, aroma and taste analysis were conducted. The results showed that the aroma of Ming guan green tea was tender, floral and fruity, with a mellow taste, the aroma of Ming guan black tea was sweet, floral, with a sweet taste, the aroma of Ming guan white tea was millets, floral, with a fresh taste, and the different processes of Ming guan tea had their own unique floral characteristics. Among the aroma components of Ming guan green tea, terpene aroma components with floral aroma were relatively more abundant, followed by ester aroma components with fruit aroma, which played an important role in the formation of the aroma of Ming guan green tea. The representative aroma components of Ming guan green tea were leaf alcohol ester of foliol caproate, 3-hexenyl caproate, 2-hexenyl caproate, nerolidol, leaf alcohol ester of butyric acid, olivetol and α-farnesene, the representative components of which were mainly esters with fruity aroma and alcohols with floral and fruity aroma, creating the characteristic of Ming guan green tea floral and fruity varieties. The representative components of Ming guan black tea were dihydrolinalool, α-cephalene, β-Ionone, γ-cadinene, methyl hexadecanoic acid and benzaldehyde, which were mainly terpenes and alcohols with floral and sweet aromas, contributing to the floral and sweet aromatic characteristics of Ming guan black tea. The representative components of Ming guan white tea were geraniol, myrcene, 3-carene, linalyl acetate and linalool, and the representative components are mainly alcohols and terpenes with floral aroma. The non-volatile components of Ming guan green tea, Ming guan black tea and Ming guan white tea vary greatly overall. The content of catechins, anthocyanins, some flavonols and flavonoid glycosides (quercetin-3-O-galactoside, quercetin-3-O-glucoside, quercetin-3-O-glucoside 7-O-rhamnoside, etc.) in Ming guan green tea was generally higher than that in Ming guan black tea and Ming guan white tea. The contents of theaflavins, phenolic acids, a few flavonol and flavonoid glycoside compounds (vitexin-2-O-galactoside, vitexin-2-O-rhamnoside, apigenin-6,8-di-C-glucoside, apigenin-6-C-glucoside, etc.) and some amino acid compounds (L-phenylalanine, L-tryptophan, L-isoleucine, L-valine, L-aspartic acid) in Ming guan black tea were higher than those in Ming guan green tea and Ming guan white tea.The content of some amino acid compounds (L-arginine, L-glutamine, L-lysine, L-histidine, L-tyrosine) in Ming guan white tea was higher than that in Ming guan green tea and Ming guan black tea, which may be affected by different processing technologies. This study could provide a theoretical basis for a comprehensive understanding of the chemical basis and quality differences of Ming guan green tea, Ming guan black tea and Ming guan white tea.

Fermentation is a critical process of black tea quality formation and oxygen is the key factor affecting the fermentation, so it is important to analyze the effect of oxygen in fermentation on the quality and metabolites of black tea. One bud and two leaves of 'Longjing 43' tea varieties were used as materials for low oxygen fermentation (5%) , natural fermentation (21%) and oxygen-enriched fermentation (36%) treatments, and the effects of oxygen concentration on sensory quality, non-volatile and volatile metabolites of black tea were analyzed by sensory evaluation combined with gas chromatography-mass spectrometry (GC-MS) and ultra-high performance liquid chromatography-mass spectrometry (UPLC-MS), and the parameters of oxygen-enriched fermentation of black tea were optimized by single factor combined with response surface analysis. Results showed that oxygen-enriched fermentation could significantly improve the taste and aroma quality of black tea compared with nature fermentation (P0.05) in oxygen-enriched fermentation. A total of 25 volatile compounds differed significantly in three treatments, including 12 aldehydes, 2 ketones, 3 alcohols, 3 alkenes, and 5 esters, and the content of most differing compounds increased with increasing oxygen concentration. The optimized parameters of oxygen-enriched black tea were: Oxygen concentration of 40%, oxygenation time of 1.5 h, fermentation time of 4 h. And the contents of TFs, TF, TF3G, TF3'G and TFDG of black tea were 2.86%, 0.25%, 1.71%, 0.24% and 0.68%, respectively. The results of this study would provide an important basis for guiding black tea processing and quality control.

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Food Safety & Quality is the property of Journal of Food Safety & Quality Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Food Science & Technology & Economy is the property of Grain Science & Technology & Economy Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to investigate the substance transformation of polyphenols in black tea before and after processing, ultra-performance liquid chromatography-high resolution mass spectrometry combined with mass spectrometry molecular network were used to analyze the tea samples before and after processing. In this study, a total of 250 polyphenolic compounds were detected from tea samples before and after processing, including 115 catechins, 62 phenolic acids and 73 flavonoids. Among the 201 compounds, 174 compounds showed significant differences in content (P<0.01). 49 compounds were newly generated after black tea processing, among which 21 were theaflavins. [ABSTRACT FROM AUTHOR]

Tea polyphenol, a vital indicator used for the detection of tea quality, is of great significance to quickly detect the tea polyphenol content via near infrared spectroscopy. In this paper, the near infrared spectroscopy in combination with partial least squares (PLS) was adopted to establish the rapid analysis models by near infrared for tea polyphenol content of powdered and complete tea samples respectively, using 144 black tea samples as the study objects, revealing that the prediction model established by SNV+first derivative+Savitzky-Golay smoothing combined with PLS had the optimal effect in the results. The correlation coefficient (r) was 0.9990 and the root mean square error of calibration (RMSEC) was 0.165% of the training set, while the r was 0.9243 and the root mean square error of prediction (RMSEP) was 0.972% of the prediction set in powered tea samples. At the same time, the r was 0.9967 and the RMSEC was 0.310% of the training set, while the r was 0.9541 and the RMSEP was 0.870% of the prediction set in complete tea samples. The results showed that the PLS model for complete tea samples was better than that for powdered tea. Therefore, rapid and nondestructive detection of tea polyphenols in black tea can be achieved by near infrared spectroscopy.

Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Storage & Process is the property of Tianjin Academy of Agricultural Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

EGCG is often regarded as the main active ingredient in tea to protect blood glucose homeostasis. The content of low molecular weight polyphenols such as EGCG in fungus fermented black tea (FFBT) is extremely low, and there are few studies on the hyperglycemic effect of FFBT. To explore the hypoglycemic effects and potential mechanisms of FFBT, GK rats with spontaneous hyperglycemic were given 280 mg⋅kg-1 FFBT extract (equivalent to 9 g of FFBT for daily human consumption) by gavage intervention. The study assessed the effects of FFBT on body weight, glucose homeostasis, regulatory factors related to glucose homeostasis, diabetic complications and liver transcription profiles in hyperglycemic rats. The results indicated that FFBT could obviously reduce the fasting blood glucose level and random blood sugar level of hyperglycemic rats, improve the abnormal glucose metabolism in hyperglycemic rats, maintain glucose homeostasis and alleviate the damage caused by diabetic complications in hyperglycemic rats. In addition, transcriptome analysis revealed that the hypoglycemic properties of FFBT might be related to the regulation of gene expression in the liver, such as Gck, Pklr, Pkm. This study found that FFBT may be a potential hypoglycemic functional beverage, providing a theoretical basis for the development and utilization of fermented tea such as FFBT. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to explore the upper limit and technical parameters of black tea brewing with suitable taste and establish the relative brewing method system of daily drinking. Methods: The black tea soup was prepared by sensory evaluation method and diluted in a gradient with one bud and two leaves and then was tasted and scored by 50 volunteers to determine the appropriate taste consistency. On the basis of determining the suitable taste concentration, the quality concentrations of water extract, theaflavin and theaflavin under the suitable taste were used as the indexes to optimize and screen the technical parameters of black tea brewing each time and the brewing times under the appropriate taste. Results: When the mass concentrations of aqueous extract, theaflavin and thearubin in black tea soup were 1.40, 0.04 and 0.60 mg/mL respectively, and it had a suitable taste. The first brewing was made with a tea-water ratio (mtea∶Vwater) of 1∶100 (g/mL) and pure water at 82 ℃ for 4.5 min, and the second brewing was made with a tea-water ratio (mtea∶Vwater) of 1∶50 (g/mL) and pure water at 86.0 ℃ for 3.5 min.The tea broth obtained in both times had a suitable taste and reached the mass concentration of water extract, theaflavin and theaflavin of suitable taste. However, after the third brewing with tea-water ratio (mtea∶Vwater) of 1∶50 (g/mL) and 97.3 ℃ pure water for 6.4 min, the resulting tea broth was too light in taste, and the water extracts and theaflavins also failed to reach the quality concentration requirement under suitable taste. Conclusion: It is appropriate to brew black tea for two times with appropriate taste kept.

To reveal the difference of quality between traditional and wild Yunnan Congou black tea, five traditional and wild Yunnan Congou black tea were collected, respectively. Sensory qualities and biochemical components were compared. Sensory evaluation results showed that the shape, infusion color and infused leaves of the samples collected in this paper conform to the characteristics of Yunnan Congou black tea, that was, color of the dry tea leaves were dark with oily gloss, the infusion were red or orange red and bright, and the infused leaves were tender and uniformity. However, traditional Yunnan Congou black tea had a strong taste, while the wild Yunnan Congou black tea had a mellow and fresh taste. The contents of water extract, total catechins and caffeine in traditional Yunnan Congou black tea were 41.07%, 18.53 and 14.60 mg/g, respectively, which were significantly higher than those of wild Yunnan Congou black tea with 38.42%, 10.58 and 9.54 mg/g, respectively. While the average content of free amino acid in traditional Yunnan Congou black tea (3.92%) was lower than that of wild Yunnan Congou black tea (5.01%). The average contents of tea polyphenols were 16.61% and 16.56%, respectively, with no significant difference. The average contents of theaflavin, thearubigins and theabrownin in traditional Yunnan Congou black tea were 0.64%, 6.75%, 10.93%, and 0.61%, 2.70%, 11.80% in wild Yunnan Congou black tea respectively, among them, the content of thearubigins were significantly different. The average contents of quercetin, rutin, kaempferol and myricetin were 0.09, 0.67, 0.01 and 0.07 mg/g in traditional Yunnan Congou black tea, while 0.14, 0.27, 0.16 and 0.15 mg/g in wild Yunnan Congou black tea, respectively, which showed significant differences. Principal component analysis (PCA) and clustering analysis (CA) based on contents of 19 biochemical components showed that traditional and wild Yunnan Congou black tea divided into two clusters, indicating that contents of biochemical component between these two type black tea were significantly different. In general, the contents of water extract, catechins, caffeine and flavonols in traditional Yunnan Congou black tea were higher, which resulting the strong taste. However, the content of free amino acids in wild Yunnan Congou black tea were higher, resulting in fresh and mellow taste.

The characteristic aroma volatile compounds of black tea were identified, the aroma profile of black tea was dissected, and the perceptual interaction of important characteristic aroma compounds was explored. On this basis, the modified vector model and Steven’s law were applied to this system. Headspace solid-phase microextraction (HS-SPME) and solvent-assisted evaporative extraction (SAFE) combined with gas chromatography-olfactometry (GC-O) were used to evaluate aroma compounds. A total of 51 characteristic aroma compounds were obtained. The major aroma substances identified were alcohols and aldehydes. The results of aroma extract dilution analysis (AEDA) and aroma intensity (OI) record showed that linalool, phenethyl alcohol, (Z)-3-hexenol, geraniol and methyl salicylate significantly contributed to the aroma of black tea. The partial least squares method was used to analyze the correlation between compounds and aroma characteristics, and the electronic nose sensors were matched with the aroma profile using the gray correlation method for comprehensive understanding of the aroma of black tea. Feller’s additive model was used to analyze the perceptual interaction of aroma compounds. Among the 10 groups of binary compounds, eight showed a masking effect, and the remaining two showed a synergistic effect. In conclusion, the above experiments can provide a reference for further study of important flavor substances in black tea.

In order to explore the processing process of black tea and its preparation of tea from 'Bashanzao' purple bud leaves. In this study, the purple bud leaves of 'Bashanzao' were selected as raw materials, and the process optimization was carried out based on the processing technology of Wanyuan black tea. The key processing technologies of black tea (withering, fermentation and drying) were carried out by single factor experiment and orthogonal experiment. The optimal process parameters of purple bud leaf black tea were determined by sensory score and ratio of the sum of theaflavins and thearubigins to theafuscin TFRB, to explore the effects of different parameters of key processing technology on the quality of black tea. Taking the green buds and leaves of 'Fuding Dabai' as the control, the new shoots of one bud and one leaf were collected and processed into black tea according to the optimized processing technology. The prepared tea sample and 'Bashanzao' purple bud and leaf black tea passed sensory evaluation, determination and analysis of internal quality components and aroma components. The results showed that the optimal processing technology of 'Bashanzao' purple bud leaf black tea was withering time 21 h, fermentation time 4.5 h, drying temperature 90 ± 2 ℃, and the highest sensory score was 92.83 ± 0.19. The sensory quality of 'Bashanzao' purple bud leaf black tea was better than the control. The contents of tea polyphenols, amino acids, soluble sugar, water extract, caffeine, theaflavin and thearubin were 12.58%, 3.62%, 2.89%, 37.89%, 4.61%, 0.38% and 3.57% respectively, which were higher than the control. TFRB was 1.07, which was its fresh taste, the material basis of red and bright soup. The contents of total amino acid components, fresh amino acid components and sweet amino acid components were 32.35, 22.68 and 3.45 mg/g respectively, which were 10.03%, 7.28% and 26.84% higher than the control respectively. 43 aroma components were detected, and the total amount was 57.72 μg/g, 11.67% higher than the control group. The processing technology of 'Bashanzao' purple bud leaf black tea determined in this study has excellent tea quality.

Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Modern Food Science & Technology is the property of Editorial Office of Modern Food Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Chinese Institute of Food Science & Technology / Zhongguo Shipin Xuebao is the property of Journal of Chinese Institute of Food Science & Technology Periodical Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to clarify the best brewing time mode of Tanyang Congou black tea with flowery-fruity flavour, six brewing time modes were designed by taking the commercially available Tanyang Congou black tea with flowery-fruity flavour as the experimental material, and the sensory evaluation was carried out on each infusion of tea under each infusing method. Then, the samples were taken to detect the content of water extract, total free amino acids, total amount of tea polyphenols and caffeine in tea soup. The results showed that; the cumulative sensory evaluation score of the eight infusions of tea under the brewing time mode of 15 s--15 s--15 s--20 s --20 s--20 s --30 s--30 s was the highest, which was shown as "obvious flowery-fruity flavour, full taste", which could be applied to daily infusing. The leaching rules of water extract, amino acid and caffeine in tea soup were similar under different brewing time modes, and the leaching peaks appeared in the second to fifth infusions. The leaching amount of tea polyphenols was relatively average in the 3rd to 8th infusions, and there was no rapid decline in the later stage of infusing. [ABSTRACT FROM AUTHOR]

The research progress of the influence of fermentation temperature, fermentation humidity, fermentation time and exogenous additives on the formation of black tea pigment were reviewed. The future research and development trend of black tea pigment formation was prospected.

Copyright of Journal of Chinese Institute of Food Science & Technology / Zhongguo Shipin Xuebao is the property of Journal of Chinese Institute of Food Science & Technology Periodical Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Food Safety & Quality is the property of Journal of Food Safety & Quality Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Food & Machinery is the property of Food & Machinery Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Modern Food Science & Technology is the property of Editorial Office of Modern Food Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Tea Science is the property of Journal of Tea Science Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to explore the origin differences of black tea metabolites, the metabolites in black tea produced in Fu 'an and Youxi of Fujian province were compared and analyzed by using sensory evaluation method and extensive targeting metabolomic determination method of ultra-performance liquid chromatography-mass spectrometry (UPLC-MS/MS). The results showed that, Fu'an black tea mainly tasted of “mellow and soft”, while Youxi black tea of “mellow and sweet”. A total of 937 metabolites including of flavonoids, phenolic acids, lipids, organic acids, amino acids and their derivatives were identified by metabonomics in the black tea of the two regions, through the principal component analysis (PCA) and orthogonal partial least-squares discriminant analysis (OPLS-DA) could significantly distinguish different producing area of black tea, and identified 410 species of metabolites with significant difference. The relative content of 291 different metabolites in Youxi black tea was higher than that of Fu 'an black tea, among which Astragalin, EC, L-glutamine, L-aspartic acid, L-lysine, L-tryptophan, L-glutamic acid, chlorogenic acid, phenethylamine, vitexin-2''-O-rhamnoside might have important contributions to the formation of different taste and quality of black tea from the two regions. Metabolic pathway analysis showed that the metabolism levels of amino acids and flavonoids of black tea between the two places were significantly different, which might be the reason for the difference in the taste and quality of black tea between the two places. The research would provide a theoretical basis for the identification of tea origin.

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Food Safety & Quality is the property of Journal of Food Safety & Quality Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Food & Machinery is the property of Food & Machinery Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Modern Food Science & Technology is the property of Editorial Office of Modern Food Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Fermentation is one of the key steps for the flavor in black tea processing. However, the traditional evaluation of fermentation grade can often be time-consuming, labor-intensive, and inaccurate at present, depending on the subjective sensory for the color observing and the flavor smelling. Since the change of color dominates the fermentation degree, machine vision can be expected to accurately and timely detect the optimum condition of fermentation in black tea processing. Nevertheless, the real-time image acquisition is still lacking so far, due mainly to the high humidity of processing workshop during tea fermentation. Herein, a real-time image acquisition system was designed for the black tea fermentation under the high humidity conditions. The high-efficient system consisted of an industrial camera, lens, defogging and moisture-proof device, surface light source, fixed bracket, vision software platform, and industrial computer. Specifically, a heating and mist elimination device was used as an upper and lower detachable aluminum alloy shell (length × width × height, 120 × 65 × 68 mm) and two end caps. Among them, three components were soldered, including an opening (50 × 45 mm) in the center of one end cover of the shell, the electrode strip resistance (9-10 Ω), and the wires. The high-temperature resistant insulating transparent glue was used to fix the electrodes on the short side of the ITO coated glass (length × width × height, 55 × 50 ×1.1 mm), where the glass surface resistance with the electrode strip was about 10 Ω. As such, a heating and defogging device was formed to fix the glass on the end cover of the central window. The 12.4 MP color CMOS vision system was equipped with the industrial cameras and the gigabit ethernet interface for 1Gbps bandwidth. The cameras were synchronized with the hardware and software triggers. C mount type was selected to connect the low-distortion 8 mm and 6 MP lens for the machine vision cameras. The specific procedure was as follows. The industrial camera was firstly fixed on one L-shaped bracket, and another was on the sidewall of the aluminum alloy shell by two screws, where the two brackets were interlocked, and the lens was 23 mm away from the ITO coated glass. Three outlet holes with the diameters of 20, 15, and 15 mm were opened on the other end cover, which was used for the outlet of the camera net cable, power cable, and heating power cable, respectively. The outlet and screw fastening positions were then sealed with the high-temperature resistant insulating transparent adhesive. The image acquisition device was fixed for the surface light source on the machine vision bracket. The curtains of the tea fermentation room were drawn to prevent the change of sunlight intensity, then the power of all devices was turned on to adjust the voltage of 6-6.5V in the heating and defogging device. The vision software platform was run for the white balance of the camera once, and then turned off the automatic exposure mode to select the image saving format and continuous trigger for the acquisition mode and the image acquisition interval. The camera was mounted over the surface of the tea, and then manually focused at a distance of about 145 mm. The results demonstrated that the machine vision system was efficient to capture the change of color of tea shoots, leaves, buds, and stem during tea fermentation. 1564 fermentation leaves images were selected to combine with the sensory evaluation and the variations in the color and smell of fermentation leaves. Four datasets were classified with the quality labels: light-, semi-, well-, and over- fermented. The datasets was then divided into the training set and test set, according to the ratio of 7:3. The training set was used to establish the deep learning model by the MobileNetV3 and Vision Transformer. The test set was used to evaluate the classification performance of the model, where the average prediction accuracy reached up to 95.68%. More importantly, a visualization software was also conducted to predict the fermentation grade of black tea using the deep learning. Consequently, the image acquisition system can be expected to acquire the real-time images of fermented leaves under the high humidity and fog environment. The finding can also provide a strong reference for the fermentation evaluation during black tea processing. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Food Safety & Quality is the property of Journal of Food Safety & Quality Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)