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Deep eutectic solvent (DES) has been widely developed and applied in extracting the functional components of teas, however, few studies devoted to revealing the composition differences of tea extracts obtained with DES. The present study aims to study the chemical composition and bioactive differences of Dianhong congou black tea extracts prepared by eight choline chloride (ChCl)-based DES. In addition, D-101 macroporous resin was used to remove DES for bioactivity analysis. High performance liquid chromatography (HPLC) and LC-mass spectrometry (LC-MS) were applied to quantitatively and qualitatively analyze chemical composition differences of DES extracts before and after DES removal. Quantitative results showed that DES4 (composed of ChCl and ethylene glycol) was suitable for extracting catechins (e.g., the extracted level of epicatechin gallate was 8.75 mg/g), theaflavins (theaflavin-3,3′-digallate, 1.59 mg/g), and monosaccharides (glucose, 4.97 mg/g), meanwhile DES5 (composed of ChCl and glycerol) was proved to be effective for extracting free amino acids (with highest level of theanine, 19.72 mg/g). LC-MS based metabolomics results showed that DES2 (ChCl-citric acid), DES3 (ChCl-proline), and DES4 had considerable remaining amounts of flavonoid glycosides, theasinensins, and hydrolysable tannins after DES removal. Although purified DES5 extract contained a comparable amount of these marker compounds to other purified DES extracts, its antioxidant and α -glucosidase inhibitory activities were the lowest among others. Combining results from above, DES4 was proved to be the optimum solvent for extracting functional components of Dianhong congou black tea. The finding provided basis for the application of DES extraction method in tea science. [Display omitted] • Eight DES-based black tea extracts were qualitatively and quantitatively studied. • DES consisted of alcohols and sugars were more suitable for extracting polyphenols. • DES consisted of sugars were not suitable for monosaccharide extraction. • Most DES extracts had higher bioactivities than water extract after DES removal. [ABSTRACT FROM AUTHOR]

While key aroma and taste compounds of Keemun Congou black teas (KCBT) form during aeration and thermal stages, it is still unknown whether these processing stages also produce non-volatile color-contributing metabolites. Through integrating metabolomics with correlation and ridge regression analyses, 190 metabolites were identified as marker compounds that reclassified 15 KCBT samples collected from five processing stages into four groups. Meanwhile, the results of quantification and heatmap analysis showed that the concentrations of theaflavins and theasinensins significantly increased, as catechin decreased, after rolling, while flavonoid aglycones and polyunsaturated fatty acids increased throughout drying. Regression analysis between marker compound levels and total color difference values (∆E) revealed that the major color contributors were 3,5-dicaffeoylquinic acid, glucosyl-dehydrodigallic acid, theacitrin A, kaempferol- O -robinobioside, and (−)-epigallocatechin, with regression coefficients (absolute value) exceeding 4 × 10−2. Overall, the present study confirmed that rolling and drying were the two vital stages responsible for the color formation of KCBT. • Rolling and drying were vital for metabolite and color changes. • Concentrations of most non-volatile metabolites decreased upon rolling. • Concentrations of lipids, theaflavins, and flavones increased upon drying. • Ridge regression algorithm was suitable for screening color contributors. [ABSTRACT FROM AUTHOR]

[Display omitted] • EC and C had the highest potential to produce luminous red color. • Catechin monomers only partially lose bioactivities to gain a considerable color. • The oxidative coupling of catechins' A-B ring dominated the red color formation. • De-hydroxylation also occurred during the enzymatic reaction of 2 R ,3 R -catechins. The capacity differences of seven catechin monomers to produce colors after treating with catechin-free extract were investigated. After 240-min reaction, only (-)-epicatechin (EC) and (+)-catechin (C) presented obvious luminous red color with L* values of 63.32–71.73, a* values of 37.13–46.44, and b* values of 65.64–69.99. Meanwhile, the decrease rate of EC and C was 43.52 %−50.35 %, which were significantly lower than those of other catechin monomers (85.91 %−100 %). The oxidized products of catechin monomers were analyzed by ultra-high performance liquid chromatography-quadrupole-time of flight-mass spectrometry coupled with diode array detector, wherein dehydro-dimers and -trimers (oxidative coupling products of catechins' A-B ring) were found to be the major chromogenic compounds of EC and C. Additionally, the antioxidant capacity of catechin monomers only decreased after 30-min reaction, while along with further enzymatic reaction, catechin monomers presented comparable oxyradical scavenging ability (e.g., the DPPH inhibitory rates of catechin monomers were in the range of 24.42 %–50.77 %) to vitamin C (positive control, DPPH inhibitory rate was 27.66 %). Meanwhile, the inhibitory effects of most catechin monomers on α -glucosidase were enhanced in different degrees. These results provided basis for the development of enzymatically-oxidized catechin monomers as functional food color additives. [ABSTRACT FROM AUTHOR]

Catechins are the primary polyphenols in tea. Enzymatic oxidation models of (-)-epicatechin (EC) and (-)-epigallocatechin gallate (EGCG) with different proportions were established to investigate the formation mechanism of oxidation products and their relationship to color characteristics. Their oxidation products were analyzed by liquid chromatography tandem mass spectrometry (LC-MS) combined with UV-visible spectrometry. These products were quantified by LC-MS and performed correlation coefficient analysis of color. The results indicated that single oxidation of EGCG dominated the whole reaction when EGCG had high proportions in the reaction mixture, promoting the formation of red pigments such as dehydrotheasinensin AQ and theacitrinin B. When EC with high ratios, the oxidation pathways preferred utilizing both EC and EGCG, promoting the formation of yellow pigments such as theaflavin and theadibenzotropolone A. This study provided the detailed oxidation mechanism of EC and EGCG mixture, suggesting that the proportions of catechol-type and pyrogallol-type catechins markedly affected the direction of enzymatic oxidation reaction and further influenced the color formation. [Display omitted] • The enzymatic oxidation products of EC-EGCG at different ratios were studied. • Higher proportion of EGCG promoted the formation of red oxidation products. • Higher proportion of EC promoted the formation of yellow oxidation products. • Two yellow oxidation products were newly identified as catechin trimmers. • It offers a fresh perspective on the differences in the color of black tea infusion. [ABSTRACT FROM AUTHOR]

• 6 grades of HSMF green tea could be classified into two types. • The marker compounds are procyanidins, flavonoid and hydrolysable tannins. • Hydrolysable tannins were tightly correlated with tea grade and sweet aftertaste. Six grades of Huangshan Maofeng (HSMF) green tea were studied by LC-MS based metabolomics combined with sensory evaluation on bitterness, astringency and sweet aftertaste. Although there was no significant correlation (p > 0.05) between tea grades and the contents of total polyphenols and flavonoids, non-targeted metabolomics revealed that all grades of tea could be classified into two groups, group 1 (T1, T2) and group 2 (T3, 1, 2, 3). The main marker compounds responsible for distinguishing the two groups were procyanidins, flavonoid glycosides, and four hydrolysable tannins, including monogalloyl glucose, digalloyl glucose, trigalloyl glucose and galloyl-hexahydroxydiphenoyl-glucose. The Pearson correlation coefficients of these hydrolysable tannins with HSMF green tea grades were between 0.82 and 0.95. Furthermore, their Pearson correlation coefficients regarding sweet aftertaste were in the range of 0.73–0.83. This study suggested combination of metabolomics and sensory evaluation could provide an insight in searching for more potential taste-active components. [ABSTRACT FROM AUTHOR]

Hydroxycinnamoyl quinic acids are important phenolic acids in tea, particularly fermented teas. However, there have been fewer studies that have confirmed their taste properties. The aim of this study was to investigate the astringent compounds in Keemun congou black tea (KBT) using a combination of mass spectrometry, turbidity analysis, and sensory evaluation. Turbidity analysis determined that p -coumaroylquinic acids were the astringent contributing compounds in KBT. Moreover, the separated compound D16 was identified as trans -4- O - p -coumaroylquinic acid (trans -4- O - p CoQA) by nuclear magnetic resonance spectroscopy and first confirmed to be the astringent contributing compound in KBT by sensory evaluation. Its astringent threshold concentration was tested to be 38 µM. The trans -4- O - p CoQA content in eight KBT samples of various grades ranged from 40.20 ± 0.15 ~ 65.53 ± 0.22 µM. Turbidity analysis combined with sensory evaluation could be a powerful tool for identifying critical compounds responsible for the astringent taste. [ABSTRACT FROM AUTHOR]

[Display omitted] • Quantitative analytical method of nine monosaccharides. • Change of monosaccharides during processing of KBT. • Theaflavins inhibit the caramelization of D-glucose. • Theaflavins-glucose adducts were identified. Monosaccharides of Keemun black tea were quantitatively determined by high performance liquid chromatography coupled with 3-methyl-1-phenyl-2-pyrazolin-5-one (PMP) pre-column derivatization. The methodology of developed analytical method was established with good linearity, recovery, repeatability and precision. The quantitative results showed that D-mannose, D-glucuronic acid, D-glucose, D-galactose and L-arabinose were detected in Keemun black tea samples. D-glucose was the predominant monosaccharide in black tea, and its concentration was continuously increased from fresh tea leaves to fermentation, but after drying its concentration was significantly decreased. Meanwhile, theaflavins' concentrations were obviously decreased after drying. When theaflavins were heated with D-glucose, the loss of theaflavins was increased. Correspondingly, theaflavins also prevented the caramelization of D-glucose and restored the loss of D-glucose during heating. Through the liquid chromatography/electrospray tandem mass spectrometry some theaflavins glucose adducts were identified. [ABSTRACT FROM AUTHOR]

[Display omitted] • Tea trichomes enhance the umami taste and reduce the bitterness and astringency of white tea. • Two acylated flavonol glycoside may affect the brightness of tea infusion. • Tea trichomes enhance the fruity and floral aroma of white tea. • Five key compounds contributing to the aroma of white tea were identified in tea trichomes. To explore the influence of tea trichomes on the quality of white tea, liquid chromatography quadrupole time-of-flight mass spectrometry (LC-Q-TOF-MS), and headspace solid phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC–MS) were used to identify non-volatile and volatile compounds white tea without trichomes (WTwt) and pure trichomes (PT). It was found that the bitter and astringent compounds, caffeine (CAF), epigallocatechin gallate (EGCG), epicatechin gallate (ECG) and flavonol glycosides, were mainly enriched in the WTwt, with 16.3-fold, 47.1-fold and 28.7-fold decrease in CAF and EGCG and ECG, respectively, and the content of these compounds in PT were lower than the taste thresholds. In PT, kaempferol-3- O -(p -coumaroyl)-glucoside and kaempferol-3- O -(di- p -coumaroyl)-glucoside were non-volatile marker compounds, and decanal was significant aroma contributor with rOAV = 250.86. Moreover, the compounds in trichomes mainly contributed to the fruity and floral aroma of white tea, among which benzyl alcohol, (E) -geranylacetone, decanal, dodecanal and 6-methyl-5-hepten-2-one were the crucial aroma components, which were 2.1, 1.7, 1.8, 1.4 and 2.2 times as much as the WTwt in the PT, respectively. In conclusion, trichomes can improve the quality of white tea by reducing the bitterness and astringency, increasing the umami, as well as enhancing the fruity and floral aromas. [ABSTRACT FROM AUTHOR]

• Ternatins B2/B3, B4, and D2 were identified in Clitoria ternatea aqueous extracts. • Epigallocatechin-3-gallate was identified by for the first time. • Anthocyanins presented structural reversibility in relation to pH changes. • Aqueous extracts at pH 3.6 and 5.4 exhibited thermal stability. • Fructooligosaccharides added to the extracts provided a protective effect on the stability. The aim of the present study was to evaluate the phenolic composition of crude lyophilized extracts (CLE) and partially purified (PPE) extracts of C. ternatea blue petals as well as the anthocyanin stability against pH, temperature and light in the presence and absence of fructooligosaccharides. Twelve compounds were tentatively identified by UHPLC-Q-TOF-MS/MS in CLE and PPE extracts. In direct/reverse spectrophotometric titration, anthocyanins showed colour changes between pH 2.25 to 10.20, and colour reversibility, maintaining antioxidant activity against the DPPH radical. The aqueous extracts at pH 3.6 and 5.4 exhibited thermal stability with the presence and absence of fructooligosaccharides with activation energy higher than 99 kJ/mol. The addition of fructooligosaccharides in the extracts at pH 5.4 exposed to light provided a protective effect against anthocyanin photodegradation. The data show the technological potential of aqueous extract of C. ternatea blue petals as a natural colourant in a functional beverage model system. [ABSTRACT FROM AUTHOR]

• Post-fermentation highly decreased the flavonol O-glycosides' contents. • Inhibitory effects on α-glucosidase and α-amylase were decreased after pile-fermentation. • Metabolomics revealed astringent compounds' contents were decreased. Pile-fermentation is the most important process of producing ripened pu-erh tea. To study the chemical changes of tea leaves during pile-fermentation (PF), liquid chromatography coupled with tandem mass spectrometry (LC-MS) was used. Untargeted metabolomics analysis revealed that the first stage of PF is crucial in transforming the original secondary metabolites, whereas the contents of flavan-3-ols and gallic acid were decreased after long-term PF. Targeted metabolomics analysis indicated that the levels of puerins (N-ethyl-2-pyrrolidinone substituted gallocatechin and catechin) were significant increased after the first stage of PF, but after long-term PF the levels of flavonol glycosides, procyanidins and galloylated flavan-3-ols were significantly decreased. Accordingly, long-term PF also decreased the inhibition of α-amylase and α-glucosidase activities of the extracts. As a conclusion, pile-fermentation is an important step of changing the polyphenols and bioactivities of pu-erh tea. [ABSTRACT FROM AUTHOR]

• LC-MS indicated that olive leaf tea (OLT) contained phenolic compounds, including hydroxytyrosol, and flavonoids glycosides. • OLT had strong inhibition on the α-glucosidase, so may prevent the postprandial blood glucose level. • OLT showed preventative effects on the plasma lipids of animal model induced by high-fat diet. In the present study, the chemical constituents and inhibitory effects of Chinese olive leaf tea (OLT) on α-amylase, α-glucosidase, and its lipid-lowering effects on obese mice induced by a high fat diet were evaluated. In total, 17 compounds including hydroxytyrosol, hydroxytyrosol-glucoside were tentatively identified as main compounds of OLT with authentic compounds or referring to published articles and accessible databases. In total 105 volatile compounds were identified, in which hexanal, benzaldehyde and nonanal were the main aroma compounds. The bioassay showed that the IC 50 values of the OLT on α-amylase and α-glucosidase were 0.2102 g/mL and 2.925 mg/mL, respectively. It also indicated that the OLT is effective in improving the glucose homeostasis by oral starch tolerance test (OSTT). The experimental results in vivo also indicated that OLT significantly improved body weight, liver weight, abdominal fat, plasma levels of lipids, hepatic and plasma malondialdehyde (MDA) levels compared with obese mice fed high-fat diet. The OLT can enhance the antioxidant enzymes' activities (SOD and GSH-Px), meanwhile prevent the hepatic inflammation induced by high-fat diet. In summary, OLT has a potential application in preventing metabolic syndromes. [ABSTRACT FROM AUTHOR]

[Display omitted] • Metabolite profiles and color contributions of oxidated trichomes were investigated. • Acylated kaempferol glucosides and EPSFs as key metabolites are found in trichomes. • Golden trichomes are responsible for the lightness and yellow hue of infusion color. Tea trichomes were regarded as an essential evaluation index for reflecting tea flavor quality in terms of aroma and influence on infusion color. This study reveals the impact of golden oxidized trichomes on the color, volatile and non-volatile metabolites of black teas through comparative metabolomics combined quantitative analysis on hongbiluo (trichomes-deficiency black teas), hongjinluo (trichomes-rich black teas), and trichomes (from hongjinluo). Forty-six volatile components were detected using headspace solid-phase microextraction gas chromatography-mass spectrometry, while the results suggested that the contribution of trichomes to black teas is limited. A total of 60 marker non-volatile compounds were identified, including catechins, catechin oxidation products, flavonoid glycosides, organic acids, hydrolysable tannins and amino acids. Notably, p- coumaroyl-kaempferol glucosides, and catechin dimers demonstrated high levels in independent trichomes and showed a positive correlation with the brightness and yellow hue of black tea infusions, specifically kaempferol 3 -O- di-(p- coumaroyl)-hexoside. Furthermore, results from fractional extraction analysis of separated trichomes provided that N -ethyl-2-pyrrolidinone-substituted epicatechin gallates, acylated kaempferol glycosides, and chromogenic catechins dimers, such as theaflavins, were primary color contributors in oxidized trichomes. Especially, we found that epicatechin gallate (ECG) and its derivates, 3′- O -methyl-ECG and N -ethyl-2-pyrrolidinone-substituted ECG, highly accumulated in trichomes, which may be associated with the varieties of hongbiluo and hongjinluo black teas. Eventually, addition tests were applied to verify the color contribution of trichome mixtures. Our findings employed comprehensive information revealing that golden oxidized trichomes contributed significantly to the brightness and yellow hue of black tea infusion, but their contribution to the aroma and metabolic profile is limited. These findings may contribute to the effective modulation of the infusion color during black tea production by regulating the proportion of tea trichomes or screening trichomes-rich or deficiency varieties. [ABSTRACT FROM AUTHOR]

• Multi-omics analysis was applied in study of black tea color. • 425–475 nm was critical absorbance band for black tea color quality. • Flavonol glycosides and hydroxycinnamoyl acids contributed to color. Nine black tea samples with different color intensity were firstly determined by chromatic difference analyzer. The color characteristics were secondly quantitatively described by UV–visible spectroscopy. Thirdly, liquid chromatography tandem mass spectrometry (LC-MS) based metabolomics analysis was applied in low-molecular-weight compounds. Finally, the color contributors were identified by the correlation analysis of color, spectrometry and mass data. UV–visible based metabolomics analysis revealed that the wavelength at 380–520 nm (VIP > 1.50) was the critical absorbance band for distinguishing different color of BT infusions, while LC-MS based metabolomics analysis indicated that there were 48 main marker compounds responsible for the classification of different BT infusions. Correlation analysis results showed that the coefficients of theaflavins, thearubigins, theabrownins, flavonoid glycosides, and some hydroxycinnamoyl acids were > 0.7, which suggested they were main color contributors of BT infusion. The present study expanded a new vision on the color analysis of BT infusion. [ABSTRACT FROM AUTHOR]

[Display omitted] • Heating under 100–110 ℃ offered best taste characteristics and color appearances. • Isomerization, degradation and Maillard reactions are mainly involved. • 110 ℃ was the critical temperature point for enhancing antioxidant capacities. As the final processing step, drying temperature between 90 and 140 ℃ is usually applied to terminate enzymatic activities and improve sensory characteristics of black tea. Liquid chromatography tandem mass spectrometry (LC-MS) based non-targeted and targeted metabolomics analyses combined in vitro biological assays were adopted to investigate the chemical and biological variations after drying. Fifty-nine differentially expressed metabolites including several hydroxycinnamic acid derivatives and pyroglutamic acid–glucose Amadori rearrangement products (ARPs) were identified, the latter of which was correspondingly accumulated with increasing temperature. The levels of theaflavins (TFs), thearubigins (TRs), monosaccharides and free amino acids gradually decreased with increasing temperature. Furthermore, the bioassays of black tea showed that drying under 110 ℃ provided the highest antioxidant capacities, but the inhibitory effects on α -glucosidase and α -amylase were decreasing along with increasing drying temperature. These results are valuable for optimizing drying process to obtain superior sensory properties and preserve bioactivities of black tea. [ABSTRACT FROM AUTHOR]

[Display omitted] • Multi-spectral omics was applied in the colored metabolites of black tea. • Critical colored compounds were identified in C. sinensis and C. assamica black tea. • Amadori product was main color contributors to black teas' color difference. The present study provided a highly efficient and systematic workflow for identifying colorants of food and beverage. Generally, the objective colorimeter and subjective human eye had different systems to identify colors, which makes the color description very challenging. Here, the Lab/LCH color system was applied to clearly illustrate color changes. Our workflow was applied to determine and verify the differential colorant substances between two groups of black tea infusions. Regarding color parameters, the infusions of black tea from Camellia sinensis and Camellia assamica differed significantly. The differential substances between black tea infusions were correlated to color parameters by mass spectrometry and nuclear magnetic resonance based multivariate statistical analysis and verified by machine learning tool. Pyroglutamic acid–glucose Amadori product, quercetin-3- O -glucoside, quinic acid and theabrownins were identified as main color contributors to black teas' color difference, which were also verified by addition test with standard black tea infusion. [ABSTRACT FROM AUTHOR]

[Display omitted] • Forest industry side-streams showed antiviral, antioxidant and antidiabetic potential. • Both wood hemicelluloses and bark polyphenols decreased erythrocyte hemolysis. • Bark polyphenols protected against Coxsackievirus A9 infection. • Cell-based experiments showed non-toxic in vitro profile of extracts. This study aimed to characterise pressurised hot water (PHW) extracts from nonconventional sources of functional carbohydrates and phenolic compounds in terms of antioxidant capacity, antiviral activity, toxicity, and human erythrocytes' protection antidiabetic potential. PHW extracts of Norway spruce bark (E1 + E2) and Birch sawdust (E3 + E4) contained mostly galactoglucomannan and glucuronoxylan. In contrast, samples E5 to E9 PHW extracted from Norway spruce, and Scots pine bark are rich sources of phenolic compounds. Overall, phenolic-rich extracts presented the highest inhibition of α-amylase and α-glucosidase and protection against stable non-enveloped enteroviruses. Additionally, all extracts protected human erythrocytes from hemolysis. Cell-based experiments using human cell lines (IMR90 and A549) showed extracts' non-toxic in vitro profile. Considering the relative toxicological safety of extracts from these unconventional sources, functional carbohydrates and polyphenol-rich extracts can be obtained and further used in food models. [ABSTRACT FROM AUTHOR]

[Display omitted] • The UPLC-QQQ-MS method for quantitation of phenolic acids was established. • The relation between phenolic acids during processing of Keemun black tea were quantified. • The adduct of (-)-epigallocatechin gallate and chlorogenic acid was identified. Phenolic acids, including benzoic acid and hydroxycinnamic acid derivatives, are the main compounds of black tea. An efficient and accurate analytical method to quantify ten phenolic acids was established and validated by ultra-performance liquid chromatography coupled with triple quadrupole mass spectrometry (UPLC-QQQ-MS/MS). The chemical shifts during the processing of Keemun black tea were analyzed and the phenolic acids were quantified. Compared with fresh tea leaves, after processing, the contents of free phenolic acids, including gallic acid, salicylic acid, p -coumaric acid, and ferulic acid, increased markedly. Still, the contents of soluble conjugated phenolic acids, including p -coumaroylquinic acid isomers and chlorogenic acid isomers, decreased. Furthermore, the total contents of lignin, and insoluble bonded phenolic acids decreased. The adduct of (-)-epigallocatechin gallate and 3-caffeoylquinic acid was detected in tea samples, and its content increased highly after fermentation. The developed and validated analytical method can be used to monitor the manufacturing process of black tea. [ABSTRACT FROM AUTHOR]

A statistical optimization study was used to maximize the extraction of bioactive compounds and antioxidant activity from green tea derived from purple leaves of Camellia sinensis var. assamica. Simultaneous optimization was applied, and a combination of 60 °C, 15 min, and a mass-solvent ratio of 1 g of dehydrated purple leaves to 62.3 mL of an ethanol/citric acid solution, were determined as the ideal extraction conditions. The optimized extract of purple tea leaves (OEPL) contained showed stability in relation to variations in pH, and lyophilized OEPL exerted cytotoxic and antiproliferative effects against cancerous cells (A549 and HCT8), demonstrated antimicrobial activity towards Listeria monocytogenes (ATCC 7644), Staphylococcus aureus (ATCC 13565) and Staphylococcus epidermidis (ATCC 12288), inhibition of α-amylase and α-glycosidase enzymes and reduced the release of pro-inflammatory cytokines (TNF-α, CXCL2/MIP-2, and IL-6) in lipopolysaccharides-stimulated RAW 264.7 macrophages. Thus, our results provide a broad assessment of the bioactivity of "green" extracts obtained by a simple and low-cost process using non-toxic solvents, and they have the potential to be used for technological applications. [Display omitted] • The optimized extract of purple tea leaves (OEPL) has antioxidant properties. • OEPL was obtained with 60 °C, at 15 min, and 1 g-62.3 mL (mass-solvent ratio). • Lyophilized OEPL inhibited α-amylase and α-glucosidase enzymes. • Exerted cytotoxic and antiproliferative effects against cancer cells. • Lyophilized OEPL has anti-inflammatory effects in RAW 264.7 macrophages. [ABSTRACT FROM AUTHOR]

• The 10-year storage is supposed to be a critical point for chemical changes of KBT. • With storing, bitterness, astringency and umami was decreased. • Quinic acid derivatives were important taste contributors for stored KBT. The black tea could be stored for a long time, and subsequently affects the flavor characteristics. In the present study, the effects of storage years (1, 2, 3, 4, 5, 10, 17 and 20 years) on the chemical profiling and taste quality of keemun black tea (KBT) were compared by metabolomics and quantitative sensory evaluation. The main polyphenols were degraded during the storing, especially 10-year storage, but caffeine and theobromine were stable. The intensity of bitterness, astringency, umami was negatively correlated to storage years, with correlation coefficient at −0.95, −0.91 and −0.83 respectively, whereas sweetness had positive correlation coefficient at 0.74. Quinic acid, galloylated catechins, linolenic acid, linoleic acid, malic acid, palamitic acid, and theaflavin-3́-gallate were marker compounds which were responsible for distinguishing short and long time preserved KBT. The contents of fatty acids were positively correlated to storage time and sweet intensity. [ABSTRACT FROM AUTHOR]

Aqueous extracts from blackcurrant press cake (BC), Norway spruce bark (NS), Scots pine bark (SP), and sea buckthorn leaves (SB) were obtained using maceration and pressurized hot water and tested for their bioactivities. Maceration provided the extraction of higher dry matter contents, including total phenolics (TPC), anthocyanins, and condensed tannins, which also impacted higher antioxidant activity. NS and SB extracts presented the highest mean values of TPC and antioxidant activity. Individually, NS extract presented high contents of proanthocyanidins, resveratrol, and some phenolic acids. In contrast, SB contained a high concentration of ellagitannins, ellagic acid, and quercetin, explaining the antioxidant activity and antibacterial effects. SP and BC extracts had the lowest TPC and antioxidant activity. However, BC had strong antiviral efficacy, whereas SP can be considered a potential ingredient to inhibit α-amylase. Except for BC, the other extracts decreased reactive oxygen species (ROS) generation in HCT8 and A549 cells. Extracts did not inhibit the production of TNF-alpha in lipopolysaccharide-stimulated THP-1 macrophages but inhibited the ROS generation during the THP-1 cell respiratory burst. The recovery of antioxidant compounds from these by-products is incentivized for high value-added applications. [Display omitted] • Maceration enhances the extraction of bioactive compounds from industrial byproducts. • Norway spruce bark (NS) extract and sea buckthorn leaves (SB) are rich sources of antioxidant compounds. • NS had the highest inhibition of rat's brain oxidation, and SB showed toxicity to a cancerous cell. • Blackcurrant press cake (BC) revealed strong anti-viral effect toward enterovirus. • Scots pine bark (SP) extract is a potential ingredient to inactivate α-amylase. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the effects of different solvents and maximize the extraction of bioactive compounds from jabuticaba (Myrciaria cauliflora) seeds. In general, the solvent system composed of water and propanone (52:48 v/v) modified the extract polarity and increased extraction yield of bioactive compounds. The optimized extract presented antioxidant capacity measured by different chemical and biological assays. The optimized extract exerted antiproliferative and cytotoxic effects against A549 and HCT8 cells, antimicrobial and antihemolytic effects, inhibited α-amylase/α-glucosidase activities and presented in vitro antihypertensive effect. Nonetheless, the optimized extract showed no cytotoxicity in a human cell model (IMR90). Vescalagin, castalagin and ellagic acid were the major phenolic compounds in the optimized extract. Our results show that jabuticaba seed may be a potential ingredient for the development of potentially functional foods. Image 1 • Water and propanone maximized the extraction of phenolic compounds from jabuticaba seeds. • Optimized extract (OE) is rich in ellagitannins and ellagic acid. • OE shows antimicrobial effect and in vitro inhibition of lipid peroxidation. • OE inhibits in vitro angiotensin-I-converting enzyme and protected human erythrocytes. • OE inhibits the in vitro activity of α -amylase and α -glucosidase enzymes. [ABSTRACT FROM AUTHOR]

• Fermented rooibos, roasted mate, and white tea extracts were combined at an optimized formulation. • The optimized extract presented the most varied phenolic composition. • DNA and LDL oxidation was decreased when pretreated with the optimized extract. • The chlorogenic acid content was related to decreased lipoperoxidation of Wistar rat brain homogenate. Studies regarding the bioactivity of teas are mainly based on the phenolic composition and in vitro antioxidant activity of the herbal species used in their preparation. The aim of this study was to compare the in vitro and ex vivo antioxidant activity, cytotoxic/antiproliferative activity against cancer cells, the inhibitory activity of α-amylase, α-glucosidase and angiotensin I-converting enzymes, as well as the inhibition of DNA-induced fission of the peroxyl radical, in relation to aqueous extracts of Camellia sinensis var. sinensis (CS), Ilex paraguariensis (IP), Aspalathus linearis (AL) and an optimised extract (OT) containing the three herb species. A bivariate and multivariate statistical approach was employed to associate functional activities with individual phenolic composition. The CS and OT extracts showed the highest levels of hesperidin, quercetin-3-rutinoside, (-)-epigallocatechin-3-gallate and isoquercitrin. The CS and OT extracts showed the highest antioxidant activity, greater ability to inhibit α-amylase and proliferation of HCT8 cells, and greater ability to reduce Folin-Ciocalteu reagent. The AL extract, which is the major source of quercetin-3-rutinoside, hesperidin and isoquercitrin, showed the highest ability to inhibit α-glucosidase, the inhibition of LDL oxidation and protection of human erythrocytes. The IP extract showed the highest inhibition of lipoperoxidation in brain homogenate of Wistar rats, antihypertensive activity, and A549 cell proliferation; chlorogenic acid was its major phenolic compound. In general, the in vitro functionality of each extract was dependent on its chemical composition and the OT extract presented the most varied phenolic composition, and biological activity similar to the CS sample. In conclusion, the mixture of CS, AL, and IP represents a chemical and functional-based strategy to develop functional teas. [ABSTRACT FROM AUTHOR]

• Camu-camu seed extracts are rich sources of antioxidant phenolics. • Extraction was optimised in terms of solvent mixtures (H 2 O, EtOH, propanone). • Optimised extract (OE) inhibited lipid oxidation and inhibited carbohydrate enzymes. • OE presented cytotoxic effects towards HCT8 and A549 cells. • OE protected human erythrocytes against hemolysis and had antyhypertensive activity. Camu-camu (Myrciaria dubia) seeds are discarded without recovering the bioactive compounds. The main aim of the present work was to optimise the solvent mixture to extract higher total phenolic content and antioxidant capacity of camu-camu seeds. The optimised solvent system increased the extraction of phenolic compounds, in which vescalagin and castalagin were the main compounds. The optimised extract displayed antioxidant capacity measured by different chemical and biological assays, exerted antiproliferative and cytotoxic effects against A549 and HCT8 cancer cells, antimicrobial effects, protected human erythrocytes against hemolysis, inhibited α-amylase and α-glucosidase enzymes and presented in vitro antihypertensive effect. Additionally, the optimized extract inhibited human LDL copper-induced oxidation in vitro and reduced the TNF-α release and NF-κB activation in macrophages cell culture. Thus, the use of camu-camu seed showed to be a sustainable way to recover bioactive compounds with in vitro functional properties. [ABSTRACT FROM AUTHOR]

• Bioactive compounds of Clitoria ternatea petals were extracted at 40 °C for 30 min. • Aqueous extract has in vitro antihemolytic and antihyperglycemic effects. • Lyophilized extract inhibited 61% of angiotensin-I-converting enzyme in vitro. • Extracts showed an inhibitory effect of DNA strand scission and LDL cholesterol oxidation. • Intracellular antioxidant activity with concentrations above 100 μg/mL of extract. The purpose of this study was to use a statistical approach to optimise the experimental conditions regarding the extraction of bioactive compounds, and to analyse the in vitro functional properties of crude lyophilized extracts (CLE) and partially purified (PPE) extracts of Clitoria ternatea petals. The results showed that the factors of temperature and time influenced the extraction of phenolic compounds, antioxidant activity and the physicochemical parameters. Simultaneous optimisation showed that the same levels of bioactive compounds were extracted when using temperatures from 11.7 to 68.3 °C and times from 8.47 to 51.12 min. Principal component analysis revealed the experimental conditions that provided the extraction producing the highest level of phenolic content (40 °C/30 min). The CLE showed antimicrobial activity; protective effect against hemolysis of erythrocytes; inhibition of α-amylase, α-glucosidase and angiotensin-I-converting (ACE-I) enzymes; and inhibition of lipid peroxidation. The CLE and PPE demonstrated oxygen radical absorption capacity; inhibition of DNA strand scission; inhibition of LDL cholesterol oxidation; intracellular antioxidant activity against reactive oxygen species (>100 μg/mL); and no cytotoxicity (IC 50 , GI 50 and LC 50 > 900 μg/mL) against A549, HCT8 and IMR90 cell lines. [ABSTRACT FROM AUTHOR]

• A mixture of I. paraguariensis , M. officinalis , and C. citratus was optimized. • The optimized extract (OHE) had antioxidant, antihypertensive and antiproliferative activity. • OHE decreased ROS generation in IMR90 and A549 cell lines. • OHE is rich in rutin, isoquercetin, and hesperidin. • OHE promoted in vitro antihypertensive properties and increased phenolics/antioxidant activity. This work aimed to optimize an aqueous extract rich in phenolic compounds and potential functional properties made of Ilex paraguariensis , Melissa officinalis , and Cymbopogon citratus. The lyophilized extract was used for the development of an ice cream. Total phenolics, FRAP, DPPH, Folin-Ciocalteu's reducing capacity, and total reducing capacity of different combinations of herbal extracts were tested and modeled using response surface methodology. Simultaneous optimisation was employed to maximize the bioactive compounds in the extract and the lyophilized optimum combination was added to ice cream. The lyophilized extract contained quercetin-3-rutinoside, hesperidin, isoquercetin, caffeic acid, and 5,7-dihydroxyflavone. The optimised extract, which showed antihypertensive, antidiabetic, and antioxidant activity using in vitro protocols, increased total phenolics and antioxidant activity in comparison to the control ice cream. The ice cream presented a sensory acceptance index of 83%. After 72 days of storage (−18 °C), total phenolics and antioxidant activity significantly decreased. [ABSTRACT FROM AUTHOR]