Pruned tea biomass plays a significant role in functional food production: A review on characterization and comprehensive utilization of abandon-plucked fresh tea leaves.

Tea is the second largest nonalcoholic beverage in the world due to its characteristic flavor and well-known functional properties in vitro and in vivo. Global tea production reaches 6.397 million tons in 2022 and continues to rise. Fresh tea leaves are mainly harvested in spring, whereas thousands of tons are discarded in summer and autumn. Herein, pruned tea biomass refers to abandon-plucked leaves being pruned in the non-plucking period, especially in summer and autumn. At present, no relevant concluding remarks have been made on this undervalued biomass. This review summarizes the seasonal differences of intrinsic metabolites and pays special attention to the most critical bioactive and flavor compounds, including polyphenols, theanine, and caffeine. Additionally, meaningful and profound methods to transform abandon-plucked fresh tea leaves into high-value products are reviewed. In summer and autumn, tea plants accumulate much more phenols than in spring, especially epigallocatechin gallate (galloyl catechin), anthocyanins (catechin derivatives), and proanthocyanidins (polymerized catechins). Vigorous carbon metabolism induced by high light intensity and temperature in summer and autumn also accumulates carbohydrates, such as soluble sugars and cellulose. The characteristics of abandon-plucked tea leaves make them not ideal raw materials for tea, but suitable for novel tea products like beverages and food ingredients using traditional or hybrid technologies such as enzymatic transformation, microbial fermentation, formula screening, and extraction, with the abundant polyphenols in summer and autumn tea serving as prominent flavor and bioactive contributors.

A comprehensive review of matcha: production, food application, potential health benefits, and gastrointestinal fate of main phenolics.

Matcha, a powder processed from tea leaves, has a unique green tea flavor and appealing color, in addition to many other sought after functional properties for a wide range of formulated food applications (e.g., dairy products, bakery products, and beverage). The properties of matcha are influenced by cultivation method and processing post-harvest. The transition from drinking tea infusion to eating whole leaves provides a healthy option for the delivery of functional component and tea phenolics in various food matrix. The aim of this review is to describe the physico-chemical properties of matcha, the specific requirements for tea cultivation and industrial processing. The quality of matcha mainly depends on the quality of fresh tea leaves, which is affected by preharvest factors including tea cultivar, shading treatment, and fertilization. Shading is the key measure to increase greenness, reduce bitterness and astringency, and enhance umami taste of matcha. The potential health benefits of matcha and the gastrointestinal fate of main phenolics in matcha are covered. The chemical compositions and bioactivities of fiber-bound phenolics in matcha and other plant materials are discussed. The fiber-bound phenolics are considered promising components which endow matcha with boosted bioavailability of phenolics and health benefits through modulating gut microbiota.

Exogenous stimulation-induced biosynthesis of volatile compounds: Aroma formation of oolong tea at postharvest stage.

Volatile organic compounds (VOCs) are produced by plants responding to biotic and abiotic stresses. According to their biosynthetic sources, induced VOCs are divided into three major classes: terpenoids, phenylpropanoid/benzenoid, and fatty acid derivatives. These compounds with specific aroma characteristics importantly contribute to the aroma quality of oolong tea. Shaking and rocking is the crucial procedure for the aroma formation of oolong tea by exerting mechanical damage to fresh tea leaves. Abundant studies have been carried out to investigate the formation mechanisms of VOCs during oolong tea processing in recent years. This review systematically introduces the biosynthesis of VOCs in plants, and the volatile changes due to biotic and abiotic stresses are summarized and expatiated, using oolong tea as an example.

Effect of Ferrous Ion on Heat-Induced Aroma Deterioration of Green Tea Infusion.

Aroma deterioration is one of the biggest problems in processing tea beverages. The aroma of tea infusion deteriorates fast during heat sterilization and the presence of ferrous ion (Fe2+) aggravates it. The underlying mechanism remains unveiled. In this study, Fe2+ was verified to deteriorate the aroma quality of green tea infusion with heat treatment. Catechins were necessary for Fe2+-mediated aroma deterioration. By enhancing the degradation of catechins, Fe2+ dramatically increased the production of hydrogen peroxide (H2O2). Fe2+ and H2O2 together exacerbated the aroma of green tea infusion with heat treatment. GC-MS analysis revealed that the presence of Fe2+ enhanced the loss of green/grassy volatiles and promoted the formation of new volatiles with diversified aroma characteristics, resulting in a dull scent of green tea infusion. Our results revealed how Fe2+ induced aroma deterioration of green tea infusion with heat treatment and could help guide tea producers in attenuating the aroma deterioration of tea infusion during processing.

Flavor characteristics and chemical compositions of oolong tea processed using different semi-fermentation times.

Flavor characteristics and chemical compositions of Tieguanyin oolong tea processed using different semi-fermentation times were investigated. Six flavor attributes of the teas, namely, astringency, bitterness, umami, sweet aftertaste, floral flavor, and green fruity flavor, were analysed. With extended semi-fermentation time, the taste intensity of sweet aftertaste increased, and the aroma intensity of floral and green fruity flavors increased, while the intensities of astringency, bitterness, and umami showed no clear trend. With increasing semi-fermentation time, the concentrations of gallated catechins, myricetin-rhamnose, quercetin-rutinoside, myricetin, and theanine greatly decreased, while those of total theaflavins, vitexin-rhamnose, kaempferol-galactose, kaempferol-rutinoside, vitexin, quercetin, and kaempferol increased significantly. The intensity of bitter taste was positively correlated with the concentrations of total catechins and gallated catechins. The intensity of astringent taste strongly correlated with the flavonoid concentrations, and that of sweet aftertaste positively correlated with the concentrations of (-)-epigallocatechin and (-)-epicatechin. However, dose-over-threshold analysis revealed that catechins, theaflavin, flavonol glycosides, and caffeine are the main taste-active compounds contributing to the taste of Tieguanyin oolong tea. The concentrations of total volatiles and most of the esters increased markedly with the semi-fermentation time, while the concentrations of low aldehydes showed a significant decrease. The flavor index was consistent with the intensity of floral aroma, increasing from 0.59 (12 h) to 0.84 (24 h) and then decreasing to 0.63 (32 h). Results of this work suggest that the flavor change is mainly due to the variation of taste-active and aroma-active compounds in oolong tea.

Strengthening Gastric Cancer Therapy by Trastuzumab-Conjugated Nanoparticles with Simultaneous Encapsulation of Anti-MiR-21 and 5-Fluorouridine.

BACKGROUND/AIMS: MicroRNA-21 is an oncogenic miR (oncomiR) frequently elevated in gastric cancer (GC). Overexpression of miR-21 decreases the sensitivity of GC cells to 5-fluorouridine (5-Fu) and trastuzumab, a humanized monoclonal antibody targeting human epidermal growth factor receptor 2 (HER2). Receptor-mediated endocytosis plays a crucial role in the delivery of biotherapeutics including anti-miRNA oligonucleotides (AMOs). This study is a continuation of earlier findings involving poly(ε-caprolactone) (PCL)-poly (ethylene glycol) (PEG) nanoparticles (PEG-PCL NPs), which were coated with trastuzumab to target GC with HER2 receptor over-expression using anti-miRNA-21 (AMO-21) and 5-Fu. METHODS: HER-PEG-PCL NPs were prepared by one-step carbodiimide coupling using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDAc) and Sulfo-NHS in aqueous phase. Covalent coupling of amino groups at the surface of PEG-PCL with the carboxyl groups of trastuzumab was analyzed by X-ray photoelectron spectroscopy (XPS). AMO-21/5-Fu NPs were formulated by a double-emulsion solvent evaporation technique. The cell line specificity, cellular uptake and AMO-21 delivery were investigated through the rhodamine-B-labeled 6-carboxyfluorescein (FAM)-AMO-21-PEG-PCL NPs coated with or without the antibody in both Her2-positive (NUGC4) and negative GC cells (SGC7901) visualized by fluorescence microscopy. The cytotoxicity of the HER-PEG-PCL NPs encapsulating AMO-21 was evaluated by MTT and apoptosis. Real-time reverse-transcription polymerase chain reaction (RT-PCR) was used to examine miR-21 and phosphatase and tensin homolog (PTEN) and Sprouty2 expression in GC cell lines. The antitumor effects of AMO-21/5-Fu NPs were compared with other groups in xenograft gastric cancer mice. RESULTS: The antibody conjugates significantly enhanced the cellular uptake of NPs. The AMO-21/5-Fu NPs effectively suppressed the target miRNA expression in GC cells, which further up-regulated PTEN and Sprouty2. As a result, the sensitivity of HER2-expressing gastric cancer to trastuzumab and 5-Fu were enhanced both in vitro and in vivo. The approach enhanced the targeting by trastuzumab as well as antibody-dependent cellular cytotoxicity (ADCC) of immune effector cells Conclusions: Taken together, the results provide insight into the biological and clinical potential of targeted AMO-21 and 5-Fu co-delivery using modified trastuzumab for GC treatment.

Improving the quality of fermented black tea juice with oolong tea infusion.

Fresh tea leaves were crushed into juice and then fermented (oxidation) to obtain fermented black tea juice, which can be used to prepare black tea beverage. The effects of addition of oolong tea infusion or tossing of tea leaves on the sensory quality and theaflavins (TFs) concentration of fermented black tea juice were investigated. The results showed that both addition of tea infusion and tossing of fresh tea leaves increased the TFs/thearubigins (TRs) ratio and improved the sensory quality of fermented black tea juice. The TFs/TRs ratio was found to be significantly correlated with the scores for flavor (r = 0.98), mouth feel (r = 0.94), and overall acceptability (r = 0.91) of the fermented black tea juices from different processes. This result suggested that a relatively high concentration of catechins and stepwise enzymatic oxidation were the crucial factors that increased the TFs/TRs ratio and improved the sensory quality. The combination of adding tea infusion and tossing fresh tea leaves greatly improved the quality of the fermented black tea juice by markedly increasing the TFs/TRs ratio (87%). Results of the present study provided useful information for improving the quality of fermented black tea juice.

Upregulated expression of long noncoding RNA SNHG15 promotes cell proliferation and invasion through regulates MMP2/MMP9 in patients with GC.

Accumulation of data indicates that misregulated long noncoding RNAs (lncRNAs) are implicated in cancer tumorigenesis and progression and might be served as diagnosis and prognosis biomarker or potential therapeutic targets. Identification of cancer-associated lncRNAs and investigation of their biological functions and molecular mechanisms are significant for understanding the development and progression of cancer. In this study, we identified a novel lncRNA SNHG15, whose expression was upregulated in tumor tissues in 106 patients with gastric cancer (GC) compared with those in the adjacent normal tissues (P < 0.001). Furthermore, increased SNHG15 expression was positively correlated with invasion depth (P < 0.001), advanced tumor node metastasis (TNM) stage (P = 0.001), and lymph node metastasis (P = 0.019). SNHG15 levels were robust in differentiating GC tissues from controls (area under the curve (AUC) = 0.722; 95 % confidence interval (CI) = 0.657-0.782, P < 0.01). Kaplan-Meier analysis demonstrated that elevated SNHG15 expression contributed to poor overall survival (P < 0.01) and disease-free survival (P < 0.01) of patients. A multivariate survival analysis also indicated that SNHG15 could be an independent prognostic marker. Furthermore, knockdown of SNHG15 expression by siRNA could inhibit cell proliferation and invasion and induce apoptosis, while ectopic expression of SNHG15 promoted cell proliferation and invasion in GC cells partly via regulating MMP2 and MMP9 protein expression. Our findings present that elevated lncRNA SNHG15 could be identified as a poor prognostic biomarker in GC and regulate cell invasion.

Corrigendum to "Optimization of a tannase-assisted process for obtaining teas rich in theaflavins from Camellia sinensis leaves" [Food Chemistry: X 13 (2022) 100203].

[This corrects the article DOI: 10.1016/j.fochx.2022.100203.].

Effect of the type of brewing water on the sensory and physicochemical properties of light-scented and strong-scented Tieguanyin oolong teas.

Variations in the quality of brewing water profoundly impact tea flavor. This study systematically investigated the effects of four common water sources, including pure water (PW), mountain spring water (MSW), mineral water (MW) and natural water (NW) on the flavor of Tieguanyin tea infusion. Brewing with MW resulted in a flat taste and turbid aroma, mainly due to the low leaching of tea flavor components and complex interactions with mineral ions (mainly Ca2+, Mg2+). Tea infusions brewed with NW exhibited the highest relative contents of total volatile compounds, while those brewed with PW had the lowest. NW and MSW, with moderate mineralization, were conducive to improving the aroma quality of tea infusion and were more suitable for brewing both aroma types of Tieguanyin. These findings offer valuable insights into the effect of brewing water on the sensory and physicochemical properties of oolong teas.

Proximal Femoral Metastasis From Epidermal Growth Factor Receptor-Mutated Lung Adenocarcinoma Mimicking Osteosarcoma on Magnetic Resonance Imaging.

The aggressive nature of lung cancer is frequently accompanied by a high incidence of bone metastasis; however, proximal femoral metastasis from lung cancer is comparatively uncommon when compared to other malignancies. In this report, we present the case of a 53-year-old Asian male who presented with pain in the left thigh and back. Magnetic resonance imaging revealed severe bone destruction with involvement of adjacent soft tissue mass at the left thigh, exhibiting imaging findings that mimic osteosarcoma. Subsequent bone biopsy confirmed the diagnosis of epidermal growth factor receptor (EGFR)-mutated lung adenocarcinoma with bone metastasis. The patient achieved survival following administration of osimertinib and underwent surgery for femoral metastases without palliative surgery for lung cancer. Therefore, proximal femoral metastasis from EGFR-mutated lung adenocarcinoma should be considered as a differential diagnosis in patients suspected to have osteosarcoma. The imaging findings of proximal femoral metastasis from EGFR-mutated lung adenocarcinoma were presented, and their therapeutic management was discussed.

[Spatio-temporal Differentiation of County Carbon Budget and Territorial Space Optimization Zoning Strategy in Gansu Province from the Perspective of Carbon Neutrality].

Under the background of comprehensively practicing the overall system concept of the "living community" in the new era, incorporating the carbon neutral development goal into the territorial spatial planning and construction and establishing the territorial spatial pattern and optimization strategy in line with the actual development of Gansu Province are of great significance for promoting the comprehensive green low-carbon transformation and high-quality development of regional economy and society. Taking counties in Gansu Province as an example, based on the perspective of carbon neutrality research, the land use carbon budget of 87 counties in Gansu Province in 2010, 2015, and 2021 was calculated and analyzed. GIS spatial analysis and social network analysis were used to further explore their spatial differentiation characteristics and the overall characteristics of the carbon emission spatial correlation network. At last, combined with the main function zoning, the low-carbon oriented land space optimization zoning was carried out, and differentiated low-carbon development strategies were proposed. The results were as follows： ① Carbon emissions in Gansu Province showed an upward trend, but the increase rate decreased, showing a spatial distribution of "high in the central and eastern part of the country, low in the southwest." Construction land was the main carbon source. The carbon uptake showed a spatial distribution of "high in the south and low in the north, high in the west and low in the east." Woodlands were the main carbon sinks. The net carbon emissions showed an increasing trend, and approximately 58.62% of the counties in the province were in a carbon imbalance situation. ② In 2021, the spatial network of county carbon emissions was closely related, showing a "core-edge" pattern. The Chenguan District and Qilihe District were in the core position of the network and received more correlation relationships in the network. The network contacts in Longzhong area were frequent, followed by the contacts in Longdongnan area. ③ Based on carbon emissions, carbon sequestration, and ecological carrying capacity coefficients and using the results of spatial correlation of social networks as role positions, the province was divided into four carbon-neutral sub-districts. At the same time, superimposed analysis of the main function zoning, the county area of the province was reconstructed into seven territorial space zones, and the differentiated regional low-carbon optimization development strategy was proposed for each zone.

Effect of osmanthus hydrolat on the aroma quality and volatile components of osmanthus black tea.

Osmanthus fragrans is an evergreen shrub with a pleasant fragrance and a wide range of applications in many fields. The condensed hydrolat obtained during the drying process of its fresh flowers was collected in a low-temperature vacuum environment and its sensory evaluation and volatile components were studied. The main aroma compounds in Osmanthus fragrans were dihydro-ß-ionone, nonanal, ß-cyclocitral, ß-ionone, benzaldehyde, α-ionone, and 6-methyl-5-hepten-2-one, whose contents were used as the main evaluation criteria, and the hydrolats obtained under different scenting and drying times were compared. This process can effectively collect the aroma components in Osmanthus fragrans and the optimal drying conditions were 50 °C for 5 h. The hydrolat was used to provide the scent of osmanthus black tea, which had a fresher and mellower taste, while the fragrance of osmanthus was abundant. These results show that osmanthus hydrolat can be used to provide the scent of floral black tea. Chemical compounds studied in this article: (-)-Catechin (PubChem CID: 1203); (-)-epigallocatechin gallate (PubChem CID: 65064); (-)-epicatechin gallate (PubChem CID: 367141); (-)-epigallocatechin (PubChem CID: 72277); (-)-epicatechin (PubChem CID: 72276); (-)-gallocatechin gallate (PubChem CID: 199472); (-)-catechin gallate (PubChem CID: 6419835); (-)-gallocatechin (PubChem CID: 9882981).

Inflammatory Myofibroblastic Tumor of the Sciatic Nerve Mimicking Lumbar Disc Herniation: A Diagnostic Challenge.

Inflammatory myofibroblastic tumors (IMTs), which involve the proliferation of fibroblastic-myofibroblastic cells mixed with inflammatory infiltrates, are exceedingly rare in the extremities. There are no reported IMTs involving the sciatic nerve. This type of involvement may cause entrapment of the sciatic nerve, whose symptoms may mimic lumbar disc herniation (LDH), especially when it occurs in patients with lumbar degenerative disc disease. We describe the case of a 40-year-old male with lumbar degenerative disc disease accompanied by IMT involving the sciatic nerve whose symptoms mimicked LDH and posed a diagnostic challenge. We showed the course of the disease as well as the systematic imaging manifestations of IMTs involving the sciatic nerve and discussed their therapeutic management.

Dynamic changes of key metabolites in Longjing green tea during processing revealed by widely targeted metabolomic profiling and sensory experiments.

In this study, widely targeted metabolomics and chemometrics were utilized to comprehensively analyse the formation of taste compounds in Longjing green tea. A total of 580 non-volatile metabolites were identified by using ultra-performance liquid chromatography-electrospray ionization-tandem mass spectrometry, and alterations in three metabolic pathways were investigated. Notably, the fixation process reduced phosphatidic acid levels, resulting in the formation of lyso-phosphatidylcholine and lyso-phosphatidylethanolamine, as well as the release of esterified polyunsaturated fatty acids. Baiye No.1 had high levels of L-glutamic acid and l-glutamine, while Longjing 43 showed elevated levels of flavones. Correlation analysis and sensory verification indicated that the specific concentration of L-leucine could decrease the umami of the tea. These findings advance our understanding of Longjing green tea quality improvement and cultivar development.

Moisture content of tea dhool for the scenting process affects the aroma quality and volatile compounds of osmanthus black tea.

To improve the quality of osmanthus black tea, samples produced with different scenting methods were prepared. The sensory quality was assessed and the characteristic aromatic components were explored using solid-phase microextraction (SPME) coupled with gas chromatography-mass spectrometry. According to the results, osmanthus black tea obtained by adding osmanthus scenting in the fermentation process had the strongest floral aroma. The major contributors to the aroma of osmanthus black tea were identified as ß-ionone, dihydro-ß-ionone, benzeneacetaldehyde, citral, geraniol, and linalool by calculating their relative odor activity values. An analysis of the causes revealed that the moisture content of tea dhool significantly affected the adsorption of fresh flower aroma by tea. The experimental results showed that osmanthus black tea produced using tea dhool containing 30% moisture content had the highest content of crucial aroma components, suggesting the tea dhool under this condition had the strongest adsorption capacity for osmanthus aroma.

Hydrolysis of green tea residue protein using proteolytic enzyme derived from Aspergillus oryzae.

Free amino acids are important chemical components which impact the taste of green tea infusion. The hydrolysis of water-insoluble protein in the green tea residue helps to increase the contents of free amino acids components except theanine. Studies indicate that the hydrolysis of the tea protein could be restricted due to interaction of polyphenols with protein. The experiment indicates that the hydrolysis of tea protein by protease is the main trend when the polyphenols concentration is lower than 5 mg ml(-1), however, the proteins (including tea protein and protease) would interact with polyphenoles instead of hydrolysis when the concentration of polyphenols is higher than 5 mg ml(-1). The hydrolysis of tea protein is absolutely restrained when concentration comes to 10 mg ml(-1).

Chemical composition and anti-cholesterol activity of tea (Camellia sinensis) flowers from albino cultivars.

Albino tea cultivars are mutant tea plants with altered metabolisms. Current studies focus on the leaves while little is known about the flowers. To evaluate tea flowers from different albino cultivars, the chemical composition and anti-cholesterol activity of tea flowers from three albino cultivars (i.e., Baiye No.1, Huangjinya, and Yujinxiang) were compared. According to the results, tea flowers from Yujinxiang had more amino acids but less polyphenols than tea flowers from the other two albino cultivars. A reduced content of procyanidins and a high chakasaponins/floratheasaponins ratio were characteristics of tea flowers from Yujinxiang. In vitro anti-cholesterol activity assays revealed that tea flowers from Yujinxiang exhibited stronger activity in decreasing the micellar cholesterol solubility, but not in cholesterol esterase inhibition and bile salt binding. It was noteworthy that there were no specific differences on the chemical composition and anti-cholesterol activity between tea flowers from albino cultivars and from Jiukeng (a non-albino cultivar). These results increase our knowledges on tea flowers from different albino cultivars and help food manufacturers in the cultivar selection of tea flowers for use.

The Effects of Structure and Oxidative Polymerization on Antioxidant Activity of Catechins and Polymers.

Polyphenols are key free radical scavengers in tea. This study screened the antioxidant active groups of catechins and dimers and analyzed the effects of the degree of oxidative polymerization and oxidative dimerization reaction on their antioxidant activities. ABTS+· free radical scavenging activity, DPPH free radical scavenging activity, and total antioxidant capacity of catechins and polymers were systematically analyzed and compared in this study. Results manifested antioxidant activities of catechins were dominated by B-ring pyrogallol and 3-galloyl, but were not decided by geometrical isomerism. 3-galloyl had a stronger antioxidant activity than B-ring pyrogallol in catechins. The number, not the position, of the galloyl group was positively correlated with the antioxidant activities of theaflavins. Theasinensin A has more active groups than (-)-epigallocatechin gallate and theaflavin-3,3'-digallate, so it had a stronger antioxidant activity. Additionally, the higher the degree of oxidation polymerization, the weaker the antioxidant activities of the samples. The oxidative dimerization reaction hindered the antioxidant activities of the substrate-catechin mixture by reducing the number of active groups of the substrate and increasing the molecular structure size of the product. Overall, pyrogallol and galloyl groups were antioxidant active groups. The degree of oxidative polymerization and the oxidative dimerization reaction weakened the antioxidant activity.

Effect of ß-glucosidase on the aroma of liquid-fermented black tea juice as an ingredient for tea-based beverages.

The effects of ß-glucosidase on the volatile profiles and aroma stability of black tea juice were evaluated using gas-chromatography-mass spectrometry coupled with sensory analysis. During liquid fermentation of tea leaves, the addition of ß-glucosidase increased the concentration of aldehydes, strengthening the undesirable "green grassy" odour. However, the "green grassy" odour was counteracted by adding green tea extract during fermentation. At the same time, "flowery" flavour notes were enhanced, improving the overall aroma quality and strengthening the characteristic "sweet" aroma of black tea. Increased addition of ß-glucosidase released more free aroma alcohols from their glucosides. Two "fruity" and "floral" aroma components, benzyl alcohol and phenylethyl alcohol, were not significantly affected by heat treatment (95 °C water bath) and the overall aroma stability was not significantly affected by ß-glucosidase treatment. ß-Glucosidase treatment improved the aroma, colour and overall suitability of fermented black tea juice as an ingredient for tea-based beverages.