Roasting pretreatment reduces retort odor formation in green tea beverages: Evidence from chemometrics and sensory evaluation.

Aroma degradation is a pivotal technical challenge restricting the development of tea beverages. Addressing the aroma stability is a pressing issue for the tea beverage industry. In this study, the effect of roasting raw materials on the formation of retort odor in green tea beverages was assessed using chemometrics and sensory evaluation.

Activity Expression and Property Analysis of Codon-Optimized Polyphenol Oxidase from in KM71.

Tea polyphenol oxidase (CsPPO) is a crucial enzyme involved in the production of tea and tea products. However, the recombinant expression of CsPPO in microorganisms is often hindered by challenges such as inclusion body formation and extremely low enzyme activity. In this study, the gene (1800 bp) from cv.

Identification of Key Taste-Active Compounds in Oolong Teas (Dongding and Rougui) by Quantitative Measurements, Recombination Experiments, and Omission Tests.

A lack of knowledge regarding taste-active compounds of Oolong tea limits the improvement of product quality. Nontargeted metabolomics and sensory quantitative descriptive analyses were performed on two representative oolong teas, resulting in 41 compounds screened for their relevance to taste characteristics, and they were quantitated. Combined taste dose-overthreshold (DoT > 1) factors with key differentiators, reconstitution of ten selected compounds successfully replicated the authentic tea infusion.

Elucidating the effect of brewing temperature on the sensory quality of Longjing tea based on multi-scale molecular sensory science.

Longjing tea is popular due to its unique flavor characteristics, and the brewing process is of crucial importance in presenting its flavor. This study investigated how brewing temperature (BT) impacts Longjing tea's sensory and molecular profile. Sensory evaluations demonstrated that lower brewing temperatures (70-80 °C, with 70 °C optimal) enhanced umami taste while diminishing bitterness and astringency.

Aroma compounds with enhanced sweet perception in tea infusions: Screening, characterization, and sweetening mechanism.

Introduction: Tea (Camellia sinensis) is globally consumed for its pleasant flavor, with sweetness being a key factor in evaluating tea quality. While taste compounds contribute to this sweetness, aroma also plays a significant role, but its contribution is not well understood in tea infusion.

Objectives: This study aimed to identify aroma compounds that enhance sweetness in tea infusion using a sensomics approach, and explore their synergistic effects through molecular docking.

Dynamic changes in metabolites during the manufacture of three distinct flavor types of Tieguanyin.

The formation mechanisms for different aroma types of Tieguanyin was investigated. In this study, the same fresh leaves were processed into three Tieguanyin samples with distinct aroma types (fresh floral scent, flower and fruit scent, sweet fruity scent). Based on sensory evaluation and metabolomic analysis, the dynamic changes of aroma- and taste-related compounds in three Tieguanyin tea samples during processing process were investigated.

Enzyme-assisted dynamic extraction as a promising method to produce high-quality fresh tea juice from summer tea leaves.

To improve the flavor of green tea juice processed from summer tea leaves, the enzyme-assisted dynamic extraction method was applied. The chemical components and taste of fresh green tea juice prepared under different extraction conditions with enzyme treatment (EM: tannase or its combination with protease/cellulase/pectinase) were investigated. The results showed that EM could reduce the bitterness and astringency of the tea juice by up to 40 % and 39 %, and enhance the sweet aftertaste to 132 %.

Effect and mechanism of calcium ions on the astringency in green tea infusion and epigallocatechin gallate solution: An in vitro oral soft tribology study.

In this study, the effect of calcium ions (Ca) on the astringency sensation in green tea infusion was explored using sensory evaluation, in vitro oral soft tribology, and targeted metabolomics. Ca enhanced the astringency intensity (from 2 to 6) and the turbidity (from 10.0 to 83.

Effect of different drying temperature settings on the color characteristics of Tencha.

Color is critical factor in the commercialization of Matcha. In this study, sensory evaluation, color difference analysis, as well as targeted and non-targeted analyses were employed to investigate the impact of different drying temperature settings on the color characteristics of Tencha. The findings revealed that compared to a single drying temperature setting, a two-stage or multi-stage drying process more effectively preserved the color quality of Tencha.

Chemometrics and sensomics-assisted identification of key odorants responsible for retort odor in shelf-stored green tea infusion: A case study of Biluochun.

The deterioration of aroma quality in tea beverages during the shelf life is a significant issue. In this study, sensomics techniques were employed to identify the characteristic factor contributing to aroma degradation in green tea infusion. Samples A (no/faint retort odor) and B (high intensity retort odor) were selected based on their retort-like odor intensity after heat treatment simulating shelf-life conditions.

Polysaccharide Conjugates' contribution to mellow and thick taste of Pu-erh ripe tea, besides Theabrownin.

Mellow and thick taste (MTT) is considered to be a typical taste characteristic of high-quality Pu-erh ripe tea. However, the role of polysaccharide conjugates remains unclear. In this study, the infusion of different grades of Pu-erh ripe tea was isolated to fractions by sensory-guided ultrafiltration technology and the key taste substances of MTT in Pu-erh ripe tea were identified and confirmed in the sensory reconstruction experiment.

Impact of heat treatment on the flavor stability of Longjing green tea beverages: Metabolomic insights and sensory correlations.

The flavor stability of tea beverages during storage has long been a concern. The study aimed to explore the flavor stability of Longjing green tea beverage using accelerated heat treatment trials, addressing the shortage of lengthy storage trials. Sensory evaluations revealed changes in bitterness, umami, overall harmonization, astringency, and ripeness as treatment duration increased.

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

Unlabelled: 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 were dihydro--ionone, nonanal, -cyclocitral, -ionone, benzaldehyde, -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.

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.

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

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

Anthocyanin-rich extract from purple tea: Chemical stability, cellular antioxidant activity, and protection of human erythrocytes and plasma.

This study aimed to obtain an anthocyanin extract from the purple leaves of cv. Zijuan using a sustainable, non-toxic, and low-cost solid-liquid extraction, employing an aqueous citric acid solution (0.2 mol/L) as the extracting solvent, and to evaluate its chemical stability at different pH values, as well as its antioxidant properties in chemical and biological terms.

Effect of the type of brewing water on the sensory and physicochemical properties of light-scented and strong-scented 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 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 Ca, Mg).

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.

Advances in Tea Chemistry.

The origins of tea, a traditional beverage in China, can be traced back to the Shennong period, about 2737 years before the birth of Christ [...

Widely targeted metabolomics reveals the effect of different raw materials and drying methods on the quality of instant tea.

Introduction: Instant teas are particularly rich in tea polyphenols and caffeine and have great potential as food ingredients or additives to improve the quality of food and enhance their nutritional and commercial value.

Methods: To determine the relationships between raw material, drying method, and sensory and other quality attributes, instant teas were prepared from three tea varieties, namely black, green and jasmine tea, using two drying methods, namely spray-drying (SD) and freeze-drying (FD).

Results: Both the raw tea material and drying method influenced the quality of the finished instant teas.

Comparison analysis of full-spectrum metabolomics revealed on the variation of potential metabolites of unscented, scented, and Lour. scented black teas.

Introduction: In recent years, scented black tea has attracted much attention due to its pleasant floral aroma and mellow flavor, but little research has been carried out on its flavor metabolic profile.

Methods: In this study, the flavor metabolic profiles of unscented, scented, and Lour. scented black teas were investigated using full-spectrum metabolomics analysis method, the first time that the flavor profiles of scented black tea were characterized in detail.

Metabolite analysis and sensory evaluation reveal the effect of roasting on the characteristic flavor of large-leaf yellow tea.

Roasting is essential for processing large-leaf yellow tea (LYT). However, the effect of the roasting on the metabolic and sensory profiles of LYT remains unknown. Herein, the metabolomics and sensory quality of LYT at five roasting degrees were evaluated by liquid/gas chromatography mass spectrometry and quantitative descriptive analysis.