An efficient artificial intelligence algorithm for predicting the sensory quality of green and black teas based on the key chemical indices.

The key components dominating the quality of green tea and black tea are still unclear. Here, we respectively produced green and black teas in March and June, and investigated the correlations between sensory quality and chemical compositions of dry teas by multivariate statistics, bioinformatics and artificial intelligence algorithm. The key chemical indices were screened out to establish tea sensory quality-prediction models based on the result of OPLS-DA and random forest, namely 4 flavonol glycosides of green tea and 8 indices of black tea (4 pigments, epigallocatechin, kaempferol-3-O-rhamnosyl-glucoside, ratios of caffeine/total catechins and epi/non-epi catechins).

The light-harvesting chlorophyll a/b-binding proteins of photosystem II family members are responsible for temperature sensitivity and leaf color phenotype in albino tea plant.

Introduction: Light-harvesting chlorophyll a/b-binding (LHCB) protein complexes of photosystem II are integral to the formation of thylakoid structure and the photosynthetic process. They play an important role in photoprotection, a crucial process in leaf development under low-temperature stress. Nonetheless, potential key genes directly related to low-temperature response and albino phenotype have not been precisely identified in tea plant.

Widely targeted metabolomics analysis of white peony teas with different storage time and association with sensory attributes.

The sensory features of white peony teas (WPTs) significantly change with storage age; however, their comprehensive associations with composition are still unclear. This study aimed to clarify the sensory quality-related chemical changes in WPTs during storage. Liquid chromatography-tandem mass spectrometry based on widely targeted metabolomics analysis was performed on WPTs of 1-13 years storage ages.

Roasting process shaping the chemical profile of roasted green tea and the association with aroma features.

Roasting process impacts the chemical profile and aroma of roasted tea. To compare the impacts of far-infrared irradiation and drum roasting treatments (light, medium and heavy degrees), the corresponding roasted teas were prepared from steamed green tea for chemical analyses and quantitative descriptive analysis on aroma, and correlations between volatiles and aroma attributes were studied. There were 8 catechins, 13 flavonol glycosides and 105 volatiles quantified.

Simultaneous Preparation of Abundant Flavonol Triglycosides from Tea Leaves.

Flavonol glycosides are important components of tea leaves, contributing to the bioactivities as well as bitterness and astringency of tea. However, the standards of many flavonol triglycosides are still not available, which restricts both sensory and bioactivity studies on flavonol glycosides. In the present study, we established a simultaneous preparation method of seven flavonol triglycoside individuals from tea leaves, which consisted of two steps: polyamide column enrichment and preparative HPLC isolation.

Polyphenol oxidase dominates the conversions of flavonol glycosides in tea leaves.

Flavonol glycosides are associated with astringency and bitterness of teas. To clarify the dominant enzymatic reaction of flavonol glycosides in tea leaves, the catalytic effects of polyphenol oxidase (PPO), peroxidase (POD) and β-glucosidase were studied, with the maintaining rates of total flavonol glycosides (TFG) being 73.0%, 99.

Broccoli byproducts for protection and co-delivery of EGCG and tuna oil.

Neat epigallocatechin gallate (EGCG) has low bioavailability and tuna oil (TO) is prone to oxidation. Broccoli byproducts (BBP) were used for preparing TO-BBP (25% oil, dry basis) and TO-EGCG-BBP (20% oil and 20% EGCG, dry basis) powders. The gross composition and surface fat of powders and morphology of reconstituted emulsions were characterized.

The contribution ratio of various characteristic tea compounds in antioxidant capacity by DPPH assay.

Tea is a worldwide health beneficial beverage for its antioxidant ability. 1,1-diphenyl-2-picryl-hydrazyl (DPPH) assay is a common method to measure the antioxidant capacity of tea compounds, yet the contribution ratio of various characteristic tea compounds is still unclear. high-performance liquid chromatography (HPLC) was used to examine the content of polyphenol compounds in 24 tea samples from four tea categories (green tea, white tea, oolong tea, and black tea).

Oxidative stability of spray dried matcha-tuna oil powders.

Matcha-tuna oil and matcha-maltodextrin-tuna oil emulsions (25% oil, dry basis), formulated to have protein: carbohydrate ratios of 1:1.1, 1:2, 1:3 and 1:4, were spray dried. Confocal laser scanning microscopy showed effective emulsification of oil in all emulsions.

MicroRNAs and their targeted genes associated with phase changes of stem explants during tissue culture of tea plant.

Elucidation of the molecular mechanism related to the dedifferentiation and redifferentiation during tissue culture will be useful for optimizing regeneration system of tea plant. In this study, an integrated sRNAome and transcriptome analyses were carried out during phase changes of the stem explant culture. Among 198 miRNAs and 8001 predicted target genes, 178 differentially expressed miRNAs and 4264 potential targets were screened out from explants, primary calli, as well as regenerated roots and shoots.

Development of broccoli by-products as carriers for delivering EGCG.

Novel delivery systems for epigallocatechin gallate (EGCG) were developed using broccoli by-products and their fractions as carriers. Puree and pomace from broccoli by-products had higher adsorption capacities for EGCG than juice at 25 °C (43.20 mg g, 39.

Fermentation-based biotransformation of glucosinolates, phenolics and sugars in retorted broccoli puree by lactic acid bacteria.

This study investigated the effect of lactic acid bacteria (LAB) fermentation on the chemical profile of autoclaved broccoli puree, using 7 broccoli-derived LAB isolates (named F1-F5, BF1 and BF2). The total concentrations of glucosinolates (glucoiberin, progoitrin and glucoraphanin) and 10 major phenolics significantly increased from trace level and 289 μg total phenolics/g dry weight (DW) respectively in autoclaved broccoli to 55 to ∼359 μg/g DW and 903 to ∼3105 μg/g DW respectively in LAB fermented broccoli puree. Differential impacts of LAB isolates on the chemical composition of autoclaved broccoli were observed, with the major differences being the significant increase in phloretic acid after fermentation by F1-F5 and an elevated glucoraphanin level in ferments by F1 and BF2.

Analysis of Differentially Expressed Genes in Tissues of Camellia sinensis during Dedifferentiation and Root Redifferentiation.

Tissue culture is very important for identifying the gene function of Camellia sinensis (L.) and exploiting novel germplasm through transgenic technology. Regeneration system of tea plant has been explored but not been well established since the molecular mechanism of tea plant regeneration is not clear yet.

Formation mechanism of the oolong tea characteristic aroma during bruising and withering treatment.

To elucidate formation mechanism of oolong tea aroma, the released and remaining volatiles during bruising and withering treatment were analyzed using head space solid-phase microextraction/gas chromatography-mass spectrometry. An increase in proportion of the released terpenoid volatiles (TVs) along with a decrease in proportion of the released C green leaf volatiles (GLVs) was observed in both cultivars 'Zhejiang139' and 'Foshou'. Proportion of remaining TVs also fluctuated reversely with GLVs although the level of these volatiles increased remarkably.

Different Catabolism Pathways Triggered by Various Methylxanthines in Caffeine-Tolerant Bacterium CT25 Isolated from Tea Garden Soil.

The degradation efficiency and catabolism pathways of the different methylxanthines (MXs) in isolated caffeine-tolerant strain CT25 were comprehensively studied. The results showed that the degradation efficiency of various MXs varied with the number and position of the methyl groups on the molecule (, xanthine > 7-methylxanthine ≈ theobromine > caffeine > theophylline > 1-methylxanthine). Multiple MX catabolism pathways coexisted in strain CT25, and a different pathway would be triggered by various MXs.

Nano- and micro-particles for delivery of catechins: Physical and biological performance.

Catechins, present in many fruits and vegetables, have many health benefits, but they are prone to degradation. Nano- and micro-particle systems have been used to stabilise catechins when exposed to adverse environments and to improve their bioavailability after ingestion. This review discusses the inherent properties of various catechins, the design of delivery formulations and the properties of catechin-loaded nano- and micro-particles.

Binding of tea catechins to rice bran protein isolate: Interaction and protective effect during in vitro digestion.

Rice bran protein isolate (RBPI) was prepared from defatted rice bran and used to deliver tea catechins. RBPI had the high adsorption selectivity for tea catechins over caffeine. The adsorption characteristics of tea catechins onto RBPI were determined over a range of time (0-300min), concentration (0.

Differential behaviors of tea catechins under thermal processing: Formation of non-enzymatic oligomers.

Tea catechins as a member of flavan-3-ols subclass with the same skeleton may behave differentially. This study investigated the chemical conversions of 8 catechins under heat treatment with the involvement of epimerization, hydrolysis and oxidation/condensation reactions. Three reactions were enhanced as temperature increased from 30 °C to 90 °C.

Studies on the mechanism of efficient extraction of tea components by aqueous ethanol.

Effect of solvent on the extraction yield and its relevant mechanism have been studied in this paper. Compared with extraction by water, catechins and caffeine could be easily extracted from green tea by aqueous ethanol, but hardly at all by absolute ethanol. Results of the vacuum-assisted extraction, solubility determination of EGCG and caffeine, as well as swelling ratio analysis of the infused leaves, indicated that an excellent leaf-matrix-swelling effect and high solubility of tea components might be the key mechanisms for high extraction efficiency by the aqueous ethanol.

Photo-induced chemical reaction of trans-resveratrol.

Photo-induced chemical reaction of trans-resveratrol has been studied. UV B, liquid state and sufficient exposure time are essential conditions to the photochemical change of trans-resveratrol. Three principal compounds, cis-resveratrol, 2,4,6-phenanthrenetriol and 2-(4-hydroxyphenyl)-5,6-benzofurandione, were successively generated in the reaction solution of trans-resveratrol (0.

Protective effect of theaflavins on neuron against 6-hydroxydopamine-induced apoptosis in SH-SY5Y cells.

Theaflavins, the oxidation products of tea polyphenols are important biologically active components of black tea. 6-hydroxydopamine is a pro-parkinsonian neurotoxin. Theaflavins could inhibit the auto-oxidation of 6-hydroxydopamine in a dose-dependent manner from 0.

Adsorption behavior of the catechins and caffeine onto polyvinylpolypyrrolidone.

Adsorbent is one of the most important factors for separation efficiency in fixed-bed purification techniques. The adsorption behavior of catechins and caffeine onto polyvinylpolypyrrolidone (PVPP) was investigated by static adsorption tests. The results showed that catechins rather than caffeine were preferred to adsorb onto PVPP since the adsorption selectivity coefficient of total catechins vs caffeine was around 22.

Preparation of tea catechins using polyamide.

An adsorption separation method using Polyamide-6 (PA) as an adsorbent was developed to separate catechins from green tea extract. The adsorption capacity of total catechins for PA was 193.128 mg g⁻¹ with an adsorption selectivity coefficient K(A)(B) of total catechins over caffeine 21.