Catechin Content Research Articles

The avocado peel as a source of catechins: A comparison between extraction technologies and the influence of fruit variety

The bioactive components in agro-industrial wastes can be extracted to obtain compounds of industrial interest. The present study is focused on analyzing the composition of avocado peel extracts obtained by solvent extraction, ultrasound, and supercritical fluids by two varieties of avocado. As a result, differences in the composition of avocado peels and the yields presented in the extraction processes are evidenced. The solvent in the extractions strongly affected the active constituents' content and their antioxidant activities. The highest recovery of catechins is presented with ethanol at 50% v/v. Extraction with supercritical fluids increased the extraction yield to 17.14% w/w for the Hass variety and 14.20% w/w for the Lorena variety. However, in the case of the Lorena variety, supercritical fluids decreased the concentration of catechins. For the Lorena variety, ultrasound favored the extraction of catechins. The highest catechin concentrations corresponded to 151.96 mg of epicatechin and 60.77 mg of catechin per 100 g of Hass variety. The conditions that improved the extraction were 60 °C, 60 min, 0.2 mg/L (mg avocado peel per liter of solvent), and a frequency of 30 kHz. Avocado peel variety Lorena presented the highest concentrations of catechins under the same conditions (269.37 mg of epicatechin and 119.88 mg of catechin per 100 g of peel). The economic study showed better economic indicators for the Hass variety than the Lorena variety by the difference in extraction yields. The minimum production cost of the extract was 8.21 USD/kg using solvent extraction. From a technical point of view, this work made it possible to demonstrate the potential of avocado peels to obtain catechins, especially when ultrasound extractions are used. However, from an economic point of view, conventional techniques such as solvent extraction are recommended to extract flavonoids such as catechins.

The manufacturing process provides green teas with differentiated nonvolatile profiles and influences the deterioration of flavor during storage at room temperature

Hundreds of green tea products are available on the tea market and exhibit different characteristics. In the present study, seven types of green tea were processed, and their nonvolatile profiles were analyzed by liquid chromatography–mass spectrometry. Non-spreading green tea contained higher concentrations of catechins and flavonoid glycosides, but lower concentrations of amino acids, caffeine, and theaflavins. Non-rolling green teas with a straight appearance contained higher concentrations of flavonoid glycosides and theaflavins. In contrast, leaf-rolling green teas contained much lower concentrations of flavonoid glycosides and catechins. These seven green tea qualities all decreased following prolonged storage, concurrent with increasing concentrations of proanthocyanidins, catechins dimers, theaflavins, and organic acids. The leaf-rolling green teas exhibited reduced levels of deterioration during storage in terms of their nonvolatile profile and sensory quality. Findings show that moderate destruction on tea leaves during green tea processing is beneficial to both tea flavor and quality maintenance during storage.

Combined metabolome and transcriptome analyses reveal that growing under Red shade affects secondary metabolite content in Huangjinya green tea.

Shading treatments impact the tea (Camellia sinensis L.) quality. The sunlight sensitive varieties can be grown under shading nets for better growth and secondary metabolite content. Here, we studied the responses of a sunlight sensitive green tea variety "Huangjinya" by growing under colored shading nets (red, yellow, blue, and black (75% and 95%) shading rates) to find out the most suitable color of the shading net. Red shading was the most promising treatment as it positively affected the weight and length of 100 one-bud-three leaves and reduced the degree and rate of new shoots burn compared to control (natural sunlight). We then explored the comparative metabolomic changes in response to red shading by using UPLC-ESI-MS/MS system. The amino acids and derivatives, flavonoids, and alkaloids were downaccumulated whereas lipids, organic acids, and lignans were upaccumulated in Red shade grown tea samples. The red shading nets caused a decreased catechin, epicatechin, dopamine, and L-tyramine contents but increased caffeine content. We then employed transcriptome sequencing to find key changes in expressions of related genes and pathways. Notably, key genes associated with the phenylpropanoid and flavonoid biosynthesis pathways exhibited complex regulation. These expression changes suggested a potential trend of polymerization or condensation of simple molecules like catechin or pelargonidin into larger molecules like glucoside or proanthocyanidins. Here, Red shading net triggered higher expression of genes enriched in lipid biosynthesis and jasmonic acid biosynthesis, suggesting an interplay of fatty acids and JA in improving tea performance. These findings contribute to the metabolic responses of Huangjinya tea to red shading nets which might have implications for flavor and health benefits. Our data provide a foundation for further exploration and optimization of cultivation practices for this unique tea variety.

Genotypic identification and catechin profiling of Uncaria gambir in West Sumatra, Indonesia

Abstract. Wardi ES, Syukur S, Chaidir Z, Jamsari J. 2024. Genotypic identification and catechin profiling of Uncaria gambir in West Sumatra, Indonesia. Biodiversitas 25: 1151-1158. The primary objective of this study is to assess genetic and chemical variability among four genotypes of Uncaria gambir cultivated in West Sumatra. Uncaria gambir is native to Indonesia, widely cultivated in West Sumatra, used as an herbal remedy, and become a significant agricultural product for Indonesian export with catechin content as a standard. The phytochemical components of this species have been extensively studied, and its extracts are employed in traditional medicine. To fingerprint genomic DNA, we employed three pairs of Specific Sequence-Related Amplified Polymorphism (SRAP) markers selected from 29 combinations tested. A total of 150 amplified bands were generated, highlighting substantial genetic variability among the tested genotypes. Notably, the highest amplified and polymorphic band was obtained with primer E combination from three selected primers (primer E, primer F, and primer T). In addition, only catechins were identified among the four types of catechins employed as HPLC standards. We detected varying catechin concentrations among the genotypes, with genotype Mancik exhibiting the highest concentration. This finding underscores the potential for genotype-specific bioactive marker identification within U. gambir. In addition, this study shows the efficiency of SRAP markers in genotype identification within U. gambir. Furthermore, the identification of catechin as a prominent bioactive marker emphasizes its significance for further exploration and conservation efforts.

Effect of different extraction solvents on bioactive phenolics and antioxidant potential of Illicium griffithii fruit

The fruits of Illicium griffithii are of medicinal and economic importance. In this study, five solvents viz. methanol, ethanol, acetone, ethyl acetate and water at 20–100% concentration analyzed for phenolic content (TPC and TFC) and antioxidant activities (DPPH and ABTS) of I. griffithii fruit. TPC was highest (40.06±0.48 mg GAE/g dw) in 80% MeOH, and TFC was highest (6.58±0.12 mg QE/g dw) in 100% EtOAc extracts. The antioxidant activities were higher in extract(s) with 100% of each solvent (93.35–94.27% inhibition) and highest in 100% EtOAc extracts. A total of 7 phenolic compounds, viz. gallic acid, catechin, chlorogenic acid, p-hydroxybenzoic acid, vanillic acid, ferulic acid, and phloridzin, were identified in different solvent extracts. 100% MeOH extracted the highest content of gallic acid (2.54 mg/g) and catechin (2.59 mg/g). The ATR-FTIR spectra showed the presence of aliphatic, aromatic, and phenolic groups. The TGA analysis exposed volatile matter, cellulose, hemicellulose, and lignin content. The FESEM analysis also revealed the morphological changes in treated samples. The extraction efficacy of phenolic compounds was better in extracts with higher concentration of solvents (60% −100%). The fruit is a rich source of phenolics and antioxidants; thus, it can provide multiple industrial benefits.

Exploitation of Catechin Extract from Pruned Tea Leaves as a Promising Food Preservative Against Lipid Oxidation

In Vietnam, a tea-producing country, the tea buds and top three leaves are normally used for tea production while older leaves are pruned and discarded as agricultural waste in the winter. The present study aimed to exploit catechins from pruned tea leaves and use them as natural antioxidants for applications in the food industry. Catechins were analyzed using the guideline of ISO 14502-2-2005 by HPLC-MWD. The contents of catechins in pruned tea leaves of ten popular tea varieties were relatively high, ranging from 65.57 to 136.88 mg/g dry weight. The optimized conditions for catechin extraction from Phuc Van Tien pruned tea leaves (one of the varieties with a high catechin content) were found using response surface methodology as follows: a liquid-to-solid ratio of 21.6/1 at 70oC for 31 minutes. The catechin-rich extract powder was added to sesame oil to inhibit lipid oxidation. During oil accelerated oxidation at 60oC, the catechin-rich extract powder inhibited the increase of the peroxide value compared with the negative and positive controls (no preservative and added tert-butylhydroquinone, respectively). Significant positive correlations between the decrease of catechin content and the inhibition of peroxide formation (r = 0.91, 0.94, 0.95, 0.97, and 0.96 for catechin, epigallocatechin gallate, epigallocatechin, epicatechin gallate, and epicatechin, respectively, P <0.05) proved that the inhibition of peroxide formation in the sesame oil was essentially due to the antioxidant capacity of the catechins in the pruned tea leaf extract. Catechin extracts from pruned tea leaves are potential sources of natural antioxidants for oil preservation.

DEVELOPMENT OF NEW TYPES OF TEA DRINKS WITH TARGETED PREVENTIVE PROPERTIES

Recently, interest in the production of tea and tea drinks has increased due to its nutritional and medicinal properties. The composition of tea is complex and is still not fully understood. Therefore, the development of new technology of tea and functional tea drinks opens a unique opportunity for domestic manufacturer to produce competitive products.In this study the technology of three types of tea drinks based on raw components of fruits, berries and medicinal plants «Antioxidant», «Immunostimulating», «Cardiovascular» with targeted preventive properties was developed, where the physicochemical, mineral composition and organoleptic parameters were studied.The results of the analysis showed that the highest concentrations of vitamin C (mg/100 g) were found in sea buckthorn fruits (215.7±18.4), black currant fruits (196.5±14.3), melissa leaves (100.1±9.9), lemon peel (90.5±8.4) and Goji berries (49.5±3.8). High β-carotene content (mg/100 g) was observed in Goji berries, lemon balm leaves and sea buckthorn fruits – 91.3±7.6; 47.2±3.6 and 33.7±2.9 mg/100 g, respectively. In addition, fruits, berries and medicinal plants selected as raw components had high levels of flavonoids, xanthophylls, tocopherols, phenolic compounds and other biologically active substances. Cranberry berries (44.8±3.2), Goji berries (31.0±2.6), black tea leaves (25.4±1.9), black currant fruits (21.6±1.2) and peppermint leaves (15.2±1.1) had high levels of total antioxidants (mg/100 g) due to the increased content of catechins, anthocyanins, carotenoids, vitamin C, tannin and bioflavonoids, contributing to the reduction of oxidative stress and protecting cells from the destructive effects of free radicals. Prophylactic tea blends have been studied and shown to have high taste, fine exquisite aroma and actively stimulating and therapeutic properties, according to the created formulations, taking into account antioxidant immunostimulating activity.

Tea plant β-1, 4-glucanase enhances the propagation of Camellia tachangensis F. C. Zhang by promoting graft wound healing

As a precious tea genetic resource in China, the ancient tea plant has a strong stress resistance and contains specific biochemical components. However, the ancient tea plant resources are vulnerable to human destruction and overuse. To better protect and utilize the individual resources of these ancient tea plants, Camellia tachangensis (Camellia tachangensis F. C. Zhang) was selected as the research object in this study, and it was grafted onto the rootstock of a cultivated tea plant (Fudingdabai) for breeding. As a glycosyl hydrolase, β-1, 4-glucanase plays a role in promoting graft wound healing in plant grafting, and can effectively break the incompatibility between different species. Therefore, a gene encoding β-1, 4 glucanase was cloned from the tea plant with a total length of 1578 bp and encodes 525 amino acids, and its expression is highest in the young leaves of the tea plant, followed by the stem. A large amount of purified β-1, 4 glucanase was obtained by yeast expression. Further analysis of this protein demonstrated that it could promote the healing of the grafted wound of Camellia tachangensis, thereby improving the grafting survival rate of Camellia tachangensis. The total catechin content, catechin index and theanine content of Camellia tachangensis after grafting with β-1,4 glucanase had no significant change compared with the no-enzyme group, and these quality components were significantly increased compared with the self-grafting of Camellia tachangensis, indicating that the quality of Camellia tachangensis could be improved by grafting with Fudingdabai as rootstock, and the use of β-1,4 glucanase not only improved the survival rate of grafted plants, but had little effect on the quality of Camellia tachangensis. In summary, in this study, a gene encoding β-1,4 glucanase was cloned from tea plant, and a large amount of purified β-1,4 glucanase was obtained. The quality and survival rate of Camellia tachangensis were improved after application of β-1,4 glucanase for grafting. This work provides new insights for the propagation of ancient tea plants.

Tea (Camellia sinensis) cultivated in three agro-ecological regions of Bangladesh: Unveiling the variability of methylxanthine, bioactive phenolic compound, and antioxidant activity

Tea (Camellia sinensis) is a widely consumed beverage known for its numerous health benefits, largely attributed to its rich content of quality determining secondary metabolites such as methylxanthine compounds and bioactive phenolic compounds. The goal of this study was to find out variations of the levels of methylxanthines, bioactive phenolic compounds, and antioxidant activity in methanolic and hot water extracts of 129 tea samples grown in three different ecological regions of Bangladesh named Panchagar, Sylhet, and Chattogram. Methylxanthine and bioactive phenolic compounds were determined by using HPLC-DAD, and the antioxidant profile was analysed by UV–vis spectrophotometric methods for methanol and hot water extracts of tea leaves. The IC50 values showed the trend as Panchagar > Sylhet > Chattogram and Sylhet > Chattogram > Panchagar for water and methanol extract, respectively. The results revealed significant (p < 0.05) variations in the levels of methylxanthines content: Panchagar > Chattogram > Sylhet. Caffeine was significantly higher (103.02 ± 5.55 mg/g of dry extract) in the methanolic extract of tea leaves of Panchagar district and lower (53.33 ± 4.30 mg/g of dry extract) in the hot water extract of Sylhet district. Panchagar and Chattogram possessed significantly (p < 0.05) higher catechin content for methanol (57.01 ± 5.50 mg/g dry extract) and hot water (55.23 ± 4.11 mg/g dry extract) extracts, respectively. The utilization of canonical discriminant functions yielded highly favorable outcomes in the classification of tea from three distinct cultivation origins in Bangladesh, relying on their inherent features. This study demonstrated the potential effects of geographical variations on the bioactive compounds and antioxidant properties of tea, emphasizing the importance of regional differences in tea cultivation for optimizing its health benefits as well as dispersing tea cultivation across the country.

ВЛИЯНИЕ МИКРООКСИДАЦИИ МЕЗГИ НА ХИМИЧЕСКИЕ И ОРГАНОЛЕПТИЧЕСКИЕ ПОКАЗАТЕЛИ КРАСНЫХ ВИН

An urgent problem in modern wine-making is to ensure long-term preservation of the color of red wine, including when it is stored in bottles. The problem is associated with the oxidation of phenolic substances under the influence of oxygen. One of the ways to prevent oxidation is the use of microoxidation – introducing a certain amount of oxygen in order to oxidize labile fractions of polyphenols at an early stage of the wine production process. However, oxygen dosages require clarification and further research. The purpose of the research is to study the effect of microoxidation with various doses of oxygen on physical and chemical parameters, including the mass concentration of phenolic substances, of wine materials from the Cabernet Sauvignon grape variety. The objects of the study were production and experimental batches of wines made from the Cabernet Sauvignon grape variety. The oxygen dosage varied from 2 to 10 mg/dm3 . A significant difference in the mass concentration of oxygen in industrial samples was established – from 0.5 to 4.3 mg/dm3 . A correlation was revealed between the color of the wine and the oxygen content: the test samples with the highest mass concentration of oxygen had garnet-red shades of color. It was shown that the concentration of all groups of phenolic substances depended on the location of the grapes and the wine producer. The greatest accumulation of the amount of phenolic substances was in wine produced in the geographical area of Novorossiysk. A general trend of changes in the concentration of various groups of phenolic compounds depending on the dosage of oxygen was revealed: with an increase in the dosage of oxygen, the concentration of the components of the phenolic complex decreases, with anthocyanins undergoing the greatest change. The concentration of catechins decreased gradually with increasing oxygen dosage. For procyandins, dosing 2-4 mg/dm3 immediately led to a decrease in their concentration by 10-15 %. A further increase in the oxygen dosage did not cause a change in the concentration of procyanidins. It has been proven that an oxygen dosage of 2-4 mg/dm3 ensures high organoleptic properties of red wine. Key words: RED WINES, PHENOLIC COMPOUNDS, MICROOXIDATION, OXIDATION, ORGANOLEPTIC EVALUATION

The effect of maturity of tea leaves and processing methods on the formation of milky flavor in white tea - A metabolomic study

Targeted metabolomics combined with chemometrics were applied to investigate the flavor profiles of 4 white tea samples, which were produced from different maturity fresh tea leaves with different withering methods. Mature leaves that underwent novel withering process at higher temperature (28-30℃) and humidity (75 ± 3 %) (MN) were characterized by intense milky flavor. The content of free amino acids, catechins, and soluble sugars in MN were significantly lower than that in the other 3 tea samples, resulting in a sweet and mellow taste with low bitterness. Meanwhile, MN possessed the highest intensity of milky aroma, which could be mainly attributed to the existence of dihydro-5-pentyl-2(3H)-furanone and 2-pentyl-furan as the key volatile substances with coconut and creamy fragrance. These findings provide insight into the substance foundations of milky flavor, and identified leaf maturity and processing method as the determining factors of the milk-flavored white tea (MFWT).

The effect of pressure on degradation kinetics of polyphenols: Impact of polyphenol structure at hyperbaric storage conditions

Understanding reaction kinetics at elevated pressures is essential for developing efficient pressure-based technologies. It is especially vital for hyperbaric storage (HS), where pressure is applied for long durations. In single and multi-component models, the influence of pressure on the degradation kinetics of different catechins and anthocyanins was studied at accelerated conditions using neutral pH at pressures up to 200 MPa (HS levels) for several hours. In the neutral baroresistant buffer, pressure enhanced the degradation of all tested flavonoids with a negative activation volume. Despite the significant structural variety and major differences in the degradation rates within each tested subgroup, no significant structure-dependent effect of pressure on the activation volume was observed, which is suggestive of a similar mechanism by which pressure accelerates the degradation. The antioxidant capacity of catechins was not affected by pressure compared to control samples when the concentration of the original catechin was similar. Industrial relevanceA better understanding of pressure effects on the degradation reaction kinetics of food components can contribute to the general understanding of mechanisms related to food component degradation under high-pressure treatments. Plant-based foods are rich in polyphenolic compounds and responsible for sensory characteristics and their related health-promoting properties. In conditions similar to HS, that are known to inhibit and even, in some cases, inactivate microorganisms, when food is exposed to high pressures for a long time, it is imperative to investigate the effect of pressure on polyphenol degradation kinetics, which can lead to differences in the polyphenol compositions during the pressurized storage. However, the impact of pressure on polyphenol degradation kinetics is often overlooked. This study provides fundamental information regarding the polyphenol structure-dependent degradation kinetics of catechins and anthocyanins under pressure while taking into account the often overlooked pressure-induced pH shifts. The presented work can promote the development of novel storage and processing technologies based on high pressure that will better preserve oxidation-liable compounds with lower energetic costs.

Quality analysis and antioxidant activity of different types of tea powder

As a natural product with health benefits, tea powder (TP) is widely used in food processing field. In order to explore sensory evaluation, quality components and antioxidant activities among different types of TP, matcha TP, Huangjinya green TP, oolong TP, black TP and Pu-erh TP were used as the research objects. Our results showed that total scores of sensory evaluation of unfermented TPs were higher than those of fermented TPs, whilst the colour of those unfermented TPs was more bright. Furthermore, taste attributes showed that sweetness was conducive to the formation of the taste of black TP, and aftertaste-bitterness was beneficial to matcha and Pu-erh TP. Umami was suggested as a vital contributing factor to the mellow taste of Huangjinya green TP, while sourness and bitterness were not propitious to form the taste quality of tea powder. The non-volatile quality components analysis revealed that tea powders with more fermentation usually contained fewer amino acids and catechins, but glutamate and gamma-aminobutyric acid were higher in black TP than in oolong TP. Theanine, glutamic acid and arginine were the main iconic components affecting the amino acid composition of different types of tea powder in our study. Meanwhile, the contents of ester catechins (ECG, EGC, EGCG) in black TP and Pu-erh TP were significantly lower than those in green TP and oolong TP. In addition, the free radical scavenging ability of unfermented TPs were stronger than that of fermented TPs. Therefore, to maximize the health benefits and sensory attributes of different types of TP, the use of unfermented tea powder is recommended. However, different manufacturing process of tea powder can enrich the taste of tea foods, thus giving people more choices.Graphical

A novel optimized eco-friendly simple spectrofluorimetric method for the determination of total catechins in green tea extract: Application to commercial tablet.

Green tea extract (GTE) contains antioxidants that are present in green tea. The active constituents of green tea extract are catechins. This study demonstrates a spectrofluorimetric method for measuring GTE's catechin concentration based on its native fluorescence. To design a quick, sensitive, and ecological spectrofluorimetric approach, all features were investigated and adjusted. This method relies on determining the GTE ethanolic solution's native fluorescence at 312 nm after excitation at 227 nm. The calibration graph displayed a linear regression for values between 0.05 and 1.0μg mL-1. The detection and quantification limits of the proposed technique were 0.008 and 0.026 μg mL-1, respectively. Two pure catechins present in GTE, (-)-epicatechin and (-)-epigallocatechin gallate, were examined by the proposed method. The analytical estimation of GTE in the pharmaceutical tablet was achieved effectively using this approach. An adequate degree of agreement was found when the findings were compared to those obtained by the comparative technique. Therefore, the novel strategy may be used in the GTE quality control study with minimal risks to people or the environment. The quantum yields of catechins were estimated. The validated technique was accepted by the International Council of Harmonization criteria.

Determination of Catechin Content in Green and Black Tea (Camellia sinensis L.) by UV-Vis Spectrophotometric Method

Tea is one of the most commonly consumed beverages around the world. The chemical compounds contained in tea have a good effect on health because they contain polyphenolic compounds, catechins. This study examined the catechin compound content of black tea and green tea from Karanganyar (A) and Malang (B). This research aims to determine the differences in catechin levels in black and green tea types in Malang, East Java, and Karanganyar, Central Java plantations. The research method used was experimental. Identification of catechin content was done using UV-Vis Spectrophotometry method. Tea is extracted by brewing, 4 grams of green tea is brewed using distilled water for 6 minutes, while 5.6 grams of black tea is brewed using distilled water for 10 minutes with the comparison used is pure catechin solution. The results obtained for green tea Karanganyar (A) had a catechin content of 3.61±0.083%, green tea Malang (B) had a level of 2.97±0.037%, black tea Karanganyar (A) had a level of 3.14±0.065%, and black tea Malang (B) had a level of 1.60±0.009%. It is concluded that the catechin content of green tea is higher than black tea, and of the two samples, the high catechin content comes from Karanganyar (A). Keywords: catechins, green tea, black tea, malang, karanganyar

Effects of Postharvest Storage Temperature on Physical Characteristic, Phenolic Compounds, and Antioxidant Activity of Cocoa Pod Husk

Cocoa pod husk (CPH) is a good source of bioactive components such as phenolic compounds, which are known to have potential as antioxidants. Research on the effects of postharvest storage conditions on bioactive compounds of CPH is still limited. Therefore, this study aimed to evaluate the impact of postharvest storage temperature (20, 30, and 40 °C) and time on the physical characteristics, phenolic compounds, and antioxidants of CPH. The results indicated that storage for nine days reduced the color and moisture content of CPH while the texture hardened (especially at 20 and 40 °C). Total phenolic compounds (TPC) increased to 97.9% when CPH was stored at 20 °C for nine days, which was associated with an increase in catechin content and antioxidant activity. The first-order kinetic model was suitable for predicting the kinetics of changes in color, moisture content, hardness, TPC, and DPPH. The calculated Ea values indicated that the storage temperature caused the color of CPH to change easily to brown and the catechin and caffeic acid compounds to form easily. Overall, it is better to store CPH at 20 °C for nine days to increase the quality.

Preparation and Physicochemical Analysis of Camellia sinensis cv. 'Ziyan' Anthocyanin Microcapsules.

The new tea cultivar Ziyan has a high content of anthocyanin and ester catechins in the raw material, but the conventional processing and application methods are limited. To explore its application potential, the freeze-drying method was used to prepare microcapsules with an embedding time of 30 min, solid content of 30%, and core to wall ratio of 1:10 (g/g). The anthocyanin recovery was 95.94 ± 0.50%, and the encapsulation efficiency was 96.15 ± 0.11%. The stability of microcapsules and composite wall materials was evaluated in the simulation system. Results showed that microcapsules employing a maltodextrin-gum arabic ratio of 2:8 (w/w) as the wall material significantly reduced degradation rates, extending anthocyanin half-life under various storage conditions. Characterization indicated improved physical properties of Ziyan anthocyanin powder post-microencapsulation. FT-IR and DSC- revealed the formation of a new phase between anthocyanins and wall materials, leading to increased enthalpy and enhanced thermal stability. The microencapsulation results of this experiment proved that the storage stability of anthocyanin was effectively enhanced.

Identification, anti-Alzheimer's disease and antiaging activities of cinnamoylated flavoalkaloids from green tea

Tea catechins are important functional and taste ingredients. The limit content of new tea catechins restricts their identification and utilization. This study proposed a new strategy including construction of tea component transformation networks (TCTN), speculation of new molecules by LC-ESI-HRMS/MS detection, and synthetic verification to address this problem. The new precursor ion 546.1749 [M-H]- detected in Yingde green tea proposed the presence of a new cinnamoylated flavoalkaloid possibly derived from theanine, p-hydroxycinnamic acid, and epicatechin through nucleophilic reaction. We thus synthesized the molecule and purified three isomers (1–3) with the same molecular weight at 547. Compounds 1–3 are widely present in 18 different cultivars of green tea by targeted LC-ESI-HRMS/MS detection. Meanwhile, 1 and 2 (50 μM) showed anti-Alzheimer's disease (anti-AD) potentials using the transgenic CL4176 strain of Caenorhabditis elegans (C. elegans). Notably, 2 (200 μM) strikingly prolonged the lifespan of wild type C. elegans by 66%. This study demonstrates that the TCTN strategy can guide us to find new molecules from tea and the potential anti-AD and antiaging values of cinnamoylated flavoalkaloids.

Differences and distribution of quality components in Fu brick tea around fungal fermentation

The differences in and distributions of the quality components of Fu brick tea before and after flowering (also called fungal fermentation and known as “Fahua” in China) remain unclear, and the standard of judging quality by the number of golden flowers (GFs; yellow closed capsules of Eurotium cristatum spores) by consumers lacks a scientific foundation. In this study, Fu brick tea (AFT) was obtained from pre-flower raw dark tea (BFT) through the traditional processing of Fu brick tea. The AFT was then hand-selected and divided into pure tea (SFT) and GFs. It was found that the flavonoid, tea polyphenol, free amino acid, aqueous extract, and ester-type catechin content in the AFT were all significantly lower than in the BFT (p < 0.05); the content of 34 types of volatile compound was significantly higher (26 alkanes, 4 alkenes, 2 alcohols, 1 ester, 1 aldehyde) (p < 0.05), and the content of 14 types of volatile compound was significantly lower (6 alkanes, 4 alcohols, 2 esters, 1 ketone, 1 alkene) than in the BFT (p < 0.05). Furthermore, the content of 39 types of nonvolatile substances, including four carboxylic acids, three flavonoids, and D-Arabitol, amino acids and their derivatives, was significantly higher in the AFT (p < 0.05). The content of flavonoids and their derivatives, including 24 types of saturated alkanes and seven types of aldehydes and esters of volatile compounds (3 alkenes, 2 alcohols, 1 ester, and 1 aldehyde) (p < 0.05), was significantly higher in the SFT than in the GFs (p < 0.05). The GFs had significantly higher content of water-soluble leachate, maltose, glycosylated flavonoids, D-salicylose, and amino acids and their derivatives than the SFT (p < 0.05). Widdrol, linalool, N-octanal, and 25 other volatile compounds (9 alkenes, 9alcohols, s aldehydes, 1 ester, 1 alkane, 1 ketone, 1 Naphthalene) were detected only in the GFs.

Mechanisms underlying the effect of walnut pellicle extracts and its four representative polyphenols on in vitro digestion of walnut protein isolate

Walnut pellicle extracts (WPE) is rich in phenolic acids. The effects of WPE and its monomeric phenolics (ellagic acid (EA), (+)-catechin (CA), chlorogenic acid (CLA), and epigallocatechin gallate (EGCG)) on in vitro digestion of walnut protein isolate (WPI) were studied. The underlying mechanisms on WPI enzymatic digestion through WPE and pure phenolic compounds with digestive enzymes (pepsin and trypsin) therein using Michaelis-Menten kinetics, fluorescence quenching, molecules docking, and surface plasmon resonance (SPR). The in vitro digestibility of WPI decreased significantly by the addition of WPE. WPE had the strong inhibitory effect on WPI digestion and pepsin and trypsin activities. The effects of polyphenols on WPI digestibility were mainly manifested in the interaction between polyphenols and digestive enzymes. SPR as well as fluorescence quenching indicated that WPE bound to pepsin and trypsin was the strongest. Among the four phenolic compounds abundant in the tested WPE, EGCG inhibited pepsin and trypsin more strongly than the other three compounds. SPR showed that EGCG was bound more tightly to pepsin and trypsin than CLA, CA, and EA. In vitro WPI digestion was strongly inhibited by WPE, mainly due to its high content of EGCG, CLA, CA, and EA causing strong inhibition of pepsin and trypsin. The study investigated the influence of plant protein by phenolic acids in the human digestive system and providing a theoretical basis for the processing and manufacturing of polyphenol-rich nut-based functional foods.