Green tea catechins during food processing and storage: A review on stability and detection

Opportunities and challenges for the nanodelivery of green tea catechins in functional foods

Green tea, the least processed tea product, is scientifically known for its rich antioxidant content originating from polyphenols, especially catechins. The most potent green tea catechin is epigallocatechin-3-gallate (EGCG), which is responsible for a wide range of health benefits including anticancer, antidiabetics, and anti-inflammatory properties. However, green tea catechins (GTCs) are very labile under both environmental and gastrointestinal conditions; their chemical stability and bioavailability primarily depend on the processing and formulation conditions. Nanocarriers can protect GTCs against such conditions, and consequently, can be applicable for designing nanodelivery systems suitable for GTCs. In this review, the latest findings about both opportunities and limitations for the nanodelivery of GTCs and their incorporation into various functional food products are discussed. The scientific findings so far confirm that nanodelivery of GTCs can be an efficient approach towards the enhancement of their health-promoting effects with a minimal dose, controlled and targeted release, lessening the dose-related toxicity, and the efficient incorporation into functional foods. However, further investigation is yet needed to fully explain the cellular mechanisms of action of GTCs on human health and to elucidate the effect of encapsulation on their bioefficacy using well-designed, systematic, long-term, and large-scale clinical interventions. There also exists a substantial concern regarding the safety of the manufactured nanoparticles, their absorption, and the associated release mechanisms.

Catechins as Model Bioactive Compounds for Biomedical Applications

Research regarding polyphenols has gained prominence over the years because of their potential as pharmacological nutrients. Most polyphenols are flavanols, commonly known as catechins, which are present in high amounts in green tea. Catechins are promising candidates in the field of biomedicine. The health benefits of catechins, notably their antioxidant effects, are related to their chemical structure and the total number of hydroxyl groups. In addition, catechins possess strong activities against several pathogens, including bacteria, viruses, parasites, and fungi. One major limitation of these compounds is low bioavailability. Catechins are poorly absorbed by intestinal barriers. Some protective mechanisms may be required to maintain or even increase the stability and bioavailability of these molecules within living organisms. Moreover, novel delivery systems, such as scaffolds, fibers, sponges, and capsules, have been proposed. This review focuses on the unique structures and bioactive properties of catechins and their role in inflammatory responses as well as provides a perspective on their use in future human health applications.

Bud-Derivatives, a Novel Source of Polyphenols and How Different Extraction Processes Affect Their Composition

The use of herbal food supplements, as a concentrate form of vegetable extracts, increased so much over the past years to count them among the relevant sources of dietetic polyphenols. Bud-derivatives are a category of botanicals perceived as a "new entry" in this sector since they are still poorly studied. Due to the lack of a manufacturing process specification, very different products can be found on the market in terms of their polyphenolic profile depending on the experimental conditions of manufacturing. In this research two different manufacturing processes, using two different protocols, and eight species (Carpinus betulus L., Cornus mas L., Ficus carica L., Fraxinus excelsior L., Larix decidua Mill., Pinus montana Mill., Quercus petraea (Matt.) Liebl., Tilia tomentosa Moench), commonly used to produce bud-derivatives, have been considered as a case study. An untargeted spectroscopic fingerprint of the extracts, coupled to chemometrics, provide to be a useful tool to identify these botanicals. The targeted phytochemical fingerprint by HPLC provided a screening of the main bud-derivatives polyphenolic classes highlighting a high variability depending on both method and protocol used. Nevertheless, ultrasonic extraction proved to be less sensitive to the different extraction protocols than conventional maceration regarding the extract polyphenolic profile.

Investigation on green tea lipids and their metabolic variations during manufacturing by nontargeted lipidomics

Lipids are hydrophobic metabolites implicated in tea flavor quality. Understanding their transformations during tea manufacture is of particular interest. To date, the detailed lipid composition and variations during green tea manufacture are largely unknown. Herein, we performed a comprehensive characterization of the dynamic changes of lipids during green tea manufacture, by applying nontargeted lipidomics using ultrahigh performance liquid chromatography-quadrupole-Orbitrap mass spectrometry (UHPLC-Q-Exactive/MS) combined with chemometric tools. Totally, 283 lipid species were detected, covering 20 subclasses. Significant lipidomic variations were observed during green tea manufacture, especially in the fixation stage, mainly associated with chlorophyll decomposition, phosphatidic acids (PAs) reduction and glycolipids degradation, which potentially contribute to tea color and aroma quality. Specifically, the most prominent decrease of PAs content during green tea manufacture was identified for the first time. This study provides insights into the lipid metabolic fates upon green tea manufacture, and their roles in green tea sensory quality.

Effect of processing on polyphenol profile, aflatoxin concentration and allergenicity of peanuts

Worldwide peanuts are often thermally processed before consumption, which might alter its bioactive composition and toxicity. The presented work explores the effect of processing methods such as roasting, frying, and pressure cooking on the bioactive composition, polyphenol profiles, aflatoxin concentration and, allergenicity response of peanuts. Effect of processing methods was assessed by monitoring total polyphenol content (TPC), total flavonoid content (TFC), antioxidant activity by DPPH & ABTS radicals, sensory analysis and, indirect ELISA. Compared to raw peanuts, all processing methods caused significant differences in TPC, TFC, DPPH & ABTS radical scavenging activities. Comparison of polyphenol profiles of raw to processed peanuts by LC-ESI-Q-TOF-MS chromatograms revealed different effects on concentrations of individual bioactive polyphenols. Indirect ELISA showed a significant decrease in the assay response on pressure cooking as compared to other samples. Total aflatoxin concentration was significantly reduced after processing in roasted (97.7%) and fried (98.3%) peanuts. Optimum processing conditions based on bioactive concentration and sensory analysis were found to be, roasting: 150 °C for 10 min, frying: 170 °C for 2 min and, pressure cooking: 15 min. Polyphenol profiles and bioactive constituents of peanuts were influenced by processing and may alter health benefits associated with them hence, vital for research and food industry applications.

Noncovalent Complexes of Cyclodextrin with Small Organic Molecules: Applications and Insights into Host-Guest Interactions in the Gas Phase and Condensed Phase

Cyclodextrins (CDs) have drawn a lot of attention from the scientific communities as a model system for host–guest chemistry and also due to its variety of applications in the pharmaceutical, cosmetic, food, textile, separation science, and essential oil industries. The formation of the inclusion complexes enables these applications in the condensed phases, which have been confirmed by nuclear magnetic resonance (NMR) spectroscopy, X-ray crystallography, and other methodologies. The advent of soft ionization techniques that can transfer the solution-phase noncovalent complexes to the gas phase has allowed for extensive examination of these complexes and provides valuable insight into the principles governing the formation of gaseous noncovalent complexes. As for the CDs’ host–guest chemistry in the gas phase, there has been a controversial issue as to whether noncovalent complexes are inclusion conformers reflecting the solution-phase structure of the complex or not. In this review, the basic principles governing CD’s host–guest complex formation will be described. Applications and structures of CDs in the condensed phases will also be presented. More importantly, the experimental and theoretical evidence supporting the two opposing views for the CD–guest structures in the gas phase will be intensively reviewed. These include data obtained via mass spectrometry, ion mobility measurements, infrared multiphoton dissociation (IRMPD) spectroscopy, and density functional theory (DFT) calculations.

Sequential extraction and enrichment of flavonoids from Euonymus alatus by ultrasonic-assisted polyethylene glycol-based extraction coupled to temperature-induced cloud point extraction

A green method for simultaneous extraction and enrichment of flavonoids from Euonymus alatus was developed by ultrasonic-assisted extraction (UAE) and temperature-induced cloud point extraction (TICPE) using PEG-base aqueous solution as the extractant. Based on screening different molecular weights of PEGs, PEG-400/water was used as the extractant, and the effects of key factors on extraction yields of flavonoids were investigated by single-factor experiments and response surface methodology (RSM). The optimum conditions of UAE were as follows: PEG-400 concentration of 16% (w/w), particle size of 80 mesh, solvent-to-material ratio of 60:1, extraction temperature of 90 °C and extraction time of 15 min. The results obtained by validation experiments were consistent with the values predicted by RSM. Temperature-induced formation of the aqueous two-phase system (ATPS) and TICPE process were further investigated by controlling temperature and adding (NH₄)₂SO₄. In the presence of (NH₄)₂SO₄, the ATPS formed at 75 ℃ and pH 3.5 could effectively improve separation and recovery of flavonoids with enrichment factor of above five times. Gallic acid, catechin, dihydromyricetin and ellagic acid in the extract were identified and confirmed by UPLC-Q-TOF-MS and the corresponding standards. The UAE-TICPE coupled to HPLC was successfully applied for extraction and determination of flavonoids in two batches of Euonymus alatus. The extraction yields of catechin, dihydromyricetin and total flavonoids were 0.377-0.684 mg/g, 1.091-1.353 mg/g and 2.612-3.146 mg/g, respectively. Compared to conventional extraction methods, PEG-based UAE integrated with TICPE in one-step procedure exhibited higher extraction efficiency and better extraction selectivity.

The Development of Hyaluronan/Fucoidan-Based Nanoparticles as Macrophages Targeting an Epigallocatechin-3-Gallate Delivery System

The aim of this study was to develop a macrophage-targeted nanoparticle composed of hyaluronan/fucoidan complexes with polyethylene glycol-gelatin to encapsulate and deliver epigallocatechin-3-gallate (EGCG), a compound that can regulate macrophage activation and pro-inflammatory mediator production. We show that our nanoparticles can successfully bond to macrophages and deliver more EGCG than an EGCG solution treatment, confirming the anti-inflammatory effects of these nanoparticles in lipopolysaccharide-stimulated macrophages. The prepared nanoparticles were established with a small mean particle size (217.00 ± 14.00 nm), an acceptable polydispersity index (0.28 ± 0.07), an acceptable zeta potential value (-33.60 ± 1.30 mV), and a high EGCG loading efficiency (52.08% ± 5.37%). The targeting abilities of CD44 binding were increased as the hyaluronan concentration increased and decreased by adding a competitor CD44 antibody. Moreover, we found that fucoidan treatment significantly reduced macrophage migration after lipopolysaccharide treatment in a dose-responsive manner. In summary, we successfully created macrophage-targeted nanoparticles for effective targeted delivery of EGCG, which should aid in the development of future anti-inflammatory drugs against macrophage-related diseases.

Introducing nano/microencapsulated bioactive ingredients for extending the shelf-life of food products

The shelf-life of foods is affected by several aspects, mainly chemical and microbial events, resulting in a considerable decline in consumer's acceptance. There is an increasing interest to substitute synthetic preservatives with the plant-based bioactive ingredients which are safe and natural. However, full implementation of this replacement is postponed by some challenges associated with bioactive ingredients, including their low chemical stability, off-flavor, low solubility, and short-term effectiveness. Encapsulation could overcome these limitations. The present review explains current trends in applying natural encapsulated ingredients for food preservation based on a classified description including essential oils, plant extracts, phenolics, carotenoids, etc. and their application for extending food shelf-life mostly dealing with antimicrobial, ant-browning and antioxidant properties. Encapsulation techniques, especially nanoencapsulation, is a promising strategy to overcome their limitations. Moreover, better results are obtained using a combination of proteins and polysaccharides as wall materials than single polymers. The encapsulation method and type of encapsulants highly influences the releasing mechanism and physicochemical properties of bioactive ingredients. These factors together with optimizing the conditions of encapsulation process leads to a cost-effective and well encapsulated ingredient which is more efficient than its free form in shelf-life improvement. It has been shown that the well-designed encapsulation systems, finally, boost the shelf-life-promoting functions of the bioactive ingredients, mostly due to enhancing their solubility, homogeneity in food matrices and contact surface with deteriorative agents, and providing their prolonged presence over food storage and processing via increasing the thermal and processing stability of bioactive compounds, as well as controlling their release on food surfaces, or/and within food packages. To this end and given the numerous wall and bioactive core substances available, further studies are needed to evaluate the efficiency of many encapsulated forms of both conventional and novel bioactive ingredients in food shelf-life extending since the interactions and anti-spoiling behaviors of the ingredients in various encapsulation systems and foodstuffs are highly variable that should be optimized and characterized before any industrial application.

Quantification of Polyphenols and Metals in Chinese Tea Infusions by Mass Spectrometry

Chemical compounds within tea (Camellia sinensis) are characterized by an extensive heterogeneity; some of them are crucial for their protective and defensive role in plants, and are closely connected to the benefits that the consumption of tea can provide. This paper is mainly focused on the characterization of polyphenols (secondary metabolites generally involved in defense against ultraviolet radiation and aggression by pathogens) and metals, extracted from nine Chinese tea samples, by integrating different mass spectrometry methodologies, LC-MS/MS in multiple reaction monitoring (MRM) and inductively coupled plasma mass spectrometry (ICP-MS). Our approach allowed to identify and compare forty polyphenols differently distributed in tea infusions at various fermentation levels. The exploration of polyphenols with nutraceutical potential in tea infusions can widely benefit especially tea-oriented populations. The worldwide consumption of tea requires at the same time a careful monitoring of metals released during the infusion of tea leaves. Metal analysis can provide the identification of many healthy minerals such as potassium, sodium, calcium, magnesium, differently affected by the fermentation of leaves. Our results allowed us: (i) to draw up a polyphenols profile of tea leaves subjected to different fermentation processes; (ii) to identify and quantify metals released from tea leaves during infusion. In this way, we obtained a molecular fingerprint useful for both nutraceutical applications and food control/typization, as well as for frauds detection and counterfeiting.

Effects of Infusion and Storage on Antioxidant Activity and Total Phenolic Content of Black Tea

This study determined antioxidant activity in terms of the 1,1-Diphenyl-2-picrylhydrazyl (DPPH) scavenging ability and total phenolic content of black tea under different infusion and storage conditions. High performance liquid chromatography analysis identified caffeine, (−)-epigallocatechin, (−)-epicatechin-3-gallate, (−)-epigallocatechin-3-gallate and (−)-gallocatechin-3-gallate in the tea sample. The water–tea leaves weight ratio did not affect the DPPH scavenging ability. However, infusion temperature affected the DPPH scavenging activity and the total phenolic content. In the present study, the 50% inhibitory concentrations (IC50) for DPPH of black tea infused at 60 to 100 °C ranged from 100.0 ± 13.7 to 28.4 ± 4.8 μg/mL. The total phenolic content of black tea steeped at 60 to 100 °C ranged from 50.4 ± 5.2 to 178.6 ± 16.4 mg gallic acid equivalent/g dry leaf. Black tea exhibited increased antioxidant activity when the infusion temperature was increased. Regarding short-term storage, the DPPH scavenging ability and total phenolic content of black tea did not significantly change within 15 days. This result was consistent for storage temperatures of 4, 9, and 25 °C.

Coumaroyl Flavonol Glycosides and More in Marketed Green Teas: An Intrinsic Value beyond Much-Lauded Catechins

Marketed green teas (GTs) can highly vary in their chemical composition, due to different origins, processing methods, and a lack of standardization of GT-based products. Consequently, biological activities become difficult to correlate to the presence/content of certain constituents. Herein, ultra-high-performance liquid chromatography (UHPLC) combined with high-resolution tandem mass spectrometry (HR MS/MS) was successfully applied to six commercial GT products, extracted by ethanol sonication, to disclose their polyphenol profile beyond the well-known catechins. The relative abundance of each class of metabolites was correlated to antiradical and antilipoperoxidant data through hierarchical clustering analysis, since it reasonably affects the beneficial properties of the product that reaches the consumer. The thiobarbituric acid reactive substances (TBARS) assay demonstrated that GT extracts effectively counteracted the UV-induced lipoperoxidation of hemp oil, which is highly rich in Polyunsaturated Fatty Acids (PUFAs), and therefore highly unstable. The Relative Antioxidant Capacity Index (RACI) comprehensively emphasized that gunpower and blend in filter GTs appeared to be the less active matrices, and except for a GT-based supplement, the Sencha GT, which was particularly rich in flavonol glycosides, was the most active, followed by Bancha GT.

Effects of cooking on the phytochemical profile of breadfruit as revealed by high-resolution UPLC-MSE

BACKGROUND

This study evaluated the impact of cooking on the profile of bioactive compounds in unripe breadfruit. To this end, the accessibility of bioactive compounds by various solvents was assessed through total phenolic content and antioxidant capacity analyses. The most efficient solvent was applied to extract the metabolites, which were evaluated by ultra-performance liquid chromatography coupled with high-resolution quadrupole time-of-flight mass spectrometry in MS^E mode.

RESULTS

Cooked and raw breadfruit presented total phenolic content and antioxidant capacities in almost all extracts, and pure water proved to be the best extractor. Globally, 146 bioactive compounds have been identified for both raw and cooked fruits' aqueous extracts. Most of these compounds were stable to the heat treatment applied (121 °C/10 min). However, results revealed that 22 metabolites contributed to significantly distinguishing the raw from the cooked samples. Among those, 15 compounds, such as pyrogallol, 1-acetoxypinoresinol, and scopolin, evidenced higher relative abundance in the cooked extracts. On the other hand, only seven metabolites, such as 4-hydroxyhippuric acid, epicatechin, and leptodactylone, decreased post-heating.

CONCLUSIONS

Cooking promoted little alteration in the bioactive compounds profile of immature breadfruit and thus appears to be an exploitation alternative for this perishable fruit, which seems to be a source of a large range of bioactive compounds. © 2019 Society of Chemical Industry.

Tea catechin role in decreasing the oxidation of dairy beverages containing linseed oil

Dairy beverages containing emulsified linseed oil is a suitable vehicle for delivering polyunsaturated fatty acids to consumers. However, these beverages are prone to oxidation. The purpose of this study was to evaluate the effect of adding various concentrations (0, 0.001, 0.01 and 0.1% (w/w)) of green tea extract (GTE) to dairy beverages (DB) containing linseed oil (2.0%, w/w), in order to inhibit lipid oxidation during storage at high temperature (50 °C) or under fluorescent light exposure. During storage, the concentration of catechin (C), epicatechin (EC) and epicatechin gallate (ECG) were significantly reduced (P ≤ 0.05) and degradation rate was greater when the DB were exposed to light (C 35%, EC 74% and ECG 68%) as compared to high temperature (C 34%, EC 45% and ECG 49%). In DB without GTE, the conjugated dienes (CD) hydroperoxides concentration increased significantly (P ≤ 0.05) from 23 mmol kg^-1 fat to 243 mmol kg^-1 fat under 6-day-light exposition, and to 83 mmol kg^-1 fat under 6-day-heat temperature. The addition of GTE significantly increased the antioxidant capacity of DB and reduced the formation of CD, propanal and hexanal, induced by light exposure or high temperature. GTE at 0.10% completely inhibited CD formation during the storage period and reduced propanal and hexanal concentrations below the threshold.

Thermostable Tannase from Aspergillus Niger and Its Application in the Enzymatic Extraction of Green Tea

Tannase is widely used in tea beverage processing because of its ability to catalyze the hydrolysis of hydrolysable tannins or gallic acid esters and effectively improve the quality of tea extracts through enzymatic extraction. A new thermophilic tannase was cloned from Aspergillus niger FJ0118 and characterized. The tannase exhibited an optimal reaction temperature of 80 °C and retained 89.6% of the initial activity after incubation at 60 °C for 2 h. The enzymatic extraction of green tea at high temperature (70 °C) for a short time (40 min) was devised on the basis of the superior thermal stability of tannase. The enzymatic reaction significantly increased the total polyphenol content of green tea extract from 137 g·kg⁻¹ to 291 g·kg⁻¹. The enzymatic reaction effectively degraded the ester catechins into non-ester catechins compared with the water extraction method. Results suggested that the thermally stable tannase exhibited potential applications in the enzymatic extraction of green tea beverage.

Synthesis of B-ring-fluorinated (−)-epicatechin gallate derivatives

Electronically modified, fluorinated catechins and epicatechins are enantioselectively synthesized in a short, convergent sequence via kinetic resolution.

Comparison of the phenolic profiles and physicochemical properties of different varieties of thermally processed canned lychee pulp

Lychee pulp is rich in phenolics and has a variety of biological activities. However, the changes in the phenolic profile under heat treatment are unknown. The effect of the heat treatment temperature on commercial varieties (Guiwei and Nuomici) of canned lychee was investigated by comparing samples that were either unheated (UH), underwent 70 °C heat treatment (HT70) or underwent 121 °C heat treatment (HT121) and then were stored at room temperature. The results showed that the total phenolic content (TPC), total flavonoid content (TFC) and antioxidant activity of the UH, HT70 and HT121 samples were significantly decreased after storage at room temperature for 9 d, 13 d and 25 d, respectively. However, the TPC, TFC and antioxidant activity of HT121 canned lychee were still significantly higher than those of the UH and HT70 samples. However, the texture characteristics of the HT121 samples were worse than those of the UH and HT70 samples, and the color of the canned lychee was darker after the HT121 treatment. Nine individual phenolic compounds were detected in the canned lychee by HPLC-DAD. The gallic acid content was increased after HT121 treatment. In particular, (−)-gallocatechin was generated by HT121 thermal processing. However, after storage at room temperature for 9 d, the contents of (−)-gallocatechin in canned Guiwei and Nuomici were decreased by 96.27% and 94.04%, respectively, and (−)-gallocatechin disappeared after 25 d. In summary, the phenolic contents and antioxidant activity of canned lychee are increased by high-temperature treatment.

Lychee pulp is rich in phenolics and has a variety of biological activities.

Development and Characterization of Gelled Double Emulsions Based on Chia (Salvia hispanica L.) Mucilage Mixed with Different Biopolymers and Loaded with Green Tea Extract (Camellia sinensis)

The aim of this research was to develop and characterize five gelled double emulsions based on chia mucilage (CM) and different biopolymers (κ-carrageenan, C; locust bean gum, L; thixogum, T; and whey protein concentrate, W) loaded with green tea extract (GTE). Gelled double emulsions consisted of W₁ (whey-protein-concentrate/sodium-azide/NaCl/GTE)/O and (PGPR/canola-oi)/W₂ (CM, CMC, CML, CMT and CMW), and were characterized based on physicochemical properties during 35 days of storage. Optical microscopy clearly showed the drops of the internal phase surrounded by droplets of oil dispersed in the second aqueous phase; the droplet size was higher for CMT and lowest for CMW. In addition, all emulsions were highly stable at creaming and were effective in reducing the loss of antioxidant activity (88.82%) and total phenols (64.26%) during storage; CMT, CML and CM were the most effective. Furthermore, all emulsions showed a protective effect by modulating the release of the GTE in a simulated gastrointestinal environment, allowing a controlled release during the gastric-intestinal digestion phases and reaching its maximum release in the intestinal phase (64.57–83.31%). Thus, gelled double emulsions are an alternative for the preservation of GTE and could be a potential alternative for their application in the development of functional foods.

Co-encapsulation of Epigallocatechin Gallate (EGCG) and Curcumin by Two Proteins-Based Nanoparticles: Role of EGCG

In this study, a novel plant-protein-based nanoparticle delivery system was developed to encapsulate and stabilize curcumin and epigallocatechin gallate (EGCG) with different polarities. The strongly hydrophobic curcumin was embedded within the hydrophobic cores of zein nanoparticles using an antisolvent method, while the weakly hydrophobic EGCG was adsorbed to the region between the zein core and caseinate shell. The physicochemical properties, structure, and stability of the core-shell particles were characterized using dynamic light scattering, particle electrophoresis, fluorescence spectroscopy, and Fourier transform infrared spectroscopy. The bioaccessibility of curcumin in the core-shell nanoparticles was determined using a simulated gastrointestinal tract. Mean particle diameters around 100-200 nm could be produced by modulating the mass ratio of curcumin to zein. The encapsulation efficiency of curcumin in the core-shell nanoparticles was higher (96.2%) in the presence of EGCG than in its absence (77.9%). Moreover, the water dispersibility and 1,1-diphenyl-2-picrylhydrazyl radical scavenging capacity of the nanoparticles were significantly improved in the presence of EGCG. The simulated gastrointestinal tract experiments indicated that curcumin had a high bioaccessibility in the optimized core-shell nanoparticles. Overall, our findings suggest that EGCG can be used to improve the functional properties of curcumin-loaded zein-caseinate nanoparticles, which may increase their use in food, cosmetics, and pharmaceutical applications.

The antioxidant and physicochemical properties of microencapsulated bioactive compounds in Securigera securidaca (L.) seed extract by co-crystallization

Securigera securidaca seed is a good source of phenolic compounds with high antioxidant properties. Preservation and maintenance of natural antioxidants have always been a challenge and microencapsulation is a suitable method for this purpose. In this study, the chemical compounds of the plant seed extract were identified by GC/MS device. Bioactive compounds from the seed ethanolic extract were microencapsulated in the sucrose matrix during the co-crystallization process. The evaluations included total phenolic compounds, radical scavenging ability, production efficiency, moisture content, and flowability characteristics of the produced powders, such as compressibility index, Hausner ratio, and angle of repose. The results showed significant differences in the phenolic compounds and the radical scavenging ability between the control sample and the co-crystallized powder (P < 0.05). The production efficiency and the moisture content of extract-containing co-crystallized powder were 84% and 0.14%, respectively. The particle size difference of the microencapsulated powder could significantly affect the powder flowability characteristics (P < 0.05), and particles with a size of 1 mm showed better flowability behaviour. FT-IR charts for samples revealed chemical bonds specific to saccharose molecule indicating no changes in covalent bonds present in saccharose molecule structure after the process. Scanning electron microscope images showed the presence of vacant spaces and porosity in the structure of saccharose crystals formed during the process of crystallization. As a result, the co-crystallized powder obtained from the plant extract can be used as an appropriate antioxidant in the food and pharmaceutical formulations.

Emerging species with nutraceutical properties: Bioactive compounds from Hovenia dulcis pseudofruits

Hovenia dulcis Thunberg is widely distributed in East Asia, where it is well known as a food, but it is rarely consumed in Western countries. Information about its composition is scarce and focused on southern hemisphere genotypes. In the present research, the main bioactive compounds of H. dulcis pseudofruits were characterised using phytochemical analysis (HPLC fingerprint) to improve knowledge about this plant and support development of potential food applications. These preliminary results showed high levels of catechins (157.18 ± 34.34 mg/100 g_FW) and other phenolic compounds responsible for antioxidant properties. Concentrations of ferulic acid were particularly high (9.66 ± 1.76 mg/100 g_FW) and further studies would advance exploitation of this plant-food.

The impacts of brewing in glass tumblers and thermos vacuum mugs on the aromas of green tea (Camellia sinensis)

This study investigated the effect of brewing apparatus on the aromatic feature of tea infusion. Huangshan Maofeng tea infusion was brewed under glass tumblers (GT) or thermos vacuum mugs (TVM) for up to 180 min. Tea infusion sensory attributes were evaluated using quantitative descriptive analysis and the composition of volatiles were analyzed using headspace solid phase microextraction coupled with gas chromatography-mass spectrometry. Results showed that GT tea infusion at each brewing duration possessed stronger 'Pure', 'Fresh' and 'Grassy' attributes than TVM tea infusion, whereas TVM tea infusion showed a higher intensity on 'Steamed' aroma. A total of 74 volatiles were detected in tea infusion, and aldehydes and alcohols appeared to be the major volatiles. Total aldehydes concentration percentage decreased in tea infusion with brewing process, whereas an increase on total alcohol percentage was found. Principal component analysis indicated that brewing duration and apparatus played vital roles in altering the volatile composition in tea infusion, whereas orthogonal partial least squares discriminant analysis (OPLS-DA) revealed that GT tea infusion samples were separated from TVM tea infusion samples. OPLS-DA also screened 20 volatiles that significantly contributed to the differentiation of GT and TVM tea infusion.

Microencapsulation of green tea polyphenols by ionic gelation and spray chilling methods

The consumption of teas has been increasing with the dissemination of information regarding the health benefits of its constituents. Obtaining food products with healthier profiles is already a reality for industry with the increasing development of new functional ingredients, including the use of tea and its derivatives (extracts). This work aimed to evaluate the encapsulation of green tea extract powder in lipid microparticles (LMP) by the spray chilling method and in ionic gelation microparticles (IGMP) by the ionic gelation method to obtain polyphenol-rich water insoluble components. Microparticles were adequately obtained in both methods, with typical physical characteristics consistent with the results in literature results, 83.5 ± 2.8% encapsulation efficiency for LMP and 72.6 ± 0.4% for IGMP, and antioxidant activity (IC50 μg/mL) of 33,169.4 ± 123.8 (IGMP) and 2099.7 ± 35.3 (LMP). The microparticles samples were considered suitable as ingredients for add polyphenols in foods.

Catechins Controlled Bioavailability of Benzo[a]pyrene (B[α]P) from the Gastrointestinal Tract to the Brain towards Reducing Brain Toxicity Using the In Vitro Bio-Mimic System Coupled with Sequential Co-Cultures

The aim of the current study was to examine the preventive effect of green tea catechins on the transport of Benzo[a]pyrene (B[α]P) into the brain using an in vitro bio-mimic system coupled with sequential co-cultures. When 72 μM of catechins was pre-treated, cellular cytotoxicity induced by IC₅₀ of B[α]P in human liver hepatocellular carcinoma (HepG2) and human brain microvascular endothelial cells (HBMECs) was reduced by 27% and 26%, respectively. The cellular integrity measured in HBMECs, which was exposed to IC₅₀ of B[α]P, slowly decreased. However, the pre-treatment of catechins retained cellular integrity that was 1.14 times higher than with the absence of catechins. Co-consumption of catechins reduced not only the bio-accessibility of B[α]P in digestive fluid, but it also decreased absorption of B[α]P in human intestinal epithelial cells (Caco-2) with a HepG2 co-culture system. It was found that approximately a two times lower amount of B[α]P was transported via the blood-brain barrier (BBB) compared to only the B[α]P intake. These results are taken in conjunction with each other support that catechins could be able to prevent brain toxicity induced by B[α]P in the human body by limiting the bio-availability of B[α]P.

Anti-atherogenic effects of CD36-targeted epigallocatechin gallate-loaded nanoparticles

Intimal macrophages play a critical role in atherosclerotic lesion initiation and progression by taking up oxidized low-density lipoprotein (oxLDL) and promoting inflammatory process. 1-(Palmitoyl)-2-(5-keto-6-octene-dioyl) phosphatidylcholine (KOdiA-PC), a major type of oxidized phosphatidylcholines (PC) found on oxLDL, has a high binding affinity to the macrophage scavenger receptor CD36 and participates in CD36-mediated recognition and uptake of oxLDL by intimal macrophages. We successfully synthesized epigallocatechin gallate (EGCG)-loaded nanoparticles (Enano), which were composed of EGCG, PC, (+) alpha-tocopherol acetate, and surfactant. We also incorporated KOdiA-PC on the surface of Enano to make ligand-coated Enano (L-Enano) to target intimal macrophages. The objectives of this study were to determine the anti-atherogenic effects of Enano and L-Enano in LDL receptor null (LDLr-/-) mice. Our in vitro data demonstrated that L-Enano had a higher binding affinity to mouse peritoneal macrophages than Enano. This high binding affinity was diminished by CD36 antibodies or knockdown of the CD36 receptor in mouse peritoneal macrophages, confirming the specific binding of L-Enano to the macrophage CD36 receptor. LDLr-/- mice were randomly divided to six groups and received weekly tail vein injection with PBS, EGCG, void nanoparticles (Vnano), Enano, ligand-coated Vnano (L-Vnano), or L-Enano once per week for 22 weeks. The dose of EGCG was 25 mg per kg body weight. L-Enano at 20 μg/mL significantly decreased production of monocyte chemoattractant protein-1, tumor necrosis factor alpha, and interleukin-6 from mouse macrophages, while having no effect on their plasma levels compared to the PBS control. There were no significant differences in blood lipid profiles among six treatment groups. Mice treated with L-Enano also had significantly smaller lesion surface areas on aortic arches compared to the PBS control. Liver EGCG content was decreased by treatments in the order of EGCG>Enano>L-Enano. Native EGCG had inhibitory effects on liver and body fat accumulation. This molecular target approach signals an important step towards inhibiting atherosclerosis development via targeted delivery of bioactive compounds to intimal macrophages.

Exploring DNA quantity and quality from raw materials to botanical extracts

OBJECTIVES

The aim of this study was to explore the variability in DNA quality and quantity along a gradient of industrial processing of botanical ingredients from raw materials to extracts.

METHODS

A data matrix was assembled for 1242 botanical ingredient samples along a gradient of industrial processing commonly used in the Natural Health Product (NHP) industry. Multivariate statistics was used to explore dependant variables for quality and quantity. The success of attaining a positive DNA test result along a gradient of industrial processing was compared among four biotechnologies: DNA barcoding, NGS, Sanger sequencing and qPCR.

RESULTS

There was considerable variance in DNA quality and quantity among the samples, which could be interpreted along a gradient from raw materials with greater quantities (50-120 ng/μL) of DNA and longer DNA (400-500bp) sequences to extracts, which were characterized by lower quantities (0.1-10.0 ng/μL) and short fragments (50-150bp).

CONCLUSIONS

Targeted molecular diagnostic tests for species identity can be used in the NHP industry for raw and processed samples. Non-targeted tests or the use of NGS for any identity test needs considerable research and development and must be validated before it can be used in commercial operations as these methods are subject to considerable risk of false negative and positive results. Proper use of these tools can be used to ensure ingredient authenticity, and to avert adulteration, and contamination with plants that are a health concern. Lastly these tools can be used to prevent the exploitation of rare herbal species and the harvesting of native biodiversity for commercial purposes.

Discriminating geographical origins of green tea based on amino acid, polyphenol, and caffeine content through high-performance liquid chromatography: Taking Lu'an guapian tea as an example

Seventy-three Lu'an guapian tea (LAGP) samples were collected from 11 growing locations in the city of Lu'an, Anhui Province, China. Through high-performance liquid chromatography, 18 amino acids, along with gallic acid, caffeine, and five catechins, were quantitatively detected. Hierarchical cluster, correlation and principal component analysis, and a support vector machine were used for geographical discrimination. The findings suggested that the differences in tea quality between the inner and outer mountain regions are related to isoleucine, leucine, phenylalanine, and valine contents, with a correlation coefficient of more than 0.85. Principal component analysis combining with support vector machine was a feasible method. The identification rates for the inner and outer mountains were 97.96% in the training set and 95.83% in the prediction set. Furthermore, the identification rates for the three counties were 91.84% and 95.83% in the training and prediction sets, respectively.

Increased Phenolic Content and Enhanced Antioxidant Activity in Fermented Glutinous Rice Supplemented with Fu Brick Tea

Glutinous rice-based foods have a long history are consumed worldwide. They are also in great demand for the pursuit of novel sensory and natural health benefits. In this study, we developed a novel fermented glutinous rice product with the supplementation of Fu brick tea. Using in vitro antioxidant evaluation and phenolic compounds analysis, fermentation with Fu brick tea increased the total phenolic content and enhanced the antioxidant activity of glutinous rice, including scavenging of 1,1-Diphenyl-2-picryl-hydrazyl (DPPH) radical, 2,2′-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) radical, and hydroxyl radical, ferric-reducing antioxidant power, and ferric ion reducing power and iron chelating capability. Besides, compared with traditional fermented glutinous rice, this novel functional food exhibited a stronger activity for protecting DNA against hydroxyl radical-induced oxidation damage. Quantitative analysis by HPLC identified 14 compounds covering catechins and phenolic acids, which were considered to be positively related to the enhanced antioxidant capability. Furthermore, we found that 80% ethanol was a suitable extract solvent compared with water, because of its higher extraction efficiency and stronger functional activities. Our results suggested that this novel fermented glutinous rice could serve as a nutraceutical food/ingredient with special sensory and functional activities.

Effects of green tea contents on the quality and antioxidant properties of textured vegetable protein by extrusion-cooking

The aim of this study was to evaluate the effects of green tea contents (0, 5, 10, and 15%) on texturization and antioxidant properties of textured vegetable protein (TVP) by using a twin-screw extruder. Extrusion conditions were fixed at 140 °C barrel temperature, 50% moisture content, 100 g/min feed rate, and 200 rpm screw speed. The integrity index, hardness, and cutting strength of TVP significantly (P < 0.05) increased with the increase in green tea levels, while cohesiveness, springiness, water holding capacity, and nitrogen solubility index (NSI) significantly (P < 0.05) decreased. Increasing the amount of green tea resulted in better DPPH radical scavenging activity, higher total phenolic, total flavonoid, catechins, and caffeine contents. The (-)-epigallocatechin gallate, (-)-epicatechin, (-)-epigallocatechin, and (-)-epicatechin gallate contents of TVP significantly (P < 0.05) decreased, compared to that of raw materials. The incorporation of green tea in TVP can negatively affect expansion and NSI while positively affect texturization and antioxidant properties.

Omics in traditional vegetable fermented foods and beverages

For a long time, food microbiota has been studied using traditional microbiological techniques. With the arrival of molecular or culture-independent techniques, a strong understanding of microbiota dynamics has been achieved. However, analyzing the functional role of microbial communities is not an easy task. The application of omics sciences to the study of fermented foods would provide the metabolic and functional understanding of the microbial communities and their impact on the fermented product, including the molecules that define its aroma and flavor, as well as its nutritional properties. Until now, most omics studies have focused on commercial fermented products, such as cheese, wine, bread and beer, but traditional fermented foods have been neglected. Therefore, the information that allows to relate the present microbiota in the food and its properties remains limited. In this review, reports on the applications of omics in the study of traditional fermented foods and beverages are reviewed to propose new ways to analyze the fermentation phenomena.