Non-phenolic Compounds Research Articles

Molecular Mechanisms of Dietary Compounds in Cancer Stem Cells from Solid Tumors: Insights into Colorectal, Breast, and Prostate Cancer.

Cancer stem cells (CSC) are known to be the main source of tumor relapse, metastasis, or multidrug resistance and the mechanisms to counteract or eradicate them and their activity remain elusive. There are different hypotheses that claim that the origin of CSC might be in regular stem cells (SC) and, due to accumulation of mutations, these normal cells become malignant, or the source of CSC might be in any malignant cell that, under certain environmental circumstances, acquires all the qualities to become CSC. Multiple studies indicate that lifestyle and diet might represent a source of wellbeing that can prevent and ameliorate the malignant phenotype of CSC. In this review, after a brief introduction to SC and CSC, we analyze the effects of phenolic and non-phenolic dietary compounds and we highlight the molecular mechanisms that are shown to link diets to CSC activation in colon, breast, and prostate cancer. We focus the analysis on specific markers such as sphere formation, CD surface markers, epithelial-mesenchymal transition (EMT), Oct4, Nanog, Sox2, and aldehyde dehydrogenase 1 (ALDH1) and on the major signaling pathways such as PI3K/Akt/mTOR, NF-κB, Notch, Hedgehog, and Wnt/β-catenin in CSC. In conclusion, a better understanding of how bioactive compounds in our diets influence the dynamics of CSC can raise valuable awareness towards reducing cancer risk.

A selective oxidative depolymerization of larch lignin to ethyl vanillate by multifunctional catalysts combining alkaline ionic liquid and polyoxometalates with hydrogen peroxide.

Ethyl vanillate (EV) is an important component of flavors and fragrances and has been widely used in the food, pharmaceutical, and cosmetic industries. The highly selective preparation of EV from lignin, the most abundant monophenolic compound in nature, is a great challenge in the field of lignin depolymerization. In this study, the multi-active catalysts from alkaline ionic liquid and polyoxometalates were constructed, which were characterized by acidity, alkaline and oxidizing ability. They can efficiently cleave the CC and CO bonds of larch lignin in an ethanol/water system at 160°C for 10h with H2O2 as an oxidizing agent. Vanillin and EV were main products with the phenolic yield of 10.14wt% and the selectivity of EV was up to 83.63%. The depolymerization of phenolic and non-phenolic lignin model compounds demonstrated that the cleavage of β-O-4 and Cα-Cβ bonds contributed to the selective preparation of EV in the catalytic system. The catalyst can be recycled up to 4 times with excellent stability and recoverability. This study provides a new approach for the production of EV, which is promising in the high-valued utilization of larch waste.

Insights into a photo-driven laccase coupling system for enhanced photocatalytic oxidation and biodegradation

Effective depolymerization of lignin into environmentally friendly aromatic chemicals under mild conditions is gaining interest. Fungal laccase is capable of catalyzing a wide range of reactions, but its low redox potential and preference for acidic pH limit its potential applications. Herein, we developed a laccase-methylene blue (LAC-MB) coupling system, combining the selectivity of enzyme catalysis with the high reactivity of photocatalysis, for the efficient degradation of lignin model compounds. Theoretical calculations indicate that the electron donor’s distance to the LAC’s active site T1 Cu is shortened from 29.7 to 7.3 Å in the LAC-MB. In this system, MB, possessing strong interaction with T1 Cu, acts as a light absorber, enabling the rapid transfer of photogenerated electrons to T1 Cu. This significantly enhances the degradation rate of guaiacol (GUA) from 28.8 % to 91.46 %. The LAC-MB can oxidize both phenolic and non-phenolic lignin model compounds under red-LED irradiation with wide pH ranging from 3.0 to 7.0 and high-efficiency. By tuning the primary coordination sphere and the access tunnel of T1 Cu, we further revealed that enhanced binding affinity and active site accessibility for the LAC-MB complex attributed to the photocatalysis’s high reactivity. Based on this, LAC variants with enhanced binding capabilities were constructed and the resulting mutant LAC-MB are characterized by higher oxygen consumption and ROS generation activated by red-LED, specifically a higher quantum yield of 1O2, demonstrating increased electron transfer and light-driven reactivity. This photo-enzyme coupling system presents a new pathway for the high-efficiency processing of lignocellulosic biomass and offers insights for designing future artificial photosynthetic systems.

Laccase: A Green Biocatalyst Offers Immense Potential for Food Industrial and Biotechnological Applications.

Laccase, a multipurpose biocatalyst, is widely distributed across all kingdoms of life and plays a key role in essential biological processes such as lignin synthesis, degradation, and pigment formation. These functions are critical for fungal growth, plant-pathogen interactions, and maintenance of soil health. Due to its broad substrate specificity, multifunctional nature, and environmentally friendly characteristics, laccase is widely employed as a catalyst in various green chemistry initiatives. With its ability to oxidize a diverse range of phenolic and nonphenolic compounds, laccase has also been found to be useful as a food additive and for assessing food quality parameters. Ongoing advancements in research and technology are continually expanding the recognition of laccase's potential to address global environmental, health, and energy challenges. This review aims to provide critical insights into the applications of laccases in the biotechnology and food industry.

HRMAS 1H NMR and CPMAS 13C NMR spectroscopies coupled with chemometrics for the metabolomic investigation of commercial teas

In this study, the metabolome of different types of tea (i.e., black, green and earl grey) is explored by means of HRMAS 1H (i.e., semisolid state) NMR and CPMAS 13C (i.e., solid state) NMR spectroscopies. By elaborating the metabolomic data with unsupervised and supervised chemometric tools (PCA, PLS-DA), it was possible to set up classification models with the aim to discriminate the different types of tea as based on differences in their chemical composition. Both the applications of the NMR spectroscopies also allowed to obtain information about the metabolic biomarkers leading the differentiation among teas. These were mainly represented by phenolic compounds. Also, some non-phenolic compounds, such as amino acids, carbohydrates, and terpenoids, played important roles in shaping tea quality. The findings of this study provided useful insights into the application of solid and semisolid state NMR spectroscopies, in combination with chemometrics, in the context of food authentication and traceability.

Revisiting the mechanism of β-O-4 bond cleavage during acidolysis of lignin part 10: reactions of C6–C2-type non-phenolic syringyl model compounds and comparison of the reactions with those of the guaiacyl analogues

A C6–C2-type non-phenolic syringyl lignin model compound (I, 2-(2-methoxyphenoxy)-1-(3,4,5-trimethoxyphenyl)ethanol) as well as its derivatives was acidolyzed in aqueous 82vol% 1,4-dioxane containing 0.2 mol/L HBr, HCl, or H2SO4 at 85ºC. The results were compared with those on the guaiacyl analogues (V as well as its derivatives) obtained in our previous reports. The acidolysis of compound I was slower than that of compound V, which is in accordance with our previous result on the formation rates of the benzyl cation intermediates (BC) from a syringyl compound and its guaiacyl analogue. The enol ether-type compound was primarily produced in the acidolysis of compound I, similar to that of compound V. The acidolysis using HBr or HCl was faster than that using H2SO4, indicating the participation of Br¯ or Cl¯, respectively, in the acidolysis. It was suggested that Br¯ (as well as Cl¯) adds to the cation center of the BC to afford the adduct in the acidolysis of compound I, similar to that of compound V, and hence, this adduct formation is a major bypass of the common route. The bypass activity in the acidolysis of compound I was about half in that of compound V.

Insights into the phytochemical composition and antioxidant potential of the Tunisian Ceratonia siliqua L.

Carob (Ceratonia siliqua L.) corresponds to an evergreen leguminous tree (Fabaceae family). The high phenolic content of numerous parts of carob has been deeply associated with several nutritional and functional benefits. The aim of this study was to investigate the physicochemical properties of ground carob pods and seeds, the effect of different extraction procedures as well a comprehensive phytochemical characterization of hydro-methanolic extracts (80/20 v/v) of pods and seeds by HPLC-DAD ESI-Q-TOF-MS/MS. Additionally, their antioxidant activity was evaluated using in vitro assays.The results showed thatthe dry matter (DM) values were 88.09% for pods and 89.10% for seeds, protein contents were 0.41 g/100 g DM for pods and 0.88 g/100 g DM for seedsand total sugars contents were 0.35 g/100 DM for pods and 26.70 g/100 g DM for seeds. Furthermore, the oil holding capacities (OHC) were 10.43 g/g for pods and 7.53 g/g for seeds, while the water holding capacities were 8.46 g/g for pods and 2.59 g/g for seeds.The hydro-methanolic extracts of both pods and seeds showed the presence of 53 secondary bioactive metabolites belonging to various classes(flavonoids, phenolic acids, tannins and non-phenolic compounds). The antioxidant activities were evidenced in DPPH (22.24 mg/ml for pods and 26.37 mg/ml for seeds), ABTS (198.50 mmol Eq Trolox/100 g for pods and 201.04 mmol Eq Trolox/100 g for seeds) and FRAP (0.39 mmol Eq Trolox/100 g for pods and 0.53 mmol Eq Trolox/100 g for seeds).Moreover,high significant (p ≤ 0.01) correlation coefficients were found between the antioxidant activity estimated by the DPPH method and total phenols (r = 0.943), orthodiphenols (r = 0.996), flavonoids (r = 0.880) and flavonols (r = 0.982). Nevertheless, lower correlations were detected with ABTS and FRAP methods.These results demonstrated that carob parts displayed an interesting potential that can be of interest for further valorizations as a natural antioxidant with multiple applications, namely functional food ingredients or prevention of many health problems.

A novel laccase from Trametes polyzona with high performance in the decolorization of textile dyes

Laccases are multicopper oxidases able to oxidize several phenolic compounds and find application in numerous industrial applications. Among laccase producers, white-rot fungi represent a valuable source of multiple isoforms and isoenzymes of these multicopper oxidases. Here we describe the identification, biochemical characterization, and application of laccase 2 from Trametes polyzona (TP-Lac2), a basidiomycete fungus emerged among others that have been screened by plate assay. This enzyme has an optimal temperature of 50 °C and in acidic conditions it is able to oxidize both phenolic and non-phenolic compounds. The ability of TP-Lac2 to decolorize textile dyes was tested in the presence of natural and synthetic mediators at 30 °C and 50 °C. Our results indicate that TP-Lac2 most efficiently decolorizes (decolorization rate > 75%) malachite green oxalate, orange G, amido black10B and bromocresol purple in the presence of acetosyringone and 2,2′-azinobis (3-ethylbenzthiazoline-6-sulfonate)—ABTS. Overall, the laccase mediator system consisting of TP-Lac2 and the natural mediator acetosyringone has potential as an environmentally friendly alternative for wastewater treatment in the textile industry.

Caatinga, Amazon and Atlantic Forest as natural sources for microbial lignocellulolytic enzymes.

Brazilian biomes are important sources for environmental microorganisms, including efficient metabolic machineries, like actinomycetes. These bacteria are known for their abilities to produce many bioactive compounds, including enzymes with multiple industrial applications. The present work aimed to evaluate lignocellulolytic abilities of actinomycetes isolated from soil and rhizosphere samples collected at Caatinga, Atlantic and Amazon Forest. Laccase (Lac), lignin peroxidase (LiP), manganese peroxidase (MnP) and cellulase were evaluated for their efficiency. These enzymes have an essential role in lignin decomposition, through oxidation of phenolic and non-phenolic compounds, as well as enzymatic hydrolysis of vegetal biomass. In this sense, a total of 173 actinomycetes were investigated. Eleven (11) of them were selected by their enzymatic performance. The actinomycete AC166 displayed some activity in all analysed scenarios in terms of Lac, MnP and LiP activity, while AC171 was selected as the most promising strain, showing the following activities: 29.7 U.L-1 for Lac; 2.5 U.L-1 for LiP and 23 U.L-1 for MnP. Cellulolytic activities were evaluated at two pH conditions, 4.8 and 7.4, obtaining the following results: 25 U.L-1 and 71 U.L-1, respectively. Thermostability (4, 30 and 60 o C) and salinity concentrations (0 to 4M) and pH variation (2.0 to 9.0) stabilities of the obtained LiP and Lac enzymatic extracts were also verified. The actinomycete strain AC171 displayed an adaptable response in distinct pH and salt profiles, indicating that bacterial LiP was some halophilic type. Additionally, the strain AC149 produced an alkali and extreme halophilic lignin peroxidase, which are promising profiles for their future application under lignocellulosic biomass at bioethanol biorefineries.

Revisiting the mechanism of β-O-4 bond cleavage during acidolysis of lignin. Part 9: Comprehensive results for guaiacyl-type compounds and the difference in participation mode of bromide and chloride anions between C6-C3-type and C6-C2-type compounds

A phenolic β-O-4-type lignin model compound with a C6-C3-type side-chain and two guaiacyl nuclei and its derivatives were individually acidolyzed in aqueous 82 vol% 1,4-dioxane containing 0.2 mol/L HBr, HCl, or H2SO4 at 85 °C in this study. The obtained results, combined with those in the series of this study in which phenolic and non-phenolic C6-C3- and C6-C2-type analogues were used, generated the following results and proposals. The H2O addition reproducing the original compound is preponderant as a reaction mode of the benzyl cation intermediate (BC) over the other modes leading to the β-O-4 bond cleavage, especially in the acidolyses using H2SO4 and those of C6-C3-type compounds. A well-known phenomenon whether formaldehyde is liberated from C6-C3-type compounds is regulated by acid types appears less clearly in phenolic than in non-phenolic compounds. Br¯ as well as Cl¯ nucleophilically assists the H¯ transfer from the β- to α-carbon of BC, especially in C6-C3-types, which accelerates and regulates the acidolyses using HBr as well as HCl. Furthermore, Br¯ is suggested to nucleophilically attack the β-carbon of non-phenolic C6-C3-type BC to cleave the β-O-4 bond, which explains the characteristically peculiar observation in the acidolysis of the non-phenolic C6-C3-type compound using HBr described in our previous report.

Synergistic, Additive and Antagonistic Interactions of Grapes' Phenolic Compounds and Organic Acids.

The antioxidant interactions between several natural phenolic and non-phenolic compounds (catechin, quercetin, rutin, resveratrol, gallic acid and ascorbic acid) and organic acids (tartaric, citric and dihydroxyfumaric acids) have been investigated through the DPPH method. Main additive and antagonistic interactions have been found for the combinations of catechin, quercetin, resveratrol and gallic acid with tartaric and citric acids; such behavoir can be due to the enhanced stability of the phenolic compounds in the acidic media. Rutin and ascorbic acid demonstrated good synergistic effects with tartaric and citric organic acids, which may rely on the polymerization processes for rutin, and change of the mechanism of action in case of ascorbic acid. In combination with dihydroxyfumaric acid, the mixtures showed dose - dependent synergistic, additive or antagonistic antioxidant interactions. Good synergystic effects have been registered for the binari mixtures of dihydroxyfumaric acid with ascorbic acid, catechin and rutin.

A novel two-domain laccase with a middle redox potential: physicochemical and structural properties

The gene for a previously unexplored two-domain laccase was identified in the genome of the actinobacterium Streptomyces carpinensis VKM Ac-1300. A two-domain laccase, named ScaSL, was produced in a heterologous expression system (Escherichia coli strain M15 [pREP4]). The enzyme was purified to homogeneity using affinity chromatography. ScaSL laccase, like most two-domain laccases, exhibited activity in the homotrimer form. However, unlike most two-domain laccases, it was also active in multimeric forms. The enzyme exhibited maximum activity at 80°C and was thermally stable. The half-inactivation time of ScaSL at 80°C was 40 min. Laccase oxidized the non-phenolic organic compound ABTS at a maximum rate at pH 4.7; oxidized the phenolic compound 2,6-dimethoxyphenol at a maximum rate at pH 7.5. Laccase stability was observed in the pH range 9-11. At pH 7.5, laccase was weakly inhibited by sodium azide, sodium fluoride, and sodium chloride; at pH 4.5, laccase was completely inhibited by 100 mM sodium azide. Km and kcat of the enzyme for ABTS are 0.1 mM and 20 s-1, respectively. Km and kcat for 2,6-dimethoxyphenol are 0.84 mM and 0.36 s-1, respectively. ScaSL catalyzed the polymerization of humic acids and lignin. The redox potential of laccase was 0.472 ± 0.007 V. Thus, ScaSL laccase is the first characterized two-domain laccase with a middle redox potential. The crystal structure of ScaSL was determined with a resolution of 2.35 Å. A comparative analysis of the structures of ScaSL and other two-domain laccases suggested that the middle potential of ScaSL may be associated with conformational differences in the position of the side groups of amino acids at position 230 (in ScaSL numbering), which belong to the second coordination sphere of the copper atom of the T1 center.

Physicochemical properties, antioxidant activities and comprehensive phenolic profiles of tea-macerated Chardonnay wine and model wine

A new type of flavored wine was produced by macerating either green tea or black tea into Chardonnay wine and model wine respectively, where the physicochemical properties (pH, titratable acidity, color) were modulated. Significant (p < 0.05) increases of total phenolic content and antioxidant activity (assessed by DPPH, FRAP and ABTS assays) were also observed in the tea macerated wines. A total of 160 phenolic and non-phenolic compounds were identified by HPLC-DAD-ESI-QTOF-MS/MS, where 55 phenolics were newly found in the tea macerated Chardonnay wine. The interaction between wine and tea phenolics led to additional 29 phenolic compounds and 4 non-phenolic compounds that were not found in either Chardonnay wine or tea. Catechin and epigallocatechin gallate were the most abundant phenolic compounds and contributed to the improved antioxidant activities. This study provided a promising prospect of tea as a novel additive in the production of flavored wine with enhanced functionalities.

White-rot fungus Phlebia floridensis ITM 12: Laccase production, oxidoreductase profile, and hydrogen-peroxide independent activity.

Phlebia genus is a relevant group of fungi with a crucial role in numerous ecosystems. In tropical and subtropical areas this genus allows the efficient degradation of lignin and carbon recovery; however, the majority of these fungal species remain undiscovered. The main purpose of this work was to determine the enzymatic activity of extracellular proteins of a novel Phlebia floridensis strain isolated in Yucatan Peninsula, Mexico. The results that are reported here demonstrate that the soluble protein extract of P. floridensis can degrade a broad spectrum of recalcitrant compounds. This induced protein extract is able to modify not only phenolic and nonphenolic compounds, but also anthroquinone dyes, even without the addition of exogenous hydrogen peroxide. Using liquid chromatography-mass spectrometry (LC-MS), we were able to identify a novel chloroperoxidase in enzymatic extract. As far as we know, this is the first report about the presence of this type of enzyme in the Phlebia genus.

Chemical and colorimetric study of the influence of grape soluble polysaccharides on the color and stability of malvidin 3-O-glucoside solutions

Red wine color is mainly due to anthocyanins’ flavylium cation. In wine, these pigments are involved in a pH-dependent equilibrium involving other forms, both colored and non-colored. This equilibrium is affected by the presence of other phenolic compounds, the so-called copigments. Moreover, other non-phenolic compounds that can be found in wine, such as polysaccharides, can also affect wine color. In this work, molecular dynamics simulations, tristimulus colorimetry and HPLC-DAD analyses have been performed to assess the effect of soluble polysaccharides (P) on the color and stability of malvidin 3-O-glucoside (Mv) solutions at different pH values, both in presence and absence of other compounds that can establish copigmentation interactions with the pigment. Results showed that P shifts the color of flavylium solutions towards a more intense color with bluer hues, which can be related to a stabilization of the blue quinoidal forms of anthocyanins. This effect is similar to that observed for quercetin 3-β-glucopyranoside (QG), although, in the case of P, it seems to be more relevant. This behavior could be due to the presence of hydrophobic regions in P that allows the interaction with the quinoidal forms, which in the case of the polysaccharide might be related to the type I rhamnogalacturonans.

A Novel Two-Domain Laccase with Middle Redox Potential: Physicochemical and Structural Properties.

The gene for a previously unexplored two-domain laccase was identified in the genome of actinobacterium Streptomyces carpinensis VKM Ac-1300. The two-domain laccase, named ScaSL, was produced in a heterologous expression system (Escherichia coli strain M15 [pREP4]). The enzyme was purified to homogeneity using affinity chromatography. ScaSL laccase, like most two-domain laccases, exhibited activity in the homotrimer form. However, unlike the most two-domain laccases, it was also active in multimeric forms. The enzyme exhibited maximum activity at 80°C and was thermally stable. Half-inactivation time of ScaSL at 80°C was 40 min. The laccase was able to oxidize a non-phenolic organic compound ABTS at a maximum rate at pH 4.7, and to oxidized a phenolic compound 2,6-dimethoxyphenol at a maximum rate at pH 7.5. The laccase stability was observed in the pH range 9-11. At pH 7.5, laccase was slightly inhibited by sodium azide, sodium fluoride, and sodium chloride; at pH 4.5, the laccase was completely inhibited by 100 mM sodium azide. The determined Km and kcat of the enzyme for ABTS were 0.1 mM and 20 s-1, respectively. The Km and kcat for 2,6-dimethoxyphenol were 0.84 mM and 0.36 s-1, respectively. ScaSL catalyzed polymerization of humic acids and lignin. Redox potential of the laccase was 0.472 ± 0.007 V. Thus, the ScaSL laccase is the first characterized two-domain laccase with a middle redox potential. Crystal structure of ScaSL was determined with 2.35 Å resolution. Comparative analysis of the structures of ScaSL and other two-domain laccases suggested that the middle potential of ScaSL may be associated with conformational differences in the position of the side groups of amino acids at position 230 (in ScaSL numbering), which belong to the second coordination sphere of the copper atom of the T1 center.

Production and characterization of novel thermostable CotA-laccase from Bacillus altitudinis SL7 and its application for lignin degradation

Laccases are multi-copper oxidases and found in ligninolytic bacteria catalyzing the oxidation of both phenolic and non-phenolic compounds, however its application in lignin degradation suffers due to low oxidation rate, which have intensified the search for new laccases. In the present study, spore coat A protein (CotA) encoding gene having laccase like activity from Bacillus altitudinis SL7 (CotA-SL7) was cloned and expressed in Escherichia coli. The purified CotA-SL7 was active at wide range of temperature and pH with optimum activity at 55 °C and pH 5.0. The kinetic parameters of CotA-SL7 was determined with Km, Vmax, and kcat values 0.4 mM, 2777 μmol/min/mg, and 5194 s−1, respectively. Molecular docking revealed the presence of Pro, Phe, Asp, Asn, His, and Ile residues at the active site taking part in the oxidation of ABTS. The purified CotA-SL7 reduced lignin contents by 31 % and changes in lignin structure were analyzed through fourier transformed infrared spectroscopy (FTIR), scanning electron microsscopy (SEM) and gas chromatography mass-spectrometry (GC-MS). The appearance of low molecular size compounds clearly indicates the cleavage of lignin polymer and opening of the benzene ring by purified CotA-SL7. Thus, high catalytic efficiency of CotA-SL7 makes it a suitable bio-catalyst for remediation of lignin contaminated wastewater from pulp and paper industries with clear insights into lignin degradation at molecular level.

Oxidative degradation of polyethylene by two novel laccase-like multicopper oxidases from Rhodococcus opacus R7.

The production of synthetic plastics, especially polyethylene, has reached a crucial level, making highly challenging plastic waste management. This paper aims to elucidate the role of two novel laccase-like multicopper oxidases in polyethylene oxidative degradation based on transcriptomic data from Rhodococcus opacus R7 grown on polyethylene. The purification of the recombinant proteins, LMCO2 and LMCO3 belonging respectively to the three- and two-domains laccase families, showed that they are endowed with different functional features. LMCO2 showed the highest enzyme activity at 65 °C with an optimal pH of 7.0, while LMCO3 exhibited the highest activity at 80 °C at acidic pH. LMCOs showed activity on both phenolic (i.e., 2,6-DMP) and non-phenolic (i.e., ABTS) compounds and they were thermostable.The oxidative activity of LMCO2 and LMCO3 on untreated low-density polyethylene was assessed by combining Fourier transform infrared spectroscopy and gas chromatography coupled with mass spectrometry analyses. Oxidation of PE was recorded within a short time range (24-48 h) and revealed previously not described patterns of alkyl compounds and oxygenated products including ketones, alcohols, and carboxylic acids. Structural analysis of LMCO2 and LMCO3 together with density functional theory calculations allowed to identify structural and electronic elements presumably involved in the oxidation of polyethylene.

From waste to wealth: Significant potential of oil palm kernel-derived biochar as alternative substrate for production of red lettuce (Lactuca sativa L.) with high bioactive metabolites content in NFT hydroponic system

Improper agricultural waste management harms the environment. Certain agricultural waste materials, such as oil palm kernel wastes, can be used as soil amendments or fertilizers. This study aimed to explore their potential as an alternative hydroponic substrate. The effects of different hydroponic substrates on lettuce metabolite production, specifically biochar, have not been previously studied. The study compared the bioactive properties and metabolite profiles of red lettuce grown under various treatments: T1 (control; hydroton), T2 (perlite), T3 (palm kernel biochar), T4 (hydroton + palm kernel biochar), and T5 (perlite + palm kernel biochar). Lettuce grown with T4 exhibited the highest chlorophyll contents, while T3 resulted in the highest carotenoid, anthocyanin, phenolic, and flavonoid contents. T3 demonstrated the highest DPPH radical scavenging activity and ferric reducing potential, while T4 exhibited the highest ABTS radical-scavenging activity. LC-MS-QTOF analysis tentatively annotated a total of 38 metabolites, with 12 compounds identified based on databases and literature search. These compounds included phenolic and non-phenolic compounds, as well as additional classes like coumarins, xanthine alkaloids, and glycosides. Red lettuce grown in T3 showed the highest number of metabolites (18), followed by T5 (15), T2 and T4 (13), and T1 (6). E-Suberenol, a potent antioxidant, displayed a strong correlation with the treatments using palm kernel biochar. This study suggests that palm kernel biochar can serve as a cost-effective, renewable, and sustainable alternative hydroponic substrate.

Pulsed electric field processing of green tea-infused chardonnay wine: Effects on physicochemical properties, antioxidant activities, phenolic and volatile compounds

Pulsed electric field (PEF) was used to develop a novel Chardonnay wine infused with green tea, where the physicochemical characteristics (pH, titratable acidity, color) were modulated. The PEF processing conditions were optimized via response surface methodology by evaluating antioxidant activity (assessed by DPPH, FRAP and ABTS assays), total free phenolic content (TPC), total free flavonoid content (TFC), and volatile content. The optimum conditions were determined as electric field strength 1.3 kV/cm and pulse number 10. The PEF-processed green tea-infused wines were also analyzed for the phenolic and volatile profiles. A total of 178 phenolics and non-phenolics were identified by HPLC-DAD-ESI-QTOF-MS/MS in the PEF-treated wines. The application of PEF resulted in additional 20 phenolic compounds and 14 non-phenolic compounds absent in either Chardonnay or green tea. Catechin was the most abundant phenolic compound, while the enhanced antioxidant power was mainly driven by epigallocatechin. There were 49 volatiles detected by HS-SPME-GC-MS in the PEF-treated wines, with 15 volatiles as odor-active compounds. Under both artificial saliva spiked and non-spiked conditions, green tea infusion diminished fruity, floral and spicy odors, and intensified citrus and green odors. The PEF treatment (0.1 and 0.5 kV/cm) could impart more intense citrus and green aromas from tea to wine. Saliva addition decreased the release of volatile acids, alcohols, esters and aldehydes, and increased the release of benzenoids and terpenes. This study forecasted a promising future of PEF as a time and energy efficient technique in the production of flavored wine with enhanced functionalities and desired aromas.