Nitro-phenolic compounds (NPs) have attracted increasing attention because of their health risks and impacts on visibility, climate, and atmospheric chemistry. Despite many measurements of ...particulate NPs, the knowledge of their gaseous abundances, sources, atmospheric fates, and impacts remains incomplete. Here, 18 gaseous NPs were continuously measured with a time-of-flight chemical ionization mass spectrometer at a background site in South China in autumn and winter. Abundant NPs were observed in the continental outflows from East Asia, with a total concentration up to 122.1 pptv. Secondary formation from the transported aromatics dominated the observed NPs, with mono-NPs exhibiting photochemical daytime peaks and nighttime enrichments of di-NPs and Cl-substituted NPs. The budget analysis indicates that besides the •OH oxidation of aromatics, the NO3• oxidation also contributed significantly to the daytime mono-NPs, while the further oxidation of mono-NPs by NO3• dominated the nocturnal formation of di-NPs. Photolysis was the main daytime sink of NPs and produced substantial HONO, which would influence atmospheric oxidation capacity in downwind and background regions. This study provides quantitative insights on the formation and impacts of gaseous NPs in the continental outflow and highlights the role of NO3• chemistry in the secondary nitro-aromatics production that may facilitate regional pollution.
•The four colored naked barley showed a diversity in phenolic compounds profile.•The all colored samples had differences in contents of phenolic compounds.•There were significant differences in ...antioxidant ability of colored naked barley.•There were significant correlation between phenolic components and antioxidation.
In the present study, the profile of phenolic compounds in colored (white, yellow, black and blue) naked barley was detected and their content and antioxidant abilities were investigated. The results showed that there were 156 phenolic substances identified, including monophenol, phenolic acids, flavonoids and other polyphenols. The black sample had the most types of phenolic. The content of phenolic varies depending on color of naked barley and the highest values of total phenolic acid and total flavonoids were observed in black and white samples. Furthermore, the strongest ferric reducing antioxidant power and the free radical scavenging ability of DPPH, ABTS, and superoxide anion showed in white, white, yellow and black naked barley. While white and yellow samples had the strongest scavenging ability of hydroxyl radical. There was significant correlation between phenolic components and anti-oxidation. This study suggests that colored naked barley grains are rich in phenolic compounds with antioxidant capacity.
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•This review discusses the two astringency perception mechanisms of phenolic compounds.•The first mechanism involves chemosensors and mechanosensors.•Friction generated in first ...mechanism may activate Piezo2 ion channel.•Another mechanism probably active Piezo2 ion channel.•Astringent phenolic compounds inhibit oxidation, inflammation, aging and cancer.
Astringency as the complex sensory of drying or shrinking can be perceived from natural foods, including abundant phenolic compounds. Up to now, there have been two possible astringency perception mechanisms of phenolic compounds. The first possible mechanism involved chemosensors and mechanosensors and took salivary binding proteins as the premise. Although piecemeal reports about chemosensors, friction mechanosensor's perception mechanisms were absent. There might be another perception way because a part of astringent phenolic compounds also triggered astringency although they could not bind with salivary proteins, however, the specific mechanism was unclear. Structures caused the differences in astringency perception mechanisms and intensities. Except for structures, other influencing factors also changed astringency perception intensity and aimed to decrease it, which probably ignored the health-promoting effects of phenolic compounds.
Therefore, we roundly summarized the chemosensor's perception processes of the first mechanism. Meanwhile, we speculated that friction mechanosensor's probably activated Piezo2 ion channel on cell membranes. Phenolic compounds directly binds with oral epithelial cells, activating Piezo2 ion channel probably the another astringency perception mechanism. Except for structure, the increase of pH values, ethanol concentrations, and viscosity not only lowered astringency perception but were beneficial to improve the bioaccessibility and bioavailability of astringent phenolic compounds, which contributed to stronger antioxidant, anti-inflammatory, antiaging and anticancer effects.
Lignin is widely available in biomass sources, and the aromatic structure can justify its use as a precursor or platform for obtaining value-added compounds. However, lignin is considered a low-price ...by-product or low-value fuel for energy recovery in the pulping industries. Therefore, the development of technologies and methodologies that promote the valorization and efficient utilization of this biopolymer becomes an essential aspect of biobased processes, especially in biorefineries. This review shows the opportunity to target lignin as a marketable by-product for value-added chemicals through thermochemical, chemical, and biochemical pathways, with or without the absence of catalysts. Likewise, the valorization of lignin includes emerging technologies to produce carbon and polymer materials. This work also emphasizes the description of technical, economic, and environmental aspects that would affect lignin in different biorefinery stages. Therefore, a discussion based on current studies and evaluations of lignin valorization processes is considered. Finally, a preliminary techno-economic and environmental assessment of a wood-based biorefinery was performed as an example to better understand the importance of lignin as a platform product in biorefineries. It includes the processing scale analysis over ten years of the project lifetime. The review established the importance of lignin valorization to increase biorefineries efficiency and sustainability.
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•Lignin depolymerization through thermal and bio-chemical routes have been discussed.•Emerging technologies for lignin-based materials are an alternative in the industry.•Efforts to define the sustainability of lignin-based biorefineries are required.•Lignin oxidation shows an economically feasible route in wood-based biorefineries.
•Compilation of articles on chemistry and properties of Theobroma spp. of the last 10 years.•Fruits with potential in the food, nutritional and medicinal areas.•Chemical composition rich in phenolic ...compounds such as flavonols and flavones.•Genus with technological interest shown in patented products and processes.
Nowadays, Brazil is considered one of the countries that still has a great biodiversity of fauna and flora, and within this wide diversity, the Malvaceae family stands out, presenting 243 genera and 4,300 species. In this family, the genus Theobroma. Is highlighted for the economic value of multiple applicability in food, nutritional, medicinal and craft sectors. Due to its importance, the major objective of this review was to compile the main articles of the last 10 years on the Theobroma spp. based on chemical, biological and pharmacological properties, as well as applications and patents of functional products. Of the 20 species of the genus Theobroma spp. reported in experimental studies, it was observed that its chemical composition is rich in phenolic acids, such as p-coumaric acids, caffeic and chlorogenic, as well as flavonols (catechin and epicatechin), flavones and derivatives such as hypoletin. Thus, this study shows the technological prospection based on the worldwide patent landscape.
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The present study was conducted to evaluate the non-ovalent modifications of whey protein isolate (WPI) with gallic acid (GA), chlorogenic acid (CA) and epigallocatechin gallate (EGCG). The ...structural and functional properties of WPI before and after binding with GA, CA and EGCG were investigated. Results showed that free sulfhydryl groups and surface hydrophobicity significantly decreased in WPI after binding with phenolic compounds. Significant structural alterations in complexes were demonstrated, characterized by a red-shifted maximum emission wavelength in intrinsic fluorescence spectroscopy, and a significant decrease in α-helix and β-sheet and a remarkable increase in β-turn and random coil contents in fourier transform infrared (FTIR) spectroscopy. Moreover, the presence of three polyphenols induced enhanced solubility, foaming and emulsifying capacities of WPI. These findings suggest the feasible application of GA, CA and EGCG to improve the functional properties of WPI and the potential uses of WPI-polyphenol complexes in food industries.
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•Structure, polarity and molecular size of phenolics affect their interaction with MP.•Hydrogen bond and electrostatic interaction were found in the interactions.•Phenolics change the ...structure of MP and affect its comprehensive properties.•Quercetin (QT) and quercitrin (QR) showed the similar comprehensive effects on MP.•Tannic acid, gallic acid, EGCG and EGC showed contrary effects of QT and QR on MP.
Effects of different phenolic compounds on the structural and functional properties of myofibrillar protein (MP) were investigated, and the phenolic compounds were applied as natural modifiers in pork meatball. Interactions between MP and phenolic compounds were determined via molecular docking to elucidate the modification mechanisms. Tannic acid, gallic acid, (-)-epigallocatechin gallate, and epigallocatechin interacted with MP primarily through hydrogen bonds, which unfolded the secondary structures of MP and lowered surface hydrophobicity. Accordingly, the solubility, gel properties, and oxidation stability of MP were improved, while the emulsifying properties significantly decreased. Quercetin and quercitrin showed electrostatic interactions with MP, which preserved α-helix structures and increased surface hydrophobicity. While, the modifications lent MP the enhanced emulsifying properties, thermal stability, and oxidation stability, but the gel properties and solubility were mitigated. In addition, the incorporation of phenolic compounds prevented MP oxidation based upon their antioxidant abilities deriving from hydroxyl groups. Once the phenolic compounds were used in pork meatball, a minced meat model, they significantly improved the quality of meatball by bettering the texture properties and controlling the oxidation level. The results suggest that phenolic compounds have great potential to be employed as natural additives in minced meat products for the modification of functional properties.
The Anaerobic Digestion Model No. 1 (ADM1) was applied in this study to simulate the anaerobic digestion (AD) of wastewaters from soluble coffee processing in sequential batch reactors. As these ...substrates present considerable levels of phenolic compounds, modifications were made to the basic structure of the ADM1. Additionally, the Luong inhibition model replaced the Monod model to describe the consumption of soluble organic matter. On the other hand, the removal of phenolic compounds was carried out using the Haldane model, appropriate when the inhibition by excess substrate is present, taking into account in this case the quantification of phenols and benzoic acid as total phenols. The new ADM1-based model was calibrated with experimental data from the AD of post hydrothermal wastewater (PHWW) of spent coffee grounds (SCG) and validated with experimental data of the AD of effluents produced during the soluble coffee processing. The simulation results demonstrated that the new model moderately described the removal of phenolic compounds ( > 90 %), methane production (2.243 kgCODm−3 in calibration and 6.16 kgCODm−3 in validation), and the production and consumption of organic acids over time. However, in future research new metabolic pathways may be included in the model to improve its quality even more.
•ADM1 was modified to simulate the anaerobic digestion of residues from soluble coffee processing.•Luong’s inhibition kinetics was incorporated into the ADM1 to describe the substrate degradation.•The removal of phenolic compounds was described by the Haldane kinetic.•The model moderately described methane production and phenolic degradation.
•Quinoa seeds were exposed to different drying temperatures.•Drying quinoa seeds at 60–70 °C enhanced the extractability of phytochemicals.•The drying process at 70 °C was the most efficient to ...extract phenolics.•Extracts of quinoa seeds dried at 60–70 °C were very rich in ferulic acid and quercetin.•Drying quinoa seeds at 60 °C allowed the greatest extractability of xanthophylls.
This investigation studied the effects of different drying temperatures on the content of phenolic compounds and carotenoids in quinoa seeds (Chenopodium quinoa) from Finland. Five drying temperatures were applied to reach a dry matter content of 94–95% w/w: room temperature, 40, 50, 60, and 70 °C. The process performed at 70 °C allowed the greatest recovery of total phenolic compounds, 994 ± 28 mg kg−1. Ferulic acid and quercetin were the main phenolics identified. The drying process performed at 60 °C allowed the greatest recovery of cumulative carotenoids, 2.39 ± 0.05 mg kg−1. The carotenoids identified were xanthophylls, e.g., lutein, zeaxanthin and neochrome. The use of heat impacted positively on the phytochemical composition of quinoa. The concentration of phenolics and carotenoids increased steadily with the rise in drying temperature. Results obtained provide scientific knowledge that can be used by producers to increase the availability of such phytochemicals in quinoa seeds.
Petroleum, one of the fossil fuels, is still the main source for liquid fuel production. Lignin derived from renewable biomass has the potential to replace petroleum. The abundance of aromatic units ...in lignin makes it potential to produce high-value liquid fuel. This review offers a summary of the extensive study that has been devoted to the catalytic hydrodeoxygenation (HDO) of lignin-derived phenolic compounds and the conversion of raw lignin into hydrocarbon liquid fuels. Based on the product classification (cyclohexanes and arenes), different catalytic systems, mainly including catalyst species, solvents and reaction conditions, are analyzed in detail. A model study of lignin-derived compounds (phenolic monomers and dimers) is usually carried out to elaborate on the HDO reaction mechanism. 100% yield of hydrocarbon liquid fuels can be achieved in most tests. With respect to the real lignin-derived bio-oil, however, hydrocarbon yields only reach 16.2%–62.8% due to the various components and high instability of the substrate. The technical barriers and challenges in this part are highlighted throughout. Moreover, the conversion of raw lignin is also comprehensively summarized, which actually combines the depolymerization of lignin and HDO of lignin-derived bio-oil in one pot, and its hydrocarbon yields are generally lower than those of lignin-derived bio-oil. In light of this, the important features of raw lignin that influence the production of hydrocarbon liquid fuels are adequately addressed. Overall, this paper focuses on the scientific and technological advances of hydrocarbon liquid fuel production from lignin, and the potential strategies to produce renewable fuels from lignin are discussed.
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•Catalytic HDO reaction mechanism of phenols is elaborated in model lignin study.•Different catalytic systems for different hydrocarbon products are analyzed.•Technical barriers and challenges to the valorization of lignin are highlighted.•Important features of raw lignin influencing the production of fuels are addressed.•Potential strategies to produce renewable fuels from lignin are discussed.
