Bio‐oil to hydrocarbon oil: An active, selective, and stable catalyst (Ni supported in zeolite HZSM‐5) allows the conversion of a wide variety of CO and CO bonds in n‐hexane‐extracted pyrolysis oil ...into hydrocarbons through a cascade of hydrogenation, hydrolysis, dehydration, and dehydroaromatization reactions. Quantitative yields of C5–C9 gasoline‐range hydrocarbons are obtained under mild conditions in water.
Bark from trees is considered a worthless raw material. However, this resource could be economically beneficial if utilized efficiently due to its rich chemical compounds. In this study, an ethanol ...toluene-soluble extractive, alpha-cellulose and lignin obtained from
Leucaena leucocephala
bark were characterized to determine their chemical functional groups. Based on FTIR spectral analysis, the results indicated that the bands of the functional groups of the extractive from the original bark remain unchanged; however, the absorbance intensity was found to be weaker in the group frequency and fingerprint regions. Removal of extractive, pectin, hemicellulose and lignin from the bark indirectly increased the strong absorbance intensity of cellulose. Broad peaks of OH stretching found in all spectra were assigned to the presence of phenolic OH and aliphatic structures for extractive and aromatic structures of lignin. It was revealed that aromatic functional groups were mainly found in the extractive, while water, carbonyl and ether were the dominant groups in cellulose, and methyl, methylene, carbonyl and carboxyl groups were enriched in lignin.
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•ChCl-Ca showed the best extraction yields of phenolic compounds.•Phenolic compounds can be recovered from DESs extracts by liquid–liquid extraction.•The regenerated DESs can be ...reused for additional extraction.•The differences and relationships among the used DESs for the extraction of phenolic compounds from mulberry leaves were also investigated.
It is of great significance to develop green solvents for promoting green and sustainable technology. Deep eutectic solvents (DESs) as new extraction solvents are emerging in the search for efficient the extraction of bioactive compounds or drugs. In this study, twelve types of DESs including choline chloride-, betaine-, and l-proline-based DESs were investigated in combination with ultrasonic-assisted extraction (UAE) for the extraction of phenolic compounds from Morus alba L. leaves. Compared with conventional extraction system, DESs composed of choline chloride/citric acid showed more effective extraction yields (22.66 mg/g vs. 15.29 mg/g). The operation conditions were also optimized systematically. In addition, liquid–liquid extraction was an effective approach to recover the major phenolic compounds in the extracts. The recovery and recyclability of DESs were also evaluated. A broad extractability of phenolic compounds in the certain designed DESs systems was observed according to principal component analysis (PCA). The developed DESs can be an alternative procedure for the green and efficient extraction of phenolic compounds from natural sources.
The development of the bamboo industry has been hindered by environmental issues caused by the application of bamboo preservatives. Chinese herbal phenolic compounds have been shown to possess ...broad-spectrum, potent antimildew properties, making them promising candidates for the development of new bamboo mildew inhibitors. In this study, we investigated the antimildew properties of three phenolic compounds, eugenol, carvacrol, and paeonol, against common mildews in bamboo materials using the Oxford cup method and the double-dilution method. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to analyze the antimildew mechanism and its effects on mildew cell morphology. Our results showed that carvacrol exhibited the strongest antimildew activity, with minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) values of 1.56 mg/mL and 1.76 mg/mL, respectively, followed by eugenol and paeonol. At a concentration of 25 mg/mL, eugenol and carvacrol had an inhibitory rate of over 50% against various mildews. Different concentrations of the three compounds significantly disrupted the morphology and structural integrity of mildew hyphae, with the extent of damage increasing with concentration and treatment duration. In the sliced bamboo mildew prevention experiment, carvacrol at a concentration of 29.25 mg/mL was found to be highly effective against all tested mildews. Our study provides new insights and a theoretical basis for the development of eco-friendly bamboo mildew inhibitors based on plant phenolic compounds.
Pumpkin seeds may be tiny, but they are densely packed with useful nutrients and nutraceuticals such as amino acids, phytosterols, unsaturated fatty acids, phenolic compounds, tocopherols, ...cucurbitacins and valuable minerals. All these bioactive compounds are important to a healthy life and well-being. The purpose of this review is to merge the evidence-based information on the potential use pumpkin seeds as a functional food ingredient and associated biological mechanisms, collected from electronic databases (ScienceDirect, ResearchGate, PubMed, Scopus and Google Scholar) up to January 2020. Bioactive compounds in pumpkin seeds exhibit promising activities such as anthelmintic, antidiabetic, antidepressant, antioxidant, antitumor and cytoprotective. Furthermore, these bioactives carry potential in ameliorating microbiological infections, hepatic and prostate disorders. As evidenced from literature, pumpkin seeds show potential to be used as both a traditional and functional food ingredient provided further animal and clinical investigations are carried out to establish the respective molecular mechanisms and safety profile.
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•Electrohydrodynamic (EHD) drying was suitable for the dehydration of citrus peel.•Electric field type (AC vs. DC) affected drying characteristics and physicochemical quality.•Applied ...voltages led to different EHD drying behaviors and quality attributes of citrus peel.•EHD drying significantly affected the phytochemical components and volatile profiles.
Based on the concept of circular economy, citrus peel was considered a valuable source of bioactive compounds for high-value foods. Electrohydrodynamic (EHD) drying is a novel technology appropriated for the dehydration of heat-sensitive products such as citrus peel. In current work, EHD drying of citrus peel was performed based on alternating current (AC) or direct current (DC) sources at various voltage levels (9, 18, 27, 36, and 45 kV). The effect of EHD on drying characteristics, water retention capacity, enzyme inactivation, phytochemical contents (phenolic compounds and carotenoids), and volatile compounds of citrus peel were evaluated and compared. Results showed that the drying time in the AC electric field was shorter compared to DC electric field at the same applied voltages due to the polarization layer formed by unipolar charges. The applied voltage determined electric field strength as well as the degree of tissue collapse and cell membrane rupture. EHD elucidated the transformation and degradation of phytochemicals including phenolic compounds, carotenoids, and volatile composition in proportion to the applied voltage. The findings indicate that EHD drying with AC improves drying behaviors, inactivates enzymes, and retains the phytochemical properties of citrus peel.
Lignin could be depolymerized into large amount of phenolic compounds via fast pyrolysis. The upgrade of phenolic compounds via hydrodeoxygenation (HDO) involves multiple reaction pathways. It is ...challenging to selectively remove the oxygen-containing groups while keeping the aromatic rings intact. In this work, hierarchical Nb2O5 (H–Nb2O5) microspheres with abundant oxygen vacancies were synthesized to anchor the Pd clusters, which is featured with strong metal-support interaction via the electron transfer between Pd species and Nb species. For phenol HDO reaction, the oxygen vacancies were prone to interact with the phenolic hydroxy groups, resulting in phenol molecule adsorbed in a “nonplanar” manner, greatly weakening the CAr-O bonds and averting the ring hydrogenation. Besides, the activated hydrogen atoms on Pd clusters could migrate to the vicinity of oxygen vacancies via spillover, promoting the cleavage of CAr-O bond to obtain benzene. Current work provides a deep insight into the synergetic catalytic mechanism of Pd/H–Nb2O5 catalyst for phenol HDO reaction, and also sheds light on the design and synthesis of high-efficient catalysts in other heterogeneous catalysis fields.
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•Hierarchical Nb2O5 microspheres with oxygen vacancies were synthesized.•Pd/H–Nb2O5 with metal-support interaction avoids the aggregation of Pd clusters.•Phenolic hydroxy occupied the oxygen vacancies in a “nonplanar” adsorption manner.•“Nonplanar” adsorption weakens the CAr-O bond and avoids the ring hydrogenation.•Hydrogen spillover promotes the cleavage of CAr-O bond to produce benzene.
The aim of this study was to monitor Apis mellifera L. honey samples from Santa Catarina State, Brazil, during prolonged storage (450 days/20 ± 4 °C), regarding physicochemical parameters (moisture, ...electrical conductivity, pH, acidity, color, dystasic activity, 5-HMF and sugars), phenolic compounds, reducing capacity (Folin-Ciocalteu reducing capacity and ferric reducing antioxidant power) and DPPH free radical scavenging capacity. Storage did not affect the 5-HMF and sucrose contents, which were below the limit of quantification. Electrical conductivity, pH, diastatic activity, and color (L*) decreased during storage, while acidity and moisture increased. Twenty-one phenolic compounds (11 phenolic acids, nine flavonoids, and one coumarin) were quantified, with salicylic (0.08–0.76 μg g−1) and p-coumaric (0.21–1.93 μg g−1) acids found in all samples studied. In general, the phenolic compounds monitored were stable during the 450 days of storage, while reducing capacity increased and DPPH free radical scavenging capacity had value fluctuations. The results obtained in this study showed that honey stored for 450 days could be considered safe for human consumption considering the physicochemical parameters evaluated, besides maintaining its bioactive components.
•Physicochemical and bioactive stability of honey was evaluated during 450 days.•The acidity increased and the pH decreased at the end of storage for all samples.•All samples showed < LOQ values for 5-HMF throughout the storage period.•Salicylic and p-coumaric acids were found in all samples until the end of storage.•For most samples, FRAP increased, while DPPH was variable during storage.
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•Inajá processing by-products are a rich source of phenolic antioxidants.•Inajá cake extract presents significant peroxyl radical scavenging capacity.•Inajá cake extract inhibits ...NF-κB activation.•Catechins and procyanidins are the main phenolics of inajá cake extract.
Agro-industrial activities generate large amounts of solid residues, which are generally discarded or used as animal feed. Interestingly, some of these by-products could serve as natural sources of bioactive compounds with great potential for industrial exploitation. This study aimed to optimize the extraction of phenolic antioxidants from the pulp residue (oil processing by-product) of inajá (Maximiliana maripa, a native species found in the Brazilian Amazon). The antioxidant properties of the optimized extract and its phenolic profile by high-resolution mass spectrometry (LC-ESI-QTOF-MS) were further determined. Central composite rotatable design and statistical analysis demonstrated that the temperature of 70 °C and 50% (v/v) ethanol concentration improved the extraction of phenolic compounds with antioxidant properties. The optimized extract also showed scavenging activity against the ABTS radical cation and reactive oxygen species (ROS; peroxyl and superoxide radical, and hypochlorous acid). Moreover, the optimized extract was able to reduce NF-κB activation and TNF-α release, which are modulated by ROS. Flavan-3-ols were the major phenolics present in the optimized extract. Collectively, our findings support the use of inajá cake as a new source of bioactive catechins and procyanidins. This innovative approach adds value to this agro-industrial by-product in the functional food, nutraceutical, pharmaceutical, and/or cosmetic industries and complies with the circular economy agenda.
Pomegranate peel was separated into outer leathery skin (PS), mesocarp (PM), and divider membrane (PD), and its phenolic compounds were extracted as free (F), esterified (E), and insoluble-bound (B) ...forms for the first time. The total phenolic content followed the order PD > PM > PS. ABTS•+, DPPH, and hydroxyl radical scavenging activities and metal chelation were evaluated. In addition, pomegranate peel extracts showed inhibitory effects against α-glucosidase activity, lipase activity, and cupric ion-induced LDL-cholesterol oxidation as well as peroxyl and hydroxyl radical-induced DNA scission. Seventy-nine phenolic compounds were identified using HPLC-DAD-ESI-MS n mainly in the form of insoluble-bound. Thirty compounds were identified for the first time. Gallic acid was the major phenolic compound in pomegranate peel, whereas kaempferol 3-O-glucoside was the major flavonoid. Moreover, ellagic acid and monogalloyl-hexoside were the major hydrolyzable tannins, whereas the dominant proanthocyanidin was procyanidin dimers. Proanthocyanidins were detected for the first time.
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