Natural phenolic compounds are rich in cereal and pulse seeds and their dietary functions tend to improve dramatically during germination. This article reviews recent research on the transformation ...of phenolic compounds during seed germination. In particular, it highlights the classification of crude phenolic compounds that can be divided into extractable and non-extractable phenolic compounds based on the biosynthesis process and extraction method. It also recommends grouping resorcinol lipids in the category of extractable phenolic compounds as non-polar solvent extractable phenolic compounds. Moreover, it discusses the variation of the different form of phenolic compounds and proposes a possible metabolic model of these phenolic compounds for seeds germination. This article is crucial for phenolic compounds research, cereal and pulse seeds germination, and food ingredients industry.
Biodegradation in marine medium of PHBV films with or without 5 % wt. of phenolic compounds (catechin, ferulic acid, and vanillin) was assessed at laboratory scale. Respirometric analyses and film ...disintegration kinetics were used to monitor the process over a period of 162 days. Structural changes in the films were analyzed throughout the exposure period using FESEM, DSC, Thermogravimetric analyses, XRD, and FTIR spectra. Respirometric tests showed complete biodegradation of all materials during the exposure period (the biodegradation half-time ranged between 63 and 79 days) but at different rates, depending on the phenolic compound incorporated. Ferulic acid and vanillin accelerate the PHBV biodegradation, whereas catechin delayed the process. Disintegration kinetics confirmed these results and showed that degradation occurred from the surface to the interior of the films. This was controlled by the degradation rate of the polymer amorphous phase and the formation of a biomass coating on the film surface. This is the result of the compounds generated by polymer degradation in combination with excretions from microorganisms. This coating has the potential to affect the enzyme diffusion to the polymer substrate. Moreover, the cohesion forces of the amorphous phase (reflected in its glass transition temperature) affected its degradation rate, while the slower degrading crystalline fragments were released, thus contributing to the disintegration process on the film's surface. Ferulic acid, with its hydrolytic effect, enhanced degradation, as did vanillin for its plasticizing and weakening effect in the amorphous phase of polymer matrix. In contrast, catechin with cross-linking effect hindered the progress of the material degradation, considerably slowing down the process rate.
Display omitted
•The biodegradation half-time of the films ranged between 63 and 79 days.•The hydrolysis of the amorphous phase controlled the rate of biodegradation.•A biomass coating delayed the internal biodegradation of the films.•Hydrolytic phenols (ferulic acid) in the amorphous phase promoted degradation.•Phenols with cross-linking ability slowed down the enzymatic hydrolysis rate.
Combustion of organic solid wastes releases phenolic compounds which can act as precursors in the formation of environmentally persistent free radicals (EPFRs) in the post-flame, cooling zone of ...waste combustion. The study investigated the generation mechanism of EPFRs from phenolic compounds catalyzed by transition metals in air atmosphere under simulated combustion conditions. Representative combustion-derived phenolic compounds were used, and SiO2 particulates containing different mass ratio of Fe2O3 were synthesized as carriers. EPFRs formed had g-factors between 1.9998 and 2.0066, indicating phenoxyl-, cyclopentadienyl-, and semiquinone-type radicals, along with paramagnetic F-centers. The promotion effect of phenolic compounds on EPFR formation during heating decreased as catechol > hydroquinone > phenol > p-cresol. This trend is related to hydroxyl groups and activation energy. In particular, catechol chemically adsorbed on Fe2O3 at 600 K led to the formation of EPFRs with relatively high spin concentrations (up to 1.28 × 1017 spin/g). Higher Fe2O3 concentrations promoted the transformation of phenoxyl-type radicals into cyclopentadienyl-type and paramagnetic F-centers. However, as the Fe2O3 loading increased from 1.25% to 5%, the density of EPFRs decreased. The findings related to the influence of various precursors and Fe2O3 concentration on EPFR formation provide valuable insights for estimating EPFR generation and associated risk during combustion processes.
Display omitted
•The underlying links between EPFRs and Phenolic Compounds were clarified.•The electron transfer between Fe2O3 and the precursor was determined by XPS.•A high concentration of Fe2O3 promotes cyclopentadienyl- and paramagnetic F-centers to form.•EPFRs concentration is related to the position of hydroxyl groups in the precursor.
Phenolic substances in semi-coking wastewater were converted into phenolic resin by formaldehyde, therefore the resources were utilized. Volatile phenol, COD, ammonia nitrogen and oil in semi-coking ...wastewater before and after phenolic resin formation were detected to optimize the reaction time, temperature and raw material ratio, eventually the optimal reaction conditions for phenolic resin preparation were determined. Meanwhile, the physicochemical analysis of phenolic resin materials was carried out by XRD and SEM. The results showed that a volume ratio of 1:40 (formaldehyde vs. semi-coking wastewater), a reaction temperature of 90°C, and a reaction time of 4 hours were the optimum reaction conditions for semi-coking wastewater treated by formaldehyde.
Display omitted
•UFPs have antioxidant and anti-inflammatory activities.•UFPs can be used in healthy products.•UFPs has high content of bioactive compounds.
This review highlights the nutritional ...content, phytochemical compounds, and biological properties of three unconventional food plants consumed in the Amazon: ora-pro-nóbis (Pereskia aculeata Mill.), taioba (Xanthosoma sagittifolium), and vitória-régia (Victoria amazonica). These plants show significant nutritional, functional, and economic potential, which can enhance the intake of daily nutrients, energy, and bioactive compounds. Ora-pro-nóbis is a rich source of caftaric acid, quercetin, and isorhamnetin; taioba contains syringic acid, caffeic acid, and quercetin; and vitória-régia shows cinnamic acid, caffeic acid, and sinapic acid in its composition. These compounds confer antioxidant, anticancer, antimicrobial, anti-inflammatory, analgesic, and antiproliferative properties on these plants. These unconventional plants can be exploited by the food industry as food and supplements and therapeutic plants to develop valuable products for food, cosmetics, pharmaceutical, and medical applications.
•Notable correlations between pellicle colors and phenolics in kernel without pellicle.•Positive correlations between TPCs of three forms in pellicle and their colors.•Dark walnuts with high contents ...of flavanols, flavones and flavonols in free form.
Although walnut kernels are a rich source of phenolic compounds, little is known about the profiles of phenolic compound forms in various colored-pellicle walnuts, which may be important for product development and utilization. In this work, the free, esterified and bound forms of phenolic compounds in various colored-pellicle walnuts were identified using ultra-high-performance liquid chromatography coupled to tandem mass spectrometry ((UHPLC-MS/MS). The total phenolics (TPCs) in pellicle, kernel without pellicle and whole kernel (with pellicle) were presented in the free form (62.6%) and bound form (1.30 %–12.2 %). Positive correlations were found between the TPCs of three forms in pellicle and the pellicle color, with correlation coefficients of 0.920, 0.990 and 0.940. In addition, the phenolic compounds in free form in the whole kernel (with dark pellicle) demonstrated notable advantages in flavanols, flavones and flavonols contents, particularly (+)-catechin (C) (40.7 μg/g) and epicatechin (EC) (25.8g/g), which were 2–153 times higher than other phenolic compounds in free form. Furthermore, the dark group of esterified phenolic acids showed advantages, particularly ellagic acid (428 μg/g) and gallic acid (130 μg/g).
•Phenolics were extracted from MOLs using customised deep eutectic solvents (DES).•DES-based ultrasonic-assisted extraction (UAE) conditions were optimized by RSM.•DES-based UAE exhibited high ...efficiency for the extraction of the phenolic compounds.•DES-based UAE showed strong antioxidant activities.•Phenolic constituents in the MOLs extracts were analyzed.
In this study, an ultrasonic-assisted extraction (UAE) procedure with selected deep eutectic solvents (DES) as solvent was first designed to simultaneously optimize the total phenolic/flavonoid content (TPC/TFC) and antioxidant activities of Moringa oleifera L. leaves (MOLs) by using response surface methodology (RSM). The key factors for RSM were selected based on the design of the experimental results along with a three-factors-five-level, central composite design (CCD), including 20 experimental runs. The analysis of variance (ANOVA) results revealed that the water content in DES had a significant influence on all responses, while the ultrasonic time and the ratio of liquid to solid had no statistically significant effects on the total phenolic content. The optimal conditions of the combination of TPC/TFC and antioxidant activities were obtained as follows: 37% water content in DES, 144 W ultrasonic power, and 40 °C ultrasonic temperature. The measured parameters corresponded with the predicted results. Moreover, a comparative study confirmed that the optimized DES-based UAE yielded further higher TPC, TFC, and antioxidant activities than other extraction methods. The results of HPLC analysis in optimized conditions verified that the MOLs extracts with DES-based UAE included 14 phenolic compounds with high concentrations of vicenin-2 (17.6 mg/g) and orientin (23.6 mg/g). The present study supplied a green and high-efficient method for extracting high levels of anti-oxidative phenolic compounds from MOLs.
