Sequential Fractionation Research Articles

Comparative study on the physicochemical characteristics of lignin via sequential solvent fractionation of ethanol and Kraft lignin derived from poplar and their applications

The challenges in high value-added utilization of lignin own to its wide molecular weight distribution and complex physicochemical properties associated with it. How to narrow the molecular weight of lignin and elucidate the differences in physiochemical properties related to molecular weight of lignins is of crucial importance for lignin conversion processing. In this study, lab-made Kraft and ethanol lignins were fractionated into several narrower molecular weight distribution components through a designed solvent system. The yield, molecular weight distribution, structural characterization and their physicochemical properties of each fractionated lignin were analyzed comparatively. The results indicated that the yield of ethanol lignin is higher (8.44 %) than that of Kraft lignin (5.26 %). Kraft lignin shows lower molecular weight (Mw=2480 g/mol), higher hydroxyl content (4.29 mmol/g), and lower content of β-O-4 and β-5 bonds compared to ethanol lignin (Mw=3682 g/mol, 2.10 mmol/g). Meanwhile, the phenolic hydroxyl content in both ethanol and Kraft lignins increased with the decrease of molecular weight. Furthermore, ethanol lignin demonstrated higher antioxidant activity and much higher (65times) tensile strength of lignin-based polyurethane elastomer than that of Kraft lignin-based polyurethane elastomer.

Air-drying causes an alteration in density fractionation of soil materials from organic horizons containing volcanic ash

Density fractionation is commonly used to isolate organic matter in soils based on organo-mineral associations. Not only mineral horizons but also organic horizons contain mineral components. Soil samples for density fractionation are sometimes air-dried or freeze-dried, which can introduce unexpected biases in the results. In this study, we compared the density fraction distributions in wet, air-dried, and freeze-dried organic horizon samples rich in reactive Al and Fe minerals. On Mt. Chokai, a volcano in northern Japan, samples were collected from organic horizons from three representative vegetation types: K1 (dwarf pine and dwarf bamboo at the summit), K2 (dwarf bamboo on the back slope), and K3 (snow meadow with predominantly Poaceae at the foot slope). Wet, air-dried, and freeze-dried samples were subjected to sequential density fractionation using cutoff values of 1.6 and 1.8 g cm–3. We then determined the mass, organic carbon, and total nitrogen distributions in the isolated fractions. Air-drying altered the mass, organic carbon, and total nitrogen distribution of each density fraction. Although we observed differences in the mass distributions of the freeze-dried and wet samples in the snow meadow samples (K3), the mass distributions in the K1 and K2 samples did not change significantly between the freeze-dried and wet samples. Therefore, freeze-drying is recommended as a pretreatment to minimize the effects of drying on density fractionation, particularly for soil samples with no drying history, high organic matter content, and/or high levels of reactive Al and Fe minerals.

Phosphorus lability in a Ferralsol as affected by land-use change in the Brazilian Cerrado

ABSTRACT Low availability of phosphorus (P) is a constraint to agricultural development in tropical soils, owing to the high fixation of P in the soil matrix. Land-use change can modify soil P dynamics. This study aimed to evaluate the effects of land-use change on P fractions in a Ferralsol under different systems of use and management. Inorganic (Pi) and organic soil P (Po) fractions were assessed by sequential fractionation using H2O, NaHCO3, NaOH, hot concentrated HCl and H2SO4-H2O2 as extractants. The systems in the study were as follows: pasture (PAST), no-tillage system (NT), organic cultivation (ORG) with 2, 6, 8 and 10 years of organic management, and conventional continuous cropping tillage (CT). A native Cerrado forest (F) area was used as reference. In general, Po forms predominated over Pi, with exception of the CT soil, where Pi represented 41% of the total P. On average, conversion of F into the CT system reduced levels of Po in the soil by up to 72%. The soil P resilience index showed that P inputs in the CT and NT systems were insufficient at recovering P availability after the land-use change. On the other hand, the most recent ORG systems demonstrated the greatest efficiency at restoring the equilibrium of the soil P state. The hypothesis that less intensive agricultural systems increase the soil labile P pool, enhancing available P levels, was confirmed. Agricultural systems that used organic inputs and reduced soil disturbance were found to be more efficient at recovering and maintaining soil P availability.

Soil phosphorus fractionations as affected by cropping systems in the central mid-hills region of Nepal.

Soil plays a critical role as the primary reservoir of phosphorus (P) in terrestrial ecosystems. Sequential fractionation has been extensively utilized to gain insights into the characteristics and dynamics of soil P. However, there is a knowledge gap regarding the different P pools in Nepalese soils. Therefore, this study aimed to investigate the impact of cropping systems on soil P fractions in the central mid-hills of Nepal. The study focused on four cropping systems: vegetable, fruit, rice, and maize-based systems, which exhibited variations in nutrient management, topography, and cropping intensity. A total of 240 soil samples (60 samples from each cropping system) were collected from multiple sites within the central mid-hill region. Standard analytical methods were used to determine the general parameters of the soils, while the sequential fractionation method was employed to assess the organic and inorganic P pools. The results indicated that the effect of cropping systems on soil pH, calcium carbonate (CaCO3) content, and the proportion of sand, silt, and clay was not statistically significant in terms of general parameters. However, significant differences were observed among the different cropping systems in organic matter (OM), electrical conductivity (EC), cation exchange capacity (CEC), and available phosphorus. Similarly, in terms of inorganic phosphorus fractions, loosely bound P (LB-P), aluminum bound P (Al-P), iron bound P (Fe-P), and reductant soluble P (RS-P) were significantly affected, while calcium bound P (Ca-P) did not show a significant difference. Furthermore, in terms of organic phosphorus fractions, labile organic P (L-Po), fluvic acid organic P (FA-Po), and non-labile organic P (NL-Po) exhibited significant differences, whereas moderately labile organic P (ML-Po) and humic acid organic P (HA-Po) did not show a significant difference. Additionally, reductant soluble P showed a significant difference, while total P did not differ significantly. The vegetable-based system exhibited higher levels of the majority of P fractions, followed by the fruit-based, maize-based, and rice-based systems. These findings emphasize the importance of considering cropping systems and their response to different phosphorus pools, as this knowledge can contribute to the development of improved soil phosphorus management strategies and promote sustainable agricultural practices in the region.

Phosphorus dynamics across a 450 ka vertical chronosequence of loess derived (paleo)soils in central US

Pedogenesis entails profound changes in terrestrial phosphorus (P) dynamics, yet means to understand how time- and climate-induced soil weathering impacts P-cycling over geologic timescales remain relatively limited to space-for-time substitution approaches with multi-site chronosequences. We tested an alternative approach for evaluating terrestrial P dynamics described by the Walker-Syers model by measuring P pools in a ~ 450 ka loess–paleosol sequence. This vertical chronosequence reflects episodic proglacial loess deposition during multiple glaciations and interglacial soil development in central North America in a four-stage loess–paleosol sequence that initiated with the pre-Illinois Episode glaciation. Changes in P pools estimated by sequential fractionation aligned with the Walker-Syers P model for interglacial periods but not glacial periods, possibly reflecting limited soil weathering in cooler and drier conditions of the latter. Total P decreased from 797 to 328 mg/kg with depth and was higher in paleosols than underlying loess parent materials. During glacial periods, primary P increased due to loess deposition and decreased during interglacial periods concomitantly with increased non-occluded and occluded secondary P pools, the extent of which reflected differences in weathering environments of paleoclimatic conditions and loess accumulation rates. That P fractions reflected the Walker-Syers model demonstrates that single-site vertical chronosequences have potential for evaluating long-term soil P dynamics.

Use and recovery of P reserves in Southern Brazil Oxisols under no-till with low and high P availability

ABSTRACT The accessibility of soil P reserves by plants on highly weathered Brazilian soils remains unclear. In this study, we assessed the contribution of soil P fractions to P uptake by soybean plants in two no-till Oxisols (Latossolos), with low and high initial content of available P. The recommended P rates (viz., 153 and 50 kg ha -1 yr -1 in the low-P and high-P soil, respectively) were applied in the form of triple superphosphate (TSP) or Bayovar rock phosphate (BRP) plus a treatment without fertilizer. Yields of winter cereals and soybean on the studied soils were examined over a period of three years. Soil samples were collected in the 0.00-0.10 m soil layer and subjected to sequential chemical fractionation of P. In the last crop season, the P content of soybean shoot biomass was determined. Soil P fractions and P content of soybean shoots were subjected to path analysis. The addition BRP in the low-P soil resulted in a winter cereal yield of 2.0 Mg ha -1 lower than TSP. In the scenario of high P, it is possible to maintain high crop yields even without phosphate fertilization for three consecutive years. Path analyses demonstrated the addition of P using either TSP or BRP boosted the contribution of the more labile inorganic P fractions. The addition of BRP should be avoided in P-deficient soils. The addition TSP or BRP reduces the pressure of plants to use soil P reserves. Therefore, the soil P legacy should be considered in fertilization recommendations for high-P soils in NT.

Selective Extraction Process and Characterization of Antioxidant Phenolic Compounds from Pereskia aculeata Leaves Using UPLC-ESI-Q-TOF-MS/MS.

This study innovates in comparing biological activities and chemical composition obtained from extracts and fractions from Pereskia aculeate leaves. Seven extracts and five fractions were produced by conventional successive solid-liquid extraction coupled with simultaneous bioguided purification using solvents of distinct polarities. A comparative analysis was conducted between these purified fractions and the original extracts to elucidate potential improvements in the bioactivity. The extract and fractions were evaluated using the ABTS, DPPH, FRAP, and Folin-Ciocalteau methods and HPLC-DAD and UHPLC-ESI-Q-TOF-MS/MS evaluated chemical composition. The fractions obtained from the hydroalcoholic extract showed better results, with the acetone fraction (Fr-Ace) exhibiting enhanced bioactivity, especially in the FRAP (1095 μmol of FeSO4/g) antioxidant capacity method. The results demonstrated that medium to high polarity solvents were the most effective in extracting bioactive phenolic compounds, with rutin being the predominant compound. The sequential hydroalcoholic fractionation (SHF) method extracted a greater variety of compounds, including vanillic acid and cinnamic acid, which were reported for the first time in P. aculeate leaves. The identified compounds by UPLC-Q-TOF-MS/MS included flavonoids derived from quercetin, isorhamnetin, and kaempferol, phenolic acids, and their derivatives. Quercetin-3-O-xyloside, kaempferol-3-O-arabinoside, trehalose, feruloyltyramine, malyngic acid, pinellic acid, and 16-hydroxy-9-oxooctadeca-10,12,14-trienoic acid were identified for the first time in P. aculeata leaves.

Lamin A/C facilitates DNA damage response by modulating ATM signaling and homologous recombination pathways

ABSTRACT Lamin A/C, a core component of the nuclear lamina, forms a mesh-like structure beneath the inner nuclear membrane. While its structural role is well-studied, its involvement in DNA metabolism remains unclear. We conducted sequential protein fractionation to determine the subcellular localization of early DNA damage response (DDR) proteins. Our findings indicate that most DDR proteins, including ATM and the MRE11-RAD50-NBS1 (MRN) complex, are present in the nuclease – and high salt-resistant pellet fraction. Notably, ATM and MRN remain stably associated with these structures throughout the cell cycle, independent of ionizing radiation (IR)-induced DNA damage. Although Lamin A/C interacts with ATM and MRN, its depletion does not disrupt their association with nuclease-resistant structures. However, it impairs the IR-enhanced association of ATM with the nuclear matrix and ATM-mediated DDR signaling, as well as the interaction between ATM and MRN. This disruption impedes the recruitment of MRE11 to damaged DNA and the association of damaged DNA with the nuclear matrix. Additionally, Lamin A/C depletion results in reduced protein levels of CtIP and RAD51, which is mediated by transcriptional regulation. This, in turn, impairs the efficiency of homologous recombination (HR). Our findings indicate that Lamin A/C plays a pivotal role in DNA damage repair (DDR) by orchestrating ATM-mediated signaling, maintaining HR protein levels, and ensuring efficient DNA repair processes.

Sequential Fractionation of Spruce Bark in a Continuous Flow-through System

Sequential Fractionation of Spruce Bark in a Continuous Flow-through System

Sequential Fractionation of Heavy Metals from Flooded and Non-Flooded Soils in Obunagha Community, Bayelsa State, Nigeria

Soil samples from flooded and non-flooded areas of different farmlands in Obunagha community, Bayelsa State were collected for this study. The aim of the study was to investigate the chemical fractionation and bioavailability of Cr, Cd, Zn, Ni, & Fe in flooded and non-flooded farmlands. The soil samples were fractionated into six chemical fractions, each containing different heavy metal concentrations and analyzed using flame atomic absorption spectrophotometer. The highest average concentration for Cadmium (Cd) is 1.50g/kg, Zinc (Zn) is 7.53g/kg, Nickel (Ni) is 10.54g/kg, Iron (Fe) is 9.52g/kg, and Chromium (Cr) is 12.62g/kg all from the flooded areas of the farmlands. Sequential extraction showed heavy metals distributed throughout all extraction steps, with the water-soluble fraction prevailing, potentially increasing the mobility and bioavailability of these metals. The %bioavailability ranged from 37.98% – 90.00%. The results indicated also that the average concentration of the metals in flood affected farmland were more than the non-flooded areas. The results indicated that floods affect farmland metal content by altering contaminant bioavailability, causing adverse environmental effects. Also, the results of the heavy metals analyses revealed that the levels of nickel, zinc, chromium, cadmium and iron in all the farmland soil samples are above the maximum allowable concentration for heavy metals in soil set by WHO Guidelines provided. Hence, the farmland soils are not safe for agricultural activities. We therefore, recommend regular monitoring of the soils to prevent excessive build-up of these toxic heavy metals.

The Potential Valorization of Corn Stalks by Alkaline Sequential Fractionation to Obtain Papermaking Fibers, Hemicelluloses, and Lignin-A Comprehensive Mass Balance Approach.

The current study deals with an examination of strategies for the sequential treatment of corn stalks (CSs) in an integrated manner aiming to obtain papermaking fibers and to recover both lignin and hemicelluloses (HCs). Several pathways of valorization were experimentally trialed, focusing on getting information from mass balance analysis in an attempt to reveal the potential outcomes in terms of pulp yield, chemical composition, and papermaking properties such as tensile and burst strength. The raw lignin amounts and purity as well as separated hemicelluloses were also characterized. In this work, pulp yields in the range of 44-50% were obtained from CSs, while lignin and hemicelluloses yielded maximum values of 10 g/100 g of CS and 6.2 g/100 g of CS, respectively. Other findings of mass balance analysis evidenced that besides the papermaking pulp, the lignin and HCs also have interesting output values. The recovered lignin yield values were shown to be less than 50% in general, meaning that even if 67 to 90% of it is removed from CSs, only about half is recovered. The removal rates of hemicelluloses were found to be in the range of approx. 30 to 60%. About 15 to 25% of the original HCs could be recovered, and polysaccharides-based products with 67 to 75% xylan content could be obtained. Some key opinions were developed regarding how the mass balance could turn as a result of the chosen CS valorization set-up. The determined antioxidant activity showed that both lignin and hemicelluloses had interesting values for IC50.

Development of a protocol for fractionating and characterising fibres from lignocellulosic food waste

This study aims to explore an advanced protocol for characterising dietary fibre (DF) fractions to meet the growing demand for accurate and reliable data. Although current enzymatic-gravimetric approaches, e.g., AOAC and Van Soest analysis, provide information about soluble and insoluble DF quantification, they present limitations related to the lack of fractions characterisation. To overcome these limitations, the proposed protocol integrates the official AOAC 991.43 method with the sequential fibre fractionation by exploiting the different resistance of the fibre fractions to acid hydrolysis treatments (TFA and H2SO4), utilising hazelnut shells as a case-study. Each hydrolysed fraction was quantified and characterised through GC–MS analysis of monosaccharides. The data obtained for hemicellulose, cellulose, and lignin fractions were then discussed and compared with the Van Soest method. This approach yields a comprehensive procedure applicable to different food and nutraceutical products, emphasising the importance of DF characterisation for a deeper understanding of their bio-functional properties.

Supercritical fluid technology for lupin hulls valorization: extraction and fractionation of lupeol

Extraction of lupeol from lupin hulls has been carried out using supercritical CO2 extraction technology under different operating conditions in order to obtain value-added extracts from the raw material of industrial lupin. The operational parameters used include CO2 pressure and flow and sequential depressurization fractionation. The highest lupeol recovery (96.8%) has been obtained using 320 bar and 50 g/min of CO2. For sequential depressurization, the best results were obtained with a CO2 density close to 728 kg/m3 providing up to 92% of lupeol in the extract and an enrichment factor of 1.2. Despite this high enrichment, lupeol recovery decreases to 50% after fractionation. Better extraction recoveries would have been expected and thus further studies are necessary to improve the extraction recovery of extracts with a high lupeol composition.

Biochemical Fractionation of Human α-Synuclein in a Drosophila Model of Synucleinopathies.

Synucleinopathies are a group of central nervous system pathologies that are characterized by the intracellular accumulation of misfolded and aggregated α-synuclein in proteinaceous depositions known as Lewy Bodies (LBs). The transition of α-synuclein from its physiological to pathological form has been associated with several post-translational modifications such as phosphorylation and an increasing degree of insolubility, which also correlate with disease progression in post-mortem specimens from human patients. Neuronal expression of α-synuclein in model organisms, including Drosophila melanogaster, has been a typical approach employed to study its physiological effects. Biochemical analysis of α-synuclein solubility via high-speed ultracentrifugation with buffers of increasing detergent strength offers a potent method for identification of α-synuclein biochemical properties and the associated pathology stage. Unfortunately, the development of a robust and reproducible method for the evaluation of human α-synuclein solubility isolated from Drosophila tissues has remained elusive. Here, we tested different detergents for their ability to solubilize human α-synuclein carrying the pathological mutation A53T from the brains of aged flies. We also assessed the effect of sonication on the solubility of human α-synuclein and optimized a protocol to discriminate the relative amounts of soluble/insoluble human α-synuclein from dopaminergic neurons of the Drosophila brain. Our data established that, using a 5% SDS buffer, the three-step protocol separates cytosolic soluble, detergent-soluble and insoluble proteins in three sequential fractions according to their chemical properties. This protocol shows that sonication breaks down α-synuclein insoluble complexes from the fly brain, making them soluble in the SDS buffer and thus enriching the detergent-soluble fraction of the protocol.

Hydroethanolic extract and fractions of Pericopsis laxiflora stem bark protect against liver injury in Rat

Pericopsis laxiflora is a medicinal plant that is ubiquitous, especially in the tropical and savannah regions. It can be used in the treatment of hemorrhoids, rheumatism, abdominal pain treatment, diarrhoea, dysentery, fever, skin diseases, and jaundice. The present study investigated the protective effect of 50% hydroethanolic extract and fractions of Pericopsis laxiflora stem bark in lead-induced hepatotoxicity in rats. The development of liver injury has become a global issue and their treatment and management mostly result in more economic problems, especially in the African population.The stem bark of P. laxiflora was processed and 50 % hydroethanolic extract (HSE) was prepared. HSE was subjected to sequential fractionation with organic solvents: chloroform (CFHSE), ethyl acetate (EFHSE), and methanol (MFHSE), to obtain respective fractions. The residue was designated as aqueous fraction (AFHSE). Hepatoprotective activities of HSE and fractions (at 250 mg/kg) and Silymarin were assessed using the lead (as lead acetate; 50 mg/kg, i.p.). Body and organ weight changes, biochemical, hematological profile, oxidative stress parameters, and pro-inflammatory cytokines (TNF-α, TGF-β, NF кβ, and COX-2) in liver homogenate were measured. A histopathological examination of the liver was performed. Treatment with HSE and fractions resulted in a significant increase in relative organ weights, GSH, CAT, SOD, and levels and a significant decrease in MDA and MPO levels against Pb, as well as the restoration of liver biomarkers and pro-inflammatory cytokines (TNF-α, TGF-β, NF кβ, and COX-2) to near-normal levels. Biochemical data were corroborated by histological observations, with MFHSE recording the highest percentage of liver protection. The present investigation suggests that HSE possesses remarkable hepatoprotective properties and this can be attributed to the inhibitory effect on oxidative stress and suppression of pro-inflammatory cytokines.

Inhibition of proliferation of human osteosarcoma cell line (MG63) by ajwain (Trachyspermum ammi L.) plant extract

Trachyspermum ammi L. (TA), popularly called ajwain, is a well-known spice plant, with fruit pods that are used in Indian traditional medicine. Fruits of this plant were scientifically investigated for medicinal properties, but no studies are reported on the vegetative parts of the plant. Hence, the present investigation is aimed to evaluate the aerial parts of the plant for anti-proliferative and antioxidant effects. Methanolic extract (Me) of TA was subjected to sequential fractionation using the solvents in the increasing order of polarity viz. hexane (He), dichloromethane (Dcm), ethyl acetate (Ea), n-butanol (n-Bu), and water (Aq). Phytochemical analyses, DPPH radical scavenging assay, and in vitro antiproliferative activity on the MG63 osteosarcoma cell line (MTT assay) were performed. Preliminary phytochemical analyses revealed the presence of reducing and non-reducing sugars, amino acids, tannins, phenols, terpenoids, and saponins. Ethyl acetate fraction showed the highest amount of total phenolics (367.90±0.02), followed by n-Bu (287.50±0.04), Dcm (193.56±0.07), Me extract (190.14±0.07), Aq (142.20±0.02) and He (80.74±0.01) fractions. Ethyl acetate fraction exhibited higher DPPH radical scavenging activity (IC50 =116.74 μg/mL) followed by n-Bu (IC50=133.81 μg/mL) fraction with a correlation to the higher amount of phenolics and flavonoids. However, maximum antiproliferative activity was exhibited by hexane fraction on MG 63 human osteosarcoma cell line which can be attributed to the presence of thymol, a monoterpenoid phenol present in ajwain. The current study indicates that the aerial parts of T. ammi Linn. can be considered as potential antioxidants and therapeutic against osteosarcoma.

Internal phosphorus loading in a chain of eutrophic hardwater lakes in Saskatchewan, Canada

Sediments can act as a source or sink of phosphorus (P) for the water column of lakes. In iron (Fe)-rich softwater lakes, redox processes are important contributors to sediment P flux. However, the contribution of redox processes to P flux in hardwater lakes, with high pH and high concentrations of redox-insensitive calcium (Ca) is unknown. Intact sediment cores, collected in different seasons (summer or fall) from a chain of eutrophic hardwater lakes in southeastern Saskatchewan, Canada, were used to quantify sediment P fluxes in laboratory incubations under hypoxic or oxic conditions at temperatures consistent with the season of sample collection. Geochemical analyses determined concentrations of sediment total (TP) and organic P (TPo), organic matter (OM), total Ca and magnesium, and total and extractable manganese, Fe and aluminum. Sediment P pools were determined using sequential fractionation and solution 31P nuclear magnetic resonance spectroscopy. Sediment P fluxes were significantly higher in sediment cores incubated under hypoxic conditions (−24.4 to 28.5 mg P m−2 d−1) than oxic conditions (−60.3 to 14.2 mg P m−2 d−1). There were significant seasonal and lake differences for TP, TPo and cation concentrations, with Ca the dominant cation in all but one lake. Phosphate bound in the redox-sensitive pool was the only sediment P fraction that significantly differed among the lakes (0.10 to 0.18 mg P g−1 d.w.; 9 to 16 % of TP), with an inverse relationship to sediment P flux. Principal component analysis suggests that high concentrations of internally-generated TPo forms and OM in surface sediments play a key role in internal P loading in these lakes. However, sediment Ca appears to have an overriding effect on sediment P, partially masking the impact of redox control on internal P loading in these hardwater prairie lakes.

Soil Biodegradation Resistance of Cotton Fiber Doped with Interior and Exterior Silver Nanoparticles.

Engineering fibers with nanomaterials is an effective way to modify their properties and responses to external stimuli. In this study, we doped cotton fibers with silver nanoparticles, both on the surface (126 ± 17 nm) and throughout the fiber cross section (18 ± 4 nm), and examined the resistance to soil biodegradation. A reagent-free one-pot treatment of a raw cotton fabric, where noncellulosic constituents of the raw cotton fiber and starch sizing served as reducing agents, produced silver nanoparticles with a total concentration of 11 g/kg. In a soil burial study spanning 16 weeks, untreated cotton underwent a sequential degradation process-fibrillation, fractionation, and merging-corresponding to the length of the soil burial period, whereas treated cotton did not exhibit significant degradation. The remarkable biodegradation resistance of the treated cotton was attributed to the antimicrobial properties of silver nanoparticles, as demonstrated through a test involving the soil-borne fungus Aspergillus flavus. The nonlinear loss behavior of silver from the treated cotton suggests that nanoparticle depletion in the soil depends on their location, with interior nanoparticles proving durable against environmental exposure.

Unveiling the contribution of Osborne protein fractions to the physicochemical and functional properties of alkaline and enzymatically extracted green lentil proteins

AbstractLentil proteins are gaining popularity as food ingredients, serving both functional and nutritional purposes. To better understand the properties of lentil proteins extracted using commercially relevant methods (alkaline and enzymatic), sequential fractionation by solubility (Osborne fractionation) was performed and the physicochemical, thermal, and functional properties of the extracts were characterized. Fractionation revealed that 43% of lentil proteins were water‐soluble (ALB, albumin‐rich), 37% salt‐soluble (GLO, globulin‐rich), 14% alkaline‐soluble (GLU, glutelin‐rich), and 3% ethanol‐soluble (PRO, prolamin‐rich). Protein extraction yields of 81% and 87% were achieved by alkaline (pH 9.0, 50 °C, 1:10 solids‐to‐liquid ratio, 60 min) and enzymatic extraction (same conditions with 0.5% (w/w) Alkaline Protease), respectively. Proteomic analysis allowed for the identification of 129 proteins among all extracts, and the ALB and GLO fractions exhibited similar protein profiles as the alkaline‐extracted proteins. The secondary structure of the protein fractions was dominated by β‐sheets (20%–35%) and unordered structures (45%–48%). Surface hydrophobicity and absolute zeta potential were negatively correlated (R2 = 0.82, p < 0.05). ALB and GLO fractions had higher denaturation temperatures than the alkaline/enzymatically‐extracted proteins, potentially due to partial denaturation. ALB and GLO fractions also had the highest solubility and emulsification capacities. Under acidic conditions, enzymatically‐extracted proteins exhibited better solubility (58 vs. 33%), emulsification (499 vs. 403 g oil/g dry sample), and similar foaming capacity (57%–69%) compared to alkaline‐extracted proteins. This study showed that alkaline and enzymatically extracted lentil proteins share physicochemical and functional characteristics with water‐ and salt‐extracted proteins, demonstrating the efficacy of these single‐stage extraction strategies in achieving high yields and desirable functionality.

Migration of phosphorus in pig manure during pyrolysis process and slow-release mechanism of biochar in hydroponic application

Pyrolysis is an effective method for treating of livestock and poultry manure developed in recent years. It can completely decompose pathogens and antibiotics, stabilize heavy metals, and enrich phosphorus (P) in biochar. To elucidate the P migration mechanism under different pig manure pyrolysis temperatures, sequential fractionation, solution 31P nuclear magnetic resonance, X-ray photoelectron spectroscopy, X-ray diffraction, and K-edge X-ray absorption near-edge structure techniques were used to analyze the P species in pig manure biochar (PMB). The results indicated that most of the organic P in the pig manure was converted to inorganic P during pyrolysis. Moreover, the transformation to different P groups pathways was clarified. The phase transition from amorphous to crystalline calcium phosphate was promoted when the temperature was above 600 °C. The content of P extracted by hydrochloric acid, which was the long-term available P for plant uptake, increased significantly. PMB pyrolyzed at 600 °C can be used as a highly effective substitute for P source. It provides the necessary P species (e.g. water-soluble P.) and metal elements for the growth of water spinach plants, and which are slow-release comparing with the Hogland nutrient solution.