Isolation and characterisation of lignin using natural deep eutectic solvents pretreated kenaf fibre biomass.

Extraction of lignin via green methods is a crucial step in promoting the bioconversion of lignocellulosic biomasses. In the present study, utilisation of natural deep eutectic solvent for the pretreatment of kenaf fibres biomass is performed. Furthermore, extracted lignin from natural deep eutectic solvent pretreated kenaf biomass was carried out and its comparative study with commercial lignin was studied. The extracted lignin was characterized and investigated through Infrared Fourier transform spectroscopy, X-ray Diffraction, thermogravimetric analysis, UV-Vis spectroscopy, and scanning electron microscopy. FTIR Spectra shows that all samples have almost same set of absorption bands with slight difference in frequencies. CHNS analysis of natural deep eutectic solvent pretreated kenaf fibre showed a slight increase in carbon % from 42.36 to 43.17% and an increase in nitrogen % from - 0.0939 to - 0.1377%. Morphological analysis of commercial lignin shows irregular/uneven surfaces whereas natural deep eutectic solvent extracted lignin shows smooth and wavy surface. EDX analysis indicated noticeable peaks for oxygen and carbon elements which are present in lignocellulosic biomass. Thermal properties showed that lignin is constant at higher temperatures due to more branching and production of extremely condensed aromatic structures. In UV-VIS spectroscopy, commercial lignin shows slightly broad peak between 300 and 400 nm due to presence of carbonyl bond whereas, natural deep eutectic solvent extracted lignin does not show up any peak in this range. XRD results showed that the crystallinity index percentage for kenaf and natural deep eutectic solvent treated kenaf was 70.33 and 69.5% respectively. Therefore, these innovative solvents will undoubtedly have significant impact on the development of clean, green, and sustainable products for biocatalysts, extraction, electrochemistry, adsorption applications.

Bioactive properties and gut microbiota modulation by date seed polysaccharides extracted using ultrasound-assisted deep eutectic solvent.

Polysaccharides are abundant macromolecules. The study extracted date seed polysaccharides (UPS) using ultrasound-assisted deep eutectic solvent extraction to valorize date seeds. UPS were subjected to comprehensive characterization and evaluation of their bioactivity, prebiotic properties, and their potential to modulate the gut microbiome. Characterization revealed UPS's heteropolysaccharide composition with galactose, mannose, fructose, glucose, and galacturonic acid respectively in 66.1, 13.3, 9.9, 5.4, and 5.1%. UPS showed a concentration-dependent increase of radical scavenging and antioxidant activities, evidenced by FRAP, TAC, and RP assays. They also displayed antimicrobial efficacy against E. coli O157:H7, S. typhimurium, S. aureus, and L. monocytogenes. Rheological analysis showed UPS's elastic-dominant nature with thixotropic tendencies. UPS inhibited α-glycosidase, α-amylase, and ACE up to 86%, and reduced Caco-2 and MCF-7 cell viability by 70% and 46%, respectively. UPS favored beneficial gut microbiota growth, releasing significant SCFAs during fecal fermentation.

Extraction of lignin-containing nanocellulose fibrils from date palm waste using a green solvent.

Lignin-containing nanocellulose (LNC) is a compelling alternative to traditional nanocellulose (NC), it offers enhanced yields and a reduction in the demand for toxic chemicals. This research involves the isolation of LNC from date palm waste using a green hydrolysis process and its subsequent characterization. The potential of using ionic liquids (ILs) as green solvents to isolate LNC has not yet been explored. Our findings suggest that 1-ethyl-3-methylimidazolium chloride ([Emim]Cl) can hydrolyze partially delignified and unbleached lignocellulose, achieving LNC synthesis. The obtained LNC showed a higher yield than its NC counterpart and exhibited rod-shaped fibers with nanoscale diameters and micrometer lengths, indicating a high aspect ratio. Dynamic Light Scattering (DLS) results indicate average particle sizes of 143.20 nm for NC and 282.30 nm for LNC, with a narrow particle size distribution conforming their monodisperse behavior. Thermogravimetric analysis and differential scanning calorimetry revealed high thermal stability (initial degradation temperature = 222.50 °C and glass transition temperature = 84.45°C) of LNC. Moreover, the obtained LNC fibers were crystalline (crystallinity index = 52.76 %). Their activation energy (124.95 kJ/mol) was determined using the Coats-Redfern method by employing eight solid-state diffusion models. Overall, this study motivates the use of ILs as green solvents to produce lignocellulose derivatives that are suitable for various applications.

Properties of low-fat Cheddar cheese prepared from bovine-camel milk blends: Chemical composition, microstructure, rheology, and volatile compounds.

Making cheese from camel milk (CM) presents various challenges due to its different physicochemical properties compared with bovine milk (BM). In this study, we investigated the chemical composition, proteolysis, meltability, oiling off, texture profile, color, microstructure, and rheological properties of low-fat Cheddar cheese (LFCC) prepared from BM-CM blends. LFCC was produced from BM or BM supplemented with 15% CM (CM15) and 30% CM (CM30), and analyzed after 14, 60, 120, and 180 d of ripening at 8°C. Except for salt content, no significant differences were observed among LFCC from BM, CM15, and CM30. The addition of CM increased the meltability and oiling off in the resulting cheese throughout storage. With respect to color properties, after melting, LFCC CM30 showed lower L* values than LFCC made from BM and CM15, and a* and b* values were higher than those of BM and CM15 samples. LFCC from CM30 also exhibited lower hardness compared with the other cheeses. Moreover, LFCC made from BM showed a rough granular surface, but cheese samples made from BM-CM blends exhibited a smooth surface. The rheological parameters, including storage modulus, loss modulus, and loss tangent, varied among cheese treatments. The determined acetoin and short-chain volatile acids (C2-C6) in LFCC were affected by the use of CM, because CM15 showed significantly higher amounts than BM and CM30, respectively. The detailed interactions between BM and CM in the cheese matrix should be further investigated.

Structural characterization, biofunctionality, and environmental factors impacting rheological properties of exopolysaccharide produced by probiotic Lactococcus lactis C15.

Exopolysaccharides (EPSs) possess distinctive rheological and physicochemical properties and innovative functionality. This study aimed to investigate the physicochemical, bioactive, and rheological properties of an EPS secreted by Lactococcus lactis subsp. lactis C15. EPS-C15 was found to have an average molecular weight of 8.8 × 105 Da and was identified as a hetero-EPS composed of arabinose, xylose, mannose, and glucose with a molar ratio of 2.0:2.7:1.0:21.3, respectively. The particle size and zeta potential represented 311.2 nm and - 12.44 mV, respectively. FITR exhibited that EPS-C15 possessed a typical polysaccharide structure. NMR displayed that EPS-C15 structure is → 3)α-d-Glcvi (1 → 3)α-d-Xylv (1 → 6)α-d-Glciv(1 → 4)α-d-Glc(1 → 3)ß-d-Man(1 → 2)α-d-Glci(1 → . EPS-C15 scavenged DPPH and ABTS free radicals with 50.3% and 46.4% capacities, respectively. Results show that the antiproliferative activities of EPS-C15 revealed inhibitions of 49.7% and 88.1% against MCF-7 and Caco-2 cells, respectively. EPS-C15 has antibacterial properties that inhibited Staphylococcus aureus (29.45%), Salmonella typhimurium (29.83%), Listeria monocytogenes (30.33%), and E. coli O157:H7 (33.57%). The viscosity of EPS-C15 decreased as the shear rate increased. The rheological properties of the EPS-C15 were affected by changes in pH levels and the addition of salts. EPS-C15 is a promising biomaterial that has potential applications in various industries, such as food, pharmaceuticals, and healthcare.

Effect of whey protein isolate addition on set-type camel milk yogurt: Rheological properties and biological activities of the bioaccessible fraction.

The manufacture of camel milk (CM) yogurt has been associated with several challenges, such as the weak structure and watery texture, thereby decreasing its acceptability. Therefore, this study aimed to investigate the effect of whey protein isolate (WPI) addition on the health-promoting benefits, texture profile, and rheological properties of CM yogurt after 1 and 15 d of storage. Yogurt was prepared from CM supplemented with 0, 3, and 5% of WPI and compared with bovine milk yogurt. The results show that the water holding capacity was affected by WPI addition representing 31.3%, 56.8%, 64.7%, and 45.1% for yogurt from CM containing 0, 3 or 5% WPI, and bovine milk yogurt, respectively, after 15 d. The addition of WPI increased yogurt hardness, adhesiveness, and decreased the resilience. CM yogurt without WPI showed lower apparent viscosity, storage modulus, and loss modulus values compared with other samples. The supplementation of CM with WPI improved the rheological properties of the obtained yogurt. Furthermore, the antioxidant activities of yogurt before and after in vitro digestion varied among yogurt treatments, which significantly increased after digestion except the superoxide anion scavenging and lipid oxidation inhibition. After in vitro digestion at d 1, the superoxide anion scavenging of the 4 yogurt treatments respectively decreased from 83.7%, 83.0%, 79.1%, and 87.4% to 36.7%, 38.3%, 44.6%, and 41.3%. The inhibition of α-amylase and α-glucosidase, angiotensin-converting enzyme inhibition, cholesterol removal, and degree of hydrolysis exhibited different values before and after in vitro digestion.

Fermented camel milk influenced by soy extract: Apparent viscosity, viscoelastic properties, thixotropic behavior, and biological activities.

During fermentation, camel milk forms a fragile, acid-induced gel, which is less stable compared with the gel formed by bovine milk. In this study, camel milk was supplemented with different levels of soy extract, and the obtained blends were fermented with 2 different starter culture strains (a high acidic culture and a low acidic culture). The camel milk-soy extract yogurt treatments were evaluated for pH value, acidity, total phenolic compounds, antioxidant capacities, degree of hydrolysis, α-amylase and α-glucosidase inhibition, angiotensin-converting enzyme inhibition, antiproliferative activities, and rheological properties after 1 and 21 d of storage at 4°C. The results revealed that some of the investigated parameters were significantly affected by the starter culture strain and storage period. For instance, the effect of starter cultures was evident for the degree of hydrolysis, antioxidant capacities, proliferation inhibition, and rheological properties because these treatments led to different responses. Furthermore, the characteristics of camel milk-soy extract yogurt were also influenced by the supplementation level of soy extract, particularly after 21 d of storage. This study could provide valuable knowledge to the dairy industry because it highlighted the characteristics of camel milk-soy yogurt prepared with 2 different starter culture strains.

Physicochemical, rheological, and bioactive properties of exopolysaccharide produced by a potential probiotic Enterococcus faecalis 84B.

Exopolysaccharides (EPS) have attracted a great interest due to their potential health-promoting properties and industrial applications. This study aimed to investigate the physicochemical, rheological, and biological properties of an EPS produced by a potential probiotic strain Enterococcus faecalis 84B. The results show that the extracted EPS, designated EPS-84B, had an average molecular weight of 604.8 kDa, particles size diameter of 322.0 nm, and mainly composed of arabinose and glucose with a molar ratio of 1:2. Furthermore, EPS-84B exhibited a shear-thinning behavior and had a high melting point. The rheological properties of EPS-84B were strongly influenced by the type of salt than by the pH value. EPS-84B displayed ideal viscoelastic properties, with both viscous and storage moduli increasing with frequency. The antioxidant activity of EPS-84B at a concentration of 5 mg/mL was 81.1 % against DPPH and 35.2 % against ABTS. At 5 mg/mL, the antitumor activity of EPS-84B against Caco-2 and MCF-7 cell lines was 74.6 and 38.6 %, respectively. In addition, the antidiabetic activity of EPS-84B towards α-amylase and α-glucosidase was 89.6 and 90.0 %, respectively at 100 µg/mL. The inhibition of foodborne pathogens by EPS-84B was up to 32.6 %. Overall, EPS-84B has promising properties that could be utilized in food and pharmaceutical industries.

Utilization of Mechanically Recycled Carbon Fibers in Vinyl Ester Composites.

As we enter the twenty-first century, the aviation sector is expected to thrive as flying becomes the primary mode of transportation between states or nations. With such a demand, there is a corresponding need to manufacture aircraft components. The study focused on recycling carbon fiber composites received from the STRATA company, which were cut-off/waste material generated during the manufacture of airplane components. The cut-offs were then reduced to powder form using a standard face milling machine in three sizes (90, 150, and 250 µm). After, the powder was utilized to fabricate vinyl ester composites with four weight percentages (10%, 20%, 30%, and 40%). The results demonstrate that the tensile strength of all composites had risen by 30.2%, 21.3%, and 17.6% for 90, 150, and 250 µm respective with the addition of 20 wt% of reinforcement. Furthermore, subsequently decreased with the additional reinforcement for all particle sizes. The compressive strength increased by 30% from 187.5 MPa to 244 MPa with 10 wt% of recycled carbon powder composite of 90µm particle size. However, samples prepared with 150 µm and 250 µm fiber size show approximately 17% and 1% increase in the compression strength with the addition of 10wt% of recycled carbon powder. A similar trend was observed for the flexural strength with an highest increase of 9% for 90 µm particle size with addition of 20 wt% reinforcement. Nonetheless, the SEM images revealed that the fiber-matrix bonding was weak, proved through the clean pullout fibers at the fracture surfaces.

Low-moisture part-skim mozzarella cheese made from blends of camel and bovine milk: Gross composition, proteolysis, functionality, microstructure, and rheological properties.

Camel (CM) milk is used in variety of ways; however, it has inferior gelling properties compared with bovine milk (BM). In this study, we aimed to investigate the physicochemical, functional, microstructural, and rheological properties of low-moisture part-skim (LMPS) mozzarella cheese, made from BM, or BM mixed with 15% CM (CM15%) or 30% CM (CM30%), at various time points (up to 60 d) of storage at 4°C after manufacture. Low-moisture part-skim mozzarella cheeses using CM15% and CM30% had high moisture and total Ca contents, but lower soluble Ca content. Compared with BM cheese, CM15% and CM30% LMPS mozzarella cheese exhibited higher proteolysis rates during storage. Adding CM affected the color properties of LMPS mozzarella cheese manufactured from mixed milk. Scanning electron microscopy images showed that the microstructure of CM15% and CM30% cheeses had smooth surfaces, whereas the BM cheese microstructures were rough with granulated surfaces. Low-moisture part-skim mozzarella cheeses using CM15% and CM30% showed significantly lower hardness and chewiness, but higher stringiness than BM cheese. Compared with BM cheese, CM15% and CM30% cheeses showed lower tan δ levels during temperature surges, suggesting that the addition of CM increased the meltability of LMPS mozzarella cheese during temperature increases. Camel milk addition affected the physicochemical, microstructural, and rheological properties of LMPS mozzarella cheese.

Isolation and Characterization of Cellulose Nanocrystals from Date Palm Waste.

This study presents the isolation, characterization, and kinetic analyses of cellulose nanocrystals (CNCs) from date palm waste in the United Arab Emirates. After bleaching date palm stem waste with acidified NaClO2 and delignification via NaOH treatments, cellulose was extracted. Mineral acid hydrolysis (62 wt % H2SO4) was performed at 45 °C for 45 min to produce crystalline nanocellulose. Fourier transform infrared (FTIR) and chemical composition analysis confirmed the removal of noncellulosic constituents. The crystallinity index increased gradually with chemical treatments, according to the obtained X-ray diffraction (XRD) results. Thermogravimetric analysis and differential scanning calorimetry results revealed that the CNC has high thermal stability. The Coats-Redfern method was used to determine the kinetic parameters. The kinetic analysis confirmed that CNC has more activation energy than cellulose and thus confirms its compact and resistive crystalline structure. This has been attributable to the stronger hydrogen bonding in CNC crystalline domains than that in cellulose crystalline domains. Scanning electron microscopy revealed that lignin and hemicellulose were eliminated after chemical pretreatments, and CNC with a rodlike shape was obtained after hydrolysis. Moreover, transmission electron microscopy confirmed the nanoscale of crystalline cellulose. ζ potential analysis indicated that the CNC afforded a stable suspension (-29.27 mV), which is less prone to flocculation. Kinetic analyses of cellulose and cellulose nanocrystals isolated from date palm waste are useful for making composites and designing selective pyrolysis reactors.

The Texture of Camel Milk Cheese: Effects of Milk Composition, Coagulants, and Processing Conditions.

Numerous people in African, Middle Asian, Middle Eastern, and Gulf Cooperation Council (GCC) countries highly value camel milk (CM) as it plays a vital role in their diet. The protein composition of CM as well as the structure of its casein micelles differs significantly from bovine milk (BM). Cheeses made from CM have a weak curd and soft texture compared to those made from BM. This review article presents and discusses the effect of milk protein composition, processing conditions (pasteurization and high-pressure treatment), and coagulants (camel chymosin, organic acids, plant proteases) on the quality of CM cheeses. CM cheese's weak texture is due to compositional characteristics of the milk, including low κ-casein-to-ß-casein ratio (≈0.05 in CM vs. ≈0.33 in BM), large micelle size, different whey protein components, and higher proteolytic activity than BM. CM cheese texture can be improved by preheating the milk at low temperatures or by high pressure. Supplementing CM with calcium has shown inconsistent results on cheese texture, which may be due to interactions with other processing conditions. Despite their structure, CM cheeses are generally well liked in sensory studies.

Low-fat akawi cheese made from bovine-camel milk blends: Rheological properties and microstructural characteristics.

Camel milk (CM) can be used as an ingredient to produce various dairy products but it forms weak rennet-induced and acid-induced gels compared with bovine milk (BM). Therefore, in this study, we aimed to investigate the effect of blending bovine milk with camel milk on the physicochemical, rheological (amplitude sweep and frequency sweep), and microstructural properties of low-fat akawi (LFA) cheese. The cheeses were made of BM only or BM blended with 15% (CM15%) or 30% (CM30%) camel milk and stored at 4°C for 28 d. The viscoelastic properties as a function of temperature were assessed. The LFA cheeses made from blended milks had higher moisture, total Ca, and soluble Ca contents, and had higher pH 4.6-water-soluble nitrogen compared with those made from BM. Analysis by scanning electron microscopy demonstrated that the microstructures formed in BM cheese were rough with granular surfaces, whereas those in blended milk cheeses had smooth surfaces. Hardness was lower for LFA cheeses made from blended milk than for those made from BM only. The LFA cheeses demonstrated viscoelastic behavior in a linear viscoelastic range from 0.1 to 1.0% strain. The storage modulus (G') was lower in LFA cheese made from BM over a range of frequencies. Adding CM reduced the resistance of LFA cheeses to flow as temperature increased. Blended cheeses exhibited lower complex viscosity values than BM cheeses during temperature increases. Thus, the addition of camel milk improved the rheological properties of LFA cheese.

The Effect of Alkaline Treatment on Poly(lactic acid)/Date Palm Wood Green Composites for Thermal Insulation.

In this work, the effect of alkaline treatment on the thermal insulation and mechanical properties of date palm wood fibers (DPWF) and polylactic acid (PLA) green composite was studied. Alkaline treatment was applied to DPWF using two different solutions: sodium hydroxide (NaOH) and potassium hydroxide (KOH), with concentration of 2 vol.%. The fibers were later incorporated into PLA with weight percentages from 10 to 40 wt.%, to form three composite types: PLA with untreated fibers (PLA-UTDPWF), PLA with KOH treated fibers (PLA-KOH), and PLA with NaOH treated fibers (PLA-NaOH). The prepared composites were for use as a green thermal insulation material. The composites were tested to assess the effect of treatment on their physical (density and degree of crystallization), thermal (thermal conductivity, specific heat capacity, thermal diffusivity, thermal degradation, glass transition, and melting temperature), and mechanical properties. Moreover, the composite structural characteristics were investigated using FTIR and SEM analysis. The alkaline treatment significantly increased the crystallinity of the composites, specifically for higher filler loadings of 30 and 40 wt.%. The crystallinity for the 40 wt.% increased from 33.2% for PLA-UTDPWF, to 41% and 51%, for PLA-NaOH and PLA-KOH, respectively. Moreover, the alkaline treatment reduced the density and produced lighter composites than the untreated specimens. For instance, the density of 40 wt.% composite was reduced from 1.43, to 1.22 and 1.30 gcm3 for PLA-NaOH and PLA-KOH, respectively.

A New Green Composite Based on Plasticized Polylactic Acid Mixed with Date Palm Waste for Single-Use Plastics Applications.

Petroleum-based plastic is widely used in almost all fields. However, it causes serious threats to the environment owing to its non-biodegradable properties, which necessitates finding biodegradable alternatives. Here, date palm rachis (DPR) waste was used as a filler (30, 40, and 50 wt%) to form a biodegradable composite with polylactic acid (PLA) and achieve cost-performance balance. DPR-PLA composites were prepared using a melt-mixing extruder at 180 °C by varying mixing time, DPR composition, and plasticizer type and composition. The biodegradable testing specimens were prepared by compression molding and analyzed using physical, thermal, and mechanical characterizations. Scanning electron microscopy images indicated a uniform dispersion of DPR (90 µm) in the PLA matrix. The esterification reaction resulting from this interaction between DPR and PLA was confirmed by Fourier transform infrared spectroscopy. The 30 wt% DPR-PLA composite was considered the optimal composite with the lowest melt flow index (16 g/10 min). This work confirmed the superior effect of addition of 10 wt% of triethyl citrate (TEC) compared with polybutylene adipate terephthalate (PBAT) by the improvement in the elongation at break of the optimal composite from 2.10% to 4.20%. Moreover, the addition of 10 wt% of PBAT to the optimal composite resulted in a lower tensile strength (21.80 MPa) than that of the composite with 10 wt% of TEC (33.20 MPa). These results show the potential of using the proposed composite as an alternative material for single-use plastics such as cutlery.

Removal of Bromine from the non-metallic fraction in printed circuit board via its Co-pyrolysis with alumina.

The effectiveness of a recycling approach of the printed circuit board (PCBs), and, thus, the quality of polymeric constituents, primarily rests on the capacity to eliminate the bromine content (mainly as HBr). HBr is emitted in appreciable quantities during thermal decomposition of PCB-contained brominated flame retardants (BFRs). The highly corrosive, yet relatively reactive HBr, renders recovery of bromine-free hydrocarbons streams from brominated polymers in PCBs very challenging. Via combined experimental and theoretical frameworks, this study explores the potential of deploying alumina (Al2O3) as a debromination agent of Br-containing hydrocarbon fractions in PCBs. A consensus from a wide array of characterization techniques utilized herein (ICP-OES, IC, XRD, FTIR, SEM-EDX, and TGA) clearly demonstrates the transformation of alumina upon its co-pyrolysis with the non-metallic fractions of PCBs, into aluminum bromides and oxy-bromides. ICP-OES measurements disclose the presence of high concentration of Cu in the non-metallic fraction of PCB, along with minor levels of selected valuable metals. Likewise, elemental ionic analysis by IC demonstrates an elevated concentration of bromine in washed alumina-PCBs pyrolysates, especially at 500 °C. The Coats-Redfern model facilitates the derivation of thermo-kinetic parameters underpinning the thermal degradation of alumina-PCB mixtures. Density functional theory calculations (DFT) establish an accessible reaction pathway for the HBr uptake by the alumina surface, thus elucidating chemical reactions governing the observed alumina debromination activity. Findings from this study illustrate the capacity of alumina as a HBr fixation agent during the thermal treatment of e-waste.

The Effect of Biopolymer Chitosan on the Rheology and Stability of Na-Bentonite Drilling Mud.

The utilization of greens resources is a grand challenge for this century. A lot of efforts are paid to substitute toxic ingredients of the conventional drilling mud system with nontoxic natural materials. In this paper, the effect of the natural polymer chitosan on the rheology and stability of sodium-bentonite drilling mud was investigated in the polymer concentration range of 0.1-3.0 wt.%. Both the shear and time dependent rheological properties of pure chitosan, pure bentonite and bentonite-chitosan dispersions were studied. Moreover, zeta potential measurements were used to evaluate the stability of bentonite-chitosan suspension. Adding chitosan improved the natural properties of drilling mud, namely: yield stress, shear thinning, and thixotropy. The viscosity of bentonite suspension increased significantly upon the addition of chitosan in the concentration range of 0.5 to 3.0 wt.% forming network structure, which can be attributed to the interactions of hydrogen bonding between -OH clusters on the bentonite surface with the NH group in the chitosan structure. On the other hand, dispersed chitosan-bentonite suspension was observed at low chitosan concentration (less than 0.5 wt.%). Increasing both bentonite and chitosan concentrations led to the flocculation of the bentonite suspension, forming a continuous gel structure that was characterized by noteworthy yield stress. The desired drilling mud rheological behavior can be obtained with less bentonite by adding chitosan polymer and the undesirable effects of high solid clay concentration can be avoided.

Physical and thermal insulation properties of the composites based on seawater-neutralised bauxite residue.

The objective of this study is to evaluate the possibility of using bauxite residue (BR), which is a highly hazardous waste, as a filler in thermoset polymer matrices for applications in insulating construction materials to minimise heat loss in buildings. Unsaturated polyester resin (UPR) blended with the seawater-neutralised BR in a ratio of 0-60 vol.% was transformed into a solid via a crosslinking process at room temperature. The pristine polyester and BR-UPR composites were characterised to ascertain their structural, physical and thermal properties. The results indicate that BR is a good filler that can be used with UPR to develop thermal insulation/construction materials. The UPR composite containing 40 vol.% BR is considered to be the optimum mixture with respect to the tested physical and thermal properties because it utilises a large amount of filler and shows promising thermal insulation characteristics with a thermal conductivity of 0.096 W/(m∙K), a thermal diffusivity of 0.161 mm2/s, a 24-h water retention of 0.15 % and a bulk density of 1484 kg/m3. Furthermore, the thermal stability of the prepared composites is positively influenced by the incorporation of BR. The overall weight loss upon heating to 900 °C decreased from 99.85 % (pristine polyester) to 46.68 % (60 vol.% BR composite).

Thermal Insulation and Mechanical Properties of Polylactic Acid (PLA) at Different Processing Conditions.

This work aims to provide an extensive evaluation on the use of polylactic acid (PLA) as a green, biodegradable thermal insulation material. The PLA was processed by melt extrusion followed by compression molding and then subjected to different annealing conditions. Afterwards, the thermal insulation properties and structural capacity of the PLA were characterized. Increasing the annealing time of PLA in the range of 0-24 h led to a considerable increase in the degree of crystallization, which had a direct impact on the thermal conductivity, density, and glass transition temperature. The thermal conductivity of PLA increased from 0.0643 W/(m·K) for quickly-cooled samples to 0.0904 W/(m·K) for the samples annealed for 24 h, while the glass transition temperature increased by approximately 11.33% to reach 59.0 °C. Moreover, the annealing process substantially improved the compressive strength and rigidity of the PLA and reduced its ductility. The results revealed that annealing PLA for 1-3 h at 90 °C produces an optimum thermal insulation material. The low thermal conductivity (0.0798-0.0865 W/(m·K)), low density (~1233 kg/m3), very low water retention (<0.19%) and high compressive strength (97.2-98.7 MPa) in this annealing time range are very promising to introduce PLA as a green insulation material.

Exopolysaccharide produced by the potential probiotic Lactococcus garvieae C47: Structural characteristics, rheological properties, bioactivities and impact on fermented camel milk.

Fermented camel milk possesses a weak (liquid-like) gel structure. We aimed to 1) investigate the characteristics, bioactivities and rheological properties of the exopolysaccharide (EPS) produced by Lactococcus garvieae-C47 (exopolysaccharide-C47 product), a potential probiotic bacterium, on milk extracted from camels and 2) examine the rheological properties of the fermented camel milk produced by L. garvieae-C47. Exopolysaccharide-C47 product (molecular weight: 7.3 × 106 Da) was composed of the following monosaccharides: glucose (82.51%), arabinose (5.32%) and xylose (12.17%). The antioxidant, antitumor and α-amylase inhibitory activities of exopolysaccharide-C47 product reached up to 67.52, 59.35 and 91.0%, respectively. The apparent viscosity of exopolysaccharide-C47 product decreased with the increase in shear rate and declined by increasing the temperature up to 50 °C. The rheological properties of exopolysaccharide-C47 product are influenced by the salt type and pH value. The exopolysaccharide product produced by L. garvieae C47 possesses valuable health benefits and has the ability to improve the weak structure of fermented camel milk.