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In order to further realize the resource reuse of walnut meal after oil extraction, walnut meal was used as raw material to prepare polypeptide, and its angiotensin-converting enzyme (ACE) inhibitory activity was investigated. The ACE inhibitory peptides were prepared from walnut meal protein by alkaline solution and acid precipitation. The hydrolysis degree and ACE inhibition rate were used as indexes to optimize the preparation process by single-factor experiment and response surface method. The components with the highest ACE activity were screened by ultrafiltration, and their antioxidant activities were evaluated in vitro. The effect of gastrointestinal digestion on the stability of walnut peptide was analyzed by measuring molecular weight and ACE inhibition rate. The results showed that the optimal extraction conditions were pH 9.10, hydrolysis temperature 54.50 °C, and hydrolysis time 136 min. The ACE inhibition rate of walnut meal hydrolysate (WMH) prepared under these conditions was 63.93% ± 0.43%. Under the above conditions, the fraction less than 3 kDa showed the highest ACE inhibitory activity among the ACE inhibitory peptides separated by ultrafiltration. The IC50 value of scavenging ·OH free radical was 1.156 mg/mL, the IC50 value of scavenging DPPH free radical was 0.25 mg/mL, and the IC50 value of scavenging O2− was 3.026 mg/mL, showing a strong total reducing ability. After simulated gastrointestinal digestion in vitro, the ACE inhibitory rate of walnut peptide decreased significantly, but it still maintained over 90% ACE inhibitory activity. This study provides a reference for the application of low-molecular-weight walnut peptide as a potential antioxidant and ACE inhibitor. [ABSTRACT FROM AUTHOR]

The ultrasonic-assisted extraction (UAE) method was employed to separate Cinnamomum camphora proanthocyanidin-rich extracts (PCEs). This extraction process was optimized by the Box–Behnken design, and the optimal conditions, on a laboratory scale, were as follows: an ethanol concentration of 75%, a liquid-to-solid ratio of 24 mL/g, an ultrasonic time of 39 min, and an ultrasonic power of 540 W. Under the obtained conditions, the PCE yield extracted by UAE was higher than that from heat reflux extraction and soaking extraction. An ultra-performance liquid chromatography–tandem mass spectrometry analysis was employed to characterize the phloroglucinolysis products of the C. camphora PCEs, by which epigallocatechin, catechin, epicatechin, and (−)-epigallocatechin-3-O-gallate were identified as the terminal units; epigallocatechin, epicatechin, and (−)-epigallocatechin-3-O-gallate were recognized as extension units. The C. camphora PCEs possessed higher anti-ultraviolet activity in vitro compared with the commercially available sunscreen additive of benzophenone with respect to their ethanol solutions (sun protection factor of 27.01 ± 0.68 versus 1.96 ± 0.07 at a concentration of 0.09 mg/mL) and sunscreens (sun protection factor of 17.36 ± 0.62 versus 14.55 ± 0.47 at a concentration of 20%). These results demonstrate that C. camphora PCEs possess an excellent ultraviolet-protection ability and are promising green sunscreen additives that can replace commercial additives. [ABSTRACT FROM AUTHOR]

Odor is an important characteristic of walnut oil; walnut oil aromas from different varieties smell differently. In order to compare the differences of volatile flavor characteristics in different varieties of walnut oil, the volatile organic compounds (VOCs) of walnut oil from five different walnut varieties in Northwest China were detected and analyzed using headspace gas chromatography–ion mobility spectrometry (HS–GC–IMS). The results showed that 41 VOCs in total were identified in walnut oil from five different varieties, including 14 aldehydes, 8 alcohols, 4 ketones, and 2 esters. Walnut oil (WO) extracted from the "Zha343" variety was most abundant in VOCs. The relative odor activity value (ROAV) analysis showed that aldehydes were the main aroma substances of walnut oil; specifically, hexanal, pentanal, and heptanal were the most abundant. Fingerprints and heat map analysis indicated that WO extracted from the "Xin2", "185", "Xin'guang", and "Zha343" varieties, but not from the "Xinfeng" variety, had characteristic markers. The relative content differences of eight key VOCs in WO from five varieties can be directly compared by Kruskal–Wallis tests, among which the distribution four substances, hexanal (M), hexanal (D), pentanal (M), (E)-2-hexanal (M), presented extremely significant differences (P<0.01). According to the results of the principal component analysis (PCA), WO extracted from the "Zha343" variety was distinct from the other four varieties; in addition, WO extracted from the "Xin2" variety exhibited similarity to WO extracted from the "185" variety, and WO extracted from the "Xinfeng" variety showed similarity to WO extracted from the "Xin'guang" variety. These results reveal that there are certain differences in the VOCs extracted from five different WO varieties, making it feasible to distinguish different varieties of walnut oil or to rapidly detect walnut oil quality based on its volatile substances profile. [ABSTRACT FROM AUTHOR]

Functionalized monomers are of utmost importance in producing new polymers and smart materials. Herein, a two-step approach involving heterogeneous catalysis was developed to produce a functionalized monomer (2-vinylfuran) from bio-based furfural, giving an overall yield of 89%. Economic analysis suggests that this facile approach incurs much lower costs, and its practicality improves the availability of 2-vinylfuran. This is due to the delicate structure of the optimized 4Na5Ce/SiO2, where Na species are present at the oxygen vacancies of the ceria that protect the catalyst structure from collapse, and the catalyst consequently displays excellent performance. Density functional theory (DFT) calculations revealed that the reaction occurs on the Na and Ce species. The adsorption of a furan group onto Na led to side reactions, which were suppressed in the presence of Ce, resulting in higher selectivity. Finally, a polymer based on 2-vinylfuran was prepared, which shows good surface properties and thermodynamic stability. [ABSTRACT FROM AUTHOR]

Catalyst deactivation is a problem of great concern for many heterogeneous reactions. Here, an urchin‐like LaPO4 catalyst was easily developed for pentane‐2,3‐diol dehydration; it has an impressive ability to restore the activity in situ by itself during the reaction, accounting for its high stability. This facilitates the efficient production of renewable penta‐1,3‐diene from pentane‐2,3‐dione via a novel approach, where penta‐2,3‐diol was obtained as an intermediate in 95 % yield under mild conditions. [ABSTRACT FROM AUTHOR]

The synthesis of functionalized 1,3-dienes has received increasing attention due to their importance in the practical development of high-performance elastomers. In the present work, furfural and acetone, acting as renewable feedstocks, are first employed to produce a functionalized 1,3-diene containing a furan group (1-(2-furyl)-1,3-butadiene, F-diene). After selective hydrogenation of the C=O group, the aldol adduct (4-(2-furanyl)-3-buten-2-ol, FAH) shows a nearly complete conversion, with an excellent selectivity (as high as 92%) towards F-diene over ceria-based catalysts in a fixed bed. BET, TEM, XRD, XPS, Raman, TPD, TPR and TGA were conducted to identify the relationship between the catalytic performance and catalyst structure. A plausible reaction pathway for the dehydration of FAH over ceria-based catalysts was proposed using a radical mechanism, which suggested the importance of the Ce4+–Ce3+ redox cycle for the dehydration of FAH to F-diene. Furthermore, the ceria-based catalysts exhibited a notable carbon resistance. [ABSTRACT FROM AUTHOR]

Hexagonal boron nitride (hBN) is usually used in thermal spreading applications because of its high thermal conductivities (400–2000 W mK−1). However, in composites with poly(2-vinylpyridine) (P2VP) and poly(5-norbornene-2-methanol) (PNBMT), the introduction of hydroxylated hBN enhances the thermal conductivity of the ternary formula but decreases it in the binary ones. This arises from the micro-interface defects and porous microstructure that form in the hBN/P2VP composite, which accounts for the thermal insulating property. In addition, the lightweight hBN/P2VP composite has good bendability and high thermal stability. The hBN/PNBMT composite possesses a wrinkled rough surface and voids, with hBN exposed or embedded in the polymer matrix, which disrupts the compact packing of polymer chains, thus increasing the extrinsic scattering and the free volume. In contrast, in the hBN/P2VP/PNBMT ternary composite, the synergistic interactions among the polymer chains and hBN result in a dense packing, lower surface area and higher density. This work provides a possible strategy to design hBN/polymer nanocomposites with tunable thermal properties. [ABSTRACT FROM AUTHOR]

Biodegradable poly(butylene succinate)/nanosized carbon black (PBS/CB) nanocomposites were prepared by melt compounding to investigate the effect of CB on flammability and mechanical properties of PBS. In the nanocomposites, CB displayed some positive effect on improving the flame retardancy of PBS, mainly on the decrease of peak of heat release rate, the increase of limited oxygen index value, and the inhibition of melt dripping. It was contributed to the formation of a good carbon layer during combustion and of a network structure in the PBS matrix. Moreover, a good balance on mechanical performances of PBS/CB nanocomposites was achieved with enhanced stiffness and high toughness, which was ascribed to the compatibilization of PBS- g-MA, leading to a good dispersion of nanofillers and strong matrix-nanoparticle interaction. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Nanosized carbon black (CB) was introduced into polypropylene/carbon nanotubes (PP/CNTs) nanocomposites to investigate the effect of multi-component nanofillers on the thermal stability and flammability properties of PP. The obtained ternary nanocomposites displayed dramatically improved thermal stability compared with neat PP and PP/CNTs nanocomposites. Moreover, the flame retardancy of resultant nanocomposites was greatly improved with a significant reduction in peak heat release rate and increase of limited oxygen index value, and it was strongly dependent on the content of CB. This enhanced effect was attributed mainly to the formation of good carbon protective layers by CB and CNTs during combustion. Rheological properties further confirmed that CB played an important role on promoting the formation of crosslink network on the base of PP/CNTs system, which were also responsible for the improved thermal stability and flame retardancy of PP. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Synthetic rubbers fabricated from 1,3-butadiene (BD) and its substituted monomers have been extensively used in tires, toughened plastics, and many other products owing to the easy polymerization/copolymerization of these monomers and the high stability of the resulting material in manufacturing operations and large-scale productions. The need for synthetic rubbers with increased environmental friendliness or endurance in harsh environments has motivated remarkable progress in the synthesis of BD and its substituted monomers in recent years. We review these developments with an emphasis on the reactive routes, the products, and the synthetic strategies with a scaling potential. We present reagents that are primarily from bio-derivatives, including ethanol, C4 alcohols, unsaturated alcohols, and tetrahydrofuran; the major products of BD and isoprene; and the by-products, activities, and selectivity of the reaction. Different catalyst systems are also compared. Further, substituted monomers with rigid, polar, or sterically repulsive groups, the purpose of which is to enhance thermal, mechanical, and interface properties, are also exhaustively reviewed. The synthetic strategies using BD and its substituted monomers have great potential to satisfy the increasing demand for better-performing synthetic rubbers at the laboratory scale; the laboratory-scale results are promising, but a big gap still exists between current progress and large scalability. [ABSTRACT FROM AUTHOR]