Influence of Phosphorylation and Acetylation on Structural, Physicochemical and Functional Properties of Chestnut Starch

Chestnut is popular worldwide for its unique flavor, high eating quality and nutrition. Here, we evaluated the influence of phosphorylation and acetylation on the structural, physicochemical and functional properties of chestnut starch. Scanning electron micrographs showed the agglomeration of starch granules and the appearance of numerous dents on the starch granule surface under phosphorylation and acetylation. X-ray diffractograms confirmed that the modification treatments did not affect the C-type crystal pattern, but reduced the relative crystallinity of the chestnut starch, particularly phosphorylation. Moreover, modification improved the paste transparency of the starch. Differential scanning calorimeter analysis revealed that the gelatinization temperature and enthalpy of the starch decreased with the increasing substitution degree, particularly in phosphorylated starch. The Rapid Visco Analyser analysis demonstrated that phosphorylation could greatly improve the pasting properties of chestnut starch. In addition, phosphorylated and acetylated starch had a smaller amount of slowly digested starch and a larger amount of resistant starch relative to native chestnut starch. In conclusion, the functional and physicochemical properties of chestnut starch can be significantly improved through phosphorylation and acetylation, demonstrating its great application potential as a food additive.

Biophysical properties of electrospun chitosan-grafted poly(lactic acid) nanofibrous scaffolds loaded with chondroitin sulfate and silver nanoparticles

The aim of this work was to study the biophysical properties of the chitosan-grafted poly(lactic acid) (CH-g-PLA) nanofibers loaded with silver nanoparticles (AgNPs) and chondroitin-4-sulfate (C4S). The electrospun CH-g-PLA:AgNP:C4S nanofibers were manufactured using the electrospinning technique. The microstructure of the CH-g-PLA:AgNP:C4S nanofibers was investigated by proton nuclear magnetic resonance (1H-NMR), scanning electron microscopy (SEM), UV-Visible spectroscopy (UV-Vis), X-ray diffraction (XRD), and Fourier transform infrared (ATR-FTIR) spectroscopy. ATR-FTIR and 1H-NMR confirm the CH grafting successfully by PLA with a substitution degree of 33.4%. The SEM measurement results indicated apparently smooth nanofibers having a diameter range of 340 ± 18 nm with porosity of 89 ± 3.08% and an average pore area of 0.27 μm2. UV-Vis and XRD suggest that silver nanoparticles with the size distribution of 30 nm were successfully incorporated into the electrospun nanofibers. The water contact angle of 12.8 ± 2.7° reveals the hydrophilic nature of the CH-g-PLA:AgNP:C4S nanofibers has been improved by C4S. The electrospun CH-g-PLA:AgNP:C4S nanofibers are found to release ions Ag+ at a concentration level capable of rendering an antimicrobial efficacy. Gram-positive bacteria ( S.aureus) were more sensitive to CH-g-PLA:AgNP:C4S than Gram-negative bacteria ( E. coli). The electrospun CH-g-PLA:AgNP:C4S nanofibers exhibited no cytotoxicity to the L-929 fibroblast cells, suggesting cytocompatibility. Fluorescence microscopy demonstrated that C4S promotes the adhesion and proliferation of fibroblast cells onto electrospun CH-g-PLA:AgNP:C4S nanofibers.

Pemanfaatan Selulosa dari Rumput Gajah (Pennisetum purpureum) pada Sintesis Karboksimetil Selulosa (CMC)

Cellulose from Pennisetum purpureum has been used as the main ingredient in the synthesis of carboxymethyl cellulose (CMC). The purpose of CMC synthesis from the cellulose of Pennisetum purpureum is to obtain CMC compounds with the best degree of substitution (DS) value and the highest yield. The study was conducted using a completely randomized design with a factorial pattern consisting of two independent variables, namely the concentration of trichloroacetic acid (10%, 20%, and 30%) and reaction time (3 and 4 hours). The results showed that the CMC with the highest DS value (0.839) was obtained using 20% trichloroacetic acid with a reaction time of 3 hours. The highest CMC yield was 30.15% which was obtained using 30% trichloroacetic acid with a reaction time of 4 hours. Keywords: Pennisetum purpureum, carboxymethyl cellulose, substitution degree.

Synthesis and Characterization of a Coagulating Agent From Plantain Peel Starch (Musa Paradisiaca), As Adjuvant in Water Treatment

Coagulation processes are widely used for water treatment, mainly with chemical coagulants. In this research, starch derived from a residue (plantain peel, Musa paradisiaca) was used as a starting point for a chemical modification. Through acetylation, its chemical structure was modified and characterized by Infrared Spectrophotometry, for its evaluation as a coadjuvant in coagulation operations to reduce the turbidity of raw water. Two experimental designs were developed to evaluate the incidence of modified starch as the main coagulant or in conjunction with a conventional coagulant (Al2(SO4)3), at different Al2(SO4)3 / acetylated starch ratios, in jar-test experiments. In the first experimental design, with the acetylated starch as the main coagulant, turbidity removal percentages reached 47.93% (average value, 41.18%). For the Al2(SO4)3 / acetylated starch coagulation process, 98.91% turbidity removal was reached in the second experimental design (average value, 97.16%). The incidence on turbidity in a jar-test of starch chemical substitution degree and the Al2(SO4)3 / Acetylated starch ratio was investigated using ANOVA analysis. There was a great incidence of the chemical substitution degree and the concentration of acetylated starch used, when modified starch was used as the main coagulant. For the second experimental design, the Al2(SO4)3 / Acetylated starch relationship had a greater incidence on the turbidity removal. Thus, modified starch obtained from plantain peel waste is a promising coadjuvant material for water coagulation processes.

Pretreatment of kraft lignin by deep eutectic solvent and its utilization in preparation of lignin-based phenolic formaldehyde adhesive

To improve the reactive sites of kraft technical lignin, a deep eutectic solvent (DES) composed of ZnCl2 / lactic acid was used to pretreat kraft lignin from coniferous wood. The modified and unmodified lignin were used to replace different proportions of phenol (50%, 60%, and 70%) to prepare the lignin-phenol-formaldehyde (LPF) adhesive. The phenolic hydroxyl content of DES-treated lignin increased from 3.12 wt% to 3.93 wt% and methoxy content decreased from 11.83 wt% to 6.64 wt% under optimized experimental conditions. The bond strength of LPF adhesive prepared by DES reagent activated lignin was higher than that of the control sample. When the substitution degree of modified lignin for phenol reached 70%, the bond strength of the plywood prepared by the DES-pretreated lignin was 0.79 MPa and the free formaldehyde content was 0.28%, which met the requirements of the Chinese national standard GB/T 9846 (2015). However, the viscosity was higher than the control sample, and results indicate that DES reagent modification cannot improve the viscosity of LPF resin.

Karakteristik Fisik, Kimia, dan Fungsional Pati Ubi Banggai Asetat pada Berbagai Variasi Waktu Reaksi

Banggai yam plant (endemic in Banggai Kepulauan Regency) is a potential raw material in production of modified starch. The one of techniques to increase the value of starch is modification of starch by acetylation method. This study objectives to determine the physical, chemical and functional characteristics of Banggai acetate yam starch at various reaction times. The study used a Completely Randomized Design with treatment time reaction (T), namely T1: 30 min, T2: 35 min, T3: 40 min, T4: 45 min, T5: 50 min, T6: 55 min. This study was conducted to determine the characteristics of yam acetate starch, which includes percent acetyl, degree of substitution, water and oil holding capacity (WHC/OHC), flammability, solubility, moisture content, ash, fat, protein, starch and amylose starch. The results showed that the longer reaction time under certain conditions will increase the acetyl percent, degree of substitution, WHC, OHC, flareability, solubility but reduce levels of fat, water, ash, fat, protein, starch and amylose starch, yam acetate. In this study at the best reaction time is (50 min), gives the acetyl percent 8.658% and substitution degree of 0.356, the value of WHC, OHC, Swelling ratio and solubility of 32.21%, 30.21%, 1.98 g/g, and 19.17% respectively.

Pourbaix-Guided Mineralization and Site-Selective Photoluminescence Properties of Rare Earth Substituted B-Type Carbonated Hydroxyapatite Nanocrystals

Rare-earth labeling in biological apatite could provide critical information for the pathologic transition (osteoclastic) and physiologic regeneration (osteogenesis) of bone and teeth because of their characteristic site-sensitive fluorescence in different coordinative conditions of various tissues in many biological processes. However, the rare-earth labeling method for biological apatites, i.e., carbonated-hydroxyapatite, has been rarely found in the literature. In this paper, we report a Pourbaix-diagram guided mineralizing strategy to controllable carbonation and doping of rare-earth ions in the hydroxyapatite (HA) lattice. The carbonation process of hydroxyapatite was achieved by controllable mineralization in hydrothermal condition with K2CO3 as the carbonate source, which results into the pure B-type carbonated hydroxyapatite (CHA) with tunable carbonate substitution degree. All of the as-synthesized materials crystalized into P63/m (No. 176) space group with the lattice parameter of a decreases and c increases with the increasing of carbonate content in the reactants. Structural refinement results revealed that the substitution of planar CO32− is superimposed on one of the faces of PO43− tetrahedral sub-units with a rotation angle of 30° in reference to c-axis. All of the hydrothermally synthesized CHA nanocrystals show hexagonal rod-like morphology with the length of 70–110 nm and diameter of 21–35 nm, and the decreasing length/diameter ratio from 3.61 to 2.96 from low to high carbonated level of the samples. Five rare-earth cations, of Pr3+, Sm3+, Eu3+, Tb3+, and Ho3+, were used as possible probe ions that can be doped into either HA or CHA lattice. The site-preference of Tb3+ doping is the same in the crystallographic site of HA and CHA according to characteristic emission peaks of 5D4–7Fj (j = 3–6) transitions in their photoluminescent spectroscopy. Our work provides a controllable carbonation method for rare-earth labeling hydroxyapatite nanomaterials with potential biologically active implant powders for bone repair and tissue regeneration.

Crystal Structure and Electrical/thermal Transport Properties of Li1-xSn2+xP2 and Its Performance as a Li-Ion Battery Anode Material

A new ternary layered pnictide, Li_1-xSn_2+xP₂, was synthesized by a solid-state reaction and its properties were examined to explore its potential as a multifunctional material. The compound crystallizes in a layered structure in the R-3m space group with buckled honeycomb Sn-P layers separated by mixed-occupation Li/Sn layers. Crystal structure analysis using synchrotron X-ray diffraction showed that the substitution degree of Li by Sn (x) is approximately 0.3. Local ordering of Li/Sn occupation was demonstrated using ³¹P nuclear magnetic resonance analysis. The lattice thermal conductivity of Li_1-xSn_2+xP₂ was found to be relatively low (1.2 Wm⁻¹K⁻¹ at 525 K). The room-temperature electrical resistivity of Li_1-xSn_2+xP₂ was found to be 0.3-0.4 mohm cm and metallic conductivity was observed down to 0.5 K. First-principles calculations demonstrated that the electronic structure and Fermi energy of Li_1-xSn_2+xP₂ are significantly dependent upon x. Electrochemical measurements using a single-particle technique demonstrated the activity of Li_1-xSn_2+xP₂ as an anode material for rechargeable Li-ion batteries. <br>

Crystal Structure and Electrical/thermal Transport Properties of Li1-xSn2+xP2 and Its Performance as a Li-Ion Battery Anode Material

A new ternary layered pnictide, Li_1-xSn_2+xP₂, was synthesized by a solid-state reaction and its properties were examined to explore its potential as a multifunctional material. The compound crystallizes in a layered structure in the R-3m space group with buckled honeycomb Sn-P layers separated by mixed-occupation Li/Sn layers. Crystal structure analysis using synchrotron X-ray diffraction showed that the substitution degree of Li by Sn (x) is approximately 0.3. Local ordering of Li/Sn occupation was demonstrated using ³¹P nuclear magnetic resonance analysis. The lattice thermal conductivity of Li_1-xSn_2+xP₂ was found to be relatively low (1.2 Wm⁻¹K⁻¹ at 525 K). The room-temperature electrical resistivity of Li_1-xSn_2+xP₂ was found to be 0.3-0.4 mohm cm and metallic conductivity was observed down to 0.5 K. First-principles calculations demonstrated that the electronic structure and Fermi energy of Li_1-xSn_2+xP₂ are significantly dependent upon x. Electrochemical measurements using a single-particle technique demonstrated the activity of Li_1-xSn_2+xP₂ as an anode material for rechargeable Li-ion batteries. <br>