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Kenaf (Hibiscus cannabinus L.) seed is a valuable protein source that could be used to prepare protein hydrolysates with antihypertensive properties. However, the potential of using kenaf seeds for health food and pharmaceutical applications has not been fully exploited. Thus, the aim of this study was to identify and characterise the Angiotensin-I-Converting Enzyme (ACE) inhibitory peptides derived from the optimized hydrolysis conditions of kenaf seed protein hydrolysates (KSPH). The optimum hydrolysis conditions determined by response surface methodology (RSM) were as follows: temperature 65 °C, pH 6.5, hydrolysis time 2.25 h, and enzyme/substrate (E/S) ratio of 0.03 (w/w). Under these conditions, the degree of hydrolysis (DH) was 55.28 % and ACE inhibitory activity was 75.51 %. Also, the low molecular weight peptide fractions, <2 kilodalton (kDa) and 2–5 kDa showed the highest ACE-inhibitory activity (82.27 % and 83.69 %, respectively). The 2–5 kDa fraction by Quadrupole-Time-of-Flight Liquid Chromatography-Mass Spectrometry (QTOF LC − MS) revealed the abundance of six peptides, LYWSYLYN, ALFYWVS, LLLHAL, AKSCVVFP, INPPSTTN, and WTIPTPS. Kinetic studies showed that peptide LYWSYLYN possessed the highest Michaelis constant (Km), maximum velocity (Vmax) values and the lowest inhibitor constant (Ki) values, suggesting of its superior ACE inhibitory activity compared to other peptides. [ABSTRACT FROM AUTHOR]

The traditional textile degumming process produces abundant wastewater, which contains a lot of monosaccharides and oligosaccharides. It is of great economic and environmental significance to utilize these carbohydrates in high value. In this study, high performance liquid chromatography (HPLC) was used to analyze the carbohydrate components in kenaf degumming wastewater, and then the production of C-dots using the wastewater was explored. The results showed that the types and content in the degumming wastewater were monosaccharides (glucose, xylose and arabinose) and oligosaccharides (dextran, xylan and araban). The carbohydrate (mainly glucan and xylan) content in wastewater accounted for 91.16 % of the total carbohydrates weight loss in kenaf degumming process. By using hydrolysis and hydrothermal reaction on kenaf degumming wastewater, blue-green carbon dots (C-dots) with good performance were prepared and successfully applied to anti-counterfeiting printing. In particular, the as-prepared C-dots prepared from kenaf degumming wastewater with urea added (WUC-dots) showed an excitation-dependent photoluminescence (PL) spectrum and quantum yield (QY) of 2.4 % in aqueous solution. The fluorescent code exhibited a clear outline, excitation-tunable color and good stability, showing a great potential for anti-counterfeiting system. [ABSTRACT FROM AUTHOR]

This study investigates the viscoelastic behavior, gelling properties, and structural characteristics of Deccan hemp seed protein (DHSP) to overcome limitations in its application in food formulations. Small amplitude oscillatory shear measurements were employed to investigate the impact of protein concentration, pH, ionic concentration, and temperature on DHSP's rheological features. The study revealed that the 20 % protein dispersion had the highest storage modulus (G') and yield stress at 63.96 ± 0.23 Pa and 0.61 Pa, respectively. DHSP dispersion exhibited pseudo-plastic behavior across various conditions. The gelling performance was higher at pH 4 and 8 and at ionic concentration in the range of 0.1 M - 0.5 M. Gelation time and temperature were observed from the temperature ramp test. Structural characterizations, including fluorescence spectroscopy, circular dichroism spectra, FTIR spectra, SEM, AFM images, zeta potential analysis, and DSC, provided insights into DHSP's tertiary and secondary conformation, surface characteristics, and thermal properties. Notably, the study highlighted DHSP's exceptional rheological properties, making it a promising gelling material for the food and nutraceutical industries. The findings also offer new insights into DHSP's structural characteristics, suggesting potential applications in food packaging and product development within the food industry. [Display omitted] • Protein concentration, pH and ionic strength affected viscoelastic behavior of Deccan hemp seed protein (DHSP). • DHSP dispersion exhibited pseudo plastic-behavior for all the three factors. • Protein denaturation and aggregation influenced the temperature induced gelation. • The gelling property of the protein dispersion was higher at pH 4 and pH 8. • Fluorescence spectroscopy and circular dichroism confirmed tertiary and secondary structures of DHSP. [ABSTRACT FROM AUTHOR]

Plastic has significant negative consequences for the environment and human health, demanding greener alternatives. Lignocellulose is a sustainable biomass material, and its paper has been considered as a potential material to replace plastics. Micro-nano lignocellulose, derived from natural plants, possesses a small size and abundant hydrogen bonding capacity. However, there is no clear explanation for the interactions between lignin and micro-nano cellulose, and little understanding of how the interaction can affect the papers' structure and optical properties. Electrostatic potential calculation is a reliable tool to explain non-covalent interactions, and can explore the binding between lignin and micro-nano cellulose. In this paper, kenaf – a non-wood fiber raw material – was employed to prepare micro-nano lignocellulose. The resulting slurry facilitated the production of transparent paper via a simple casting method. The prepared transparent micro-nano paper exhibited high transparency (~90 %), UVA resistance (~80 %), and hydrophobicity (~114°). More importantly, the electrostatic potential calculation demonstrates the inherent relationship between structure and performance, providing practical knowledge for constructing film materials. [Display omitted] [ABSTRACT FROM AUTHOR]

Kenaf fiber has recently garnered exponential interest as reinforcement in composite materials across diverse industries owing to its superior mechanical attributes, ease of manufacture, and inherent biodegradability. In the discourse of this review, various methods of manufacturing kenaf/Polylactic acid (PLA) composites have been discussed meticulously, as delineated in recently published scientific literatures. This paper delves into the chemical modification of kenaf fiber, examining its consequential impact on tensile strength and thermal stability of the kenaf/PLA composites. Further, this review illuminates the role of innovative 3D printing techniques and fiber orientation in augmenting the mechanical robustness of the kenaf/PLA composites. Simultaneously, recent insightful explorations into the acoustic properties of the kenaf/PLA composites, underscoring their potential as sustainable alternative to conventional materials have been reviewed. Serving as a comprehensive repository of knowledge, this review paper holds immense value for researchers aiming to utilize the capabilities of kenaf fiber reinforced PLA composites. • Kenaf fiber has gained popularity as a reinforcement in composite materials for its superior mechanical properties and biodegradability. • Recent manufacturing methods of kenaf/PLA composites and their effect on mechanical, thermal and acoustic properties have been investigated. • Chemical modifications enhance the mechanical and thermal properties of the kenaf/PLA composites, broadening the scope of application. • Advancements in 3D printing technologies contribute significantly to the mechanical properties of the kenaf/PLA composites. [ABSTRACT FROM AUTHOR]

• This work to isolate lignin from kenaf biomass using three different pulping method. • Isolate lignin was characterized to study the potential as filler in rubber field. • Kraft lignin showed smaller particle size as compared to soda and organosolv lignin. • Kraft lignin showed high molecular weight and high thermal stability. • Kraft lignin possess the possibility to be an alternative filler in rubber field. Lignin from kenaf (Hibiscus cannabinus) core was investigated as an alternative filler for rubber. Three types of extraction methods were used to isolate lignin from kenaf, namely kraft, soda and organosolv process. The particle size, surface area, functionalities changes, molecular weight and thermal properties of the lignin were characterized. The results showed that Kraft lignin (KL) has the smallest particle size (40.41 μm) compared to soda lignin (SL) (63.85 μm) and organosolv lignin (OL) (66.85 μm). This is in good agreement with the BET surface area of 9.52 m2/g, 1.25 m2/g and 2.40 m2/g respectively. However, the smaller surface area of SL compared to OL is due to the smaller pore size and pore volume of SL. KL also showed high hydroxyl content with corresponding high thermal stability as confirmed by NMR and TGA. The thermal stability of the lignin correlates well with the molecular weight (MW). From the overall characteristics, it can be concluded that KL, SL and OL can be used as an alternative filler in rubber compounds to substitute common fillers like silica and carbon. [ABSTRACT FROM AUTHOR]

Abstract The recent study focused on lignin-phenol-glyoxal (LPG) as an alternative way to replace toxic formaldehyde used in commercially available wood adhesives. The concern of the uses of carcinogenic formaldehyde in wood adhesive industry has become major problem over human health, environmental and economy issues. In this study, lignin isolated from Kenaf (Hibiscus cannabinus) via soda and Kraft pulping were modified into SLPG (soda lignin-phenol-glyoxal) and KLPG (Kraft lignin-phenol-glyoxal) adhesives and were compared to phenol-formaldehyde (PF). Complementary analyses such as Fourier Transform Infrared (FTIR) spectroscopy, 1H and 13C Nuclear Magnetic Resonance (NMR) spectroscopy, thermal stability; Thermogravimetric analysis (TGA) and Differential Scanning Calorimetry (DSC) were utilized to characterize all isolated lignin samples. The physical properties of the resins were further characterized in term of viscosity, gel time and total solid content. It was found that soda lignin comprised higher phenolic OH content and greater molecular weight compared to Kraft lignin. Various molar ratio of adhesives were applied on plywood and were mechanically tested. The 30% (w/w) SLPG has shown to have higher tensile strength and internal bonding stress at 72.08 MPa and 53.83 N mm−2 respectively to that of PF. Highlights • Isolation of Kraft and soda lignin from kenaf core. • Preparation of lignin phenol glyoxal (LPG) wood adhesive. • 30% SLPG adhesive shows higher tensile strength (72 MPa) than that of PF. [ABSTRACT FROM AUTHOR]

In the present study, iminodiacetic acid (IDA)-modified kenaf fiber, K-IDA formed by the chemical modification of plant kenaf biomass was tested for its efficacy as a sorbent material towards the purification of waste water. The K-IDA fiber was first characterized by the instrumental techniques like Fourier transform infrared (FTIR) analysis, elemental analysis (CHNSO), and scanning electron microscopy (SEM). On testing for the biosorption, we found that the K-IDA has an increment in the adsorption of Cu 2+ ions as compared against the untreated fiber. The Cu 2+ ions adsorption onto K-IDA fits very well with the Langmuir model and the adsorption maximum achieved to be 91.74 mg/g. Further, the adsorption kinetics observed to be pseudo second-order kinetics model and the Cu 2+ ions adsorption is a spontaneous endothermic process. The desorption study indicates a highest percentage of Cu 2+ of 97.59% from K-IDA under 1 M HCl solution against H 2 SO 4 (72.59%) and HNO 3 (68.66%). The reusability study indicates that the efficiency did not change much until the 4th cycle and also providing enough evidence for the engagement of our biodegradable K-IDA fiber towards the removal of Cu 2+ ions in real-time waste water samples obtained from the electroplating and wood treatment industries. [ABSTRACT FROM AUTHOR]

Lignin has been regarded as a potential natural sun screening agent. However, the dark color of traditional industrial lignin hinders its application in the field of skincare. In this study, a green and facile approach was developed to extract light-colored lignin. p -Toluenesulfonic acid (p -TsOH) was used to separate lignin and fibers from Kenaf stalks. During the isolation of lignin, formaldehyde was added to preserve the β-O-4 bonds of lignins in the form of stable acetals. The obtained lignin was further employed to prepare nanoparticles (LNPs) as sunscreen additives. After adding 4 wt% LNPs, the SPF values of the cream increased from 7.05 to 27.84. The residual fibers from the Kenaf stalks can be utilized for papermaking as the raw materials. by mixing them with softwood pulp to reduce the consumption of commercial pulp. With the addition of 5 wt% residual fibers in commercial softwood pulp, the produced paper showed better mechanical properties. The ring crush strength index and tear index of the samples increased from 2.49 N·m/g and 4.63 mN·m2/g to 2.62 N·m/g and 4.75 mN·m2/g, respectively. This study paved a way for the comprehensive utilization of Kenaf stalks towards not only papermaking but also daily chemical products. • Light-colored lignin was fractionated from Kenaf Stalk by p -TsOH/FA solvent. • LNPs showed great enhancement of UV resistant to the commercial lotions. • The residual Kenaf fibers can improve the physical properties of paper. [ABSTRACT FROM AUTHOR]

Cellulosic nanofibers (NFs) from kenaf bast were used to reinforce glycerol plasticized thermoplastic starch (TPS) matrices with varying contents (0–10 wt%). The composites were prepared by casting/evaporation method. Raw fibers (RFs) reinforced TPS films were prepared with the same contents and conditions. The aim of study was to investigate the effects of filler dimension and loading on linear and non-linear mechanical performance of fabricated materials. Obtained results clearly demonstrated that the NF-reinforced composites had significantly greater mechanical performance than the RF-reinforced counterparts. This was attributed to the high aspect ratio and nano dimension of the reinforcing agents, as well as their compatibility with the TPS matrix, resulting in strong fiber/matrix interaction. Tensile strength and Young’s modulus increased by 313% and 343%, respectively, with increasing NF content from 0 to 10 wt%. Dynamic mechanical analysis (DMA) revealed an elevational trend in the glass transition temperature of amylopectin-rich domains in composites. The most eminent record was +18.5 °C shift in temperature position of the film reinforced with 8% NF. This finding implied efficient dispersion of nanofibers in the matrix and their ability to form a network and restrict mobility of the system. [ABSTRACT FROM AUTHOR]

Abstract: Toward the development of biocomposites for packaging applications, the possibility of using kenaf cellulose (KC) was investigated in the production of low-density polyethylene (LDPE)/KC/polyethylene glycol (PEG) biocomposites. First, cellulose was extracted from the cell walls of kenaf-bast fibers. Then, different weights of LDPE, KC, and PEG were blended, and the effects of varying the concentrations of KC and PEG on the synthesis process were evaluated, and the resulting composites were characterized with respect to their mechanical, thermal, biodegradability and water-absorption properties. A scanning electron microscope (SEM) was also used to observe the surface morphology of the samples before and after biodegradation tests. The results showed that the mechanical properties of the biocomposites decreased slightly as the KC content was increased from 0 to 50wt% in the biocomposite formulation; however, there was a good homogeneity between samples with added PEG. The addition of KC improved the thermal resistance of these biocomposites; PEG also had positive role in the thermal behavior of the composites. Based on a soil-burial test, the biodegradability of the composites showed a clear trend of increase degradation with increasing KC content in the formulation. While water-absorption values for the composites were higher than that of pure LDPE polymer, the addition of PEG to the formulation reduced the water absorption of the composites. [Copyright &y& Elsevier]